BTW, I might suggest a target memory segment a little further out under memory-hungry DOS 5.0. When I ran DEBUG the CS was already 145D, so that didn't end well. Maybe make it 3000 just to be safe!

1debug
2n px-hdc.bin
3M C800:0 2000 3000:0
4W 3000:0
5q

I see 3 jumpers on the card. What do they do?
Could this be a similar sort of situation to the jumpers which would restrict larger IDE drives to ~8gb?
A 20mb "compatibility mode" of sorts

myne wrote on 2024-04-26, 01:39:

I see 3 jumpers on the card. What do they do?
Could this be a similar sort of situation to the jumpers which would restrict larger IDE drives to ~8gb?
A 20mb "compatibility mode" of sorts

already been answered
Re: Working XTA (IDE on XT) setup on GLaBIOS
Re: Working XTA (IDE on XT) setup on GLaBIOS

I was so hopeful with this trip to the garage! I tried a typoless version (I think!?) of weeedeewee's suggestion, but the computer freezes after the M command.

I tried 640k's debug command, which seemed to work! But... produced another file full of FF (huh!?)

I'm also distracted by work atm so I'll do some more trial and error. At least we got to a point where the ROM was read, now just to get debug to write it properly (I'll also try one from freedos and DOS 6 fwiw)

highvoltage wrote on 2024-04-26, 08:12:

I was so hopeful with this trip to the garage! I tried a typoless version (I think!?) of weeedeewee's suggestion, but the computer freezes after the M command.

I tried 640k's debug command, which seemed to work! But... produced another file full of FF (huh!?)

I'm also distracted by work atm so I'll do some more trial and error. At least we got to a point where the ROM was read, now just to get debug to write it properly (I'll also try one from freedos and DOS 6 fwiw)

yeah the freezing is likely due to the 1000:0
Change it to 3000:0 like 640KB said.

It is pretty weird though, displaying it works, yet writing to file doesn't. I admit I don't know too much about the workings of debug.
I guess doing a display dump of the bios at c800 would also be usable 😀
[code]D C800:0 2000[/code] nevermind that will require a little more command redirection to get it into a usable file for upload.

1copy con dump.txt
2D C800:0 2000
3Q
4^Z <- this means press Control & Z
5
6debug <dump.txt >dump.bin

weedeewee wrote on 2024-04-26, 08:36:

[…]
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1copy con dump.txt
2D C800:0 2000
3Q
4^Z <- this means press Control & Z
5
6debug <dump.txt >dump.bin

That didn't quite work, it seemed to have also copied the debug commands into the file and generated a 40k file (perhaps a loop?)

Anyway! I tried your original suggestion on FreeDOS, and it just worked first time! So perhaps there's some bug on DOS 5's debug.com command? Troubleshooting that is an adventure for another day, for now, here's the ROM!

https://jonathancarter.org/files/temp/xt/PX-HDC.BIN

It does seem to be aware of some 40MB disks (perhaps it can only detect miniscribe capacities, haven't looked to closely into it) and it seems to contain a whole low level format utility!

highvoltage wrote on 2024-04-26, 10:05:

That didn't quite work, it seemed to have also copied the debug commands into the file and generated a 40k file (perhaps a loop? […]
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weedeewee wrote on 2024-04-26, 08:36:

[…]
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1copy con dump.txt
2D C800:0 2000
3Q
4^Z <- this means press Control & Z
5
6debug <dump.txt >dump.bin

That didn't quite work, it seemed to have also copied the debug commands into the file and generated a 40k file (perhaps a loop?)

Anyway! I tried your original suggestion on FreeDOS, and it just worked first time! So perhaps there's some bug on DOS 5's debug.com command? Troubleshooting that is an adventure for another day, for now, here's the ROM!

https://jonathancarter.org/files/temp/xt/PX-HDC.BIN

It does seem to be aware of some 40MB disks (perhaps it can only detect miniscribe capacities, haven't looked to closely into it) and it seems to contain a whole low level format utility!

No that is actually a text file hexdump of the bios.
you verify it by doing

1type dump.bin

Given some copy/paste block selection magic it would've been easy enough to enter into a hexeditor and create the actual file.

I doubt you want to try a low level format, but if you want to see it I guess you could

1debug
2g c800:5

weedeewee wrote on 2024-04-26, 11:16:

I doubt you want to try a low level format, but if you want to see it I guess you could […]
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I doubt you want to try a low level format, but if you want to see it I guess you could

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1debug
2g c800:5

It's so tempting, although from what I understand from other docs, once I format a disk in XTA mode it can't be read on an ATA host (which might be useful for this disk). This disks were extremely cheap (and extremely common) in my country in the early 90's, so I'm going to try to get some more of these and then I can low level format one of them (because I am very curious to see what this low level format tool looks like in action!)

If you look in the ROM at file offset 025B you can see what would appear to be drive type tables with five built in drive types.

1                                                              ; #  Cyl  H  RWC  WPC  EC  Step  SPT  Size  FMT
20000025b    67 02 04 67 02 67 02 0b 05 00 00 00 00 00 11 00   ; 0: 615  4  615  615  11  5 ... 17   20MB  MFM
30000026b    25 03 02 25 03 25 03 0b 05 00 00 00 00 00 1a 00   ; 1: 805  2  805  805  11  5 ... 26   20MB  RLL
40000027b    25 03 04 25 03 25 03 0b 05 00 00 00 00 00 1a 00   ; 2: 805  4  805  805  11  5 ... 26   40MB  RLL
50000028b    25 03 04 25 03 25 03 0b 05 00 00 00 00 00 11 00   ; 3: 805  4  805  805  11  5 ... 17   28MB  MFM
60000029b    34 01 04 34 01 34 01 0b 05 00 00 00 00 00 11 00   ; 4: 308  4  308  308  11  5 ... 17   10MB  MFM

So yours would appear to be none of those, in theory you could replace one of the built-in types with this:

10000025b    34 03 06 34 03 34 03 0b 05 00 00 00 00 00 11 00   ; 0: 820  6  820  820  11  5 ... 17   40MB  MFM

The controller appears to determine the drive type from this table by reading I/O port 322, which on XTA would be determined by settings on the drive so probably a combination of the drive id and the capacity jumpers. Regardless your drive is selecting type 0 the way it is set now.

Here's the ROM modded as above, with updated checksum: PX-HDC40.BIN

Of course, usual disclaimer - this is totally untested so no promises it will work or not corrupt data. 😀

Good luck!

640KB wrote on 2024-04-26, 15:16:

If you look in the ROM at file offset 025B you can see what would appear to be drive type tables with five built in drive types. […]
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If you look in the ROM at file offset 025B you can see what would appear to be drive type tables with five built in drive types.

Copy code to clipboard

1                                                              ; #  Cyl  H  RWC  WPC  EC  Step  SPT  Size  FMT
20000025b    67 02 04 67 02 67 02 0b 05 00 00 00 00 00 11 00   ; 0: 615  4  615  615  11  5 ... 17   20MB  MFM
30000026b    25 03 02 25 03 25 03 0b 05 00 00 00 00 00 1a 00   ; 1: 805  2  805  805  11  5 ... 26   20MB  RLL
40000027b    25 03 04 25 03 25 03 0b 05 00 00 00 00 00 1a 00   ; 2: 805  4  805  805  11  5 ... 26   40MB  RLL
50000028b    25 03 04 25 03 25 03 0b 05 00 00 00 00 00 11 00   ; 3: 805  4  805  805  11  5 ... 17   28MB  MFM
60000029b    34 01 04 34 01 34 01 0b 05 00 00 00 00 00 11 00   ; 4: 308  4  308  308  11  5 ... 17   10MB  MFM

So yours would appear to be none of those, in theory you could replace one of the built-in types with this:

Copy code to clipboard

10000025b    34 03 06 34 03 34 03 0b 05 00 00 00 00 00 11 00   ; 0: 820  6  820  820  11  5 ... 17   40MB  MFM

The controller appears to determine the drive type from this table by reading I/O port 322, which on XTA would be determined by settings on the drive so probably a combination of the drive id and the capacity jumpers. Regardless your drive is selecting type 0 the way it is set now.

Here's the ROM modded as above, with updated checksum: PX-HDC40.BIN

Of course, usual disclaimer - this is totally untested so no promises it will work or not corrupt data. 😀

Good luck!

Wow, amazing, thanks! I was reading this and thinking I have to hack this and there's already a whole BIOS extention already to download and burn!

Not sure if it would make a difference, but the ST351A/X is an RLL drive though?

https://stason.org/TULARC/pc/hard-drives-hdd/ … -SL-IDE-AT.html

highvoltage wrote on 2024-04-26, 15:29:

Wow, amazing, thanks! I was reading this and thinking I have to hack this and there's already a whole BIOS extention already to […]
Show full quote

640KB wrote on 2024-04-26, 15:16:

Here's the ROM modded as above, with updated checksum: PX-HDC40.BIN

Wow, amazing, thanks! I was reading this and thinking I have to hack this and there's already a whole BIOS extention already to download and burn!

Not sure if it would make a difference, but the ST351A/X is an RLL drive though?

https://stason.org/TULARC/pc/hard-drives-hdd/ … -SL-IDE-AT.html

I was just going by the translated geometry that's in that sheet: 820 c , 6 h, 17 spt. That does come out to 43M so it seems to make sense.

highvoltage wrote on 2024-04-26, 14:49:

It's so tempting, although from what I understand from other docs, once I format a disk in XTA mode it can't be read on an ATA host (which might be useful for this disk). This disks were extremely cheap (and extremely common) in my country in the early 90's, so I'm going to try to get some more of these and then I can low level format one of them (because I am very curious to see what this low level format tool looks like in action!)

I'm not really familar with this drive, but the docs say that once you low-level format it on an XTA controller it can never ever be used again on an ATA controller? If so, that's concerning.

Being optimistic, the fact that it read the partition table from the drive when the wrong type was set implies there's at least a chance that the drive will work with the existing format and partition if the drive parameters match the previous format. Otherwise, as LLF'ing an IDE drive is generally considered to be perilous, if the modified ROM doesn't work I'm not sure I'd try the XTA ROM formatter. You've already got a different drive than the Miniscribes that this controller was intended to support, and so no guarantees that it wouldn't be somehow destructive.

640KB

it's an early IDE drive. does it matter if it uses mfm or rll encoding in this case since it's connected as an XTA drive and not via an old MFM or RLL controller.

I'm wondering if changing the drive geometry after booting could work, though that would likely mean the drive itself is no longer bootable due to CHS differences in pre boot vs post boot
Would the XT-IDE bios work for XTA drives ?

Do these old drives even have some sort of Device Identify command that could be implemented and used in the current bios ?

weedeewee wrote on 2024-04-26, 15:36:

I'm wondering if changing the drive geometry after booting could work, though that would likely mean the drive itself is no longer bootable due to CHS differences in pre boot vs post boot
Would the XT-IDE bios work for XTA drives ?

I came across this post that touched on that, and also other compatibility issues with these drive types. It was from 2010, so no idea if XT-IDE has since added support or not.

weedeewee wrote on 2024-04-26, 15:36:

Do these old drives even have some sort of Device Identify command that could be implemented and used in the current bios ?

Yeah, see my earlier post. I found this post that clued me in that reading IO port 322 gives a simple (and somewhat model/vendor dependent) drive type. That's what this code at C800:0622 is doing:

1                         DRIVE_TYPE_OFFSET:              ; drive type to HDP offset table (8 bytes)
2C800:0616                      DB    20h, 20h, 10h, 00h  ; if bit 4 is 0
3                               DB    00h, 00h, 00h, 00h  ; if bit 4 is 1
4...
5C800:0622  BA 0322             MOV   DX, 0322h      ; XTA "drive size bits" port
6C800:0625  A0 0077             MOV   AL, [0077h]    ; get port offset to current fixed disk adapter
7C800:0628  02 D0               ADD   DL, AL         ; DX = current port
8C800:062A  EC                  IN    AL, DX         ; read drive size bits
9C800:062B  80 E2 FC            AND   DL, 11111100b  ; reset to base I/O port
10C800:062E  8A E0               MOV   AH, AL         ; save result
11C800:0630  24 03               AND   AL, 0011b      ; isolate disk type bits
12C800:0632  F6 C4 10            TEST  AH, 00010000b  ; flag in bit 4 set?
13C800:0635  74 02               JZ    NO_BIT_4       ; jump if not
14C800:0637  0C 04               OR    AL, 0100b      ; add 4 to drive type
15                        NO_BIT_4:
16C800:0639  32 E4               XOR   AH, AH         ; zero extend drive type to AX
17C800:063B  8B F8               MOV   DI, AX         ; move to index
18C800:063D  2E 8A 85 0616       MOV   AL, BYTE PTR CS:DRIVE_TYPE_OFFSET[DI]  ; get drive type/HDP offset from table
19C800:0642  26 C4 3E 0104       LES   DI, WORD PTR ES:[0104h]  ; ES:DI = current Hard Disk Parameter table  (INT 41h)
20C800:0647  03 C7               ADD   AX, DI         ; add type offset for new HDP

Haven't really looked for any docs about the other bits, but assume they represent the jumpers on the drive in one way or another. Bit 4 changes the drive type maps, though if it's on then they all just map to the default 20MB. Also, with this table it seems it will never use drive types 3 or 4 so who knows. More study would be required here!

Sorry for being a bit vague with the drive identifier.
I was more alluding to the command in the newer drives that reports the drive geometry and or amount of sectors as for LBA, and is not some lookup from a BIOS table.
Without such a command XT-IDE would need a preconfigured CHS value.

But Yes, more documentation would easily satisfy that inquiry.

weedeewee wrote on 2024-04-26, 17:24:

Sorry for being a bit vague with the drive identifier. I was more alluding to the command in the newer drives that reports the d […]
Show full quote

Sorry for being a bit vague with the drive identifier.
I was more alluding to the command in the newer drives that reports the drive geometry and or amount of sectors as for LBA, and is not some lookup from a BIOS table.
Without such a command XT-IDE would need a preconfigured CHS value.

But Yes, more documentation would easily satisfy that inquiry.

Yeah, based on that quick peek at the source I'd guess the identify drive command is not available on XTA, or they'd have used it. Would imagine quality documentation would be a bit harder to come by too, and it sounded like there were non-trivial differences between manufacturers too.

Who can say how many working original XTA drives are in existence today, but I'd think you're very lucky to have one @highvoltage!

640KB wrote on 2024-04-26, 18:03:

weedeewee wrote on 2024-04-26, 17:24:

Sorry for being a bit vague with the drive identifier. I was more alluding to the command in the newer drives that reports the d […]
Show full quote

Sorry for being a bit vague with the drive identifier.
I was more alluding to the command in the newer drives that reports the drive geometry and or amount of sectors as for LBA, and is not some lookup from a BIOS table.
Without such a command XT-IDE would need a preconfigured CHS value.

But Yes, more documentation would easily satisfy that inquiry.

Yeah, based on that quick peek at the source I'd guess the identify drive command is not available on XTA, or they'd have used it. Would imagine quality documentation would be a bit harder to come by too, and it sounded like there were non-trivial differences between manufacturers too.

Who can say how many working original XTA drives are in existence today, but I'd think you're very lucky to have one @highvoltage!

Agreed, very lucky to have one, and looking for more of the same.
I have four different machines which could use an XTA drive but I have no XTA drives and never had one.
A simple emulator would be great. Wouldn't be surprised if a pi pico could be turned into one. likely already overkill.

@640K and @weedeewee: I'll look out for drives for you. The ST351A/X was really popular in low end 386's in my country, so there's likely more of them popping up soon.

Cards seem a little more rare, but I have a sharp eye for things that look weird so I'll keep an eye out for those too. Will flash the new rom tomorrow, I'm very curious to try it out!

FYI, off the top of my head, the computers that I have which support an XTA drive are...
ie they have a 40 pin connector where a hard drive normally would get connected eventhough many of these machines were shipped with an MFM or RLL drive&controller
- Commodore PC10-III
- Philips NMS 9100
- Amstrad PC-1640
- ? can't remember, maybe it was only three.

Enjoy !

weedeewee wrote on 2024-04-26, 20:51:

FYI, off the top of my head, the computers that I have which support an XTA drive are... ie they have a 40 pin connector where […]
Show full quote

FYI, off the top of my head, the computers that I have which support an XTA drive are...
ie they have a 40 pin connector where a hard drive normally would get connected eventhough many of these machines were shipped with an MFM or RLL drive&controller
- Commodore PC10-III
- Philips NMS 9100
- Amstrad PC-1640
- ? can't remember, maybe it was only three.

Enjoy !

I can remember the CompuAdd V20 line used them also (manual) and several in the Tandy line did as well as the PS/2 model 25 and 30.

Of course, I don't have any of these. Always wanted one of those CompuAdd pizza boxes tho.