INTRODUCTION: THE LIBRARY CONCEPT
LU Command Conventions
SUMMARY OF LU OPERATIONS
Looking Over Existing Libraries: LDIR
Unpacking Entire Libraries: LUNLOAD
Selecting Libraries for Access: -O
Accessing Individual Members in Libraries: -L -E
Executing Programs in Libraries: LRUN
Building and Maintaining Libraries: -D -N -A -R
Finishing Up: -C -X
HANDLING SPECIAL SITUATIONS
Insuring Enough Memory Capacity: -B
Changing Drives and Switching Disks -- Precautions: -U
Staying Out of Trouble: Error Recovery
HOW LIBRARIES ARE ORGANIZED
:LU 3.00c NOTICE: Current Version Numbers dh: 84-01-15
===============================
This material applies to version 3.00 of LU.COM. Libraries created by
LU 3.00 can be read by all previous versions, and vice versa, but version
3.00 provides additional protection against undetected damage in files that
it creates and accesses.
Copyright 1982, 1983 by Gary P. Novosielski
All rights reserved.
Permission is hereby granted to copy and distribute this work for any
non-commercial purpose. Any use of this material for commercial advantage
without prior written consent of the copyright owner is prohibited. Please
report any problems and suggestions for enhancement to the author via
CompuServe CP-MIG or EMAIL posting to user number 70160,120; or by voice
phone to (201) 935-4087, evenings (eastern time) and weekends.
LU.HLP #3.00a first derived by Dennis E. Hamilton on 83-10-30.
next: What is a Library?
INTRODUCTION: THE LIBRARY CONCEPT
=================================
Library Utility (LU) is a system for storing several files as
components of one larger file. The resulting library (.LBR) file has its
own PRIVATE DIRECTORY.
Library files provide an additional dimension for the collection,
organization, and maintenance of your work. And because of CP/M disk-usage
rules, libraries tend to require less space than the same files stored
separately. In addition, libraries release CP/M disk-directory entries for
other uses, especially when the library holds many tiny files.
The maximum number of components -- library MEMBERS -- to be contained
in a library must be specified in advance. But the limit can be changed
later on when the library is re-organized.
Because library members are tucked away within other, larger, CP/M
files, they have to be extracted -- taken off the shelf -- in order to be
worked on or used by typical programs. The modifed results are also
restored to the library by using LU.
next: How LU Utilities Help
To make it easy to keep executable routines in libraries, the LRUN
utility is provided. LRUN is a small program which will execute your .COM-
file programs directly from the libraries which hold them. With LRUN, it
is not necessary to extract a program into a separate disk file before
execution.
Also, when material is packed in a library for convenient distribution
in one piece, there is another utility, LUNLOAD, which unpacks everything.
The basic library utility, LU, lets you start new libraries and
* Add new members to any specified library as long as there is room
* Extract copies of any members for use outside of the library
* Delete and rename members, as needed
* Reorganize a library to change its capacity and recover deleted space.
* Produce a directory to any library's current content.
The utility LDIR allows inspection of a library's directory and there
are variants, such as LRUNZ and LDIRZ, that support the extended
conventions of ZCPR2. There is a trend to have newer CP/M utilities also
accomodate .LBR files in their operation.
next: Why (not) to LU
WHY USE LIBRARIES?
* Libraries make more compact use of disk capacity.
* Libraries require fewer disk-directory entries, cutting down on
clutter and releasing entries for other purposes.
* Libraries aid the transfer of software from one system to another.
Only one file is distributed, reducing the chance of omissions and
oversights.
* Libraries allow more flexible choice of file names, since uniqueness
is important only within each separate library.
WHAT IS THE PRICE?
* Files within a library are unavailable to "normal" programs. A file
will usually have to be extracted from the library before its data can
be used.
* When a library member is deleted, space is not automatically released
for re-use. The library must be explicitly re-organized in order to
recover the directory entry and space of a deleted member.
On balance, LU lends tremendous support for disciplined organization and
maintenance of your programs and data.
::LUCMD LU COMMAND CONVENTIONS
======================
LU is guided by a miniature language of COMMAND-STRING OPERATIONS. If
you are unfamiliar with the notation and conventions of this tidy little
language, you should locate the file LUCMD.HLP and review it using the
command
a>HELP LUCMD
There you will find out about
* Different ways of initiating LU and supplying command string
* General format of the command-string: use of spacing and line-breaks
* Notation for specifying operations
* Notation for selecting files
* LU place-keeping and default assumptions
: SUMMARY OF LU OPERATIONS
========================
OP OPERAND(S) OPERATION
-A file-spec ... Add the selected files to the open library.
-B s Set the buffer size to s (1 to 255) records.
-C Close any library that is presently open.
-D file-spec ... Delete selected files in the open library.
-E file-spec ... Extract selected files from the open library.
-L List a directory for the open library.
-N new=old ... Rename selected files in the open library.
-O file-spec Close any open library and open the specified one.
If the library does not exist, one will be created.
-R Re-organize the open library.
-U [u/][d:] Close, change to the given defaults, and reset the disk
-X Exit from LU after the current line is processed.
An empty command-stream line implies -X.
In a pinch, you can ABORT processing with ^C at the input prompt. This
leaves the open library directory as it was at the end of the last -C, -O,
-A, -R or -U operation. Do -L and cleanup as needed, following with -R.
::LDIR LOOKING OVER EXISTING LIBRARIES
===============================
When all you want to do is find out, or remind yourself, what is IN a
library, the LDIR utility (and LDIRZ, its ZCPR2 counterpart) are just the
ticket.
Typically, LDIR lets you examine a library via a specification of the
form
d>LDIR library ...
where library identifies the library that you want to know about
Command "d>LDIR COMMAND will, with this convention, show everything
that is known about files in library COMMAND.LBR. For specific information
about the version of LDIR available on this system, you should locate the
file LDIR.HLP for review via
When a library file is used as a "carton" for a group of files being
distributed together, there is an easy way to make separate copies of its
entire content:
a>b:LUNLOAD c:library
will, for example, "unpack" the files of c:library onto the a: disk.
Precise operation of the currently-supported LUNLOAD version is
specified in the file LUNLOAD.HLP. Locate that file and review it via
a>HELP LUNLOAD
Note that the functions of LUNLOAD can be obtained with LU, but not so
directly. Also, LUNLOAD may succeed where LU is unable to obtain enough
storage for operation.
: SELECTING THE LIBRARY TO ACCESS
===============================
Unless you are willing to use a library of name LIBRARY.LBR, you need
to specify the actual library to use with an OPEN command-string sequence:
-O library
* Any library file that is already open will be closed.
* The default u/, d:, and file type .LBR are used to complete the
library filespec, as necessary.
* If the specified library exists, it is opened for use as the
current library.
* If the specified library does not exist, a NEW LIBRARY is
created. LU will request information from the console in order
to allocate a library with sufficient capacity for the intended
members. (Refer to the information on "Building and Maintaining
Libraries" for further treatment of this case.)
: ACCESSING MATERIAL IN LIBRARIES
===============================
In addition to using an LDIR utility, you can review the contents of
the currently-open library using the LU command-string
-L
for "LISTING" the library directory while LU is operating.
When you need to work with separate copies of members, the LU command-
string
-E filespec ...
"EXTRACTS" copies of those members selected by each following filespec.
Every library member that matches a single filespec is copied. The copy
has the same filename as the original member.
WHERE copies go is determined by the u/d: determined for each
filespec. (Read-only files cannot be overwritten in this way, however.)
next: Understanding the Library Directory
LIBRARY DIRECTORY ENTRIES
The information presented in response to the -L operation consists of
the following:
filename for each current member (and DIRECTORY for the
library's own directory space)
index of the library record where the member starts (needed
by the library utilities in finding the data)
size of the member in CP/M RECORDS (128-byte units). Divide
by 8 for size in 1k units.
CRC a special kind of check code carried for each member
and used to help detect the presence of damage to the
library
In addition to this information about the "active" entries, LU
indicates how many members can be added and how many deleted members and
deleted records are cluttering the library. (The waste for deleted members
is eliminated by reorganizing with -R.)
::LRUN EXECUTING PROGRAMS IN LIBRARIES
===============================
Usually, library data that is going to be used by a program must be
extracted first.
But programs that are kept in libraries can be executed without having
to be removed first. This is accomplished by use of the LRUN utility or
one of its kin. For more information on the current release of LRUN,
locate the file LRUN.HLP and review it by
a>HELP LRUN
::LBRBUILD BUILDING AND MAINTAINING LIBRARIES
==================================
With a set of well-organized libraries in hand, most access will be in
order to USE the material that the library contains. LU supports this
effort as do the more-specialized utilities such as LDIR and LRUN.
But LU is also designed to be used in constructing and modifying new
libraries of your own material.
Once you are comfortable with the general concepts of LBR-usage and LU
operation, the additional provisions for building libraries will be easy to
grasp. The file LBRBUILD.HLP describes these additional, advanced
features. You can review it with the command
a>HELP LBRBUILD
: FINISHING UP
============
When operations on a library have been finished, there are three ways
to move on. Command-string
-C will "CLOSE" any currently-open library, if there is one,
making sure that all changes are reflected in its directory.
There is now no current directory.
-X has the same effect as -C, followed by termination of LU,
UPON COMPLETION OF THE CURRENT COMMAND-STRING LINE
The end of the command-string, or the occurence of an empty line
within it, has the same effect as the -X operation.
: HANDLING SPECIAL SITUATIONS
===========================
There are three areas where operation of LU can become tricky. First,
it is possible to exceed the capacity of your computer in trying to
manipulate a library with allowance for a great number of members. The LU
operation
-B nn
may be used to obtain relief in some cases.
Also, when it is necessary to change disks in the course of working on
a library, there are some special precautions involved. The LU operation
-U [u/][d:]
helps to reset things properly after changing disks, when possible at all.
Finally, use of .LBR files puts a lot of eggs in one basket. There
are some useful tips available for making sure that the .LBR does not
go the way of Humpty Dumpty.
::LBRSIZE INSURING ENOUGH MEMORY CAPACITY
===============================
Besides the space taken for program and housekeeping during LU opera-
tion, there are two large data buffers: one for DISK ACCESS and one for
LIBRARY DIRECTORY.
If your CP/M system has a very large TPA (transient program area),
there is not much to worry about. But you should still review the
capacity rules to get a sense of the headroom available.
Command string: -B nn
changes the disk-access buffer allocation to nn records as a way to
increase performance or to accomodate a larger directory instead. Complete
details about this and related adjustments are found in the file
LBRSIZE.HLP. You should review this file with command
a>HELP LBRSIZE
: CHANGING DRIVES AND SWITCHING DISKS
NEVER REMOVE OR CHANGE ANY DISK ON WHICH THERE IS AN OPEN LIBRARY. LU
carries information about the library in computer memory. This information
is not recorded on the disk until the last possible moment. If you change
a disk without giving LU a chance to bring the disk and memory copies of
data into agreement, OPERATION WILL FAIL. THERE IS THE POSSIBILITY OF
DAMAGE TO MATERIAL RECORDED ON ONE OR MORE DISKS.
The way to guarantee that all disks are in a "clean" condition is to
CLOSE THE CURRENT LIBRARY with the -C operation. (If you are all done, -X
does this too.) You can now remove and replace disks as desired.
To continue (when there is no CON: redirection), try operation
-U filespec ...
to "log" into the new u/ and d: defaults specified in the following
filespec(s). The filespecs should have only the u/ and d: fields, as
needed. IF CONDITIONS ARE SAFE for -U, LU will close any current library,
reset the disk system, and change the default para
meters. You can now
(re)-open the library to use next.
::LUTIPS STAYING OUT OF TROUBLE: ERROR RECOVERY
======================================
When you are building, modifying, and re-organizing libraries, a
n
umber of problems can "spoil" an entire library's worth of work. Tips on
protecting your investment in library-stored material have been compiled in
the file LUTIPS.HLP. The file can be reviewed, once located, using command
a>HELP LUTIPS
::LBR HOW LIBRARIES ARE ORGANIZED
===========================
.LBR files are organized in a special format that is only intelligible
to special-purpose utilities such as LU, LDIR, and LRUN. So that
specialists can incorporate .LBR access into other utilities, the format
rules have been compiled in the file LBR.HLP. If you have access to this
file, you can review it with the command
a>HELP LBR
:
:
:
: LU.HLP #3.00 was first created on 83-10-30 by Dennis E. Hamilton.
