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Subject: Enhanced IDE/Fast-ATA/ATA-2 FAQ [1 of 2]
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Date: 24 Jan 2000 10:58:49 GMT
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Summary: This FAQ addresses issues surrounding Enhanced IDE, ATA-2,
   ATAPI and Enhanced BIOSes. It includes practical questions,
   background information and lists of net resources.
Precedence: bulk
Xref: senator-bedfellow.mit.edu comp.sys.ibm.pc.hardware.storage:202953 comp.sys.ibm.pc.hardware.misc:148803 comp.answers:39389 news.answers:175809

Name: Yet Another Enhanced IDE/Fast-ATA/ATA-2 FAQ
Version: 1.92
Archive-name: pc-hardware-faq/enhanced-IDE/part1
Posting-Frequency: Monthly (the 24th)
Last-modified: 1998/01/23
URL: http://come.to/eide
Maintained-by: Peter den Haan <[email protected]>

 The Enhanced IDE/Fast-ATA FAQ
 John Wehman ([email protected]) and Peter den Haan
 ([email protected])
 v1.92, 1998/01/23

 This FAQ addresses issues surrounding Enhanced IDE, ATA-2, ATAPI and
 Enhanced BIOSes. It includes practical questions, background informa-
 tion and lists of net resources.

 1.  First off...

 2.  Introduction
 2.1.  EIDE and Fast-ATA
 2.2.  IDE and ATA
 2.3.  ATA-2
 2.4.  ATA-3
 2.5.  ATA Packet Interface
 2.6.  Ultra-ATA
 2.7.  ATA-4
 2.8.  The Enhanced BIOS
 2.9.  The secondary port and beyond

 3.  General questions
 3.1.  What are the main features of EIDE and Fast-ATA?
! 3.2.  What are the main features of Ultra-ATA?
! 3.3.  Are those rumors about buggy interfaces true?
! 3.4.  What is a megabyte?

 4.  Before buying...
 4.1.  What should I look for in an ATA-2 (Fast-ATA, EIDE) interface?
 4.2.  Is my BIOS Enhanced?  How can I recognize this?
 4.3.  Is my 50MHz VL bus system compatible with ATA-2 interfaces?
! 4.4.  Are old IDE drives compatible with EIDE and U-ATA interfaces?
! 4.5.  Can I use EIDE and U-ATA drives with my old (E)IDE interface?
 4.6.  Will an ATAPI (EIDE) CD-ROM work with an IDE interface?
 4.7.  Do I need a BIOS update to connect an ATAPI CD-ROM?
 4.8.  Can large drives be used with my old BIOS?
 4.9.  I need an Enhanced BIOS to access >504MB. How do I get one?
 4.10.  Can I use a large harddisk with OSs other than DOS/Windows?
 4.11.  I heard that Win95 provides support for large IDE disks.
 4.12.  Can I use more than 2 or 4 hard drives?
 4.13.  Does <insert operating system> support ATAPI (IDE) CD-ROMs?
 4.14.  I need a PCI ATA-2 interface that uses only one slot.
 4.15.  Will adding an Ultra-ATA interface help my drives' performance?

 5.  Installation
 5.1.  Which drive/device should be Slave?
 5.2.  Does it matter how I connect the devices to the cable?
 5.3.  Does an old HD or CDROM slow down a new drive?
 5.4.  I need a longer IDE cable; how long can I make it?
 5.5.  Can I safely move my harddisk between computers?

 6.  Configuration
 6.1.  Should I use my interface's device drivers?
 6.2.  What should I use: Normal, LBA or Large?
 6.3.  Can I safely change the BIOS' xlation mode (None, LBA, Large)?
 6.4.  Should I enable EIDE busmastering in my BIOS?
 6.5.  FDISK sees only 504MB of my disk!
 6.6.  FDISK will partition only 2GB.
 6.7.  I have no fancy EBIOS, but I have an 1GB partition and it works.
 6.8.  I have software to break the 504MB barrier. Should I use it?
 6.9.  Can I keep my Disk Manager/EZDrive partition with a new BIOS?
 6.10.  I need to remove Disk Manager/EZDrive.
 6.11.  I can enable write caching on my harddisk. Should I?
 6.12.  My drive letters have changed!

 7.  Performance
 7.1.  Why isn't my drive as fast as it's advertised to be?
 7.2.  Why is my new EIDE, U-ATA interface no faster than my old one?
 7.3.  I benchmarked my drive and it's getting slower!
 7.4.  A guy on the net has the same drive and he gets 33MB/s!
 7.5.  Busmastering drivers don't do much...

 8.  Troubleshooting
 8.1.  Why do I get NO ROM BASIC, SYSTEM HALTED?
 8.2.  I have problems with my Award 4.50G BIOS and large drives.
 8.3.  My 2GB+ drive is not recognized or crashes.
 8.4.  My 4GB+ drive has problems in MSDOS 6.22 or below.
 8.5.  Help! I have OnTrack Disk Manager installed and now...
 8.6.  My mode 3-4-5-6 drive has data corruption problems.
 8.7.  Are there supposed to be bad sectors on the drive?
 8.8.  I keep getting CRC errors and serial overruns.
 8.9.  Can my drive do 32-bit access?
 8.10.  Help! Windows 3.x 32-bit disk access doesn't work anymore!
 8.11.  Help! Windows for Workgroups' 32-bit file access fails!
 8.12.  Help! Win95 indicates my drive uses compatibility mode!
 8.13.  My partitions become a mess in MS-DOS mode.
 8.14.  Win95 sees my partitions, but DOS doesn't.
 8.15.  Win95 keeps losing my second IDE channel!
 8.16.  The Win95 busmastering drivers won't work.
 8.17.  My ATAPI (IDE) CD-ROM driver won't recognize the CD-ROM.

 9.  The user's net.resource guide
 9.1.  The user's net.resource guide: I/O card drivers
 9.2.  The user's net.resource guide: hardware manufacturers
 9.3.  The user's net.resource guide: software and BIOS houses

 10.  ATA: harddisks
 10.1.  How does ATA(-2) work?
 10.2.  What are PIO modes?
 10.3.  What are DMA modes?
 10.4.  How are the ATA(-2,PI) I/O ports assigned?
 10.5.  What does an ATA-2 interface do?
 10.6.  What is Block mode?
 10.7.  What is LBA?
 10.8.  How does security work?
 10.9.  What is S.M.A.R.T.?
 10.10.  What is PRML?
 10.11.  What are MR heads?

 11.  ATAPI: CD-ROMs and tapes
 11.1.  How does ATAPI differ from, and coexist with, ATA(-2)?
 11.2.  What's so special about the secondary port?

 12.  The EBIOS: translation
 12.1.  Why translation?
 12.2.  How does translation work?
 12.3.  I'd like to know how translation works in detail.
 12.4.  What is in the Enhanced Disk Parameter Table?
 12.5.  How many types of translating/Enhanced BIOSes are there?

 13.  Software details
 13.1.  Details on OnTrack Disk Manager
 13.2.  How does Windows' 32-bit disk access work?

 14.  Hacker's resource guides
 14.1.  The hacker's documentation guide
 14.2.  The hacker's net.resource guide


 1.  First off...

 This FAQ is the work of John Wehman ([email protected]) and Peter den
 Haan ([email protected]). The homepage of the FAQ is

 o  <http://come.to/eide>

    The HTML version should also be online on

 o  <http://www.wi.leidenuniv.nl/ata/>

    and the text version is available by FTP from

 o  <ftp://ftp.netcom.com/pub/cl/clau/ide_ata/>

 o  <ftp://ftp.rahul.net/pub/lps/hard-disk/ya-ata.faq>

 o  <ftp://ftp.wi.leidenuniv.nl/pub/faqs/>

 o  <ftp://rtfm.mit.edu/pub/usenet/news.answers/pc-hardware-
    faq/enhanced-IDE/>

    You can also get it by e-mail from [email protected] by sending a
    message with "EIDE FAQ text" in the Subject: header. The body of
    the message will be ignored. You can replace "text" by "PostScript"
    or "html" if you want something more fancy than plain text.
    Anything else will probably break the mail server and cause it to
    send you an uuencoded coredump :-)


    DISCLAIMER.
       The information in this FAQ comes without any warranty. The
       authors or distributor will not accept responsibility for any
       damage incurred directly or indirectly through use of the
       information contained in this FAQ.


    COPYRIGHT.
       This document is copyright (c) John Wehman and Peter den Haan.
       You are free to distribute it by electronic means and make as
       many copies as you want on electronic or magnetic media, convert
       it to a different format, and embed control sequences, as long
       as the text of this document remains unmodified, with copyright
       notices intact. Splitting up this document is allowed on the
       condition that the resultant parts are presented as a
       recognizable whole that makes up the full, unmodified text.  You
       are allowed to make paper copies of this document for personal
       use; however, distribution of printed copies for profit is
       prohibited without the authors' prior permission.


    THANKS.
       To everyone on comp.sys.ibm.pc.hardware.storage for
       encouragement and feedback, especially those who took the time
       to communicate their comments in some detail. To Hale Landis
       without whom the FAQ would have been considerably less accurate
       on a number of key points; to Stephanie Brady from OnTrack for
       extensive Disk Manager related information; to Aron Eisenpress
       for critically reading the FAQ time and again; and many, many
       others.


    TODO.

    o  Drop the definition of megabyte as 1048576 bytes, which is
       nonstandard in this context, and use 1000000 byte MBs instead.

    o  Reorganize the FAQ, with a complete overhaul of the text.

    o  Write howto type documents walking through specific tasks.

    o  Tweak the HTML output more. Perhaps find another translator.


    NOTE.
       The text, PostScript and HTML versions of the FAQ are all
       produced from a common linuxdoc-SGML source. This solution is
       not perfect and all versions do contain some infelicities.
       Apologies.  Suggestions for improvement are most welcome, as are
       complimentary copies of more professional multi-format authoring
       tools.



 2.  Introduction

 The aim of this introduction is to make you familiar with the most
 important buzzwords used in this FAQ and to provide a concise overview
 of the issues involved. To get the most out of the information in the
 FAQ proper, start here.


 2.1.  EIDE and Fast-ATA

! The IDE field has seen a great number of changes since a few years
! ago. These novelties are commonly known under the names Enhanced IDE
! (EIDE) and Ultra-ATA. EIDE has caused a lot of confusion since it is
! merely a marketing program from Western Digital which, in turn, builds
! on a couple of real standards: ATA-2 and ATAPI. Fast-ATA, launched by
 Seagate and endorsed by Quantum in response to WD's marketing is
! similar. It builds on ATA-2 only. Ultra-ATA is a widely supported
! extension of ATA-2 (and ATA-3) adding high speed DMA modes.


 2.2.  IDE and ATA

 IDE (Integrated Drive Electronics--or numerous other interpretations)
 and ATA (AT Attachment) are one and the same thing: a disk drive
 implementation designed to integrate the controller onto the drive
 itself, thereby reducing interface costs, and making firmware
 implementations easier. This low cost/easy integration created a boom
 in the disk drive industry, as PC integrators readily ate up the low-
 cost alternative. Since the late 80's, ATA (as it is properly called)
 has become the drive of choice for the cost inhibited buyer.


 2.3.  ATA-2

 When it became clear that improvements in harddrive technology and the
 increasing demands made by software would eventually strain the
 capacity of the ATA interface, the drive industry, in the form of the
 Small Form Factor (SFF) Committee, created a compatible extension of
 ATA called ATA-2. This standard not only adds faster PIO modes and DMA
 modes, but also improves upon Plug'n'Play and compatibility with
 future revisions of the standard.

 While there is also a new way of addressing sectors on the harddisk
 (LBA), this is merely a simplification. Contrary to common myth LBA
 proper has nothing to do with breaking the famous 504MB (528 million
 bytes) barrier. In fact, even in the old ATA/IDE standard the capacity
 limit is well over 100GB.


 2.4.  ATA-3

 The latest revision of the standard is ATA-3. Key features include:
 improved reliability, especially of PIO mode 4; a simple password-
 based security scheme; more sophisticated power management; and Self
 Monitoring Analysis and Report Technology (S.M.A.R.T.), allowing the
 drive to warn you about certain types of impending failure.

 ATA-3 does not define any faster modes. Even though some manufacturers
! were once marketing "mode 5" equipment, there will never be a PIO mode
! beyond ATA-2 PIO mode 4.


 2.5.  ATA Packet Interface

 One of the disadvantages of ATA is that it was designed for harddisks
 only. That was fine back when a high end PC shipped with just a floppy
 drive and a 40MB harddisk, but today CD-ROM and tape drives are
 commonplace devices that should preferably run off a single low-cost
 interface. The ATA Packet Interface (ATAPI) is a standard designed for
 devices such as CD-ROMs and tape drives that plug into an ordinary ATA
 (IDE) port.

 The principal advantage of ATAPI hardware is that it's cheap and works
 on on every PC with an IDE or 'EIDE' adapter.  ATAPI tape drives can
 enjoy superior performance and reliability compared to the popular
 QIC117 'floppy' tape devices.

 Beware that although ATAPI devices plug into the IDE interface, they
 differ considerably from an IDE harddisk. Caching controllers and
 other intelligent interfaces will not work unless they're ATAPI aware.
 Booting from an ATAPI CD-ROM is only possible with the latest BIOSes.


 2.6.  Ultra-ATA

 Ultra-ATA is somewhat similar to Ultra-SCSI in the sense that it
! bridges the gap between the current standard (ATA-3) and ATA-4, which
! isn't quite finished yet. Ultra-ATA adds a new, high performance mode:
! DMA/33 with 33MB/s bandwidth, twice that of DMA mode 2. It is
! supported by Intel's Pentium II chipset, the TX Pentium chipset, the
! latest Intel competitors and a few add-on (PCI) cards.


 2.7.  ATA-4

 Work on the next standard, predictably called ATA-4, has already
 started. First and foremost it is a much-needed attempt to merge ATA-3
 and ATAPI into one. Faster transfer modes are also on the agenda, of
 course: it will incorporate Ultra-ATA's DMA/33, at least.

 Regarding other features, the future for strong command overlap looks
 rather bleak: the current proposal is a hideous animal and important
 players like Microsoft do not plan on supporting it in its present
 form. More limited forms of overlap stand a somewhat better chance of
 surviving.
 2.8.  The Enhanced BIOS

 A rather different issue was the 504MB (or, equivalently, 528 million
 bytes) capacity limit that becomes apparent when accessing IDE drives
 through the BIOS. It is caused by the disk geometry (cylinders, heads,
 sectors) supported by the combination of an IDE drive and the BIOS'
 software interface ('int13').  Both IDE/ATA and the BIOS are capable
 of supporting huge disks, but their combined limitations conspire to
 restrict the useful capacity of the drive to 504MB. Since only MSDOS
 still uses the BIOS for harddisk access, this is sometimes erroneously
 thought to be an MSDOS limitation; other operating systems experience
 the same restrictions at boot time though.

 An Enhanced BIOS works around this problem by representing the drive
 to the software using a different geometry than the native geometry of
 the drive itself. This juggling act is called 'translation'.  For
 example, if your drive has 1500 cylinders and 16 heads, a translating
 BIOS will make software programs think that the drive has 750
 cylinders and 32 heads.

 You do not need an "EIDE" adapter to use harddisks greater than 504MB.

 The de facto standard is described in the Microsoft/IBM "INT 13
 Extensions" document. Phoenix has presented a superset in their
 "Phoenix Enhanced BIOS" specification. Phoenix, AMI, Award and MR
 BIOSes are based on the Microsoft/IBM specification.


 2.9.  The secondary port and beyond

 Last but not least, the usual limit of two devices was far too
 restrictive if CD-ROMs and tape drives were to be connected to the IDE
 interface in addition to the harddisk(s). Fortunately the solution was
 already known in the form of a so-called secondary harddisk interface.
 The possibility of such an interface has been there for a long time,
 but support was lacking.

 There is nothing special about a secondary channel; it is an ordinary
 (E)IDE port that uses a different interrupt and I/O addresses to avoid
 clashes with the ordinary (primary) one. A secondary interface allows
 you to connect another ribbon cable with two more ATA devices
 (harddisk, ATAPI CD-ROM or ATAPI tape).  Today, many interfaces
 combine both primary and secondary port on a single board to make a
 dual-ported interface that handles up to four devices.

 To use harddisks on the secondary port with DOS and Windows 3.x, you
 will need BIOS (either system BIOS or adapter BIOS) or driver support.
 You can recognize a BIOS with four drive support by the fact that it
 allows for four sets of drive parameter in the BIOS setup.

 There are two further (semi-)standard channels beyond the secondary
 port: the tertiary and quaternary ones. Some soundcard IDE interfaces
 can be configured as tertiary or quaternary. See section 10.4 for the
 I/O and IRQ assignments.  Software support for these is still rare.



 3.  General questions


 3.1.  What are the main features of EIDE and Fast-ATA?

 The fast transfer modes (PIO modes 3 and 4, multiword DMA modes 1 and
 2) are the cornerstones of Fast-ATA and EIDE. These are marketing
 terms contrived by disk drive manufacturers.  Enhanced IDE is a
 Western Digital trademark; Fast-ATA is a term coined by Seagate, and
 endorsed by Seagate and Quantum.

 EIDE consists of:

 o  Fast transfer modes: PIO mode 3 or better, multiword DMA mode 1 or
    better,

 o  LBA mode (explained in section 10.7),

 o  Four devices on the ATA interface: secondary port,

 o  No 504MB limit with DOS: WD Enhanced BIOS,

 o  tape backup and CD-ROM devices on the ATA interface: ATAPI.

 Fast-ATA and Fast-ATA-2 embrace:

 o  PIO mode 3 (and 4 for Fast-ATA-2), multiword DMA mode 1 (and 2 for
    Fast-ATA-2),

 o  Read/Write multiple commands (also known as block mode; see Q10.6),

 o  LBA mode.

 The difference between the two schemes is mainly in the scope of EIDE.
 Hardware can be tagged 'EIDE' even if only part of the EIDE feature
 set has been implemented, which can lead to some confusion.  This FAQ
 will avoid the term EIDE whenever possible, discussing its component
 parts (ATA-2, ATAPI, etc) instead. This allows you to see exactly what
 'EIDE' features you need in your specific situation.


! 3.2.  What are the main features of Ultra-ATA?
!
! To everything EIDE has on offer, Ultra-ATA adds the following:
!
! o  Even faster transfer modes, most importantly DMA/33 with double the
!    bandwidth of DMA mode 2 and PIO mode 4. There are no new PIO modes.
!
! o  Improved reliability using DMA/16 and DMA/33. A checksum is added
!    to the data sent over the ATA interface.  That way, data corruption
!    can be detected and the data retransmitted.  On an ordinary EIDE
!    interface you wouldn't notice the corruption until it was too late.
!
! Ultra-ATA was first proposed by Quantum and is widely accepted now.
!
!
! 3.3.  Are those rumors about buggy interfaces true?

 Very true, unfortunately.

 This FAQ doesn't really deal with specific interfaces, but two very
 popular interface chips have been shown to contain bugs too serious to
 ignore:

 o  the CMD640x, a dual-channel PCI to EIDE interface used on many
    mainboards (Intel!) and interface boards, has a number of dangerous
    bugs you need to be aware of.

 o  The PC-Tech RZ-1000, used on AT&T, Dell, Gateway and Intel boards,
    also has two data-corrupting bugs. See also
    <http://www.intel.com/procs/support/rz1000/index.htm>.

 In both cases, the corruption occurs only in specific software
 environments and is very subtle; you can go on working for months
 without suspecting anything more than buggy software. The damage can
 be immense. For all the details, look at Roedy Green's ([email protected])
 "PCI EIDE controller flaws" FAQ included with his EIDE test
 <ftp://garbo.uwasa.fi/pc/diskutil/eidete19.zip> program which will
 test your system for the bugs.

 BE WARNED that you're playing Russian roulette with your data if you
 continue working on an affected machine without taking notice of this
 problem.


 3.4.  What is a megabyte?

 The word "mega" is an ISO prefix designating a factor 1,000,000.  A
 proper megabyte is 1,000,000 bytes. Because computers use binary
 technology and like working with powers of two, 2^20 bytes, that is
 1048576 bytes, is also usually referred to as a megabyte.

 Which of the two types of megabyte you're dealing with depends on the
 context. For storage devices, a megabyte usually means 1,000,000
 bytes. Some software uses "binary" megabytes, though, and will show a
 smaller capacity than the drive label says! This includes most BIOSes.

 This FAQ uses megabytes of 1048576 bytes throughout.



 4.  Before buying...


 4.1.  What should I look for in an ATA-2 (Fast-ATA, EIDE) interface?

 There are a number of 'EIDE' features which can be desirable in a new
 interface. Some features, however, may already be present on your
 system or be unimportant to you.

!
! o  The least a modern interface should provide is PIO mode 3 transfers
    (up to 11.1MB/s) for drives that support it. It should also be able
    to use slower PIO modes (0, 1 and 2) to ensure compatibility with
!    older drives.
!
! o  True direct memory access (DMA) is found mostly on interfaces
!    integrated into mainboards, Intel 430*X based boards being the most
!    common example. This will improve system performance in
!    multitasking operating systems. Ultra-ATA will give you DMA/33,
!    which actually isn't all that much faster but a lot safer for your
!    data.

 o  Since ATAPI CD-ROMs have rapidly become very popular in the low-end
    market, and ATAPI tapestreamers are similarly taking off, a
    secondary port allowing you to connect a total of four ATA* devices
    is hardly a luxury. Note that a few modern soundcards provide a
    secondary or tertiary ATA/IDE interface instead of the traditional
    proprietary CD-ROM connectors.  Beware of conflicts in combination
    with a dual-ported interface.

    If you intend to connect harddisks to the second port and use them
    with DOS or Windows 3.x, remember that many older BIOSes have no
    support for the secondary channel and many interfaces do not ship
    with the required drivers.

 o  You will want an on-card Enhanced BIOS too if your mainboard BIOS
    doesn't support translation or if its support is buggy or outdated.
    The interface BIOS will override the mainboard BIOS' harddisk
    routines.

    A BIOS ROM will, just like a mainboard with integrated EIDE, often
    have the added advantage that you don't need separate DOS drivers.
    The BIOS on an interface will occupy 8 to 16k of UMB space, though,
    and you will still want drivers for every other operating system
    you use.

 o  Drivers! Without well-designed drivers most interfaces could as
    well be old-fashioned ISA cards for all the good they'll do. Even
    if the card has a BIOS, which usually removes the need for a driver
    under DOS, you will still need drivers for other operating systems,
!    including Windows and Win95. Newer versions of Windows (Win95 OEM2
!    and beyond) ship with a large amount of drivers.

! Note that some 'EIDE' interfaces which used to be popular were
! slightly to very buggy. This ranged from minor problems with ATA-2
! compliance to obscure things like the use of a single buffer for both
! primary and secondary channel or a badly designed prefetch buffer,
! both of which may cause data corruption under very specific
! circumstances.


 4.2.  Is my BIOS Enhanced?  How can I recognize this?

 Good question.

 Unfortunately, I know no easy answer. The mere ability to specify more
 than 1,024 cylinders in the BIOS setup is not conclusive. In your BIOS
 setup, drive related settings like "LBA", "ECHS" or even something
 silly like "Large" are telltale signs of a BIOS with translation
 support, which should be good for disk capacities of up to 8GB. A
 copyright before 1994, on the other hand, reduces your chances to
 something close to zero :-(

 o  For AMI, I only have reliable information on their HiFlex BIOS; it
    can be recognized by its characteristically funky orange and green
    color scheme. There at least two other types: WinBIOS with a
    Windows like interface, and a custom BIOS used with Intel Pentium
    boards.  Both may translation even if they have a (much) earlier
    copyright. I have no further information on those.

    AMI HiFlex BIOSes dated 7-25-94 and later and support translation.
    The date is embedded in the long number displayed at the bottom of
    the screen on bootup; it must be 072594 or later to support LBA.

    40-0100-00101111-111192-486-ABC-F  (111192 will not support LBA)

    50-0100-001292-00101111-072594-ABCDEF-F  (072594 will support LBA)


 o  Award seems to call all its BIOSes 4.50G :-) Some have translation
    support, some don't, some have buggy support (see 8.2). With a BIOS
    dated 12/31/1994 or later you have full translation support, with
    one dated earlier (7/29/1994, perhaps earlier than that as well)
    buggy support only.

 o  Phoenix BIOS v4.03 and later are reported to support translation.
    Some revisions of Phoenix v4.03 may not support it, though,
    depending on the computer or system board manufacturer.

 o  MR BIOS incorporated CHS translation--roughly the same as today's
    Large mode--as early as 1990!

 Note that only BIOSes fully implementing the IBM/Microsoft/Phoenix
 standards will allow access to disks larger than 8GB. Fortunately,
 these are becoming more and more common these days. We are not aware
 of utilities that will detect the presence of such a BIOS.

 Western Digital has a utility available by ftp that examines the
 Enhanced Disk Parameter Table (EDPT), if present. If it finds one on
 your system, your BIOS has all the bells and whistles to go up to 8GB
 <ftp://ftp.wdc.com/drivers/hdutil/chkbios.exe>. Beware that BIOSes
 conforming to the WD Enhanced BIOS specification won't build an EDPT
 unless LBA is enabled. Beware also that with a WD EBIOS it is highly
 unsafe to enable LBA on a disk that already contains data. This is due
 to a flaw in the specification.


 4.3.  Is my 50MHz VL bus system compatible with ATA-2 interfaces?

 It should be, but there are problematic cases.

 It has been observed that some controllers will base their I/O cycle
 times on the bus clock of the computer. This means that with a 50MHz
 bus, the cycle time will be faster than with a 33MHz bus. This could
 lead to undesirable results if these cycle times are faster than the
 drive can handle. Make sure your controller supports multiple bus
 speeds in the software setup, and if necessary program it correctly.


 4.4.  Are old IDE drives compatible with EIDE and U-ATA interfaces?

 This should work fine.

 Older drives do not support the high-speed advanced transfer modes
! defined by ATA-2 and, later, Ultra-ATA. To retain compatibility with
! these drives, ATA-2 and Ultra-ATA interfaces have programmable timing.
! The driver or BIOS queries the drive regarding its maximum transfer
! rate and will configure the interface to match. A few interfaces are
! jumper configurable in which case the responsibility is yours.

 If you intend to put an older drive on the same cable as an ATA-2
 drive, you may want to verify that your interface is capable of using
 independent timing for master and slave device. Otherwise, your old
 drive might end up slowing down your newer one because the controller
! is forced to use the lowest common speed. Modern interfaces like the
! Intel PIIX3 (430HX and VX and 440FX chipset), PIIX4 (430TX chipset)
! and, to a lesser extent PIIX (430FX chipset) don't suffer from this
! problem.


 4.5.  Can I use EIDE and U-ATA drives with my old (E)IDE interface?

 Fast-ATA and EIDE devices can be used without fear on regular ISA or
 VLB IDE controllers. The thing about advanced modes is that the drive
 is ready for the data in the fastest mode; the slower the controller,
 the easier it is on the drive. Of course you should expect the
 transfer rates to come out lower than on a full ATA-2 interface.

! Likewise, an Ultra-ATA drive will do fine on an ATA-2 (EIDE)
! interface. Better even, using DMA mode 2, its performance will be
! hardly any slower than it would be on an Ultra-ATA interface.
!
 It is not necessary to use an EIDE interface for harddisks of over
 504MB.  An Enhanced BIOS is all you need for DOS and Windows; for many
 other operating systems such as OS/2 or Linux you won't need even
 that.


 4.6.  Will an ATAPI (EIDE) CD-ROM work with an IDE interface?

 Yes. These devices were designed to be compatible with ATA (IDE) from
 the very start, and should work fine.

 4.7.  Do I need a BIOS update to connect an ATAPI CD-ROM?

 No. These CD-ROMs ship with a driver that provides complete support.
 The BIOS doesn't need to support them and usually doesn't even know
 they're there. Some modern BIOSes are ATAPI aware and have a special
 setting; barring those, you can generally leave the corresponding
 harddisk entry at 'Not Installed'.


 4.8.  Can large drives be used with my old BIOS?

 Yes, in principle, but there's still the small matter of the 504MB
 barrier. If the new drive exceeds this capacity, you must have an
 Enhanced BIOS in order to use more than 504MB with DOS, Windows or
 Win95 (see Q4.10 for other operating systems). It is important to note
 that this is a software only issue: you do not need a special
 interface to support large drives.

 BE WARNED that some older BIOSes will incorrectly handle drives with
 more than 1024 cylinders. Instead of truncating the number of
 cylinders to 1024, they use the cylinder count modulo 1024, which
 means that a 2300 cylinder drive will appear to have just 252
 cylinders. The solution is to specify 1024 cylinders in the BIOS
 setup.

 This becomes a real problem when a BIOS with this error also won't
 allow you to enter the drive parameters manually. Among IBM systems,
 the 1991-vintage PS/2 models 35sx and 40sx, the ValuePoint I, and at
 least some of the ValuePoint Si models have this flaw. With these
 machines, you should either try go get a BIOS upgrade from
 <ftp://ftp.pcco.ibm.com> if you have a flash BIOS, or verify that the
 drive you intend to use has a way to fake having no more than 1024
 cylinders (Western Digital has a utility for their 540MB drive, and
 many Maxtor drives have a jumper). The Promise EIDEMax is also
 reported to work, and will allow you to use drives of up to 8GB in
 full. Note that some operating systems, such as Linux and OS/2, allow
 you to override the BIOS' drive geometry information, which may also
 help addressing this problem. Another option is using OnTrack Disk
 Manager version 7.


 4.9.  I need an Enhanced BIOS to access >504MB. How do I get one?

 The options are: a new mainboard BIOS, add-on BIOS, or software.

 o  To upgrade your mainboard BIOS, either with a newer version of your
    current BIOS or using a custom made BIOS from firms such as Microid
    Research (MR BIOS), is probably the best option. It may or may not
    be more effective to replace the entire mainboard and get all the
    latest bells and whistles for $100 more.

 o  The next option is to purchase a card with an add-on BIOS that
    effectively replaces the harddisk portion of your mainboard BIOS.
    An example is LBA Pro from Storage Technologies, sold in the USA by
    Unicore software, or AMI's AMIDisk Extender. DataTechnology (DTC)
    also sell such a card.

 o  Most BIOSes on ATA-2 interfaces, if they have a BIOS at all, also
    do this. That may be a nice way to go if your present interface
    isn't up to snuff. For the ISA bus, there are a few "EIDE"
    interfaces that have a BIOS: examples are the Promise EIDEMax and
    the SIIG IDE Enhancer.

 Either way, you will have to repartition and reformat the (large)
 harddisk.

 o  A final option is to use a software solution, like Disk Manager or
    EZDrive. Software is often supplied free with the drive and
    relatively easy to install, but has inherent drawbacks. See also
    Q6.8.


 4.10.  Can I use a large harddisk with OSs other than DOS/Windows?

 Using a large harddisk is usually no big problem, even if you don't
 have an Enhanced BIOS. However, some OSs don't understand translation,
 which makes the combination with DOS, Windows and Win95 problematic.

 With operating systems such as NetWare, Unix, Win/NT and OS/2, the
 only thing you need to use large ATA disks is a BIOS that allows more
 than 1024 cylinders in the drive type setup.  There is one caveat
 though: the BIOS is still used to boot the operating system, so you
 will have to ensure that everything necessary to get the OS running in
 the first place resides below cylinder 1024. Remember that if you have
 an Enhanced BIOS, drives up to 8GB will appear to have no more than
 1024 cylinders, so in those cases these boot restrictions are removed.

 Once running, these operating systems use their own software to
 control the disks (Win95 also does this, but has a special position;
 see below). That way, they are not subject to the BIOS' restrictions
 such as the capacity limit.  Unfortunately, this also means that if
 you have a translating EBIOS or software driver, the OS has to be
 aware of the translation scheme used, or conflicts will arise between
 the operating system and DOS/Win/Win95. If you can set up partitions
 so that all DOS and boot partitions reside below the first 1024
 cylinders (504MB), you can avoid translation altogether and all the
 hassles with it.

 Older operating systems don't understand translation at all. Newer
 ones (OS/2 3.x, Linux 1.2 or better, Win95, SCO 5.0.x) will handle
 standard translation schemes out of the box, but not always those
 employed by some software drivers (EZDrive, Disk Manager v6.x or
 older). In the case of DM 6, fixes or updates are available for some
 operating systems (see above).

 Novell has a NetWare driver IDE.DSK version 3.0 dated September 2,
 1994. This version of the driver uses the Identify Device ATA command
 to get the drive parameters and ignores the BIOS parameters. This
 means that Novell now works with big IDE drives.

 A final remark: OS/2 enforces DOS compatibility for FAT partitions.
 That means that without an Enhanced BIOS, only HPFS partitions can
 extend beyond cylinder 1024.


 4.11.  I heard that Win95 provides support for large IDE disks.

 True, but it doesn't necessarily mean you can actually benefit from
 that support in all cases.

 Despite a large number of significant changes, in its way of handling
 harddisks Win95 largely resembles Windows for Workgroups. Just like
 OS/2, Linux and other operating systems, Win95 uses 32-bit protected
 mode drivers for the harddisks (unless it's using compatibility mode),
 and is happy to handle harddrives of respectable size: well over
 100GB. However, unlike OS/2 and Linux, and like Windows for
 Workgroups, Win95 boots from the same old DOS we all love to hate.
 Even once Win95 has booted, DOS hasn't gone. Win95 always keeps it
 behind the scenes and uses it to run devices in compatibility mode. In
 'safe mode', important for troubleshooting, Win95 completely relies on
 DOS.

 What all of this implies is that even though Win95's protected-mode
 disk driver may support gargantuan drives, it will never change the
 setup it inherits from DOS in order to retain compatibility with the
 latter. If you can only get at the first 504MB of your drive in DOS,
 it will be the same in Win95. You will still need one of the usual >
 504MB solutions mentioned elsewhere in this FAQ. For details, see also
 Microsoft KnowledgeBase article Q126855, "Windows 95 Support for Large
 IDE Hard Disks".


 4.12.  Can I use more than 2 or 4 hard drives?

 For DOS and Windows you probably want BIOS support for all your
 harddisks. Older BIOSes support drives on the primary channel only,
 just two; newer ones add support for the secondary channel for a total
 of four. Few BIOSes support more than that; MR BIOS is an exception.

 If the BIOS supports just two drives and you want more, there's a
 software solution available: 3drives (see the net.resource guide).
 Some interface cards also ship with the necessary support. Creative
 Labs has drivers for CD-ROMs on the tertiary and quaternary port.

 Other operating systems such as Win95 and OS/2 support both primary
 and secondary interface without aid from the BIOS. Linux will support
 a nearly arbitrary number of interfaces; you'll have to pass kernel
 parameters to specify the ones beyond the first two.


 4.13.  Does <insert operating system> support ATAPI (IDE) CD-ROMs?

 The current versions of most operating systems support ATAPI CD-ROMs.
 That includes OS/2 3.0, Linux 1.2 and above, and Win95.

 Unfortunately, hardware manufacturers have started designing these CD-
 ROM units while the ATAPI standard was still evolving, so there are
 now a couple of versions implemented in the real world. Moreover, the
 complexity and novelty of ATAPI means that there are some variations
 even among implementations of the same revision. Writing an OS ATAPI
 driver that works with all CD-ROMs, therefore, is a daunting task and
 not all have succeeded equally well. So although these OSs all support
 ATAPI, they do not work with all ATAPI equipment.

 See Microsoft KnowledgeBase Q131499, "CD-ROM Drives Requiring Real-
 Mode Drivers", for more details on Win95 support. For OS/2, take a
 look at  <http://www.austin.ibm.com/pspinfo/os2hw.html>; for updated
 drivers use the latest install disk upgrade or
 <ftp://ftp.pc.ibm.com/pub/os2_drivers/atapi.zip>.


 4.14.  I need a PCI ATA-2 interface that uses only one slot.

 There is a problem with PCI and multi-I/O or dual-ported IDE
 interfaces. Such interfaces need two or more predetermined interrupts
 which cannot be shared with other PCI devices, which is probably
 impossible with your PCI slots. The usual workaround consists of
 either integration of I/O functions on the mainboard, or the use of a
 tiny 'paddle' board that plugs into an ISA slot.

 This is not so much a weakness in the design of PCI, but a conflict
 between PCI's plug'n'play philosophy and the requirement that these
 interfaces be fully compatible with oldfashioned I/O cards.

 Some vendors use PCI interfaces that rely on a proprietary extension
 of the PCI bus. This is obviously not portable; you often can't even
 move the card to a different slot in the same machine. Moreover, such
 extensions may cause compatibility problems since they use PCI signals
 reserved for other purposes.


 4.15.  Will adding an Ultra-ATA interface help my drives' performance?

 A new interface may or may not help; it is possible to make a rough
 prediction if a better interface would really speed things up.

 Hardware vendors and marketing people would love to see everyone rush
! out and buy the latest generation of 'Ultra-ATA' adapters. To achieve
! this noble goal they tend to juggle with too-good-to-be-true
! performance figures. The relation between this advertising hype and
! the real world is shaky at best.

 The main point to remember is: a slow drive is a slow drive no matter
 how good the interface is. If the speed at which the drive physically
 transfers the data to/from the media is the limiting factor in
 performance, and it often is, the only way to make things go
 significantly faster is to purchase a better drive. Note that the
! transfer modes supported by modern drives (those 33MB/s figures) have
! little to do with their real-world performance.

! In addition, an 'ordinary' ATA-2 (EIDE) interface already offers
! respectable bandwidth---the fastest ATA-2 transfer mode is
! theoretically 16.6MB/s, which is more than any Ultra-ATA drive on the
! market today can sustain. In addition it usually supports the CPU-
! cycle-saving DMA modes. An IDE interface, on the other hand, makes a
! much better candidate for replacement since it rarely has a bandwidth
! over 2.5MB/s, which is cramped by today's standards, and doesn't
! support DMA.

 How to determine if the drive is the bottleneck? You can get a rough
 idea using Coretest version 3 <ftp://ftp.rahul.net/pub/lps/hard-
 disk/core303.exe>. This version of Coretest gives two performance
 figures of interest here: the (B)uffered transfer rate which is an
 indication of the bandwidth between drive and interface, and the
 (S)ustained rate which is related to the speed of the drive media. If
 your drive has a small buffer cache, you may have to use the /B16
 option to get the correct buffered transfer rate.

 Usually you'll find that the first figure exceeds the second by a
 considerable margin (say, a factor two or more). This means that the
 physical properties of the drive itself are the bottleneck, and
 improving the interface speed any further won't help much. The only
 thing that may improve performance somewhat is using block mode (using
 either a BIOS option or a driver).  Only if the drive throughput
 starts to approach the interface bandwidth will you have a fair chance
 that a new interface will have a large impact on performance, provided
 the drive supports faster modes than the one currently used.

 This is not an endorsement of Coretest as a disk benchmark; there are
 more reliable ones around, such as QBench
 <ftp://ftp.rahul.net/pub/lps/hard-disk/qbench.zip>.

 Be sure to read question 7.2 to get a more complete picture.



 5.  Installation


 5.1.  Which drive/device should be Slave?

 o  A single device on a cable, either a harddisk (ATA) or CD-ROM
    (ATAPI), should according to the specs never be configured as
    slave. However, as any ATAPI CD-ROMs come preconfigured as slave,
    most software works with a masterless slave CD-ROM simply because
    it saves tech support calls. Moreover some BIOSes have trouble with
    an ATAPI device jumpered as master. Formally it isn't a valid
    configuration though; remember this if you have trouble getting the
    CD-ROM recognized.

 o  Two harddrives on one channel should be configured as master and
    slave, respectively. It usually doesn't matter which is which, but
    older harddisks may not work in all configurations if they predate
    the standardization of the master/slave protocol. In that case a
    degree of experimentation will be necessary. Some Conner drives
    have an ATA/ISA jumper: ATA is the now-standard protocol, ISA is
    used by older Conners.

 o  Two ATAPI devices such as CD-ROMs and tapes should work fine as
    long as one device is master and the other slave, just like
    harddrives.

 o  If you need to put a harddisk and an ATAPI device on the same
    cable, the spec says the harddisk must be the master. Although the
    reverse will usually work as well in practice, still you'd better
    avoid the configuration.


 5.2.  Does it matter how I connect the devices to the cable?

 Not much. If you have only one drive on the cable, it is best to put
 it at the very end, especially when you're using any of the faster
 modes. For two devices, it doesn't matter where you put the master and
 the slave, or which end of the cable you plug into the controller.
 Just take care that you plug them in the right way: the red wire is
 supposed to correspond to pin 1.

 When Plug'n'Play ATA arrives the Cable Select (CS) setting will be
 used, and all of this will change. Some name brand machines may
 already employ a similar setup.


 5.3.  Does an old HD or CDROM slow down a new drive?

 This is not necessarily the case. Still, it is generally preferable to
 connect older drives and CD-ROMs to the secondary channel.

 If this is not feasible, or if you're wondering if you should upgrade,
 a few points.

 o  The speed loss usually referred to is in the interface timing, i.e.
    the speed at which the devices communicate with the computer. This
    does not necessarily translate into a real world performance
    penalty.

! o  This is mostly an issue with older ATA-2 (EIDE) interfaces and some
!    VL IDE ones. If you have an ordinary ISA IDE interface, it can't
!    get any slower.

! o  All modern interfaces support distinct timing for master and slave.
!    With these, the slow device does not directly affect the fast one.

! o  Many CD-ROMs support at least PIO mode 3. This is enough to operate
!    most harddisks on the market today near their maximum speed.

    You can use Coretest <ftp://ftp.rahul.net/pub/lps/hard-
    disk/core303.exe> to determine if and how performance is affected;
    see Q4.15 for a recipe.

 OS/2 and Unix users have another reason to put slow ATA devices such
 as tapes and CD-ROMs on a channel of their own. As long as one unit on
 a given channel is executing a command, the other is inaccessible. A
 CD-ROM can easily occupy the channel for 300ms that way.


 5.4.  I need a longer IDE cable; how long can I make it?

 Less than 18 inches. In some cases, the limit is no more than 7
 inches.

 The cable is a pretty weak link in the whole ATA-2 interface. For the
 fast transfer speeds used in 'EIDE' systems, there aren't enough
 ground signals; the cable is unterminated and unshielded. Noise is a
! real problem. All of this applies to ATA-2 (EIDE) systems more than
! Ultra-ATA systems, since the latter use checksums to ensure data
! integrity.
!
! For those reasons, you should take the 18" limit specified by the
! ATA(-2) standard pretty seriously if you want to avoid data corruption
! and system hangs.  Even worse, some dual-channel 'EIDE' interfaces
! such as CMD640x based ones have a peculiar design employing only a
! single buffer for both cables. Most signals on the two cables are
! directly connected with each other: this means that electrically, the
! cable lengths add up. Take into account that the copper traces on the
! circuit board are often a couple of inches long as well and you're
! facing a maximum cable length of roughly 7" per cable if you want to
! remain within spec.

 If you have difficulties fitting everything in with a standard length
 cable, consider adding a new plug to it or rolling a complete cable
 yourself. It's not hard to do, or to track down a friend willing to do
 it, and you can buy the parts in all electronic parts stores. Do use
 quality parts, work carefully, and watch that length.

 Disregard the above at your own peril. Noise induced problems usually
 pop up sporadically, can be very hard to detect and even harder to
 track down. Not least because they may appear completely unrelated and
 involve devices other than the harddisk.


 5.5.  Can I safely move my harddisk between computers?

 Transferring a partitioned and formatted harddisk between computers is
 potentially dangerous if they use different translation schemes (see Q
 6.3). This includes moving a disk from an old computer that doesn't
 support translation to a new one that does. This is really a little
 known issue.  Usually everything goes smoothly, but you would not be
 the first to be caught by surprise.

 WARNING. Do not assume it won't happen to you just because it works
 out fine most of the time---it has destroyed data, and will do so
 again.



 6.  Configuration


 6.1.  Should I use my interface's device drivers?

 Yes. Often these drivers are essential to get any kind of performance
 out of your interface.

 The PIO or DMA mode used when transferring data is determined by the
 interface card. Some cards have jumpers that determine the speed in
 hardware; these work in the fast mode from the microsecond you switch
 on the computer.

 Most interfaces, however, are software configurable. At bootup, they
 default to the slowest possible speed. Somewhere during the boot
 process, a piece of software belonging to your adapter figures out
 what kind of transfer rates the drives support and configures the
 controller chip to match. There are a couple of cases to distinguish:

 o  Onboard I/O with full BIOS support. The controller is fully
    configured when your computer boots. You can usually set the
    desired mode for each harddisk in the CMOS setup. Many modern
    boards fall in this category.

 o  Onboard I/O with incomplete BIOS support. For some unfathomable
    reason, some mainboards do not support or only imperfectly set up
    their integrated I/O ports.  In that case, you'll have to use DOS
    or other drivers to get full functionality.

 o  Interface card with BIOS. This is similar to the two categories
    above. The main difference is that these cards don't necessarily
    have setup screens; in that case, they must use other means to
    determine the transfer mode to be used. For example, the Promise
    2300+ uses a combination of jumpers and a table in ROM containing
    the parameters for a number of different drives. It may or may not
    be necessary to use drivers for best performance.

 o  Interface card without BIOS. Since there is no way the mainboard
    BIOS can know how to set up all those different interface cards out
    there, you must use the supplied device drivers to profit from the
    fast modes. That is, unless your card is hardware configurable
    using jumpers, which is quite rare.

 Usually, there are drivers for other operating systems as well, such
 as Windows, Win95, OS/2 and so forth. These serve a couple of
 purposes.

 o  The driver may be necessary to configure the adapter as described
    above. This doesn't apply to Windows, where the DOS device driver
    usually has already done that job.

 o  The standard drivers built into operating systems don't support all
    of the advanced features of your interface and drives. Examples are
    32-bit transfers, block mode and DMA.

 o  Windows only: the standard driver (*wdctrl) that ships with Windows
    and Windows for Workgroups has some serious restrictions. See Q8.10
    for details.

 In view of this it is rather unfortunate that so often, the drivers
 supplied with an interface are of mediocre quality.


 6.2.  What should I use: Normal, LBA or Large?

 The difference between the three is this.

 o   'Normal' causes the BIOS to behave like an old fashioned one
    without translation. Use this if your drive doesn't need it (ie.
    has fewer than 1024 cylinders) or if you want to use the drive with
    an operating system that doesn't understand about translation.

 o   'Large' or ECHS or XCHS tells the BIOS to use CHS translation. It
    uses a different geometry (Cylinders/Heads/Sectors) when accessing
    the drive than when talking to the software through int13. This
    type of translation works with all drives.

    Note. Some BIOSes have a braindead Large implementation which works
    only for disks of up to 1GB. Fortunately, all larger disks support
    LBA.

 o   'LBA' differs from 'Large' in that it uses LBA addressing to
    access the harddisk. The advantage is that it theoretically is a
    little faster. The disadvantages are that some older drives don't
    support it, and it often turns out to be slower, depending on the
    drive.

 WARNING. Some BIOSes change the (translated) geometry if you change
 from Normal or Large to LBA. The same thing may happen if you transfer
 a disk that has been formatted on an old, non-LBA computer to a new
 one that uses LBA. This has destroyed data. Don't let it happen to
 you.

 Section 10 tells more about the differences between these three.


 6.3.  Can I safely change the BIOS' xlation mode (None, LBA, Large)?

 Unfortunately, no. Proceed with care.

 While with many BIOSes, the sectors on the disk are addressed in the
 same order independent of the translation mode, a few use a different
 type of translation algorithm. The latter type of BIOS will shuffle
 your data as if it were a deck of cards if you alter the translation
 mode.

 Moreover, BIOSes that conform to the WD Guide may use completely
 dissimilar drive geometries in the software (int13) interface
 depending on the translation mode. If this happens it will wreak havoc
 with your data. This represents a major flaw in the WD EBIOS
 specification.

 In both of these cases, after changing the translation mode, you must
 repartition and reformat your disk.



 6.4.  Should I enable EIDE busmastering in my BIOS?

 The only reason why you would want to enable this option is that DMA
 modes are less likely to corrupt data than PIO modes. There will be no
 difference in CPU usage. (when DMA/33 arrives, the improved bandwidth
 will be another reason).

 Unfortunately, at least one user has reported a drastic decline in
 drive throughput with DMA enabled. The reasons are unclear, so YMMV.


 6.5.  FDISK sees only 504MB of my disk!

 First and foremost, do you have an Enhanced BIOS? See section 2.8 and
 Q1 for more details. If you do have an EBIOS, make sure you have
 enabled translation: usually, either 'Large' or 'LBA'. If you see no
 such options in your BIOS setup, remember that some types of BIOS
 offer them only when you tell it to autodetect the drives.

 Last but not least, remove all old partitions before trying to create
 new ones after changing the translation mode.


 6.6.  FDISK will partition only 2GB.

 There's nothing wrong; this is a limitation of the DOS FAT and Win95
 VFAT filesystems. You will have to create multiple partitions in order
 to use the full drive size.

 This limitation has been addressed in Microsoft's new FAT32
 filesystem, currently only available in the Win95 OEM 2 release. It
 allows giant multi-gigabyte partitions. At the time of writing this
 release can be sold with new hardware only and is unavailable to
 ordinary mortals.


 6.7.  I have no fancy EBIOS, but I have an 1GB partition and it works.

 Some try to work around the 504MB / 1024 cylinders issue by making a
 large partition using a friend's computer, Linux' fdisk, or something
 else. They use it for a day or two, conclude that it works, then post
 a triumphant article claiming that they found the Solution To
 Everyone's Problems[TM].

 It will work... for precisely 1024 cylinders. The very moment the OS
 or anything else attempts to write something to cylinder 1025 through
 int13 calls, the write wraps around to cylinder 0. This cylinder
 happens to hold some of the most important data structures on the
 disk: the Master Boot Record, partition table, both FAT copies and the
 root directory of the first partition. Overwrite these and probably
 only a specialized data recovery company will be able to salvage your
 data.

 Try it if you must. If you know exactly what you're doing, you can
 make it work using Win95. Sort of. The first error will be fatal. But
 please don't post any stories about it, recommending the procedure to
 everyone. The spectres of their valuable data will come back to haunt
 you.


 6.8.  I have software to break the 504MB barrier. Should I use it?

 This is a convenient option, but there are caveats.

 The software, sometimes bearing an exotic name depending on the
 licensee, is usually a version of either MicroHouse's EZ-Drive or
 OnTrack's Disk Manager. Disk Manager, when used on the boot drive, has
 to resort to some trickery in order to be loaded very early during the
 boot process (which is necessary for technical reasons). This is
 accomplished by modifying the Master Boot Record (MBR), the first
 piece of code the BIOS loads and executes when the computer boots, and
 storing a Dynamic Drive Overlay (DDO) on the very first disk track.
 EZ-Drive works in a similar fashion.

 An annoying side effect of using a software solution is that operating
 system installations, which often overwrite the MBR, will render the
 contents of your harddisk inaccessible. You will need to restore the
 MBR from the installation floppy to regain access to your partitions.

 Moreover, such software tends to create partitions quite different
 from 'standard' translation schemes as used by most Enhanced BIOSes.
 Many device drivers dealing with the disk will fail even if they work
 fine with other schemes. Important examples are (E)IDE interface
 drivers; remember that without these drivers an interface will in
 general be much slower. You'll need drivers that are specifically
 aware of the translation software you use. Also, many operating
 systems other than DOS will not be able to access or use the drive, at
 least not 'out of the box'. Disk fixing utilities may fail to work if
 the partition table or the overlay is damaged.

 This also makes it difficult to upgrade to a BIOS based solution.
 OnTrack Disk Manager version 7 includes a migration utility for the
 purpose and improves on version 6 in a number of other ways. It allows
 multiple operating systems and is compatible with most interfaces and
 drivers, including those for ATAPI CD-ROMs. Owners of version 6.03,
 which is still often included with hard drives, can download an update
 patch from OnTrack  <http://www.ontrack.com/pub/software/dmpatch.zip>
 that gives some of the benefits of version 7. View
 <http://www.ontrack.com/dm.html> for general information.

 For older versions of Disk Manager, IBM and Microsoft have fixes for
 OS/2 (in FixPak 5 or later, or out of the box in Warp FullPack and
 Warp Connect) and NT (Service Pack 2). Win95 should support Disk
 Manager and EZDrive out of the box (see Microsoft KnowledgeBase
 article Q126855, "Windows 95 Support for Large IDE Hard Disks"). More
 about Disk Manager in section 13.1.


 6.9.  Can I keep my Disk Manager/EZDrive partition with a new BIOS?

 If you have a Disk Manager or EZDrive partition and are upgrading to a
 translating BIOS, you have three options.

 o  The utility is compatible with LBA translation, or has a migration
    feature. This makes for a smooth upgrade path. (I'm only certain
    about Disk Manager v7).

 o  The above isn't true and you don't want to go through a backup,
    repartition, restore cycle. Tell the BIOS to use Normal mode for
    the harddisk and the utility should continue to work as usual.

 o  Backup, repartition, restore. See 6.10 if you experience
    difficulties removing the utility.

    Always back up your data before doing a system upgrade.


 6.10.  I need to remove Disk Manager/EZDrive.

 This software is usually installed in the boot drive's Master Boot
 Record (MBR). Normal repartitioning and reformatting of the drive
 usually does not refresh the MBR, which can make for a frustrating
 experience. Fortunately, it's not very hard once you know how.

 The best way to deinstall is to follow the procedure outlined in the
 utility's documentation. If this is not available, the following
 procedure usually works: boot from a clean floppy with at least DOS,
 FORMAT.COM and FDISK.COM on it. Then type FDISK /MBR. This should
 refresh the code in your MBR. After that, repartition and reformat as
 usual.

 For reasons I do not understand, some Disk Manager versions are
 reported to cling to life rather tenaciously (perhaps due to
 overambitious virus protection by the BIOS?). In that case, you need
 DM.EXE. Type DM /Y-. If that fails as well, the following procedure
 was reported to work by Mark Brown ([email protected]).

 1. run DM (in this case, v.6.03)

 2. press ALT-T

 3. select (D)isk Sub-System Overview

 4. select appropriate hard drive

 5. press CTRL-F10  to clear out the MBR

 6. press Y to confirm

 7. press ESC to exit out of DM, rebooting from a clean floppy

 If you have faced similar situations and can add to this, please share
 your knowledge. A good candidate would be a utility that simply zaps
 the partition table---any takers?

 WARNING. Disk Manager and EZDrive partitions differ from those created
 by a translating BIOS. Expect your data to be inaccessible after this
 operation. An exception is v7.x of OnTrack's Disk Manager; DM.EXE has
 a Migrate feature that works with many BIOSes.

 WARNING. Some controllers and security software stores information on
 track 0 which FDISK /MBR will clear. In this case, the data on the
 disk is lost anyway, but there are a number of circumstances where
 this command can destroy data.


 6.11.  I can enable write caching on my harddisk. Should I?

 Do not confuse this with Smartdrive (or whatever) lazy writes: what is
 meant here is altering the drive's buffer cache management algorithm.
 This is possible using newer versions of Drive Rocket, with hdparm
 under Linux, and probably other utilities too. Provided, of course,
 the drive supports this feature. Sometimes it can also be done using
 jumpers on the drive.

 There seem to be problems with this, if a program will issue a soft-
 reset (which on Intel Pentium Motherboards also issues a hardware-
 reset) as soon as it sees the last IRQ, which overall ends up
 corrupting data. Use with care, and backup.


 6.12.  My drive letters have changed!

 MS-DOS assigns drive letters as follows.

 o  Letters a: and b: are reserved for floppy drives.

 o  All primary partitions on all (system and adapter) BIOS supported
    harddisks get their drive letters starting from c:, in order.
    Normally, you can have just one primary DOS/Windows partition on
    every drive.

 o  Only then, all logical drives inside extended partitions get their
    letters. This means, for example, that if you had one drive with c:
    and d:, adding a second drive with one primary partition on it will
    bump the former d: partition up to e:. If you want to avoid this,
    do not define primary partitions on all drives except the first
    one.

 o  After that, MS-DOS parses the CONFIG.SYS and AUTOEXEC.BAT files.
    Some devices such as CD-ROMs have no BIOS support and get their
    drive letters only here.

    Remember that some programs, including disk compression software,
    may do shuffling tricks with drive letters. Be also warned that
    some BIOS setup screens, in a misguided attempt at user
    friendliness, refer to harddisk units using drive letters. In
    trivial cases, this may be right, but in nontrivial setups the BIOS
    may be all wrong.
 7.  Performance


 7.1.  Why isn't my drive as fast as it's advertised to be?

 Good question. The basic answer is that the advertised modes are
 theoretical transfer rates.

 This is the case at two levels. First and foremost, the oft-quoted
 rates do not represent the speed at which the drive can actually read
 data from, or write data to, the magnetic media. Instead, they give
 the speed at which data can be exchanged between the drive's buffer
 cache and the CPU. While the latter gives the more imposing figures,
 the former has greater impact on real world performance. "It is really
 as if the government had had a speed limit of 250 km/h on the
 highways, then raised it to 1600 km/h and tried to impress you by
 telling you that now you can drive faster"--Aaron Bilger
 ([email protected]).

 Second, even once you accept that these transfer rates can be achieved
 only when the drive happens to have the data ready in the buffer
 cache, these figures are pretty optimistic.  Realistically, drives do
 more than just give data to the host out of the cache. For each sector
 transferred to the host, the drive's controller needs to get one from
 the media; internal controller processing, table updates, positioning
 and buffer cache management all take some of the controller's
 attention. All reduce the throughput from the cache to the host.

 On top of that, depending on the benchmark used to determine the
 'throughput', the rate can vary from 3MB/s to 30MB/s and upwards, all
 on the same drive.  This depends on what the utility actually
 measures, how it measures it, and even where on the drive it measures
 it (different zones on the same drive can vary up to a factor two in
 speed).  Plus, system configuration (MHz CPU, RAM, harddisk cache,
 processor cache) make a difference as well.

 Bottom line is, whatever benchmark you use, you will not 'see' the
 advertised transfer rate. The real test is how well it improves your
 day to day applications. The rest is just fluff.


 7.2.  Why is my new EIDE, U-ATA interface no faster than my old one?

! There are several reasons why it is possible that an Ultra-ATA
! interface is no faster than an older one even if the drivers are
 installed and everything works properly. The first, and most
 important, is that the bandwidth of the fastest ATA-2 mode, 16.6MB/s,
 exceeds the real world transfer rate of most drives on the market
 today by a considerable margin. If this is the case for your drive,
 increasing the interface bandwidth beyond this will have no noticeable
 effect.

! A further possibility is that your drive does not support the Ultra-
! ATA transfer modes at all. In that case, an Ultra-ATA interface may
! improve performance relative to an old-fashioned ISA bus or VL bus
! interface, but it will be no faster than a good PCI ATA-2 (EIDE)
! interface.


 7.3.  I benchmarked my drive and it's getting slower!

 Believe it or not, but this is completely normal. First, filesystem
 fragmentation affects some benchmarks; try defragging the drive.
 Second, not all parts of the drive are equally fast.


 Physically, a harddrive consists of one or more rotating platters,
 where the tracks are concentrical circles on these platters.
 Obviously, the outermost tracks are longer than the innermost ones.
 Because they are longer, they can hold more sectors. As you work your
 way inwards and the track length decreases, the number of sectors
 decreases in a number of steps. This is referred to as Zone Bit
 Recording (ZBR).

 Back to the benchmarks. Since the platter spins at a constant rate,
 more sectors in a track give a proportionally higher transfer rate.
 The very first cylinder of your drive is right at the edge of the
 platter, in the fastest zone. This is the area that was tested when
 you got your drive and tried to find out how well it performed. As
 your drive fills up, you start using higher cylinder numbers---and
 slower zones. Depending on the type of benchmark you use, this may be
 reflected in lower scores.

 The difference in sectors per track (and hence transfer rate) between
 the fastest and the slowest zone may be as much as a factor two.
 Typical drives have anything from five to twenty zones, all with a
 different number of sectors per track.


 7.4.  A guy on the net has the same drive and he gets 33MB/s!


      "Usenet is like a herd of performing elephants with diar-
      rhea--massive, difficult to redirect, awe-inspiring, enter-
      taining, and a source of mind-boggling amounts of excrement
      when you least expect it."


 -- Gene Spafford ([email protected]), 1992



 7.5.  Busmastering drivers don't do much...

 First of all, busmastering will generally not do much with the
 transfer rates themselves. What it does is relieve the CPU from the
 chore of shovelling data around, so that it can do something more
 useful. However if you tend to do only one thing at a time, or you're
 running a benchmark, the extra CPU time can't be used for anything and
 busmastering will have no appreciable effect.


 Second, you will not see any decrease in CPU usage with the System
 Monitor in Win95 because it tracks the amount of time spent in the
 "system idle" loop. However, with a pending I/O operation, the system
 doesn't spend its spare cycles there, but in the "waiting for I/O to
 complete" loop.

! Third, you need to use DMA to profit from the improved data integrity
! and enhanced transfer rates of Ultra-ATA.
!


 8.  Troubleshooting


 8.1.  Why do I get NO ROM BASIC, SYSTEM HALTED?

 This should get a prize for the PC compatible's most obscure error
 message. It usually means you haven't made the primary partition
 bootable or, in  Microsoft-speak, 'Active'. Use FDISK to fix this.
 Don't fret, you won't have to repartition or reformat anything unless
 you have no primary partition at all.

 The earliest true-blue PCs had a BASIC interpreter built in, just like
 many other home computers those days. Even today, the Master Boot
 Record (MBR) code on your harddisk jumps to the BASIC ROM if it
 doesn't find any active partitions. Needless to say, there's no such
 thing as a BASIC ROM in today's compatibles, and this action ends in
 the above error message.


 8.2.  I have problems with my Award 4.50G BIOS and large drives.

 If your 4.50G BIOS is dated earlier than 12/13/1994, the address
 translation table is faulty. To access drives with more than 1024
 cylinders, you cannot use address translation (Large) but must use
 LBA. In versions dated 12/13/1994 or later this has been fixed. Be
 warned that switching to LBA will probably force you to repartition
 and reformat your drive; do back up your data.


 8.3.  My 2GB+ drive is not recognized or crashes.

 Many BIOSes dated before 1996 contain bugs making them incompatible
 with drives of more than 4096 cylinders, which works out to be about
 2GB in size.  Some BIOSes have similar problems at the 8192 cylinder
 boundary (4GB). The effects may range from not being able to use the
 full capacity to a crashing BIOS during bootup or upon detecting the
 drive.

 Possible solutions include

 o  a flash BIOS update, if you've got a flash BIOS and your board
    manufacturer makes a fixed BIOS image available;

 o  non-flash BIOS ROM ugrade;

 o  a software disk manager like using OnTrack Disk Manager or EZDrive;

 o  if the BIOS allows a user definable drive type, manually setting
    the cylinder count to 4095 (8191). This means you can use no more
    than the first 2GB (4GB) of the drive.

    In the last case, you can use the remaining capacity of the disk to
    give Linux a test drive.



 8.4.  My 4GB+ drive has problems in MSDOS 6.22 or below.

 Some BIOSes assign a drive of over 8192 cylinders a translated
 geometry with 256 heads. MSDOS 6.22 and below fail when they try to
 access the last head.

 If your BIOS allows a user definable drive type, use a geometry with
 15 heads and 16/15 times the original number of cylinders, rounded
 down. Thanks to universal translation you can always do this. Remember
 to write down the geometry somewhere so that you can reproduce it if
 necessary! If no user definable drive type is possible, there's little
 you can do about this except upgrade to Win95.


!
!
 8.5.  Help! I have OnTrack Disk Manager installed and now...

 OnTrack has a web site:  <http://www.ontrack.com/>. Most importantly,
 you can find their Disk Manager FAQ at
 <http://www.ontrack.com/ontrack/faqhome.html>. There's also a bit
 about DM in section 13.1. If all of that doesn't help, contact OnTrack
 tech support at [email protected].

 Beware that some licensed versions are supported by the OEM rather
 than by OnTrack. In such cases the OEM usually offers help, FAQs etc.
 on their web site.


 8.6.  My mode 3-4-5-6 drive has data corruption problems.

 Try using a slower mode or disable fast modes altogether. Mode 3 and
 especially mode 4 are very sensitive to timing problems, and not all
 adapters follow the ATA-2 specification really closely. Don't dismiss
 the possibility too easily: if you changed anything on your system, it
 is very well possible that a drive which marginally worked so far now
 starts to corrupt data.

 Some controllers seem to configure themselves according to the
 capabilities of the master drive. This can mean trouble if the slave
 handles only slower modes.

 Moreover, check your cables, and ensure they aren't too long (see
 Q5.4). Removable drive brackets may also cause problems with fast PIO
 modes for roughly the same reasons.


 8.7.  Are there supposed to be bad sectors on the drive?

 No. All modern drives support error management, which completely hides
 any bad sectors that may be on the disk before leaving the factory.
 Even a single bad sector is sufficient grounds to return the drive
 under warranty. If you want to continue using it, the drive should be
 viewed with the utmost suspicion.

 Western Digital's wdat_ide.exe utility can hide grown bad sectors on
 many Caviar disks.

 There is one exception. Under rare circumstances, use of bad (too
 fast) timing by the disk adapter can cause bad sectors on a disk. This
 type of error can be fixed simply by writing fresh data to these
 sectors, as there is no actual media defect.


 8.8.  I keep getting CRC errors and serial overruns.

 Often, this is caused by the use of block mode (see Q10.6 for an
 explanation). Large blocks can take a long time to transfer; during
 the transfer, interrupts are disabled and the serial ports are not
 serviced by the CPU. Eventually, the buffer for incoming data may
 overflow, leading to overruns and CRC errors.

 The solution is to reduce the number of sectors per block, if
 possible, or disabling block mode altogether. 16550 compatible serial
 ports have a larger buffer, but with excessively large block sizes
 this problem may still occur.


 8.9.  Can my drive do 32-bit access?

 There appears to be an awful lot of confusion about this subject,
 partly due to some unhappy terminology.

 In the most literal sense, no ATA(-2,-PI) drive will allow 32-bit
 access.  Data is transferred to and from the drive over a 16 bit bus.
 However, many local bus interfaces are capable of combining two 16-bit
 words into a 32-bit doubleword when reading data from the disk, and
 the reverse when writing. This way, data transfer between the CPU and
 the interface can be done in 32-bit chunks. This is often called
 '32-bit access', although '32-bit host bus transfers' would be a
 better name.

 With 32-bit host bus transfers, more efficient use is made of the
 computer's bus and CPU. On the other hand, these are seldom the
 bottleneck, so don't expect miracles from this feature. Windows'
 32-bit disk and file access are completely unrelated issues and the
 subject of question 8.10 and 8.11.


 8.10.  Help! Windows 3.x 32-bit disk access doesn't work anymore!

 There are numerous reasons why this can fail; you will more easily be
 able to do something about it (or decide if you want to fix it in the
 first place) once you know some background.

 Windows' 32-bit disk access (32BDA) is a bit of a misnomer, actually,
 since it has nothing to do with 32-bit data transfers. A slightly
 better name for it is 'FastDisk'. It is a feature of Windows in 386
 Enhanced mode that allows one to replace the BIOS' disk routines by
 Windows' own routines that work in protected mode. A much better name,
 then, would be "protected mode controller access".  For some reason
 Microsoft decided not to use the latter.

 Anyway, the main advantage of this feature is that it allows Windows
 to use virtual memory for its DOS sessions. Without 32-bit disk
 access, DOS sessions cannot be swapped out and every DOS box takes
 640k of real memory. Because it also reduces the number of switches
 between virtual and protected mode Windows has to make, it gives a
 slight performance improvement as well, but usually nothing dramatic.
 Only if 32BDA is used together with Windows for Workgroups' 32-bit
 file access feature, it will eliminate these mode switches altogether
 (at least for most disk operations), which gives a far more
 interesting performance boost.

 Unfortunately, the standard FastDisk routines that are internal to
 windows, called *wdctrl, are severely limited in their capabilities.
 The *wdctrl software understands nothing of non-IDE hardware (e.g.
 SCSI), more than two harddrives, drives with more than 1024 cylinders,
 32-bit host bus transfers, block transfers, or ATAPI CD-ROM drives on
 the primary channel. If you use any of these things, 32-bit disk
 access won't work unless you have a *wdctrl replacement.

 Today, that means that 32-bit disk access won't work 'out of the box'
 for most of us.

 Most interfaces that are incompatible with *wdctrl come with their own
 FastDisk routines (usually with a .386 extension). For the rest of
 you, many drive manufacturers offer replacement FastDisk software.
 Many drive manufacturers have such drivers on their WWW sites these
 days; take a look in the net.resource guide below. You can also
 contact your vendor to find out what is available. Last but not least,
 the ontrackw.386 driver in
 <ftp://ftp.ontrack.com/pub/software/dmpatch.zip> is reported to work
 fine on all drives even if you don't use Disk Manager.

 Most of these drivers won't give you 32-bit disk access if you have an
 ATAPI CD-ROM on the same cable as the harddisk. Only a few CD-ROMs
 come with a special VxD driver which does the job.

 Note: these drivers are incompatible with the Stealth feature of some
 versions of Quarterdeck's QEMM.  Quarterdeck's fix can be found on
 <ftp://ftp.wdc.com/drivers/hdutil/32bda.com>.


 8.11.  Help! Windows for Workgroups' 32-bit file access fails!

 The idiosyncrasies of the 32-bit disk access feature with respect to
 disk hardware has led to the popular myth that 32-bit file access has
 similar problems. However, that's all it is: a myth. If 32-bit file
 access fails, you should first check your filesystem and the programs
 that use it. As little as a single open file, e.g. from a printer
 spooler, will cause 32BFA to fail. Oh, and put
 DEVICE=C:\WINDOWS\IFSHLP.SYS in your CONFIG.SYS, and make sure your
 SYSTEM.INI contains the correct magic incantations (vfat.386,
 vcache.386). If this doesn't help, there's a first rate FAQ on this
 topic (see the net.resource guide for details).


 8.12.  Help! Win95 indicates my drive uses compatibility mode!

 The culprit usually is a virus. Do get a recent virus scanner.

 If that turns out negative, it may also be DOS (real-mode) driver that
 loads in the CONFIG.SYS or AUTOEXEC.BAT, or an old version of
 EZDrive/Disk Manager loading from the MBR.


 8.13.  My partitions become a mess in MS-DOS mode.

 See the next question.


 8.14.  Win95 sees my partitions, but DOS doesn't.

 If you've used Win95's fdisk utility to partition your drive, you may
 run across a nasty bug.

 Win95 supports extended int13 calls to break the 8GB barrier. To avoid
 problems with old versions of DOS, partitions extending beyond 8GB
 must be made invisible. Unfortunately, the Win95 FDISK sometimes hides
 partitions this way even if your drive is much smaller than 8GB.
 Incidentally, this also hides them from all other operating systems,
 including old versions of DOS, and can cause all kinds of problems.

 Under circumstances, these new partition types can completely mess up
 things when going from the Win95 graphical shell to MS-DOS mode. Drive
 contents may appear to be corrupted or be replaced by the contents of
 C:. Don't try anything fancy when this happens; it is really easy to
 corrupt your data. Don't use the "Restart in MS-DOS mode" option and
 don't run programs configured to run in MS-DOS mode. MS-DOS windows
 are still fine.

 The most comfortable way to fix this is to change the partition types
 using Partition Magic <http://www.powerquest.com>, but ONLY version
 2.03 or later. You can get an update patch for older versions.

 The alternative is to back up your data and repartition using FDISK
 /X, which disables the use of the new partition types, or DOS 6 FDISK.
 Also be sure to apply the Win95 ios bugfix and other fixes available
 from Microsoft's web site.


 8.15.  Win95 keeps losing my second IDE channel!

 If you have a Triton II or Natoma based board, the retail version of
 Win95 may not recognize the PIIX3 interface. This will trigger an
 entertaining bit of Plug'n'Pray magic which eventually causes the BIOS
 to disable the secondary IDE channel on the next reboot.

 To determine if this is really your problem, go into the device
 manager and click on Hard Disk Controllers. If you see the following
 devices listed:

 o  Primary IDE Controller (single FIFO)

 o  Standard Dual PCI IDE Controller

 o  Standard IDEESDI Hard Disk Controller/

    your Win95 mshdc.inf needs a little update. You can download this
    from <ftp://ftp.intel.com/pub/patch/ideinfup.exe>.


 8.16.  The Win95 busmastering drivers won't work.

 The Win95 busmastering drivers sometimes have trouble co-operating
 with older harddisks and ATAPI CD-ROMs. Try installing the latest
 drivers.

 If that doesn't help, you could try this registry hack. Move all old
 devices to the secondary port. Back up the registry (system.dat and
 user.dat in the Win95 directory). Start regedit and look for

 HKEY_LOCAL_MACHINE/System/CurrentControlSet/control/Services/hdc

 Here is where the entries for both ports should be located. In the
 second entry, change the key PortDriver from "ideatapi.mpd" to
 "esdi_506.pdr". This will cause the secondary channel to be handled by
 the default driver.


 8.17.  My ATAPI (IDE) CD-ROM driver won't recognize the CD-ROM.

 If the CD-ROM is connected to the secondary channel, make sure this
 channel is enabled. Some BIOSes will enable the channel only if one or
 more harddisks using this channel are defined in the setup; in that
 case, you can't avoid putting the CD on the same cable as a harddisk
 until you manage to get your BIOS updated.

 You may also get trouble if the CD-ROM is jumpered as slave and
 there's no master on its channel.

 Finally, the PIO mode (speed) used by the interface may be too high,
 especially if the CD-ROM shares its cable with a harddisk. Many
 interface drivers and BIOSes are not ATAPI-aware and don't take the
 CD-ROM into account when determining the maximum possible speed. The
 best fix is to move the CD-ROM to a different channel. Manually
 lowering the mode a notch or two should also help; this is usually
 done either through the BIOS setup or by passing options to a device
 driver in the CONFIG.SYS.


 9.  The user's net.resource guide

 There are a large number of FAQs and other resources on the net.
 Daniel Tauritz ([email protected]) no longer maintains his
 EIDE Mini-FAQ that contains a short but potentially useful list of
 available interfaces; it needs to be expanded and maintained---any
 takers?  There is another, technically oriented, FAQ on ATA-2, EIDE
! etcetera by Hale Landis ([email protected]).  All of this and more can
! be found on

 o  <ftp://ftp.wi.leidenuniv.nl/pub/faqs>

 o  <http://www.wi.leidenuniv.nl/ata>

 An incredible range of hardware related issues is addressed by the
 comp.sys.ibm.pc.hardware FAQ, maintained by Ralph Valentino
 ([email protected]). It can be found on comp.answers and the FAQ
 repository  <ftp://rtfm.mit.edu>.  It incorporates the world-famous
 'Jumper FAQ' <ftp://rtfm.mit.edu/pub/usenet/news.answers/pc-hardware-
 faq/part3>.

 On the tangential subject of Windows for Workgroups' 32-bit file
 access, Mike McCormick ([email protected]) has a good FAQ,
 posted on comp.os.ms-windows.windows.setup and many other groups. It
 can also be found on comp.answers and therefore on rtfm.mit.edu as
 well.

 Roedy Green's ([email protected]) "PCI EIDE controller flaws" FAQ is
 included with his EIDE test
 <ftp://garbo.uwasa.fi/pc/diskutil/eidete17.zip> program. The latter
 will test your system for the bugs that may arise if it has a CMD640
 or RZ1000 interface chip (used on many pre-Triton Intel Pentium
 boards, for instance). With either of these, your data is in danger
 every day you postpone reading this.

 The SimTel repository, the primary mirror of which is
 <ftp://ftp.coast.net/SimTel> or  <http://www.coast.net>, contains an
 immense number of useful programs (PD, freeware and shareware). A tiny
 selection, all from /SimTel/msdos/diskutil/:

 o  ideinf10.zip (will determine the properties of your
    harddisk(s)--not a benchmark).

 o  3drvs260.zip (gives support for 3 harddisks under DOS).

 o  dqwik211.zip (block mode driver).

 o  no_idle.zip (disables the auto-idle power saving feature of some
    harddrives).

 o  1seagate.zip (specs for *all* Seagate harddrives).

 o  wasted15.zip (shows wasted space due to cluster size).

 o  presz111.zip (nondestructive partition resizer).  r

    Note that the version numbers may have changed; also, you should
    preferably use a mirror close to you instead of the oakland site.


 A more manageable selection of useful utilities, drivers and
 information (this FAQ :-) can be found on

 o  <ftp://ftp.netcom.com/pub/cl/clau/ide_ata>
    (this represents the latest known location of Chung Y. Lau's famous
    wandering FTP site)

 o  <ftp://ftp.rahul.net/pub/lps/hard-disk>

    One of the most thorough low level harddisk benchmarks on Earth,
    Marnix Timmermans' Check Harddisk, is in beta. Check it out at
    <http://huizen.dds.nl/~checkhd>. Of course, the usual precautions
    with beta software apply.

 SimTel has a copy of TheRef[TM] by F. Robert Falbo, a giant hardware
 reference; it is rather outdated, but fortunately you can access a
 more up to date copy on the web at  <http://theref.c3d.rl.af.mil>.

 Frank Pikelner ([email protected]) has compiled an excellent, up to
 date list of >500MB harddisk and >4x CD-ROM drive specifications. You
 can access it through
 <http://www.cs.yorku.ca/People/frank/Welcome.html>.


 9.1.  The user's net.resource guide: I/O card drivers

! DriversHQ  <http://www.drivershq.com> is one of the most well known
! sources for drivers.
!
 In Finland, someone got the immensely useful idea of setting up a site
 with all kinds of IDE card drivers. You can find it on
 <ftp://ftp.funet.fi/pub/drivers/pc/disk/ide_ata>. If you can't find a
 driver here and manage to pick it up somewhere else, please upload it.
 Help making the net work.


 9.2.  The user's net.resource guide: hardware manufacturers

 A number of disk and controller manufacturers now have FTP and web
 sites; these are

 o  CMD
    <http://www.cmd.com>

 o  Conner
    <http://www.conner.com>

 o  Creative Labs
    <http://www.creaf.com>

    Among other, non EIDE related items, this site has drivers for the
    tertiary ATA/IDE port found on some SoundBlaster cards.

 o  DTC
    <http://www.datatechnology.com>

 o  Fujitsu
    <http://www.fujitsu.com>

 o  Hewlett-Packard
    <http://www.hp.com>

 o  IBM
    <http://www.storage.ibm.com/storage>
    <ftp://hddtech.millcomm.com>
    <http://www.pc.ibm.com> (PC Company)
 o  Iomega
    <http://www.iomega.com>

 o  Maxtor
    <http://www.maxtor.com>
    <ftp://ftp.maxtor.com>

    All files from their BBS are on the FTP site, including
    biosbnch.zip, a benchmarking utility; greendrv.zip, to set the
    sleep mode timer on 'green' drives; and the latest version of
    MaxBlast (OnTrack Disk Mananager) at
    <http://www.maxtor.com/readme/dm.html>.

 o  Promise
    <http://www.promise.com>
    <ftp://ftp.promise.com>
    [email protected]

    This site doesn't only contain drivers for Promise products but
    also for clone cards such as the VG4.

 o  Quantum
    <http://www.quantum.com>

    No official FTP site, although drivers to use Quantum's large
    harddisks with a non-translating BIOS can be found in
    <ftp://ftp.rahul.net/pub/lps/hard-disk/ide_dos.exe>. This is NOT an
    official Quantum support site and may disappear. This site contains
    miscellaneous storage-related programs and information too, not
    least the white papers on topics such as S.M.A.R.T., PRML channels,
    MR heads and more:  <http://www.quantum.com/products/whitepapers/>.

 o  Seagate
    <ftp://ftp.seagate.com>
    <http://www.seagate.com>

    This includes specifications of ALL Seagate drives, including
    detailed diagrams/pictures. The Seagate 32-bit disk access driver
    is available as <ftp://ftp/seagate.com/techsuppt/sea32bit.exe>;
    there is a FAQ on this driver at
    <http://www.seagate.com/techsuppt/win32drv.html>.  There is some
    general technical information available, on topics such as MR
    heads:  <http://www.seagate.com/new/sep96/mr_techp.shtml>.  A
    formatting utility for Seagate drives, sgatfmt4, is also available.

 o  Tekram
    <http://www.tekram.com>

 o  Tyan
    <http://www.tyan.com>

 o  Western Digital
    <ftp://ftp.wdc.com>
    <http://www.wdc.com>

    Many drivers and utilities, some of which won't work if you don't
    have at least one WD Caviar drive in your system. Goodies to be
    found: a good Windows FastDisk driver in /drivers/hdutil/win31.exe;
    a Windows helpfile explaining Enhanced IDE in /docs/eide.exe; a
    utility to examine the Enhanced DPT of your BIOS:
    /drivers/hdutil/chkbios.com.

 o  Winbond
    <http://ntwww.winbond.com.tw>

    Drivers are in the /DNLOAD/ directory.
    Pointers to sites offering software from other manufacturers would
    be appreciated.


 9.3.  The user's net.resource guide: software and BIOS houses


 o  AMI
    <http://www.megatrends.com>
    <ftp://ftp.megatrends.com>

 o  Award
    <http://www.award.com>

 o  IBM
    <http://www.ibm.com>
    <http://www.pc.ibm.com> (PC Company)
    <http://ps.boulder.ibm.com> (a really good link for OS/2 install
    and update info)
    <ftp://ftp.pc.ibm.com>

    Flash BIOS upgrades for the IBM ValuePoints are in /pub/valuepnt/.

 o  MicroHouse

    <http://www.microhouse.com>

    Drive specifications and jumper settings:
    <http://www.microhouse.com/mtl/vip/hd.htm>. EZDrive FAQs and files
    can be found on FAQ/ALLKEY.htm and FTP/EZ.htm respectively.

 o  Microsoft

    <ftp://ftp.microsoft.com>
    <http://www.microsoft.com>

    General Windows and DOS updates, fixes and Microsoft Knowledge Base
    articles can be found on the Microsoft FTP site.  Unfortunately,
    the structure of this site can hardly be called intuitive (which,
    some would argue, is characteristic of Microsoft products in
    general). The WWW site allows searches in the Knowledge Base, which
    is much more useful.

 o  MR BIOS
    <http://www.mrbios.com>
    [email protected]

    Information on MR BIOS bioses. Contains downloadable shareware BIOS
    images for some popular boards with Flash ROM as well.

 o  Novell
    <http://www.novell.com>
    <http://www.netware.com> (Netware info)

 o  OnTrack
    <http://www.ontrack.com>
    [email protected] (tech support)
    [email protected] (sales)

 o  Phoenix
    <http://www.ptltd.com>

 o  SCO
    <http://www.sco.com>


 o  Unicore software
    <http://www.unicore.com>

    Calls itself a BIOS solutions site. Contains, among other things,
    information about the LBA Pro BIOS add on board.

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