• Please review our updated Terms and Rules here

SCSI hard drive on 486

T

The_Maister

New Member
Joined
Jan 2, 2023
Messages
4
Hello all,
I just got a full height 1.2GB micropolis hard drive (1598-15D), and trying to run it on my 486.

The system has windows 95 installed on IDE hard drive, which attached to a on board IDE controller.
There is also a PCI SCSI adapter, adaptec AVA-2902I (Chip: AIC-7856T) without BIOS, which I attached the SCSI hard drive to.

I installed on windows a package called "Adaptec EZ-SCSI Deluxe Edition v5.0 for Windows" as SCSI controller drivers.
Device manager recognizes the controller with no problems.
I also configured the hard drive by jumpers to be "ID0".
I don't have a SCSI terminator, but it is the only device on the bus, and I didn't attached it to the end of the cable. Is it necessary? Is there any built-in termination on the hard drive itself?

I just can't see the drive anywhere, and I really don't know where to look for it. fdisk does not recognize it, and I couldn't find any other device management tool in windows.
Where should I look for the drive? How can I format it and assign a drive letter for it so I can use it like a standard drive?

Thanks!
 
I would guess you need the terminator or set those that might be on the drive itself. I seem to remember that Windows is more of a stickler for
proper termination than Linux is. Most SCSI drives have onboard termination at least that I know of. Hopefully others more knowledgeable can
verify that.
 
Doesn't the drive have a jumper to enable termination? Are the termination resistor networks gone with the wind?

You might have better luck using the the drivers here.

If all else fails, try installing the drivers for DOS and see if ASPI sees the drive.
 
The_Maister said:
I don't have a SCSI terminator, but it is the only device on the bus, and I didn't attached it to the end of the cable.
Click to expand...
That is both wrong. You can not have an unused part of the cable after the last device (unless you terminate the cable end itself), nor can you run the SCSI bus without proper termination on both ends. You need to fix those two issues before dealing with drivers.

Termination on hard disks was done by three resistor packs on early drives. Later it was just a single jumper.
 
Last edited:
The Micropolis 1598-15D requires a differential SCSI host adapter.

You probably didn't damage the host adapter, but did probably damage the drive. It's possible you got lucky.
 
Thanks for the comments.
I made some homework on the spoken above.

As I understand, I can attach a terminator to the hard drive itself, and put it at at the end of the interface cable, or else, I can attach a separate terminator to the end of the cable. I don't have any of them, that's the way I got the drive.

As for the differential interface issue - I found the same warning on adaptec site unfortunately. Any possible way to know if I damage the hard drive somehow? Do you have any idea what can go wrong in there?
If I will be sure that the hard drive is damaged, and irreparable, I probably won't bother getting the right controller for it. Otherwise, I'll buy all the stuff I need and retry running it.
 
High voltage differential drives such as the OP's Micropolis cannot be used with a low voltage differential host adapter, either.
 
Did you use an active or passive 50 pin adapter? You can use that drive with that card but need an active powered adapter, how I use LVD drives with an ISA SCSI II Adaptec. Rest easy I went through same problem and had to learn myself. I did not damage the drives luckily. Downside, they are getting harder to find, and not cheap usually... Other option is grab another card. A 2940UW If I remember right works for both. (edit: 2944uw I think and not just a 2940uw will work , I dunno memory is a tiny bit fuzzy after a few glasses of wine LOL )

Here's an active adapter...
1672804930463.png
This one is passive
1672804884843.png
 
Last edited:
So like that Quantum drive I was trying to use and was soooo slow on the PPro. Gotcha. Ya I'm lucky to have a bunch of different converters now from that LOL! Not worth the effort for 1-1.5MBps. I got some LVD drives for 10 bux a piece that are 30gb or so. 8.1GB that it will see is fine by me. 👍
 
Last edited:
I think I will go on the compatible controller route, but I'll keep in mind the adapter/converter option.
Any recommendations for an ISA controller compatible with differential SCSI2?
 
Your choices will be somewhat limited. Adaptec 2944UW and 3944UW come to mind. The Symbios 22802 is another.
LSI logic, I believe made a couple of models as well.

Do note that you cannot run SE/LVD devices on an HVD conntroller !
 
Those are PCI boards. I can think of some EISA HVD boards, but I think ISA ones are going to be very thin on the ground. Offhand I can't think of an Adaptec or DPT model that exists. Buslogic might have made one.
 
Bear -- poster says he's using a PCI board on his 486 box. Granted, the PCI is probably 1.0, but worth a try with the 2944.
There is also a PCI SCSI adapter, adaptec AVA-2902I (Chip: AIC-7856T) without BIOS, which I attached the SCSI hard drive to.
Click to expand...
 
Sure. But he asked for a recommendation of an ISA model. The AHA2944 is probably a reasonable choice, though I have had unexplained trouble in practice trying to use an 8-bit HVD device on any of several 16-bit HVD host adapters. Not sure if there are non-wide 2944s, or indeed if a 2944W would exhibit the same kind of trouble I ran into.
 
Well, that's going to be a problem. There's the HP 25525B which is EISA, but that's as close as I can get--then there's the matter of finding drivers for an uncommon card. If the OP wants an ISA or VLB card, it'll have to be a SE card used with a converter. For narrow SCSI, those are pretty thin on the ground. Rancho and Black Box made some back in the day; maybe one of those will turn up somewhere. eBay has a couple of Ancot converters, but wall warts aren't included and I have no knowledge of them.

Personally, I'd get rid of the drive. HVD was never really popular--and used almost exclusively on external drives.
 
Last edited:
You must log in or register to reply here.
Back
Top