I downloaded all sorts of drivers I found in another thread. They either don't work at all (can't detect the cf reader,) or the drivers load properly and detect the reader AND the size of the inserted card AND the light flashes when the drivers are loaded or when a card is inserted, but I get a "write protect on drive a" error when trying to access the drive letter assigned to the reader. I have tried changing the parallel port settings in the bios to no avail.

It is frustrating as this device is working in XP and I think I had it working in DOS either on this same 486 or it was with one of my Gateway P3s. Also, I am reading posts on VOGONS and elsewhere on the net where people are using these sorts of parallel port CF readers on machines older than this 486. As of now, I can shut down the 486 and grab one of the CF cards I use as a hard drive and put it in a card reader on my main machine, copy files, then put it back in the 486 and turn it back on. While this is an option, I would rather have a hotswap option which lets me keep my 486 running.

Hi, this is a strange problem. I can only guess what's going on.
If it's a software issue, these things are worth a try.
a) run DOS in Real-Mode (no V86, EMM386, QEMM)
b) don't load umbpci.sys (if installed)
c) try to temporarily disable MSCDEX and CD-ROM drivers
d) don't load SmartDrive

The CD-ROM thing is because of network drives.
I don't know how the datafab driver implements the drive letter, but it may do it same way like MSCDEX does.

If everything fails, you can try out both MS-DOS 6.2x and MS-DOS 7.x.
One of them via boot floppy, if needed.

If you suspect a hardware damage you can try running CheckIt! v3.
It can test both parallel and serial ports, I think.

The logical side of testing works with out a test plug (dongle).
The physical side is about the electrical aspect (buffer stages etc).

Other programs are Port Test V1.1 or Parallel Port Debug Tool 2.0.

Just keep in mind to better not have the CF reader plugged in when testing.
Some LPT port pins can be toggled between input/output via software.
So there's a danger of shorting.

Good luck! 🙂

What is the size of the CF you tried it with under DOS?

Jo22 wrote on 2024-02-28, 08:53:

Hi, this is a strange problem. I can only guess what's going on. If it's a software issue, these things are worth a try. a) run […]
Show full quote

Hi, this is a strange problem. I can only guess what's going on.
If it's a software issue, these things are worth a try.
a) run DOS in Real-Mode (no V86, EMM386, QEMM)
b) don't load umbpci.sys (if installed)
c) try to temporarily disable MSCDEX and CD-ROM drivers
d) don't load SmartDrive

The CD-ROM thing is because of network drives.
I don't know how the datafab driver implements the drive letter, but it may do it same way like MSCDEX does.

If everything fails, you can try out both MS-DOS 6.2x and MS-DOS 7.x.
One of them via boot floppy, if needed.

If you suspect a hardware damage you can try running CheckIt! v3.
It can test both parallel and serial ports, I think.

The logical side of testing works with out a test plug (dongle).
The physical side is about the electrical aspect (buffer stages etc).

Other programs are Port Test V1.1 or Parallel Port Debug Tool 2.0.

Just keep in mind to better not have the CF reader plugged in when testing.
Some LPT port pins can be toggled between input/output via software.
So there's a danger of shorting.

Good luck! 🙂

Thank you for your reply and suggestions! I didn't consider a faulty parallel port. I am using a Tomato 4dps so the parallel port is connected via ribbon cable to the mobo. I am using standard Microsoft files in my startup files, but I will try REMming out EMM386 and MSCDEX. I will attempt the tests you have suggested!

lolo799 wrote on 2024-02-28, 09:53:

What is the size of the CF you tried it with under DOS?

On y 486 I have tried an 8GB, two 4gb, and a 2gb SD via CF adapter card. All are detected by the drivers and present their size. When I tested this same parallel port CF reader in Windows 98SE on my P3, it could read a 128GB SD card via the SD-CF adapter card, and it could read my other cards. On the Athlon XP/WinXP machine, I tested my 8gb card and successfully read, copied, and deleted files from the card.

I am thinking that either there is something wrong with my 486 parallel port, or some BIOS setting is being weird, or perhaps there is a chipset incompatibility. My mobo has a SiS chipset. I found a Datafab readme.txt with one of the driver sets I tried and it list a bunch of boards and chipsets as being tested to be compatible, though I don't think that SiS is listed.I swear that I have at least one strange and obscure issue with each of my retro PCs, hehehe...

Is the power its stealing from keyboard port working? might be issue with it being only powered by LPT port.

rasz_pl wrote on 2024-02-29, 07:46:

Is the power its stealing from keyboard port working? might be issue with it being only powered by LPT port.

That's an interesting thought!

It's not same, but I think I've heard that certain old AT computer keyboards
didn't work on modern computers anymore because they drew too much current.

So maybe the problem really is related to power in one way or another.

Maybe a DIY cable can be made that connects to the +5v pin of one of the Molex/FDC plugs?
I'm just thinking out loud here.

Using an external PSU is possible, as well, of course.
Though it may introduce electric noise also. Hm.

rasz_pl wrote on 2024-02-29, 07:46:

Is the power its stealing from keyboard port working? might be issue with it being only powered by LPT port.

Jo22 wrote on 2024-02-29, 13:43:

That's an interesting thought! […]
Show full quote

rasz_pl wrote on 2024-02-29, 07:46:

Is the power its stealing from keyboard port working? might be issue with it being only powered by LPT port.

That's an interesting thought!

It's not same, but I think I've heard that certain old AT computer keyboards
didn't work on modern computers anymore because they drew too much current.

So maybe the problem really is related to power in one way or another.

Maybe a DIY cable can be made that connects to the +5v pin of one of the Molex/FDC plugs?
I'm just thinking out loud here.

Using an external PSU is possible, as well, of course.
Though it may introduce electric noise also. Hm.

I tried using AT adapters, running a PS2 extension cable from a powered AthlonXP system, and I tried using a USb-PS2 adapter with an AC -USB block. The led on the reader lights up brightly whenever it is "supposed" to work. That is the weird thing. It is detecting the size of the cards and the light does its thing when it is supposed to, but the PC just can't seem to access the card. I ordered a different Datafab-branded device still in the box with a driver CD which lists DOS and Windows 3.1 right on it. If that doesn't work (but is tested to work on different systems,) I will diagnose the issue as a mobo chipset (stupid SiS) incompatibility.

Update:

I had ordered a Datafab MDCFE-SR. I took a break from retro stuff for a couple of weeks, but I finally tested it today. The same error is occurring. The reader and the CF in it are detected, but accessing the drive letter and doing anything at all gives the error. I am diagnosing it as a SIS chipset issue since they are not listed on any document I have found and read concerning tested motherboard chipsets. I do not think that there is a solution to this problem. It looks as if there are no options for a hot-swap/portable data solution for my Tomato 4dps board. The only option I can think of is to try to find another socket 3 board, but that may be expensive, risks of failure due to age, and difficulty in finding a board with equal features (this 4dps is neat with what it can do and has a PS/2 mouse port.)

All well...

why not ordinary IDE-CF adapter mounded in the front panel?

rasz_pl wrote on 2024-03-13, 10:56:

why not ordinary IDE-CF adapter mounded in the front panel?

That is what I am using for my "hard drives." I have a dual slot IDE-CF in a 3.5 3d printed mount I grabbed from ebay. The problem is, is that you can't hotswap them. It is a minor inconvenience, I supposed. Shutting down and powering back on takes less than a minute. I am also looking into a network option with an FTP or a Windows 3.11 install on an 86box PC.