Contents
========

* PC BIOS hard disk parameter tables
* Format of the table
* 1st Reference
* 3rd Reference
* Olivetti-386sx16
* IBM
* IBM PC 330 (6577)
* AMI-286
* Phoenix-A368SX
* Phoenix 286 ROM BIOS Version 3.01
* Award-486
* Compaq Deskpro 386
* The number of sectors per track
* Hard disk capacities over the years
* Capacity Limits

PC BIOS hard disk parameter tables
==================================

In ancient times one had to specify the parameters of one's MFM or
RLL disk to the BIOS, or add them as user-defined type (often type
47 or 48).

Often, the table with these parameters is found at 0xe400 (0162000).
Below the results found for five different BIOSes and two programs to
investigate other machines.

See also:

* dump.awk, which writes the BIOS area to dump.hex
* dtable.awk, which prints the BIOS disk type table from dump.hex

Adapted FROM: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-1.html>

Format of the table
===================

The table is a series of 16-byte entries with the following structure.

struct hdtype {
short cylinders;
char heads;
/* XT: 1-8,
* AT: 1-16,
* ESDI: 1-32
*/
short reduced_write_current_starting_cyl; /* XT only */
short pre_compensation_starting_cyl;
char max_ECC_data_burst_length; /* XT only */
char control; /* AT and later */
/* bit 7: 1 - do not retry on access error
* bit 6: 1 - do not retry on ECC error
* bit 5: 1 - there is a bad block map past the last cylinder
* bit 4: 0
* bit 3: 1 - more than 8 heads on the drive
* bit 2: 0 - no reset
* bit 1: 0 - disable IRQ
* bit 0: 0
*/
char normal_timeout; /* XT only */
char formatting_timeout; /* XT only */
char drive_check_timeout; /* XT only */
short landing_zone; /* AT and later */
char sectors_per_track; /* AT and later */
char unused;
};

Unused fields are zero.

The pointer to the parameters for drive 0 is found at the location
for interrupt 0x41, at 0x0104. The pointer to the parameters for
drive 1 is found at the location for interrupt 0x46, at 0x0118.

SCSI and ESDI drives do not use this table, and have drive type 0.

Adapted FROM: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-2.html>

1st Reference
=============

With the IBM AT and early AT clones, CHS figures never appeared on
the screen. Armed with the CHS figures (and other figures [e.g. WPC])
you would consult the technical manual for your computer. That would
give you a drive type number to enter via your SETUP.EXE

For the first 23 drive types, most clones emulated the 23 drive types
defined in the IBM AT (that helped the clone makers to justify their
"100% IBM compatible" statement).

Thus try using a drive type using the following IBM AT list:

The first version of the IBM/AT had a ROM BIOS that supported 15
drive types:

Type Cyl Hd WPC Ctrl LZ Sec Cap (Mb)
---- ---- -- ----- ---- ---- --- --------
1 306 4 128 00h 305 17 10.2
2 615 4 300 00h 615 17 20.4
3 615 6 300 00h 615 17 30.6
4 940 8 512 00h 940 17 62.4
5 940 6 512 00h 940 17 46.8
6 615 4 65535 00h 615 17 20.4
7 462 8 256 00h 511 17 30.7
8 733 5 65535 00h 733 17 30.4
9 900 15 65535 08h 901 17 112
10 820 3 65535 00h 820 17 20.4
11 855 5 65535 00h 855 17 35.5
12 855 7 65535 00h 855 17 49.7
13 306 8 128 00h 319 17 20.3
14 733 7 65535 00h 733 17 42.6
15 0 0 0 00h 0 0 Reserved

The second version of the IBM/AT extended the support to 22 different
types:

Type Cyl Hd WPC Ctrl LZ Sec Cap (Mb)
---- ---- -- ----- ---- ---- --- --------
16 612 4 0 00h 663 17 20.3
17 977 5 300 00h 977 17 40.6
18 977 7 65535 00h 977 17 56.8
19 1024 7 512 00h 1023 17 59.5
20 733 5 300 00h 732 17 30.4
21 733 7 300 00h 732 17 42.6
22 733 5 300 00h 733 17 30.4

The third and final version of the IBM/AT extended the support to 23
different types:

Type Cyl Hd WPC Ctrl LZ Sec Cap (Mb)
---- ---- -- ----- ---- ---- --- --------
23 306 4 0 00h 336 17 10.2

From: <https://vintage-pc.tripod.com/types.html>

3rd Reference
=============

Type Hd Sec Cyl Pre-comp LZ Cap (Mb)
---- -- --- ---- -------- ---- --------
1 4 17 306 128 305 10
2 4 17 615 300 615 21
3 6 17 615 300 615 32
4 8 17 940 512 940 65
5 6 17 940 512 940 65
6 4 17 615 no 615 21
7 8 17 462 256 511 32
8 5 17 733 no 733 31
9 15 17 900 no 901 117
10 3 17 820 no 820 21
11 5 17 855 no 855 37
12 7 17 855 no 855 52
13 8 17 306 128 319 21
14 7 17 733 no 733 44
16 4 17 612 all 663 21
17 5 17 977 300 977 42
18 7 17 977 no 977 59
19 7 17 1024 512 1023 62
20 5 17 733 300 732 31
21 7 17 733 300 732 44
22 5 17 733 300 733 31
23 4 17 306 all 336 10
24 5 17 977 no 976 42
26 7 17 1024 no 1023 62
27 11 17 1024 no 1023 98
28 15 17 1024 no 1023 133
29 8 17 1024 no 1023 71
30 11 17 1024 no 1023 98
32 9 17 925 no 926 72
33 10 17 1024 no 1023 89
34 12 17 1024 no 1023 106
35 13 17 1024 no 1023 115
36 14 17 1024 no 1023 124
37 2 17 1024 no 1023 17
38 16 17 1024 no 1023 142
40 6 17 820 no 820 42
41 5 17 1024 1024 1023 44
42 8 17 615 512 615 42
43 7 17 1186 no 1186 72

From: <https://vintage-pc.tripod.com/types.html>

Olivetti-386sx16
================

Type Cyl. Head Sect. Write Land
p-comp Zone
-------------------------------------
1 306 4 17 128 305
2 615 4 17 256 700
3 925 5 17 128 924
4 697 5 17 128 696
5 1024 9 17 -1 1023
6 820 6 17 256 819
7 615 8 17 128 664
8 981 5 17 -1 980
9 981 5 17 128 980
10 1024 6 17 -1 1023
11 925 7 17 128 924
12 1024 8 17 -1 1023
13 925 9 17 128 924
14 1024 5 17 -1 1023
15 -- reserved --
16 612 4 17 128 656
17 612 4 17 -1 663
18 820 6 17 -1 819
19 872 6 17 0 871
20 612 4 17 0 663
21 820 6 26 -1 819
22 820 6 26 128 819
23 615 8 26 384 664
24 820 10 34 -1 822
25 1021 8 34 -1 1023
26 1021 4 34 -1 1023
27 823 10 17 512 822
28 615 8 17 512 614
29 615 8 26 512 614
30 981 5 26 -1 980
31 635 4 33 -1 639
32 615 4 17 -1 614
33 776 8 33 -1 775
34 745 4 28 -1 744
35 965 5 17 -1 964
36 805 4 26 -1 804
37 776 8 33 -1 775
38 -- not used or user defined --

From: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-3.html>

IBM
===

The original AT BIOS (01/10/84) has types 1-14. Later versions also
have types 16-N with N=23 (AT, 11/15/85) or N=24 (XT), or N=33, or
N=44, At the end of the table one usually had one or two or three
user-defined types.

Type Cyl. Head Sect. Write Land
p-comp Zone
-------------------------------------
1 306 4 17 128 305
2 615 4 17 300 615
3 615 6 17 300 615
4 940 8 17 512 940
5 940 6 17 512 940
6 615 4 17 -1 615
7 462 8 17 256 511
8 733 5 17 -1 733
9 900 15 17 -1 901
10 820 3 17 -1 820
11 855 5 17 -1 855
12 855 7 17 -1 855
13 306 8 17 128 319
14 733 7 17 -1 733
15 -- reserved --
16 612 4 17 0 663
17 977 5 17 300 977
18 977 7 17 -1 977
19 1024 7 17 512 1023
20 733 5 17 300 732
21 733 7 17 300 732
22 733 5 17 300 733
23 306 4 17 0 336
24 612 4 17 305 663
25 306 4 17 -1 340
26 612 4 17 -1 670
27 698 7 17 300 732
28 976 5 17 488 977
29 306 4 17 0 340
30 611 4 17 306 663
31 732 7 17 300 732
32 1023 5 17 -1 1023
33 614 4 25 -1 663
34 775 2 27 -1 900
35 921 2 33 -1 1000
36 402 4 26 -1 460
37 580 6 26 -1 640
38 845 2 36 -1 1023
39 769 3 36 -1 1023
40 531 4 39 -1 532
41 577 2 36 -1 1023
42 654 2 32 -1 674
43 923 5 36 -1 1023
44 531 8 39 -1 532
45 -- not used or user defined --
46 -- not used or user defined --
47 -- not used or user defined --

From: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-3.html>

IBM PC 330 (6577)
=================

dtable.awk output from a 1999 era IBM PC.

Type Cyl. Head Sect. Write Land Cap (MB)
p-comp Zone
-----------------------------------------------
1 306 4 17 128 305 10
2 615 4 17 300 615 20
3 615 6 17 300 615 30
4 940 8 17 512 940 62
5 940 6 17 512 940 46
6 615 4 17 -1 615 20
7 462 8 17 256 511 30
8 733 5 17 -1 733 30
9 900 15 17 -1 901 112
10 820 3 17 -1 820 20
11 855 5 17 -1 855 35
12 855 7 17 -1 855 49
13 306 8 17 128 319 20
14 733 7 17 -1 733 42
15 -- not used or user defined --
16 612 4 17 0 663 20
17 977 5 17 300 977 40
18 977 7 17 -1 977 56
19 1024 7 17 512 1023 59
20 733 5 17 300 732 30
21 733 7 17 300 732 42
22 733 5 17 300 733 30
23 1024 5 17 -1 1023 42
24 925 9 17 -1 925 69
25 699 7 17 256 700 40
26 1024 4 17 -1 1023 34
27 1024 5 17 -1 1023 42
28 1024 8 17 -1 1023 68
29 512 8 17 256 512 34
30 615 2 17 615 615 10
31 989 5 17 0 989 41
32 1020 15 17 -1 1024 127
33 615 4 26 -1 615 31
34 820 6 26 -1 820 62
35 1024 9 17 1024 1024 76
36 1024 5 17 512 1024 42
37 1024 5 26 512 1024 65
38 823 10 17 256 824 68
39 615 4 17 128 664 20
40 496 246 17 3588 0 1012
41 917 15 17 -1 918 114
42 1023 15 17 -1 1024 127
43 823 10 17 512 823 68
44 1027 255 63 0 3 8056
45 -- not used or user defined --
46 -- not used or user defined --
47 -- not used or user defined --

AMI-286
=======

Type Cyl. Head Sect. Write Land
p-comp Zone
-------------------------------------
1 306 4 17 128 305
2 615 4 17 300 615
3 615 6 17 300 615
4 940 8 17 512 940
5 940 6 17 512 940
6 615 4 17 -1 615
7 462 8 17 256 511
8 733 5 17 -1 733
9 900 15 17 -1 901
10 820 3 17 -1 820
11 855 5 17 -1 855
12 855 7 17 -1 855
13 306 8 17 128 319
14 733 7 17 -1 733
15 -- reserved --
16 612 4 17 0 663
17 977 5 17 300 977
18 977 7 17 -1 977
19 1024 7 17 512 1023
20 733 5 17 300 732
21 733 7 17 300 732
22 733 5 17 300 733
23 306 4 17 0 336
24 925 7 17 0 925
25 925 9 17 -1 925
26 754 7 17 754 754
27 754 11 17 -1 754
28 699 7 17 256 699
29 823 10 17 -1 823
30 918 7 17 918 918
31 1024 11 17 -1 1024
32 1024 15 17 -1 1024
33 1024 5 17 1024 1024
34 612 2 17 128 612
35 1024 9 17 -1 1024
36 1024 8 17 512 1024
37 615 8 17 128 615
38 987 3 17 987 987
39 987 7 17 987 987
40 820 6 17 820 820
41 977 5 17 977 977
42 981 5 17 981 981
43 830 7 17 512 830
44 830 10 17 -1 830
45 917 15 17 -1 918
46 1224 15 17 -1 1223
47 -- not used or user defined --

From: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-3.html>

Phoenix-A368SX
==============

Type Cyl. Head Sect. Write Land
p-comp Zone
-------------------------------------
1 306 4 17 128 305
2 615 4 17 300 615
3 615 6 17 300 615
4 940 8 17 512 940
5 940 6 17 512 940
6 615 4 17 -1 615
7 462 8 17 256 511
8 733 5 17 -1 733
9 900 15 17 -1 901
10 820 3 17 -1 820
11 855 5 17 -1 855
12 855 7 17 -1 855
13 306 8 17 128 319
14 733 7 17 -1 733
15 -- reserved --
16 612 4 17 0 663
17 977 5 17 300 977
18 977 7 17 -1 977
19 1024 7 17 512 1023
20 733 5 17 300 732
21 733 7 17 300 732
22 733 5 17 300 733
23 306 4 17 0 336
24 1004 12 17 -1 1005
25 683 16 38 -1 684
26 1024 4 17 -1 1023
27 1024 5 17 -1 1023
28 1024 8 17 -1 1023
29 762 8 39 -1 763
30 814 9 32 -1 815
31 989 5 17 0 989
32 1020 15 17 -1 1024
33 968 10 34 -1 969
34 873 13 36 -1 874
35 1024 9 17 1024 1024
36 1024 5 17 512 1024
37 1024 5 26 512 1024
38 823 10 17 256 824
39 980 10 17 -1 981
40 615 8 17 128 664
41 917 15 17 -1 918
42 1023 15 17 -1 1024
43 823 10 17 512 823
44 820 6 17 -1 820
45 1024 5 17 -1 1023
46 925 9 17 -1 925
47 699 7 17 256 700
48 -- user defined --

From: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-3.html>

Phoenix 286 ROM BIOS Version 3.01
=================================

Type Cyl. Head Sect. Write Land
p-comp Zone
-------------------------------------
1 306 4 17 128 305
2 615 4 17 300 638
3 615 6 17 300 615
4 940 8 17 512 940
5 940 6 17 512 940
6 615 4 17 -1 615
7 462 8 17 256 511
8 733 5 17 -1 733
9 900 15 17 -1 901
10 820 3 17 -1 820
11 855 5 17 -1 855
12 855 7 17 -1 855
13 306 8 17 128 319
14 733 7 17 -1 733
15 0 0 0 0 0
16 612 4 17 0 633
17 977 5 17 300 977
18 977 7 17 -1 977
19 1024 7 17 512 1023
20 733 5 17 300 732
21 733 7 17 300 733
22 733 5 17 300 733
23 0 0 0 0 0
...
35 0 0 0 0 0
36 1024 5 17 512 1024
37 830 10 17 -1 830
38 823 10 17 256 824
39 615 4 17 128 664
40 615 8 17 128 664
41 917 15 17 -1 918
42 1023 15 17 -1 1024
43 823 10 17 512 823
44 820 6 17 -1 820
45 1024 8 17 -1 1024
46 925 9 17 -1 925
47 1024 5 17 -1 1024

From: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-3.html>

Award-486
=========

Type Cyl. Head Sect Write Land Example
p-comp Zone Models
------------------------------------------------------------------
1 306 4 17 128 305 TEAC SD510, MMI 112, 5412
2 615 4 17 300 615 Seagate ST225, ST4026
3 615 6 17 300 615
4 940 8 17 512 940
5 940 6 17 512 940
6 615 4 17 -1 615 Seagate ST125, Tandon TM262
7 462 8 17 256 511
8 733 5 17 -1 733 Tandon TM 703
9 900 15 17 -1 901
10 820 3 17 -1 820
11 855 5 17 -1 855
12 855 7 17 -1 855
13 306 8 17 128 319 Disctron 526, MMI M125
14 733 7 17 -1 733
15 -- reserved --
16 612 4 17 0 663 Microscience HH725,
Syquest 3250, 3425
17 977 5 17 300 977
18 977 7 17 -1 977
19 1024 7 17 512 1023
20 733 5 17 300 732
21 733 7 17 300 732
22 733 5 17 300 733 Seagate ST4038
23 306 4 17 0 336
24 977 5 17 -1 976 Seagate ST4051
25 1024 9 17 -1 1023 Seagate ST4096
26 1224 7 17 -1 1223 Maxtor 2085
27 1224 11 17 -1 1223 Maxtor 2140, Priam S14
28 1224 15 17 -1 1223 Maxtor 2190, Priam S19
29 1024 8 17 -1 1023 Maxtor 1085, Micropolis 1325
30 1024 11 17 -1 1023 Maxtor 1105, 1120, 4780
31 918 11 17 -1 1023 Maxtor 1170
32 925 9 17 -1 926 CDC 9415
33 1024 10 17 -1 1023
34 1024 12 17 -1 1023
35 1024 13 17 -1 1023
36 1024 14 17 -1 1023
37 1024 2 17 -1 1023
38 1024 16 17 -1 1023
39 918 15 17 -1 1023 Maxtor 1140, 4380
40 820 6 17 -1 820 Seagate ST251
41 1024 5 17 -1 1023 Seagate 4053,
Miniscribe 3053/6053
42 1024 5 26 -1 1023 Miniscribe 3053/6053 RLL
43 809 6 17 -1 852 Miniscribe 3650
44 809 6 26 -1 852 Miniscribe 3675 RLL
45 776 8 33 -1 775 Conner CP3104
46 684 16 38 -1 685 Conner CP3204
47 -- user defined --

From: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-3.html>

Compaq Deskpro 386
==================

Type Cyl. Head Sect. Write Land
p-comp Zone
-------------------------------------
1 306 4 17 128 305
2 615 4 17 128 638
3 615 6 17 128 615
4 1024 8 17 512 1023
5 940 6 17 512 939
6 697 5 17 128 696
7 462 8 17 256 511
8 925 5 17 128 924
9 900 15 17 -1 899
10 980 5 17 -1 980
11 925 7 17 128 924
12 925 9 17 128 924
13 612 8 17 256 611
14 980 4 17 128 980
15 -- reserved --
16 612 4 17 0 612
17 980 5 17 128 980
18 966 6 17 128 966
19 1023 8 17 -1 1023
20 733 5 17 256 732
21 733 7 17 256 732
22 805 6 17 -1 805
23 924 8 17 -1 924
24 966 14 17 -1 966
25 966 16 17 -1 966
26 1023 14 17 -1 1023
27 966 10 17 -1 966
28 748 16 17 -1 748
29 805 6 26 -1 805
30 615 4 25 128 615
31 615 8 25 128 615
32 905 9 25 128 905
33 748 8 34 -1 748
34 966 7 34 -1 966
35 966 8 34 -1 966
36 966 9 34 -1 966
37 966 5 34 -1 966
38 611 16 63 -1 611
39 1023 11 33 -1 1023
40 1023 15 34 -1 1023
41 1023 15 33 -1 1023
42 1023 16 63 -1 1023
43 805 4 26 -1 805
44 805 2 26 -1 805
45 748 8 33 -1 748
46 748 6 33 -1 748
47 966 5 25 128 966

From: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-3.html>

The number of sectors per track
===============================

We look at the number of sectors per track for these old drives, and
give examples from the seagate archive.

Almost all MFM drives have 17 sectors per track, like the
prototypical ST506, with 512 bytes per sector. The st419 had
32 sectors per track (geometry C/H/S=306/6/32, total capacity
15.0 MB). Maybe also 26 occurs.

Almost all RLL drives have 26 sectors per track with 512 bytes per
sector. (And these may well be the same drives that have 17 sectors
per track with MFM; indeed, RLL is a denser recording technique.) The
st225r had 31 sectors per track (geometry C/H/S=667/2/31, total
capacity 21.2 MB), just like the st250r (with 4 heads, twice as
large). Also 25 occurs.

ESDI drives can be soft sectored or hard sectored dependent upon the
controller used. Hard sectored controllers use 34 sectors per track
and soft sectored controllers can use 34, 35 or 36 sectors per track.
The drive must be jumpered for hard/soft sectoring to match the
constraints of the controller. (Here we see the first traces of the
"translation" disease: For systems with BIOS types that only support
17 sectors per track, the controller may be jumpered for translation
mode. In ESDI translation mode, the controller converts the drive to
a 17 sectors per track drive by logically doubling the number of
physical heads.) A few other values occur: 53 (e.g. the Seagate
st4766e or the Maxtor 9780E)), 54 (e.g. the st2182e), 63 (e.g. the
st4767e), 71 (e.g. the Maxtor XT 8800E). Also 26 and 72 occur.

IDE (ATA) drives usually have a variable number of sectors per track
and here we see that one has to use a geometry that is unrelated to
the actual hardware. Sometimes only a single geometry (specified by
the manufacturer) will work; usually any geometry that multiplies to
the right total capacity will be OK.

Thus, we see a great variety of values for the number of sectors per
track here, and it is not always clear in which cases this is an
obligatory value. Examples: 16 (e.g. the st9100ag), 17 (e.g. the
st325ax), 24 (e.g. the st9190ag), 27 (e.g. the st280a), 28 (e.g. the
Maxtor 8051A), 29 (e.g. the st1162a), 32 (e.g. the st9051a), 34 (e.g.
the st3195a), 35 (e.g. the st3283a), 36 (e.g. the st1239a), 38 (e.g.
the st3211a), 47 (e.g. the st9150ag), 50 (e.g. the st3291a), 51 (e.g.
the st9385ag), 52 (e.g. the st9240ag), 53 (e.g. the st3271a), 55
(e.g. the st2274a), 56 (e.g. the st2383a), 59 (e.g. the st9550ag), 60
(e.g. the st9300ag), 61 (e.g. the st1401a), 62 (e.g. the st3385a), 63
(e.g. the st3270a).

Of course, all modern drives use 63 sectors per track.

From: <https://aeb.win.tue.nl/linux/hdtypes/hdtypes-4.html>

Hard disk capacities over the years
===================================

Year: 1983 to 1986
Capacity: 10 to 20 MB
Notes:
MFM encoding. Hard disk was connected to a hard disk controller
card (8-bit ISA). "Hard cards" arrived late 1985 (hard disk
physically mounted on a long controller card in the ISA slot).
First IDE interface created in 1986 (ATA-1).

Year: 1987 to 1989
Capacity: 20 to 65 MB
Notes:
MFM or RLL encoding. Hard disk was connected to a hard disk
controller card (8-bit or 16-bit ISA).

Year: 1990
Capacity: 20 to 85 MB
Notes:
MFM or RLL encoding is still common, but some IDE drives start to
arrive.

Year: 1991
Capacity: 40 to 120 MB
Notes: ATA (IDE) hard disks become more commonplace.

Year: 1992
Capacity: 40 to 160 MB
Notes: IDE hard disks taking over. MFM/RLL not seen anymore.

Year: 1993
Capacity: 40 to 300 MB
Notes:
IDE hard disks supporting ATA Mode 4 standard. Motherboards start
to appear with embedded IDE sockets, so no need for a separate host
adapter card using up an expansion slot.

Year: 1994
Capacity: 300 to 500 MB
Notes:
EIDE (Enhanced IDE) arrives - some manufacturers make their own
versions called "Fast ATA" or "Fast ATA-2".

Year: 1995
Capacity: 300 MB to 1 GB
Notes:
Motherboards now almost universally come as standard with
IDE sockets.

Year: 1996
Capacity: 300 MB to 1.5 GB
Notes:
Introduced LBA (Logical Block Addressing) for larger drives up to
8.4 GB

Year: 1997
Capacity: 300 MB to 2 GB
Notes:
ATA-3 arrived, with 16.6 Mbps (megabits per second). Hard disks
started to arrive with S.M.A.R.T. for hard disk health monitoring.

From: <https://dosdays.co.uk/topics/hard_disks.php>

Capacity Limits
===============

Limit Cyl Hd Sec Maximum Capacity
--------------- ------ --- --- ------------------------
BIOS 1,024 255 63 7.84 GB, aka "8 GB"
ATA Interface 65,536 16 255 127.5 GB, aka "128 GB"
Hard Disk 1,024 16 63 504 MB
DOS 2.x 16 MB
DOS 3.x 32 MB partition size
DOS 4.0 to 6.22 2 GB
DOS 7.1 124.5 GB

From: <https://dosdays.co.uk/topics/hard_disks.php>