Having trouble getting CF / SD card working with 486 \ VOGONS

Having trouble getting CF / SD card working with 486

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First post, by edisgreat

Posted on 2025-03-26, 03:09

edisgreat Offline

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I am trying to set up an old 486 to use either sd or compactflash for a harddrive. I am having a lot of trouble.

My setup is:

- Motherboard with integrated 486 / SX chip. Pretty sure its this: https://theretroweb.com/motherboards/s/ast-br … c-4-33d-lc-4-50

- Original HDD from ~1991 that will load ok.

- 256 mb sd card with ide to sd

- 256 mb cf card with ide to cf

- 3.5" disks from msdos. Tried both from REMOVED and REMOVED

At first I tried just loading it normally, allowing bios to autodetect the HDs. I encounter Im pretty sure the exact error here: https://retrocomputing.stackexchange.com/ques … ter-fails-at-99 which is that is gets to 99%, and then tries to read / write command.com and fails. Whats interesting is the command.com is actually on the drive just fine. But the installiation errors out. Same error for both CF and SD card.

Loading it from the cards at this point just ends up with a cursor on the screen with no boot.

I tried playing around with the bios settings and lowering the cylinders. I also tried a full hard format on an external computer, or using fdisk and format on the actual machine. All same error.

I then tried the instructions here: https://www.dreamcast.nu/en/how-to-install-ms … using-a-floppy/ which actually got MSDOS installed correctly on the drive while it was virtualized. But then it wouldnt recognize it as a system disk in the actual machine.

Using FDISK /MBR also didnt help with any of these steps.

Im a bit lost at what to try here. I was going to try doing the virtualbox install again. But Im wondering if the 486 / SX is the actual problem. Wondering if I should jsut get a whole new motherboard.

Or maybe its the bios settings. I saw some recoomendations for idediag.exe or equivilents. Maybe the bios autodetect is wrong. Or even a whole new dos (5.0? )

Reply 1 of 10, by Cbb

Posted on 2025-03-28, 10:40

Cbb Offline

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CF cards are not the same as HDDs.
option 1. try another CF card
option 2. use mbr fix to boot from patched card.

Reply 2 of 10, by OVERK|LL

Posted on 2025-03-28, 11:02

OVERK|LL Offline

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What CF adapter are you using?

DD: Mac Pro 5,1 - X5690, 64GB, RX 580 - OCLP w/Sequoia
Projects:
- Hewitt-Rand 8088 - 640KB, 20MB, Hercules mono
- IBM PS/1 2133 w/Thermalwrong solder mod - ODP 486DX4-100, 32MB
- PCPartner VIB806DS w/233MMX, 128MB, G450
- Jetway J-TX98B w/P75, 256MB

Reply 3 of 10, by wierd_w

Posted on 2025-03-28, 16:29

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OVERK|LL wrote on 2025-03-28, 11:02:

What CF adapter are you using?

This, AND, are you trying to share an IDE channel with a slave device (cdrom, zip drive, etc) as well?

A great many SD->IDE devices are based on the 'sintechi' design, which DOES NOT ALLOW slave device presence on the channel.

It also DOES NOT do LBA48, even though it pretends it does. If this is the kind of adapter you have, DO NOT put an SDcard larger than 128gb in it. You will experience only pain and frustration if you do.

As for "use in a 486", you almost certainly will need either a NIC with XTIDE bios in the socket, (or an XTIDE equipped controller), or a dynamic drive overlay (DDO) of some flavor.

Vogon's driver archive has EZDrive available, which will '0$' provide a 'period accurate' solution to the 'old INT13 implementation' problem. (And give you 32bit multiword transfer mode).

XTIDE is preferable though.

Reply 4 of 10, by keenmaster486

Posted on 2025-03-28, 16:42

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Which CF adapter?
Which CF cards?

World's foremost 486 enjoyer.

Reply 5 of 10, by edisgreat

Posted on 2025-04-02, 19:01

edisgreat Offline

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UPDATE:

I got it working with the following method:

- Bought a Transcend Industrial 512mb CF card
- When I tried to install it on the actual machine again hitting the 99% error
- Install on a virtual box using the sd as a hard drive using the method I linked earlier
- Also on virtualbox, used EZ Drive to install the ez-drive driver, set LBA = true, Multi-sector transfer = false
- Brought to new computer and it loaded MS-DOS!
- Successfully installed windows, Direct access, games, mouse drivers, etc.

Thank you all for the help!

Reply 6 of 10, by douglar

Posted on 2025-04-02, 19:49

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edisgreat wrote on 2025-04-02, 19:01:
UPDATE: […]
Show full quote

UPDATE:

I got it working with the following method:

- Bought a Transcend Industrial 512mb CF card
- When I tried to install it on the actual machine again hitting the 99% error
- Install on a virtual box using the sd as a hard drive using the method I linked earlier
- Also on virtualbox, used EZ Drive to install the ez-drive driver, set LBA = true, Multi-sector transfer = false
- Brought to new computer and it loaded MS-DOS!
- Successfully installed windows, Direct access, games, mouse drivers, etc.

Thank you all for the help!

I've seen stuff like that on a Dell OptiPlex GX Pro.

The BIOS detects the CF devices as "EIDE" and won't let me manually configure a CHS geometry.

Formatting fails near the end of the volume. EZ Drive won't install, complaining about the last sectors not working right.

My guess is that the BIOS is new enough that it thinks it can use LBA addressing, but it is using LBA22 and the CF is speaking LBA28, but that's just a guess. LBA22 should go up to 2GB. Could be it is just failing to get the geometry correct.

Adding an option rom like XTiDE or DTC IDE BIOS seems to help.

Last edited by douglar on 2025-04-02, 20:06. Edited 1 time in total.

Reply 7 of 10, by nfraser01

Posted on 2025-04-02, 19:58

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edisgreat wrote on 2025-03-26, 03:09:

I am trying to set up an old 486 to use either sd or compactflash for a harddrive. I am having a lot of trouble.

I had the same problem with a Dell 486. Never got it working despite using industrial CF cards and reading the actual HCS etc. Reverted to spinnig rust in the end, which I kind of prefer anyway...

Glad you got it working.

Reply 8 of 10, by edisgreat

Posted on 2025-04-03, 02:28

edisgreat Offline

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nfraser01 wrote on 2025-04-02, 19:58:

edisgreat wrote on 2025-03-26, 03:09:

I am trying to set up an old 486 to use either sd or compactflash for a harddrive. I am having a lot of trouble.

I had the same problem with a Dell 486. Never got it working despite using industrial CF cards and reading the actual HCS etc. Reverted to spinnig rust in the end, which I kind of prefer anyway...

Glad you got it working.

I reallllly wanted to avoid spinning rust so I can get my vision of dozens of games all on Directaccess. Hoping to get a showcase and Ill post a success video down the line

Reply 9 of 10, by edisgreat

Posted on 2025-04-03, 02:31

edisgreat Offline

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Joined: 2025-03-26, 03:07

douglar wrote on 2025-04-02, 19:49:
I've seen stuff like that on a Dell OptiPlex GX Pro. […]
Show full quote

edisgreat wrote on 2025-04-02, 19:01:
UPDATE: […]
Show full quote

UPDATE:

I got it working with the following method:

- Bought a Transcend Industrial 512mb CF card
- When I tried to install it on the actual machine again hitting the 99% error
- Install on a virtual box using the sd as a hard drive using the method I linked earlier
- Also on virtualbox, used EZ Drive to install the ez-drive driver, set LBA = true, Multi-sector transfer = false
- Brought to new computer and it loaded MS-DOS!
- Successfully installed windows, Direct access, games, mouse drivers, etc.

Thank you all for the help!

I've seen stuff like that on a Dell OptiPlex GX Pro.

The BIOS detects the CF devices as "EIDE" and won't let me manually configure a CHS geometry.

Formatting fails near the end of the volume. EZ Drive won't install, complaining about the last sectors not working right.

My guess is that the BIOS is new enough that it thinks it can use LBA addressing, but it is using LBA22 and the CF is speaking LBA28, but that's just a guess. LBA22 should go up to 2GB. Could be it is just failing to get the geometry correct.

Adding an option rom like XTiDE or DTC IDE BIOS seems to help.

Yeah that was going to be my next path, getting new IDE port with the XTIDE stuff. But I cant solder and that would have been another $60 or so. So I was trying to hit all the low hanging fruit with what I had.

Whats reallllly interesting was the dos installer kept erroring on the same file: command.com . Always an error reading it, even though it was on the disk. I saw someone somewhere suggest the install via virtualbox, and I kept trying combos to get it working and finally got lucky

Reply 10 of 10, by douglar

Posted on 2025-04-03, 03:13

douglar Offline

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edisgreat wrote on 2025-04-03, 02:31:

douglar wrote on 2025-04-02, 19:49:
I've seen stuff like that on a Dell OptiPlex GX Pro. […]
Show full quote

edisgreat wrote on 2025-04-02, 19:01:
UPDATE: […]
Show full quote

UPDATE:

I got it working with the following method:

- Bought a Transcend Industrial 512mb CF card
- When I tried to install it on the actual machine again hitting the 99% error
- Install on a virtual box using the sd as a hard drive using the method I linked earlier
- Also on virtualbox, used EZ Drive to install the ez-drive driver, set LBA = true, Multi-sector transfer = false
- Brought to new computer and it loaded MS-DOS!
- Successfully installed windows, Direct access, games, mouse drivers, etc.

Thank you all for the help!

I've seen stuff like that on a Dell OptiPlex GX Pro.

The BIOS detects the CF devices as "EIDE" and won't let me manually configure a CHS geometry.

Formatting fails near the end of the volume. EZ Drive won't install, complaining about the last sectors not working right.

My guess is that the BIOS is new enough that it thinks it can use LBA addressing, but it is using LBA22 and the CF is speaking LBA28, but that's just a guess. LBA22 should go up to 2GB. Could be it is just failing to get the geometry correct.

Adding an option rom like XTiDE or DTC IDE BIOS seems to help.

Yeah that was going to be my next path, getting new IDE port with the XTIDE stuff. But I cant solder and that would have been another $60 or so. So I was trying to hit all the low hanging fruit with what I had.

Whats reallllly interesting was the dos installer kept erroring on the same file: command.com . Always an error reading it, even though it was on the disk. I saw someone somewhere suggest the install via virtualbox, and I kept trying combos to get it working and finally got lucky

You probably don’t need a new ide port, you just need the Xub bios patch.

It might be worth while to see if EZ drive can fix the issue:
https://vogonsdrivers.com/getfile.php?fileid=1900

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