-  + ``` + B.asm86 86dos.bcz -5. Copy
CHESS.DOC from drive B to drive C.
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
- 
+
+
+ Error Count = 0
+
+ B.asm86 asm.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 boot.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 chess.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 command.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 dosio.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 edlin.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 hex2bin.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 rdcpm.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 sys.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.asm86 trans.bcz
+
+ Seattle Computer Products 8086 Assembler Version 1.00
+ Copyright 1979 by Seattle Computer Products, Inc.
+
+
+
+ Error Count = 0
+
+ B.
+ ```
+
+5. Copy `CHESS.DOC` from drive B to drive C.
+
+ ```
+ B.xfer c:chess.doc=b:chess.doc
+ XFER (Transfer) version 01.07
+ 1K-bytes read
+
+ B.dir c:
+ 86DOS HEX 9K ASM HEX 16K
+ BOOT HEX 1K CHESS HEX 9K
+ COMMAND HEX 3K DOSIO HEX 2K
+ EDLIN HEX 4K HEX2BIN HEX 1K
+ RDCPM HEX 2K SYS HEX 1K
+ TRANS HEX 8K CHESS DOC 1K
+ *** 12 Files, 13 Entries, 57 K Displayed, 184 K Left ***
+ B.
+ ```
6. Power on the 8086 S-100 machine and boot the earlier version of 86-DOS.
- 
+ ```
-7. Remove the disk in drive C of the Z-2D machine and insert it into drive C of the S-100 machine.
+ 86-DOS version 0.11
+ Copyright 1980 Seattle Computer Products, Inc.
+
+ A:
+ ```
+
+7. Remove the disk in drive C of the Z-2D machine and insert it into drive C
+ of the S-100 machine.
8. Insert a blank formatted 8" SSSD disk into drive B.
-9. For each .HEX file on drive C (except for 86DOS.HEX, BOOT.HEX and DOSIO.HEX):
- 1. Run RDCPM C:\.HEX A:
- 2. Run HEX2BIN \
+9. For each `.HEX` file on drive C (except for `86DOS.HEX`, `BOOT.HEX` and
+ `DOSIO.HEX`):
+ 1. Run `RDCPM C:-  + ``` + A:rdcpm c:command.hex a: -10. Run
RDCPM C:CHESS.DOC A:.
+ A:hex2bin command
- 
+ A:rdcpm c:rdcpm.hex a:
-11. Run EDLIN CHESS.DOC and exit with the command E (to remove extra bytes at the end of CHESS.DOC).
+ A:hex2bin rdcpm
- 
+ A:rdcpm c:hex2bin.hex a:
-12. Run ERASE ????????.HEX (to delete all .HEX files).
+ A:hex2bin hex2bin
- 
+ A:rdcpm c:asm.hex a:
-13. Run ERASE ????????.BAK (to delete all .BAK files).
+ A:hex2bin asm
- 
+ A:rdcpm c:trans.hex a:
-14. Run CLEAR B: and type Y (to put a filesystem on drive B).
+ A:hex2bin trans
- 
+ A:rdcpm c:sys.hex a:
-15. Copy all files from drive A to drive B (to create a "fresh" and "clean" disk).
+ A:hex2bin sys
- 
+ A:rdcpm c:edlin.hex a:
+
+ A:hex2bin edlin
+
+ A:rdcpm c:chess.hex a:
+
+ A:hex2bin chess
+
+ A:
+ ```
+
+10. Run `RDCPM C:CHESS.DOC A:`.
+
+ ```
+ A:rdcpm c:chess.doc a:
+
+ A:
+ ```
+
+11. Run `EDLIN CHESS.DOC` and exit with the command `E` (to remove extra bytes
+ at the end of `CHESS.DOC`).
+
+ ```
+ A:edlin chess.doc
+ *e
+
+ A:
+ ```
+
+12. Run `ERASE ????????.HEX` (to delete all `.HEX` files).
+
+ ```
+ A:erase ????????.hex
+
+ A:dir
+ COMMAND COM
+ RDCPM COM
+ HEX2BIN COM
+ ASM COM
+ TRANS COM
+ SYS COM
+ EDLIN COM
+ CHESS COM
+ CHESS BAK
+ CHESS DOC
+
+ A:
+ ```
+
+13. Run `ERASE CHESS.BAK` (to delete `CHESS.BAK`).
+
+ ```
+ A:erase chess.bak
+
+ A:dir
+ COMMAND COM
+ RDCPM COM
+ HEX2BIN COM
+ ASM COM
+ TRANS COM
+ SYS COM
+ EDLIN COM
+ CHESS COM
+ CHESS DOC
+
+ A:
+ ```
+
+14. Run `CLEAR B:` and type `Y` (to put a filesystem on drive B).
+
+ ```
+ A:clear b:
+ Erase all files (Y/N)? y
+ A:
+ ```
+
+15. Copy all files from drive A to drive B (to create a "fresh" and "clean"
+ disk).
+
+ ```
+ A:copy command.com b:
+
+ A:copy rdcpm.com b:
+
+ A:copy hex2bin.com b:
+
+ A:copy asm.com b:
+
+ A:copy trans.com b:
+
+ A:copy sys.com b:
+
+ A:copy edlin.com b:
+
+ A:copy chess.com b:
+
+ A:copy chess.doc b:
+
+ A:
+ ```
16. Remove the disk in drive B and insert it into drive D of the Z-2D machine.
17. Remove the disk in drive C and insert it into drive C of the Z-2D machine.
18. Go back to the Z-2D machine and change to drive C.
- 
+ ```
+ B.c:
-19. For 86DOS, BOOT and DOSIO:
- 1. Run DEBUG \.HEX .
- 2. Quit DEBUG and dump the correct number of pages by running SAVE \.COM \ . The number of pages is given by ⌈(NEXT - 0x100) ÷ 0x100⌉.
+ C.
+ ```
- 
+19. For `86DOS`, `BOOT` and `DOSIO`:
+ 1. Run `DEBUG -20. Run
DOSGEN D:.
+ ```
+ C.debug 86dos.hex
+ DEBUG version 00.20
+ NEXT = 0DDD
+ NEXTM = 0DDD
+ -^C
+ C.save 86dos.com 13
- 
+ C.debug boot.hex
+ DEBUG version 00.20
+ NEXT = 0160
+ NEXTM = 0160
+ -^C
+ C.save boot.com 1
+
+ C.debug dosio.hex
+ DEBUG version 00.20
+ NEXT = 03B1
+ NEXTM = 03B1
+ -^C
+ C.save dosio.com 3
+
+ C.
+ ```
+
+20. Run `DOSGEN D:`.
+
+ ```
+ C.dosgen d:
+ System transfered
+
+ C.
+ ```
21. The disk in drive D now contains a complete copy of 86-DOS 0.11.
### Source of Details
-If you examine the steps above, you'll notice that the disk containing the .HEX files is to be inserted into drive C of the SCP S-100 machine. Clearly, inserting the disk into any drive would work just as well. So, why did I specifically mention drive C? Well, because that's the drive Paterson used. Please refer to [Analysis of Uninitialized Data](#analysis-of-uninitialized-data) for further details.
+If you examine the steps above, you'll notice that the disk containing the .HEX
+files is to be inserted into drive C of the SCP S-100 machine. Clearly,
+inserting the disk into any drive would work just as well. So, why did I
+specifically mention drive C? Well, because that's the drive Paterson used.
+Please refer to
+[Analysis of Uninitialised Data](#analysis-of-uninitialised-data) for further
+details.
## The Chicken and Egg Problem
-In order to create a working copy of 86-DOS 0.11 from scratch, we need an earlier version of 86-DOS. However, we don't have that. Of course, we could simply use the original 0.11 distribution disk, but then we face a problem: How was that distribution disk made in the first place? Maybe with a copy of 86-DOS 0.10? But then this leads to another question: How was 86-DOS 0.10 built?
+In order to create a working copy of 86-DOS 0.11 from scratch, we need an
+earlier version of 86-DOS. However, we don't have that. Of course, we could
+simply use the original 0.11 distribution disk, but then we face a problem:
+How was that distribution disk made in the first place? Maybe with a copy of
+86-DOS 0.10? But then this leads to another question: How was 86-DOS 0.10
+built?
-You see, to build 86-DOS, you need 86-DOS, and to get 86-DOS, you need to build 86-DOS... so how was the very first copy of 86-DOS built?
+You see, to build 86-DOS, you need 86-DOS, and to get 86-DOS, you need to build
+86-DOS... so how was the very first copy of 86-DOS built?
### The First Egg
-Now, I'll guide you through creating a minimum build of 86-DOS 0.11 without the need of another copy of 86-DOS. I call this the first "egg".
+Now, I'll guide you through creating a minimum build of 86-DOS 0.11 without the
+need of another copy of 86-DOS. I call this the first "egg".
#### Requirements
*Same as [Building 86-DOS 0.11 :: Requirements](#requirements).*
> [!IMPORTANT]
-> You will need to make a temporary copy of the source code disk, because you will be modifying DOSIO.A86 to use LARGECRO instead of COMBCRO.
+> You will need to make a temporary copy of the source code disk, because you
+will be modifying `DOSIO.A86` to use `LARGECRO` instead of `COMBCRO`.
#### Steps
1. Power on the Z-2D machine and boot the CDOS disk.
2. Insert the 86-DOS source code disk (copy) in drive B.
3. Insert a blank formatted 8" SSSD disk in drive C.
-4. Change to drive B and edit DOSIO.A86 to use the LARGECRO drive configuration.
+4. Change to drive B and edit `DOSIO.A86` to use the `LARGECRO` drive
+ configuration.
- 
+ ```
+ A.b:
-5. For 86DOS, BOOT, COMMAND, DOSIO, HEX2BIN and RDCPM:
- 1. Assemble to .HEX object by running ASM86 \.BCZ .
+ B.edit dosio.a86
- 
+ CROMEMCO Text Editor version 00.10
+ *n
+ End of Input File
+ *fCOMBCRO:EQU^I
+ *d
+ *i
+ COMBCRO:EQU 0*
+ LARGECRO:EQU 0 ;4 large drives
+ *f^I
+ *d
+ *i
+ LARGECRO:EQU 1*
-6. Change to drive C and for 86DOS, BOOT, COMMAND, DOSIO, HEX2BIN and RDCPM:
- 1. Load the .HEX object to memory by running DEBUG \.HEX .
+ *-2t
+ COMBCRO:EQU 0 ;2 large drives and 1 small one
+ LARGECRO:EQU 1 ;4 large drives
+ *e
+ Goodbye
- 
+ B.
+ ```
- 2. Quit DEBUG and dump the correct number of pages by running SAVE \.COM \ . The number of pages is given by ⌈(NEXT - 0x100) ÷ 0x100⌉.
+5. For `86DOS`, `BOOT`, `COMMAND`, `DOSIO`, `HEX2BIN` and `RDCPM`:
+ 1. Assemble to `.HEX` object by running `ASM86 -  + ``` + B.asm86 86dos.bcz -  + Seattle Computer Products 8086 Assembler Version 1.00 + Copyright 1979 by Seattle Computer Products, Inc. + + + + Error Count = 0 + + B.asm86 boot.bcz + + Seattle Computer Products 8086 Assembler Version 1.00 + Copyright 1979 by Seattle Computer Products, Inc. + + + + Error Count = 0 + + B.asm86 command.bcz + + Seattle Computer Products 8086 Assembler Version 1.00 + Copyright 1979 by Seattle Computer Products, Inc. + + + + Error Count = 0 + + B.asm86 dosio.bcz + + Seattle Computer Products 8086 Assembler Version 1.00 + Copyright 1979 by Seattle Computer Products, Inc. + + + + Error Count = 0 + + B.asm86 hex2bin.bcz + + Seattle Computer Products 8086 Assembler Version 1.00 + Copyright 1979 by Seattle Computer Products, Inc. + + + + Error Count = 0 + + B.asm86 rdcpm.bcz + + Seattle Computer Products 8086 Assembler Version 1.00 + Copyright 1979 by Seattle Computer Products, Inc. + + + + Error Count = 0 + + B.dir c: + 86DOS HEX 9K BOOT HEX 1K + COMMAND HEX 3K DOSIO HEX 2K + HEX2BIN HEX 1K RDCPM HEX 2K + *** 6 Files, 6 Entries, 18 K Displayed, 223 K Left *** + B. + ``` + +6. Change to drive C and for `86DOS`, `BOOT`, `COMMAND`, `DOSIO`, `HEX2BIN` + and `RDCPM`: + 1. Load the `.HEX` object to memory by running `DEBUG
+ + ``` + B.c: + + C.debug 86dos.hex + DEBUG version 00.20 + NEXT = 0DDD + NEXTM = 0DDD + -^C + C.save 86dos.com 13 + + C.debug boot.hex + DEBUG version 00.20 + NEXT = 0160 + NEXTM = 0160 + -^C + C.save boot.com 1 + + C.debug command.hex + DEBUG version 00.20 + NEXT = 05AC + NEXTM = 05AC + -^C + C.save command.com 5 + + C.debug dosio.hex + DEBUG version 00.20 + NEXT = 03B7 + NEXTM = 03B7 + -^C + C.save dosio.com 3 + + C.debug hex2bin.hex + DEBUG version 00.20 + NEXT = 0271 + NEXTM = 0271 + -^C + C.save hex2bin.com 2 + + C.debug rdcpm.hex + DEBUG version 00.20 + NEXT = 044D + NEXTM = 044D + -^C + C.save rdcpm.com 4 + + C.dir + 86DOS HEX 9K BOOT HEX 1K + COMMAND HEX 3K DOSIO HEX 2K + HEX2BIN HEX 1K RDCPM HEX 2K + 86DOS COM 4K BOOT COM 1K + COMMAND COM 2K DOSIO COM 1K + HEX2BIN COM 1K RDCPM COM 1K + *** 12 Files, 12 Entries, 28 K Displayed, 213 K Left *** + C. + ``` 7. Insert a blank formatted 8" SSSD disk into drive D. -8. Run
DOSGEN D: N.
+8. Run `DOSGEN D: N`.
- 
+ ```
+ C.dosgen d: n
+ System transfered
-9. Pop out the disks in drives C and D, and insert them into drives C and A of the S-100 machine, respectively.
+ C.
+ ```
+
+9. Pop out the disks in drives C and D, and insert them into drives C and A of
+ the S-100 machine, respectively.
10. Boot up the 8086 S-100 machine.
- 
+ ```
-11. Run run RDCPM C:HEX2BIN.COM A: to copy HEX2BIN.COM over.
+ 86-DOS version 0.11
+ Copyright 1980 Seattle Computer Products, Inc.
- 
+ A:dir
+ COMMAND COM
+ RDCPM COM
-12. The disk in drive A now contains a minimal build of 86-DOS 0.11, which can be used to facilitate the building of a complete copy of 86-DOS 0.11.
+ A:
+ ```
-## Analysis of Uninitialized Data
+11. Run run `RDCPM C:HEX2BIN.COM A:` to copy `HEX2BIN.COM` over.
-### What is Uninitalized Data
-SCP's 8086 assembler (hereinafter referred to as ASM86) supports a DS (Define Storage) pseudo-op, similar to MASM's DB n DUP(?). Since ASM86 generates Intel HEX files, when it encounters a DS, it increments the program counter variable by the specified number of bytes, which, in turn, increases the address in the .HEX file. The same goes for specifying a custom put base, which literally tells the assembler to emit code at a specified address.
+ ```
+ A:rdcpm c:hex2bin.com a:
-When a .HEX file is loaded, the parser reads it line by line and copies the data to the address specified at the beginning of each line. This means that if there is a gap between the addresses of two lines, which would be the case when the put base is incremented by DS or PUT, the data inside the gap will be uninitialized and, therefore, undefined.
+ A:dir
+ COMMAND COM
+ RDCPM COM
+ HEX2BIN COM
+
+ A:
+ ```
+
+12. The disk in drive A now contains a minimal build of 86-DOS 0.11, which can
+ be used to facilitate the building of a complete copy of 86-DOS 0.11.
+
+## Analysis of Uninitialised Data
+
+### What is Uninitalised Data
+SCP's 8086 assembler (hereinafter referred to as ASM86) supports a `DS` (Define
+Storage) pseudo-op, similar to MASM's `DB n DUP(?)`. Since ASM86 generates
+Intel HEX files, when it encounters a DS, it increments the program counter
+variable by the specified number of bytes, which, in turn, increases the
+address in the .HEX file. The same goes for specifying a custom put base, which
+literally tells the assembler to emit code at a specified address.
+
+When a `.HEX` file is loaded, the parser reads it line by line and copies the
+data to the address specified at the beginning of each line. This means that if
+there is a gap between the addresses of two lines, which would be the case when
+the put base is incremented by `DS` or `PUT`, the data inside the gap will be
+uninitialised and, therefore, undefined.
+
+Suppose that I originally have this data at address `0x100`:
-Suppose that I originally have this data at address 0x100:
```
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
@@ -169,7 +651,9 @@ Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00000140 61 6B 20 74 68 69 73 21 ak this!
```
-Now, I load this Intel HEX file (notice the gap of 18 bytes between the second and third line):
+Now, I load this Intel HEX file (notice the gap of 18 bytes between the second
+and third line):
+
```
Len Addr Type Data Hash
: 1A 0100 00 2CC3EB8233940FDC4C1C9507C82F8C88237F9602D154EC95F3C6 2F
@@ -178,6 +662,7 @@ Now, I load this Intel HEX file (notice the gap of 18 bytes between the second a
```
The memory then becomes this:
+
```
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
@@ -186,13 +671,15 @@ Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00000120 B2 24 C9 70 61 73 73 77 6F 72 64 20 69 73 20 61 ²$Épassword is a
00000130 62 63 31 32 33 74 CF DA 54 78 D2 CC A5 C7 9A 6D bc123tÏÚTxÒ̥ǚm
00000140 8B D6 CB 32 62 9E DE 90 ‹ÖË2bžÞ.
-
```
-The 18-byte buffer at offset 0x123 is what we call uninitialized data, which in this case, happens to contain the leftover string password is abc123.
+The 18-byte buffer at offset `0x123` is what we call uninitialised data, which
+in this case, happens to contain the leftover string `password is abc123`.
-#### Case Study: CHESS.COM
-Let's take a look at this fragment of uninitialized data at offset 0x64 of CHESS.COM. It's only 156 bytes, but you will be surprised by the amount of information that can be inferred from these bits.
+#### Case Study: `CHESS.COM`
+Let's take a look at this fragment of uninitialised data at offset `0x64` of
+`CHESS.COM`. It's only 156 bytes, but you will be surprised by the amount of
+information that can be inferred from these bits.
```
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
@@ -207,10 +694,15 @@ Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
000000D0 00 00 53 55 50 43 48 45 53 53 43 4F 4D 00 00 00 ..SUPCHESSCOM...
000000E0 32 88 89 8A 8B 8C 8D 8E 00 00 00 00 00 00 00 00 2ˆ‰Š‹Œ.Ž........
000000F0 00 00 44 41 4E 20 20 20 20 20 20 20 20 00 00 00 ..DAN ...
-
```
-What we first see is a string ile name\r\n$. If we examine RDCPM.COM, we will see that it has the exact same string at offset 0x1D5. So, we are probably looking at a partial memory dump of RDCPM. There is a 1-byte size difference between that copy of RDCPM.COM and 86-DOS 0.11's RDCPM.COM, because the string ends at offset 0xE of that paragraph instead of 0xF. Since we have identified the origin of the data, we can take a look at the RDCPM source code to determine the meaning of the rest of the data.
+What we first see is a string `ile name\r\n$`. If we examine `RDCPM.COM`, we
+will see that it has the exact same string at offset `0x1D5`. So, we are
+probably looking at a partial memory dump of `RDCPM`. There is a 1-byte size
+difference between that copy of `RDCPM.COM` and 86-DOS 0.11's `RDCPM.COM`,
+because the string ends at offset `0xE` of that paragraph instead of `0xF`.
+Since we have identified the origin of the data, we can take a look at the
+`RDCPM` source code to determine the meaning of the rest of the data.
```x86asm
BADFN: DB 13,10,"Bad file name",13,10,"$"
@@ -219,11 +711,17 @@ DSTFCB: DS 32
DB 0
DIRBUF: DS 128
```
-The byte at 0x6F is the DRIVE variable, which holds the drive ID of the CP/M disk. A value of 0x02 signifies drive C. Next comes DSTFCB, the FCB of the destination file. We can see from the first 12 bytes that it's the file A:CHESS.HEX. This gives us the RDCPM command line RDCPM C:CHESS.HEX A:.
+The byte at `0x6F` is the `DRIVE` variable, which holds the drive ID of the
+CP/M disk. A value of `0x02` signifies drive C. Next comes `DSTFCB`, the FCB of
+the destination file. We can see from the first 12 bytes that it's the file
+`A:CHESS.HEX`. This gives us the `RDCPM` command line `RDCPM C:CHESS.HEX A:`.
-If we look further at DSTFCB, we will notice that it does not actually match up with the FCB format of 86-DOS 0.11. This strongly suggests that RDCPM was run under an earlier version of 86-DOS.
+If we look further at `DSTFCB`, we will notice that it does not actually match
+up with the FCB format of 86-DOS 0.11. This strongly suggests that `RDCPM` was
+run under an earlier version of 86-DOS.
-After the FCB, we have DIRBUF, which holds a directory sector of the CP/M disk. We can decode it:
+After the FCB, we have `DIRBUF`, which holds a directory sector of the CP/M
+disk. We can decode it:
| Filename | Size | Blocks | Block List |
| - | - | - | - |
@@ -232,19 +730,31 @@ After the FCB, we have DIRBUF, which holds a directory sector of th
| SUPCHESS.COM | 6400 | 7 | 136, 137, 138, 139, 140, 141, 142 |
| DAN | ? | ? | ? |
-I have no idea what PRILSTDL was; if I had to guess, it probably had something to do with the printing of assembly language listings. SUPCHESS.HEX had the exact same size as the .HEX file for 86-DOS 0.11's CHESS program, and SUPCHESS.COM had the same size as CHESS.COM, so SUPCHESS thing was just CHESS. I doubt anyone will ever be able figure out what DAN was.
+I have no idea what `PRILSTDL` was; if I had to guess, it probably had
+something to do with the printing of assembly language listings. `SUPCHESS.HEX`
+had the exact same size as the `.HEX` file for 86-DOS 0.11's `CHESS` program,
+and `SUPCHESS.COM` had the same size as `CHESS.COM`, so the `SUPCHESS` thing
+was just `CHESS`. I doubt anyone will ever be able to figure out what `DAN`
+was.
-The most crucial information we can infer from this directory fragment is the format of the CP/M disk in drive C. RDCPM only ever supported 2 CP/M disk formats out of the box - the standard 8" SSSD format with a sector skew of 6, and the 5" Cromemco format with a sector skew of 5. The largest block number for the 5" format is about 82, so based on this alone, we can deduce that this directory fragment belonged to an 8" disk.
+The most crucial information we can infer from this directory fragment is the
+format of the CP/M disk in drive C. `RDCPM` only ever supported 2 CP/M disk
+formats out of the box - the standard 8" SSSD format with a sector skew of 6,
+and the 5" Cromemco format with a sector skew of 5. The largest block number
+for the 5" format is about 82, so based on this alone, we can deduce that this
+directory fragment belonged to an 8" disk.
##### Summary (TL;DR)
-1. The file CHESS.HEX file was converted to CHESS.COM under 86-DOS.
-2. RDCPM was used to copy CHESS.HEX from a CP/M disk.
-3. The RDCPM command was RDCPM C:CHESS.HEX A:.
+1. The file `CHESS.HEX` was converted to `CHESS.COM` under 86-DOS.
+2. `RDCPM` was used to copy `CHESS.HEX` from a CP/M disk.
+3. The `RDCPM` command was `RDCPM C:CHESS.HEX A:`.
4. The disk in drive C was a standard 8" SSSD CP/M disk.
- 1. Given that drive C was 8", the drive configuration was LARGECRO.
+ 1. Given that drive C was 8", the drive configuration was `LARGECRO`.
+
+#### Case Study: `SYS.COM`
+`SYS.COM` also has some uninitialised data, this time only a partial directory
+sector.
-#### Case Study: SYS.COM
-SYS.COM also has some uninitialized data, this time only a partial directory sector.
```
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
@@ -256,6 +766,7 @@ Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
000000E0 05 26 00 00 00 00 00 00 00 00 00 00 00 00 00 00 .&..............
000000F0 00 00 43 4F 4D 4D 41 4E 44 20 48 45 58 00 00 00 ..COMMAND HEX...
```
+
| Filename | Size | Blocks | Block List |
| - | - | - | - |
| ?.A86 | 5504 | 6 | 76, 77, 92, 104, 105, 106 |
@@ -263,9 +774,22 @@ Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
| SYS.BAK | 640 | 1 | 38 |
| COMMAND.HEX | ? | ? | ? |
-There's nothing particularly interesting here, but SYS.BAK (presumably produced by editing SYS.A86 with EDIT or WordMaster) had the exact same size as my reconstructed SYS.A86, so my SYS disassembly can't be too far off the original. I'm not sure what that .A86 file was, but my educated guess is it was COMMAND.A86.
+There's nothing particularly interesting here, but `SYS.BAK` (presumably
+produced by editing `SYS.A86` with `EDIT` or WordMaster) had the exact same
+size as my reconstructed `SYS.A86`, so my `SYS` disassembly can't be too far
+off the original. I'm not sure what that `.A86` file was, but my educated guess
+is it was `COMMAND.A86`.
-#### File Sizes and RDCPM
-The size of files copied off CP/M disks should always be multiples of the block size of the CP/M disk, because RDCPM completely ignores the record count and uses only the block pointers to determine when to stop reading. For instance, if the record size is 1K and the file size is 128, when transferred to a DOS disk with RDCPM, it will be 1024 bytes long.
+#### File Sizes and `RDCPM`
+The size of files copied off of CP/M disks should always be multiples of the
+block size of the CP/M disk, because `RDCPM` completely ignores the record
+count and uses only the block pointers to determine when to stop reading. For
+instance, if the record size is 1K and the file size is 128, when transferred
+to a DOS disk with `RDCPM`, it will be 1024 bytes long.
-Since none of the files on the original 86-DOS 0.11 distribution disk are exact multiples of 1K, none of them were directly transferred from CP/M disks. This implies that all the .COM binaries were generated by HEX2BIN from .HEX files copied off CP/M disks. CHESS.DOC was either created from scratch under 86-DOS, or transferred from a CP/M disk and then edited by EDLIN under 86-DOS.
+Since none of the files on the original 86-DOS 0.11 distribution disk are exact
+multiples of 1K, none of them were directly transferred from CP/M disks. This
+implies that all the `.COM` binaries were generated by `HEX2BIN` from `.HEX`
+files read from CP/M disks. `CHESS.DOC` was either created from scratch under
+86-DOS, or transferred from a CP/M disk and then edited by `EDLIN` under
+86-DOS.
diff --git a/CPM Tools/README.md b/CPM Tools/README.md
index 4a2c582..dd83ee3 100644
--- a/CPM Tools/README.md
+++ b/CPM Tools/README.md
@@ -1,16 +1,34 @@
# CP/M Building Tools
-This folder contains some of the Z80 tools required for building and deploying 86-DOS 0.11 under CP/M (or Cromemco CDOS, the operating system [@TimPaterson](https://github.com/TimPaterson) used). You will need these if you wish to create a working copy of 86-DOS 0.11 from pure source code.
+This folder contains some of the Z80 tools required for building and deploying
+86-DOS 0.11 under CP/M (or Cromemco CDOS, the operating system
+[@TimPaterson](https://github.com/TimPaterson) used). You will need these if
+you wish to create a working copy of 86-DOS 0.11 from pure source code.
> [!WARNING]
-> These tools have only been tested under Cromemco CDOS 2.x. There is no guarantee that they will work under the official CP/M operating system or other CP/M-like operating systems. The source files are to be assembled using Cromemco's CDOS Z80 assembler, and you must have a Z80 CPU to run the binaries.
+> These tools have only been tested under Cromemco CDOS 2.x. There is no
+guarantee that they will work under the official CP/M operating system or
+other CP/M-like operating systems. The source files are to be assembled using
+Cromemco's CDOS Z80 assembler, and you must have a Z80 CPU to run the binaries.
## ASM86
-This is a reconstruction of the SCP Z80/8086 Cross Assembler [@TimPaterson](https://github.com/TimPaterson) used to develop 86-DOS. Original copies of this cross assembler are long gone, and the only thing we have now is [a manual](https://bitsavers.org/pdf/seattleComputer/Z80_8086_Cross_Assembler_Preliminary.pdf) for it. Given that the 86-DOS ASM assembler is essentially an 8086 translation of this assembler, I wrote a utility that does the exact opposite of TRANS (named CIS) to translate 86-DOS 0.11's assembler back to Z80. After making some minor tweaks to the output, I was able to make it work, so here it is.
+This is a reconstruction of the SCP Z80/8086 Cross Assembler
+[@TimPaterson](https://github.com/TimPaterson) used to develop 86-DOS. Original
+copies of this cross assembler are long gone, and the only thing we have now is
+[a manual](https://bitsavers.org/pdf/seattleComputer/Z80_8086_Cross_Assembler_Preliminary.pdf)
+for it. Given that the 86-DOS `ASM` assembler is essentially an 8086
+translation of this assembler, I wrote a utility that does the exact opposite
+of `TRANS` (named CIS) to translate 86-DOS 0.11's assembler back to Z80. After
+making some minor tweaks to the output, I was able to make it work, so here it
+is.
> [!TIP]
-> The Z80 source of the assembler is actually easier to read than the 8086 source because this assembler was originally written in the Z80 assembly language. When it was translated to 8086, a lot of boilerplate code were added, which made the code slightly difficult to follow. Now that it has been translated back to Z80, those boilerplate code have been removed.
+> The Z80 source of the assembler is actually easier to read than the 8086
+source because this assembler was originally written in the Z80 assembly
+language. When it was translated to 8086, a lot of boilerplate code were added,
+which made the code slightly difficult to follow. Now that it has been
+translated back to Z80, those boilerplate code have been removed.
-ASM86 takes the following parameters: [x:]ASM86 [y:]name[.ijk] [S]
+ASM86 takes the following parameters: `[x:]ASM86 [y:]name[.ijk] [S]`
where
@@ -22,33 +40,67 @@ where
ASM86.COM file. This parameter is required only if the COM file is NOT located on either drive A or the current drive. Legal values are A, B, C, and D.ASM86.COM file. This parameter is required
+ only if the COM file is NOT located on either drive A or
+ the current drive. Legal values are A, B, C, and D.
+ A86 is always assumed and may not be overriden.A86 is
+ always assumed and may not be overriden.
+ Z if no object file is desired. The third letter is the name of the drive to which the listing file will be written, or X to send the listing to the console, or Z if no listing file is desired. Assembling with no listing is much faster since the source file will not be read from disk a second time.Z if no
+ object file is desired. The third letter is the name of the
+ drive to which the listing file will be written, or
+ X to send the listing to the console, or
+ Z if no listing file is desired. Assembling with
+ no listing is much faster since the source file will not be
+ read from disk a second time.
+ SLOAD command. If you are using CDOS, which does not have LOAD, you will have to use DEBUG to load the .HEX file to memory and SAVE to save the loaded pages as a disk file.
+This assembler can only produce Intel HEX files for object code, therefore you
+must convert them to binary before they can be executed on the 8086. Under
+CP/M, this can be done using the `LOAD` command. If you are using CDOS, which
+does not have `LOAD`, you will have to use `DEBUG` to load the .HEX file to
+memory and `SAVE` to save the loaded pages as a disk file.
## TRANS86
-This is a reconstruction of the SCP Z80 to 8086 Translator shipped together with ASM86. Like ASM86, original copies are long gone and this is the 8086 version from 86-DOS 0.11 translated back to Z80.
+This is a reconstruction of the SCP Z80 to 8086 Translator shipped together
+with ASM86. Like ASM86, original copies are long gone and this is the 8086
+version from 86-DOS 0.11 translated back to Z80.
-TRANS86 takes the following parameters: [x:]TRANS86 [y:]name.ext
+TRANS86 takes the following parameters: `[x:]TRANS86 [y:]name.ext`
where
@@ -60,25 +112,39 @@ where
TRANS86.COM file. This parameter is required only if the COM file is NOT located on either drive A or the current drive. Legal values are A, B, C, and D.TRANS86.COM file. This parameter is required
+ only if the COM file is NOT located on either drive A or
+ the current drive. Legal values are A, B, C, and D.
+ SYSGEN utility.
+This is a tool I wrote to copy 86-DOS system files to the system area of IBM 8"
+SSSD floppies. It works in a similar way to CP/M's `SYSGEN` utility.
-DOSGEN takes the following parameters: [x:]DOSGEN y: [N]
+DOSGEN takes the following parameters: `[x:]DOSGEN y: [N]`
where
@@ -90,17 +156,32 @@ where
DOSGEN.COM file. This parameter is required only if the COM file is NOT located on either drive A or the current drive. Legal values are A, B, C, and D.DOSGEN.COM file. This parameter is required
+ only if the COM file is NOT located on either drive A or
+ the current drive. Legal values are A, B, C, and D.
+ NCOMMAND.COM and RDCPM.COM will be written alongside the system.COMMAND.COM and
+ RDCPM.COM will be written alongside the system.
+ BOOT.COM, DOSIO.COM and 86DOS.COM on the current drive. If a new file system is to be created, COMMAND.COM and RDCPM.COM must also exist.
+ To copy 86-DOS to a new floppy disk, you must have the files `BOOT.COM`,
+ `DOSIO.COM` and `86DOS.COM` on the current drive. If a new file system is to
+ be created, `COMMAND.COM` and `RDCPM.COM` must also exist.
diff --git a/Disk Images/86-DOS 0.11 Source Code.img b/Disk Images/86-DOS 0.11 Source Code.img
index 82e75e4..f41e8e4 100644
Binary files a/Disk Images/86-DOS 0.11 Source Code.img and b/Disk Images/86-DOS 0.11 Source Code.img differ
diff --git a/README.md b/README.md
index c0a9568..7d53138 100644
--- a/README.md
+++ b/README.md
@@ -1,33 +1,65 @@
# 86-DOS 0.11 Source Code Reconstruction
-Full source code reconstruction of 86-DOS 0.11 - the earliest released version of the earliest operating system for the Intel x86 architecture.
+Full source code reconstruction of 86-DOS 0.11 - the earliest released version
+of the earliest operating system for the Intel x86 architecture.
> [!IMPORTANT]
-> All 8086 assembly language source files in this repository use the extension `.A86`, because 86-DOS was originally assembled using the SCP Z80/8086 Cross Assembler running under Cromemco CDOS. To build 86-DOS under 86-DOS itself or MS-DOS, you would have to rename all `.A86` files to `.ASM`.
+> All 8086 assembly language source files in this repository use the extension
+`.A86`, because 86-DOS was originally assembled using the SCP Z80/8086 Cross
+Assembler running under Cromemco CDOS. To build 86-DOS under 86-DOS itself or
+MS-DOS, you would have to rename all `.A86` files to `.ASM`.
## Progress
-
+
+
+
+
+
+
## Author
-This software was written by [@TimPaterson](https://github.com/TimPaterson) in 1980. The reconstructed source code in this repository compiles back to the exact same binaries shipped by Seattle Computer Products. Therefore, it can be fully regrded as Paterson's work.
+This software was written by [@TimPaterson](https://github.com/TimPaterson) in
+1980. The reconstructed source code in this repository compiles back to the
+exact same binaries shipped by Seattle Computer Products. Therefore, it can be
+fully regrded as Paterson's work.
> [!IMPORTANT]
-> Please do not file feature requests or make pull requests to fix bugs in the code. This is not my OS and I want this important piece of digital computing history to be preserved in its most original state. I will not accept anything that alters the assembled binaries in any way, shape or form.
+> Please do not file feature requests or make pull requests to fix bugs in the
+code. This is not my OS and I want this important piece of digital computing
+history to be preserved in its most original state. I will not accept anything
+that alters the assembled binaries in any way, shape or form.
## Disclaimer
-This source code reconstruction is a product of reverse engineering. It is important to note that Microsoft Corporation has not released the source code for this specific version of DOS, and its legality may be in a gray area.
+This source code reconstruction is a product of reverse engineering. It is
+important to note that Microsoft Corporation has not released the source code
+for this specific version of DOS, and its legality may be in a gray area.
-The source code reconstruction was undertaken with the understanding that Microsoft Corporation has open-sourced later versions of this operating system under the name MS-DOS, under the MIT License. The intention behind this source code reconstruction project is purely for historical and educational purposes, with a focus on preserving the heritage of early computing.
+The source code reconstruction was undertaken with the understanding that
+Microsoft Corporation has open-sourced later versions of this operating system
+under the name MS-DOS, under the MIT License. The intention behind this source
+code reconstruction project is purely for historical and educational purposes,
+with a focus on preserving the heritage of early computing.
-While efforts have been made to ensure compliance with applicable laws and regulations, the legal status of this source code reconstruction project may not be entirely clear. Users are advised to exercise caution and seek legal advice before using or redistributing any code extracted from this repository.
+While efforts have been made to ensure compliance with applicable laws and
+regulations, the legal status of this source code reconstruction project may
+not be entirely clear. Users are advised to exercise caution and seek legal
+advice before using or redistributing any code extracted from this repository.
-This project acknowledges the intellectual property rights of Microsoft Corporation and does not seek to infringe upon any proprietary rights. The reconstructed source code is shared in the spirit of historical preservation, education, and appreciation for this wonderful operating system.
+This project acknowledges the intellectual property rights of Microsoft
+Corporation and does not seek to infringe upon any proprietary rights. The
+reconstructed source code is shared in the spirit of historical preservation,
+education, and appreciation for this wonderful operating system.
-By accessing and using the reconstructed source code provided in this repository, you agree to do so at your own risk and assume all responsibility for any legal implications that may arise.
+By accessing and using the reconstructed source code provided in this
+repository, you agree to do so at your own risk and assume all responsibility
+for any legal implications that may arise.
## Building
*See [Building 86-DOS 0.11](./Building.md).*
## Special Thanks
-* [@TimPaterson](https://github.com/TimPaterson) - For writing this amazing OS and providing the source code of 86-DOS 1.00.
+* [@TimPaterson](https://github.com/TimPaterson) - For writing this amazing OS
+ and providing the source code of 86-DOS 1.00.
* [@geneb](https://github.com/geneb) - For providing a copy of 86-DOS 0.11.
-* [@RichCini](https://github.com/RichCini) - For figuring out some hard-to-decipher logic and for testing and debugging the reconstructed Tarbell-specific code on physical hardware.
+* [@RichCini](https://github.com/RichCini) - For figuring out some
+ hard-to-decipher logic and for testing and debugging the reconstructed
+ Tarbell-specific code on physical hardware.