The 80-pin cable also has only 40 data conductors, like the 40-pin cable. The other 40 is shielding (for safe faster transfer). Both cables can be connected to one and the same connector. I'm not sure, if the BIOS motherboard, in which you use the controller, can detect a 20 GB disc - the limits of the time were much lower - 512MB or 8.4GB, if I'm not mistaken.

~500MB on older bios, ~2GB on FAT16 filesystem, ~8GB or ~32GB or ~128GB on newer bioses.

According to what is the limiting factor, there are different workarounds for that.

Does your BIOS allow for LBA setup?

If yes: you could probably got up to 2GB and possibly the whole 8GB. Some systems wind allow for more than 2GB for some reason. You just figure out 😀

If no: chs is the only way, so the 528MB limit will be there. You might get away with setting up the hard drive as 1024/16/63 (528MB) and let drive overlay take care of the rest.

As for the 80w cable: your system won't do ATA66 or faster. The cable would be overkill. As mentioned: shielding is the key.
If your cable doesn't fit because of the 'filled' hole, you could open it up with a small drill. Or snip away the particular pin on the controller (I wouldn't, but it's possible)

The Driver will be the limiting factor.
My DTC VLB controller driver only supports up to 410mb hard drives.
You need to use the driver in order to get the second channel to work.
But if you use a CF card forget about the driver limitations.
With a CF card you can get good performance in 16bit mode.
The Driver might work in 32bit mode with CF card. But I have never tried it.
I dont know how the driver will react to a CF card ?

Intel486dx33,
pshipkov seems to have no problem getting a large CF or HDD working on the DTC VLB card.Re: 3 (+3 more) retro battle stations

The BIOS does allow me to enable LBA mode and I can enter in CHS values up to 8.4GB using the Maxtor provided settings. However, even after entering these values I still get an HDC error after power on and MS-DOS can't see the drive during setup. I've also tried adding a jumper on the drive to limit the capacity. The drive does work so I'm thinking it's the 40 wire cable. I'll try hollowing out pin 20 on the connector of an 80 wire cable so it will fit over the pin on the interface card.

chestertonic wrote on 2021-03-17, 20:39:

The BIOS does allow me to enable LBA mode and I can enter in CHS values up to 8.4GB using the Maxtor provided settings. However, even after entering these values I still get an HDC error after power on and MS-DOS can't see the drive during setup. I've also tried adding a jumper on the drive to limit the capacity. The drive does work so I'm thinking it's the 40 wire cable. I'll try hollowing out pin 20 on the connector of an 80 wire cable so it will fit over the pin on the interface card.

Just to be sure...

You did verify pin 1 on the controller goes to pin 1 on the cable, and goes to pin 1 on the hard drive , since it looks like that vlb controller would allow for such mistakes to be made ?

I think most people got used to setting IDE drives to cable select and old gear wants drives jumpered for either master or slave.

Try using a different cable.

Try running a program called “ClearHDD”
See LGR video
https://youtu.be/VWfTgga7rmA

weedeewee wrote on 2021-03-17, 20:54:

chestertonic wrote on 2021-03-17, 20:39:

The BIOS does allow me to enable LBA mode and I can enter in CHS values up to 8.4GB using the Maxtor provided settings. However, even after entering these values I still get an HDC error after power on and MS-DOS can't see the drive during setup. I've also tried adding a jumper on the drive to limit the capacity. The drive does work so I'm thinking it's the 40 wire cable. I'll try hollowing out pin 20 on the connector of an 80 wire cable so it will fit over the pin on the interface card.

Just to be sure...

You did verify pin 1 on the controller goes to pin 1 on the cable, and goes to pin 1 on the hard drive , since it looks like that vlb controller would allow for such mistakes to be made ?

Yup, the VLB card has pin 1 labeled. That was one of the first things I checked because it is a bit ambiguous.

Edit: Checking again I noticed the cable was indeed plugged in backwards. So thank you. The hard drive is now recognized, however, the system hangs after bootup.

Finally got the HDD working. Thanks weedeewee for making me double check for the correct cable placement. Seems that the Maxtor provided CHS values were incorrect. Using the auto-detect feature in the BIOS finally worked and detected the drive. It only allows 7GB but that plenty for what I'm doing. Will probably go with a compact flash solution for a secondary drive.