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Updated some DOS READMEs and made the onReset handler honor the running state of the CPU

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This commit is contained in:
Jeff Parsons 2017-06-29 15:27:22 -07:00 • committed by Jeff Parsons
commit 85b3aade36
11 changed files with 931 additions and 911 deletions
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55
disks/pcx86/dos/compaq/1.11/README.md
View file

@ -5,7 +5,7 @@ permalink: /disks/pcx86/dos/compaq/1.11/
machines:
- id: ibm5150-compaq111
type: pcx86
config: /devices/pcx86/machine/5150/mda/64kb/machine.xml
config: /devices/pcx86/machine/5150/mda/64kb/debugger/machine.xml
resume: 1
autoMount:
A:
@ -18,7 +18,7 @@ machines:
COMPAQ MS-DOS 1.11
------------------
Released in 1983 by COMPAQ Computer Corp, this early version of MS-DOS displays the following messages on boot:
Released in 1983 by COMPAQ Computer Corp, this early version of MS-DOS displays on startup:
The COMPAQ Personal Computer DOS
Version 1.11
@ -27,7 +27,8 @@ Released in 1983 by COMPAQ Computer Corp, this early version of MS-DOS displays
(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).
To learn more about this double-sided 320Kb diskette, see the
[Directory Listing](#directory-of-compaq-ms-dos-111-diskette) and [Boot Sector](#compaq-ms-dos-110-boot-sector) below.
{% include machine.html id="ibm5150-compaq111" %}
@ -71,6 +72,16 @@ A directory listing of the 320Kb diskette is provided [below](#directory-of-comp
28 file(s) 256320 bytes
53248 bytes free
One 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
### COMPAQ MS-DOS 1.11 Boot Sector
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.|
@ -106,32 +117,40 @@ The boot sector of the COMPAQ MS-DOS 1.11 disk image contains the following byte
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
Note that 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:
To resolve the mounting problem, one solution is to use the [DiskDump](/modules/diskdump/) utility's *--forceBPB*
option, which creates a mountable disk image by making 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:
The following (hex) 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
- 0000-0002: 2-byte Intel x86 JMP instruction followed by 1-byte x86 NOP
- 0003-000A: 8-byte OEM signature string (we use the fake "PCJS.ORG" OEM signature)
- 000B-001D: 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.
One common misconception is that the last word of a mountable boot sector must also contain 0xAA55 (ie, the low
byte at offset 0x1FE must be 0x55 and the high byte at offset 0x1FF must be 0xAA). This claim is often backed up
by pointing out that some (newer) ROMs will not boot from a disk if that signature is missing.
diskdump --disk=COMPAQ-DOS111.img --format=json --output=COMPAQ-DOS111-BPB.json
However, that evidence is misleading, because those ROMs check only *hard disk* boot sectors for the 0xAA55 signature,
not diskettes. Which makes sense, because hard disk support didn't exist in DOS until version 2.0 -- the same version
of DOS that also introduced BPBs and boot sector signatures.
Here's how you can use [DiskDump](/modules/diskdump/) to a mountable disk. Note that *two* DiskDump commands are
required, because BPB modification only happens when converting an IMG file to a JSON file; the second DiskDump command
converts the modified JSON back into an IMG file.
diskdump --disk=COMPAQ-DOS111.img --format=json --forceBPB --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
@ -141,12 +160,4 @@ a separate IMG file, preserving the original.
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/)]

16
disks/pcx86/dos/ibm/1.00/README.md
View file

@ -20,9 +20,11 @@ PC-DOS 1.00
PC-DOS 1.00 was completed in August 1981 and announced at an IBM press conference on August 12, 1981, when IBM
introduced the original IBM PC (Model 5150).
PC-DOS 1.00 was released on one single-sided (160Kb) diskette. To learn more, see the
[Directory Listing](#directory-of-pc-dos-100-diskette) and [PC-DOS 1.00 Boot Sector](#pc-dos-100-boot-sector)
below.
To learn how to use PC-DOS 1.00, see the [Documentation](/pubs/pc/software/dos/PCDOS100/).
To learn more about this single-sided (160Kb) diskette, see the
[Directory Listing](#directory-of-pc-dos-100-diskette) and [Boot Sector](#pc-dos-100-boot-sector) below.
{% include machine.html id="ibm5150-pcdos100" %}
@ -75,8 +77,7 @@ CHKDSK reports:
160256 bytes total disk space
6144 bytes remain available
PC-DOS 1.00 Boot Sector
-----------------------
### PC-DOS 1.00 Boot Sector
A number of people have already delved into the guts of the PC-DOS 1.00 boot sector, including:
@ -439,8 +440,7 @@ And finally, `IBMBIO_COM` (0x7D76) and `IBMDOS_COM` (0x7D82):
&7D78 6D 62 69 6F 20 20 63 6F-6D B0 69 62 6D 64 6F 73 mbio com.ibmdos
&7D88 20 20 63 6F 6D B0 C9 00-00 00 00 00 00 00 00 00 com...........
Additional Information From [PC DOS Retro](https://sites.google.com/site/pcdosretro/doshist)
--------------------------------------------------------------------------------------------
### Additional Information From [PC DOS Retro](https://sites.google.com/site/pcdosretro/doshist)
- distributed on 1 160KB floppy disk
- initial release (equivalent to 86-DOS 1.14)
@ -469,5 +469,3 @@ Additional Information From [PC DOS Retro](https://sites.google.com/site/pcdosre
- INT 27h terminate and stay resident (implemented in COMMAND.COM)
- CP/M CALL 0 interface (executes INT 20h)
- CP/M CALL 5 interface supporting INT 21h functions 00h-24h
See [PC-DOS 1.00 Documentation](/pubs/pc/software/dos/PCDOS100/) for more information.