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Filename Latest commit message Latest commit date
Jeff Parsons 8d5c618b78 Updated page on COMPAQ DOS 1.11
2017-06-26 07:33:03 -07:00
..
COMPAQ-DOS111.json Starting work on disambiguating PCjs the emulator from PCjs the project/website; the emulator will become PCx86 2016-05-16 20:55:32 -07:00
manifest.xml Started work on v1.35.1 2017-06-21 11:18:02 -07:00
README.md Updated page on COMPAQ DOS 1.11 2017-06-26 07:33:03 -07:00

README.md

layout title permalink machines
page COMPAQ MS-DOS 1.11 /disks/pcx86/dos/compaq/1.11/
id type config resume autoMount
ibm5150-compaq111 pcx86 /devices/pcx86/machine/5150/mda/64kb/machine.xml 1
A B
name
COMPAQ MS-DOS 1.11
name
None

COMPAQ MS-DOS 1.11

Released in 1983 by COMPAQ Computer Corp, this early version of MS-DOS displays the following messages on boot:

The COMPAQ Personal Computer DOS
Version 1.11


(C) Copyright COMPAQ Computer Corp. 1982
(C) Copyright Microsoft 1981, 82

A directory listing of the 320Kb diskette is provided below.

{% include machine.html id="ibm5150-compaq111" %}

Directory of COMPAQ MS-DOS 1.11 Diskette

 Volume in drive A has no label

Directory of A:\

IOSYS    COM      1998 05-13-83  12:00p
MSDOS    COM      6136 05-13-83  12:00p
COMMAND  COM      4959 05-13-83  12:00p
LINK     EXE     41856 05-13-83  12:00p
EDLIN    COM      2432 05-13-83  12:00p
SYS      COM       645 05-13-83  12:00p
DEBUG    COM      6619 05-13-83  12:00p
BASIC    COM       549 05-13-83  12:00p
BASICA   COM       547 05-13-83  12:00p
FORMAT   COM      3296 05-13-83  12:00p
EXE2BIN  EXE      1280 05-13-83  12:00p
DISKCOPY COM      1812 05-13-83  12:00p
DISKCOMP COM      1291 05-13-83  12:00p
MODE     COM      1800 05-13-83  12:00p
CHKDSK   COM      1720 05-13-83  12:00p
COMP     COM      1484 05-13-83  12:00p
WORDS             1242 05-13-83  12:00p
BASICA   EXE     54272 05-13-83  12:00p
TEST     EXE     18560 05-13-83  12:00p
DEMO     BAT        14 05-13-83  12:00p
DEMO     BAS      7808 05-13-83  12:00p
DEMO1    BAS     17920 05-13-83  12:00p
DEMO2    BAS     17792 05-13-83  12:00p
DEMO3    BAS     21120 05-13-83  12:00p
DEMO4    BAS      6528 05-13-83  12:00p
JUGGLER  DAT     16128 05-13-83  12:00p
USA      DAT     16128 05-13-83  12:00p
INTEREST BAS       384 05-13-83  12:00p
       28 file(s)     256320 bytes

Total files listed:
       28 file(s)     256320 bytes
                       53248 bytes free

The boot sector of the COMPAQ MS-DOS 1.11 disk image contains the following bytes:

00000000  fa bc e7 01 b8 c0 07 8e  d0 fb 8e d8 8e c0 33 c0  |..............3.|
00000010  cd 13 b8 01 02 bb 00 02  b9 04 00 33 d2 e8 8b 00  |...........3....|
00000020  eb 1c bb da 00 8a 07 3c  24 74 0c 53 b4 0e bb 07  |.......<$t.S....|
00000030  00 cd 10 5b 43 eb ee 33  c0 cd 16 eb c3 c3 fc 8b  |...[C..3........|
00000040  f3 bf c4 00 b9 0b 00 f3  a6 75 d7 83 c6 15 b9 0b  |.........u......|
00000050  00 f3 a6 75 cd b8 01 02  bb 00 02 b9 02 00 33 d2  |...u..........3.|
00000060  e8 48 00 8a 27 80 fc fe  be 26 01 74 0a 80 fc ff  |.H..'....&.t....|
00000070  74 02 eb ae be 3c 01 b8  60 00 50 07 8b 04 33 db  |t....<..`.P...3.|
00000080  8b 4c 02 8b 54 04 e8 22  00 8b 44 06 03 5c 08 8b  |.L..T.."..D..\..|
00000090  4c 0a 8b 54 0c e8 13 00  8b 44 0e 03 5c 10 8b 4c  |L..T.....D..\..L|
000000a0  12 8b 54 14 e8 04 00 ff  2e 52 01 bf 05 00 57 50  |..T......R....WP|
000000b0  cd 13 72 03 58 58 c3 33  c0 cd 13 58 5f 4f 75 ee  |..r.XX.3...X_Ou.|
000000c0  58 e9 5e ff 49 4f 53 59  53 20 20 20 43 4f 4d 4d  |X.^.IOSYS   COMM|
000000d0  53 44 4f 53 20 20 20 43  4f 4d 0a 0d 4e 6f 6e 2d  |SDOS   COM..Non-|
000000e0  53 79 73 74 65 6d 20 64  69 73 6b 20 6f 72 20 64  |System disk or d|
000000f0  69 73 6b 20 65 72 72 6f  72 0a 0d 52 65 70 6c 61  |isk error..Repla|
00000100  63 65 20 61 6e 64 20 73  74 72 69 6b 65 20 61 6e  |ce and strike an|
00000110  79 20 6b 65 79 20 77 68  65 6e 20 72 65 61 64 79  |y key when ready|
00000120  0a 0d 24 47 41 53 01 02  08 00 00 00 08 02 00 02  |..$GAS..........|
00000130  01 01 00 00 08 02 00 10  01 02 00 00 06 02 03 00  |................|
00000140  00 01 08 02 00 0c 01 01  00 00 03 02 00 10 01 01  |................|
00000150  00 01 00 00 60 00 28 43  29 43 6f 70 79 72 69 67  |....`.(C)Copyrig|
00000160  68 74 20 43 4f 4d 50 41  51 20 43 6f 6d 70 75 74  |ht COMPAQ Comput|
00000170  65 72 20 43 6f 72 70 6f  72 61 74 69 6f 6e 20 31  |er Corporation 1|
00000180  39 38 32 00 00 00 00 00  00 00 00 00 00 00 00 00  |982.............|
00000190  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001a0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001c0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

Consequently, the disk cannot be mounted by a modern operating system (e.g., macOS), because it lacks a proper BPB at offset 0x000B.

One solution is to use the --forceBPB option of the DiskDump utility, which creates a mountable disk image with the following boot sector modifications:

00000000  eb fe 90 50 43 4a 53 2e  4f 52 47 00 02 02 01 00  |...PCJS.ORG.....|
00000010  02 70 00 80 02 ff 01 00  08 00 02 00 00 00 00 00  |.p..............|
00000020  00 00 00 00 00 8a 07 3c  24 74 0c 53 b4 0e bb 07  |.......<$t.S....|

The following byte ranges are modified:

  • 0x0000-0x0002: 2-byte Intel x86 JMP instruction followed by 1-byte x86 NOP
  • 0x0003-0x000A: 8-byte OEM signature string (we use the fake "PCJS.ORG" OEM signature)
  • 0x000B-0x001D: 19-byte BPB describing a 320Kb diskette image with 8 sectors/track and 2 heads

Ordinarily, only the 19-byte BPB would be required, but it turns out that macOS won't mount the disk image unless the boot sector also begins with an Intel x86 JMP instruction. So the --forceBPB option updates all 30 bytes at the beginning of the boot sector, making the disk image mountable, but also rendering it unbootable -- which is OK if all you want to do is mount the image and copy files from it.

Here's a sample command sequence. Note that two DiskDump commands are required, because BPB modification only happens when converting an IMG file to a JSON file; the second command converts the JSON file back into a separate IMG file, preserving the original.

diskdump --disk=COMPAQ-DOS111.img --format=json --output=COMPAQ-DOS111-BPB.json
warning: BPB has been updated
327680-byte disk image saved to COMPAQ-DOS111-BPB.json
diskdump --disk=COMPAQ-DOS111.json --format=img --output=COMPAQ-DOS111-BPB.img
327680-byte disk image saved to COMPAQ-DOS111-BPB.img
chmod -w COMPAQ-DOS111-BPB.img
open COMPAQ-DOS111-BPB.img
mkdir COMPAQ-DOS111
cp -pr /Volumes/Untitled/ COMPAQ-DOS111

Another curiosity regarding this disk are the BASIC files. BASIC.COM and BASICA.COM are nothing more than tiny programs to load BASICA.EXE, a stand-alone version of BASIC that doesn't require any BASIC ROMs. And BASICA.EXE reports a version number that differs from the DOS version:

The COMPAQ Personal Computer BASIC
Version 1.13
(C) Copyright COMPAQ Computer Corp. 1983

[Return to COMPAQ MS-DOS Disks]