What rom is located at C800 ?

weedeewee wrote on 2024-04-23, 13:27:

What rom is located at C800 ?

That's the ROM on the XTA card. I intend to dump it, perhaps someone might find it useful or use it to make their own XTA card (since it has so few components anyway).

fairly certain that one detects the harddrive and then glabios uses the reported configuration to display the information you're seeing.
It should be an easy enough dump using dos debug, it's just an 8K eprom.
Maybe someone more knowledgeable can have a look at it and patch it up.

Any idea/experience what the three jumpers on the card are for ?

https://dosdays.co.uk/topics/xt_ide_vs_ide.php

Maybe the chs need setting?

myne wrote on 2024-04-23, 13:56:

https://dosdays.co.uk/topics/xt_ide_vs_ide.php

Maybe the chs need setting?

How would you do that on OP's XT ? 😀

No idea. But there's the settings

Yeah, GLaBIOS calls the HD controller's BIOS after it's set up its drive table to get the number of drives and sizes (INT 13h, AH=8) and displays that. I'd take a guess that those two jumpers on the right select one of four built-in drive types in that ROM... since what's it's reporting is a bog standard 20MB drive's geometry, the controller seems to be working correctly. The question is... what size does DOS see in FDISK (warning: any attempt to write to the disk will certainly result in data loss, so if you've got anything on there you want, back it up first 😀 ).

As @weedeewee mentioned if you wanted to dump that ROM we could probably confirm this and maybe patch in your drive geometry (if it's not already one of the built-in ones).

640KB

640KB wrote on 2024-04-25, 13:41:

Yeah, GLaBIOS calls the HD controller's BIOS after it's set up its drive table to get the number of drives and sizes (INT 13h, AH=8) and displays that. I'd take a guess that those two jumpers on the right select one of four built-in drive types in that ROM... since what's it's reporting is a bog standard 20MB drive's geometry, the controller seems to be working correctly. The question is... what size does DOS see in FDISK (warning: any attempt to write to the disk will certainly result in data loss, so if you've got anything on there you want, back it up first 😀 ).

As @weedeewee mentioned if you wanted to dump that ROM we could probably confirm this and maybe patch in your drive geometry (if it's not already one of the built-in ones).

Wow, a reply from 640KB !!! 😁

I'm not sure if I dumped the file correctly, I did:

1debug
2-n PX-HDC.BIN
3-RCX
4:2000
5-M100 L2000 C800:0
6-W
7-Q

Here's the resulting file: https://jonathancarter.org/files/temp/xt/PX-HDC.BIN

I did another stab at playing with jumpers, here are some results:

There's 3 pins on the left, and 6 on the right, I made up some names for them:

1       .                   :  J2
2       :  J1               :  J3
3                           :  J4

I've found that whenever J2 is closed (with nearly any other combination of jumpers), the bootrom loads at CA00 and no drives are detected.
When J3 is closed, nothing is detected.
When jumper J4 is shorted, the ROM still loads at C800 and the disk is detected as 20MB.

I've tried the above with J1 being up and down and clear, it doesn't seem to have an effect.

I'm attaching an image with the drive jumpers as well, this should be XT mode 40MB according to
https://stason.org/TULARC/pc/hard-drives-hdd/ … -SL-IDE-AT.html
(search "XT jumpers") - seems like the headers are upside down from what I would expect, I'm going to go test this yet again (also a bit nervous with this disk, since the wrong jumper settings can destroy it)

Thanks for reading!

PS: In FDISK the drive partition shows as 40MB (as expected) and the actual drive size is displayed as 20MB (as expected since that is what the BIOS reports)

highvoltage wrote on 2024-04-25, 15:03:

[…]
Show full quote

Copy code to clipboard

1debug
2-n PX-HDC.BIN
3-RCX
4:2000
5-M100 L2000 C800:0
6-W
7-Q

I think the dump is wrong.
If you do a

1d c800:0

You should see what the real rom looks like.
You also do not have to worry about shadow ram on an XT. remove the M line and do a

1W C800:0

ergo

1debug
2n PX-HDC.BIN
3RCX
42000
5W C800:0
6Q

the first two bytes should be 0x55 0xAA

weedeewee wrote on 2024-04-25, 15:23:

the first two bytes should be 0x55 0xAA […]
Show full quote

Copy code to clipboard

1debug
2n PX-HDC.BIN
3RCX
42000
5W C800:0
6Q

the first two bytes should be 0x55 0xAA

Thanks weedeewee! That was very helpful. If I do the -d, I see something that looks like a ROM and even a copyright string (picture attached)! But when I do a w (even from scratch verbatim as above), I just get a file full of hex FF.

Any ideas?

I found another reference to an 8 bit miniscribe card, right here on Vogons! - Re: Miniscribe M8225XT Controller

At least one of its jumper settings (which is usefully printed on that board) corresponds to mine. That is, when it's in the top position, it uses the address CA00. And as that one, I think my one jumper chooses IRQ (which I wouldn't have noticed any change from during POST).

At the moment no ideas aside from it's likely to be something utterly obvious that we're overlooking 😀

highvoltage wrote on 2024-04-25, 15:58:

weedeewee wrote on 2024-04-25, 15:23:

the first two bytes should be 0x55 0xAA […]
Show full quote

Copy code to clipboard

1debug
2n PX-HDC.BIN
3RCX
42000
5W C800:0
6Q

the first two bytes should be 0x55 0xAA

Thanks weedeewee! That was very helpful. If I do the -d, I see something that looks like a ROM and even a copyright string (picture attached)! But when I do a w (even from scratch verbatim as above), I just get a file full of hex FF.

Any ideas?

Wait. with this screen output, you say the file is filled with FF ?
I just tried the same steps here in a dosbox and it works for me.
to view the file
just

1debug PX-HDC.BIN
2d
3q

weedeewee wrote on 2024-04-25, 16:16:

Wait. with this screen output, you say the file is filled with FF ? I just tried the same steps here in a dosbox and it works f […]
Show full quote

Wait. with this screen output, you say the file is filled with FF ?
I just tried the same steps here in a dosbox and it works for me.
to view the file
just

Copy code to clipboard

1debug PX-HDC.BIN
2d
3q

Yep, it looks like it dumps it fine to screen, but not to disk... photos attached.

ok maybe

1debug
2n px-hdc.bin
3M C800:0 2000 1000:0
4W 1000:0
5q

Which DOS are you using ?

weedeewee wrote on 2024-04-25, 16:58:

ok maybe […]
Show full quote

ok maybe

Copy code to clipboard

1debug
2n px-hdc.bin
3M C800:0 2000 1000:0
4W 1000:0
5q

Which DOS are you using ?

No such luck. This is MS-DOS 5.0, I can try something else?

you made a typo 😀
not once
not twice
but three times !

1debug
2n px-hdc.bin
3
4M C800:0 2000 1000:0
5^ !!!!!!!!!!!!!!!!!!!!!!! it's an m for mama or mother or majestic !
6
7W 1000:0
8q

I tried the exact same thing DEBUG commands on DOS 5 and it worked for me on a HD controller at C800.

Here's a variation on a theme that *should* be the same thing as the others... but who knows maybe you'll get lucky.

1-n px-hdc.bin
2-r cx
3:2000
4-r cs
5:c800
6-w cs:0

Now we really want to see this ROM! 😀