--- layout: page title: COMPAQ MS-DOS 1.11 permalink: /disks/pcx86/dos/compaq/1.11/ machines: - id: ibm5150-compaq111 type: pcx86 config: /devices/pcx86/machine/5150/mda/64kb/machine.xml resume: 1 autoMount: A: name: COMPAQ MS-DOS 1.11 B: name: None autoType: $date\r$time\r --- 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](#directory-of-compaq-ms-dos-111-diskette). {% 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](/modules/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](/disks/pcx86/dos/compaq/)]