PDA

View Full Version : IBM AT 5170 and SCSI HDD ?



Sandisk78
May 15th, 2017, 10:50 AM
I have a working 6mhz AT 5170 with 640k RAM and 20 + 30 mb MFM HDD. Tried to use in it common ISA-16 IDE IO card and a ISA-16 SCSI card, working on "common" 1988-1990 AT 286's, but in the IBM 5170 they hang the system(... Can it be solved or maybe some special SCSI hard must be found ? I heard people use SCSI HDD's in XT class machines... Common ISA16 VGA and SB clone work in that 5170 wel..

krebizfan
May 15th, 2017, 11:09 AM
You may want to say which controllers you are using. Some can be trickier than others. Are you trying to have multiple controllers or replace the MFM controller? Replacing should be fairly easy if your cards have bootable ROMs. Having both MFM and IDE controllers in the same system didn't work when I tried it.

If you want to try to have both MFM card and SCSI card, you will likely need to disable the SCSI ROM and install SCSI drivers on the MFM boot drives. I know I hooked up external SCSI drives to an AT clone which booted off MFM hard drives. I remember it as being easy but it has been about 25 years since I did it.

lutiana
May 15th, 2017, 11:17 AM
I had the exact same issue with an Adaptec SCSI card (i'll have to look up the model number later). Would not work in the system, no matter what I tried. From the research I did I found a few people who had had issue with that exact same SCSI card.

EDIT: Nevermind, my issue was exactly like OP's issue here (http://www.vcfed.org/forum/showthread.php?39010-Adaptec-AHA-1542cp-on-IBM-5170)

kgober
May 15th, 2017, 11:39 AM
If you have "MFM" hard disks then you really need to use "MFM" controllers. It is possible that if your drives are of good quality (or if you are lucky) you may be able to use them with "RLL" controllers as well. But you can't use an "MFM" drive with an "IDE" or "SCSI" controller unless you have some kind of converter.

SCSI typically uses a single 50-pin cable. IDE uses a single 40-pin cable. MFM and RLL use a 34-pin control cable that attaches to both drives, and one 20-pin data cable for each drive (so if you have 2 drives that means 3 cables total, 1 control cable and 2 data cables).

-ken

Sandisk78
May 15th, 2017, 12:03 PM
If you have "MFM" hard disks then you really need to use "MFM" controllers. It is possible that if your drives are of good quality (or if you are lucky) you may be able to use them with "RLL" controllers as well. But you can't use an "MFM" drive with an "IDE" or "SCSI" controller unless you have some kind of converter.

SCSI typically uses a single 50-pin cable. IDE uses a single 40-pin cable. MFM and RLL use a 34-pin control cable that attaches to both drives, and one 20-pin data cable for each drive (so if you have 2 drives that means 3 cables total, 1 control cable and 2 data cables).

-ken

I know all that - I use and collect vintage computers since 2006. The question is - why SCSI card and a SCSI HDD works fine in "noname AT 286", but hangs the IBM AT 5170... Tomorrow I'll write the exact name of the SCSI controller - it's on another place now(

Stone
May 15th, 2017, 12:18 PM
If you have "MFM" hard disks then you really need to use "MFM" controllers. It is possible that if your drives are of good quality (or if you are lucky) you may be able to use them with "RLL" controllers as well. But you can't use an "MFM" drive with an "IDE" or "SCSI" controller unless you have some kind of converter.Really? What converter(s) do you suggest with MFM drives to use them with SCSI or IDE controllers?

Sandisk78
May 15th, 2017, 12:26 PM
I don't want to use MFM HDD's with SCSI controller - I just want to say it boots with MFM controller and HDD and refuses to work with SCSI HDD and controller..)

Of course I removed the MFM controller before trying IDE or SCSI one )

RichCini
May 15th, 2017, 01:01 PM
I'm using an Adaptec AHA-1522A with an Imprimis/Seagate ST2502N SCSI drive on my 5170 and it seems to work well. I removed the stock AT controller and use the Adaptec for both floppy and SCSI.

I will say that occasionally the SCSI bus hangs, requiring a reboot, but it's infrequent. In the SETUP you have to remember to set the CMOS to "no" hard drives and let the SCSI BIOS take over.

paul
May 15th, 2017, 02:28 PM
Really? What converter(s) do you suggest with MFM drives to use them with SCSI or IDE controllers?

OMTI made such devices for SCSI drives.

paul
May 15th, 2017, 02:33 PM
I know all that - I use and collect vintage computers since 2006. The question is - why SCSI card and a SCSI HDD works fine in "noname AT 286", but hangs the IBM AT 5170... Tomorrow I'll write the exact name of the SCSI controller - it's on another place now( So you've established which controller will host the boot drive and disabled the other? Almost certainly an MFM will need to remain the boot drive and the SCSI bios disabled with a driver added to access them.

bhtooefr
May 16th, 2017, 09:07 AM
Really? What converter(s) do you suggest with MFM drives to use them with SCSI or IDE controllers?

Adaptec and others made quite a few - many early SCSI external hard drives were actually just MFM drives with a SCSI-based controller in the box.

Chuck(G)
May 16th, 2017, 09:26 AM
I have to admit that I'm having trouble following this discussion.

But if the OP wants to boot from an MFM hard drive and access the data on the SCSI disk, I recommend that he disable the SCSI BIOS and load drivers for the card after booting.

glitch
May 16th, 2017, 09:32 AM
Adaptec AHA-15x2 (1522 or 1542, don't remember) worked fine in my IBM 5170 PC/AT when I was using it regularly. I don't recall there being any particular difficulty in getting it going. I also completely removed the MFM/Floppy board and uses the Adaptec SCSI board for both.

Chuck(G)
May 16th, 2017, 09:49 AM
Also, if retrieval of SCSI data is the object, there are other solutions that will work with a 5170, such as the Adaptec MA348/358 parallel port adapters.

SomeGuy
May 16th, 2017, 10:45 AM
If I read the OP's post right, they simply have an ISA SCSI card that works in another computer, but freezes up in an IBM AT 5170.

In general, this should work.

I'd suspect some compatibility problem or hardware conflict. Try removing all other cards from the system and see if the card operates then.

Does the IBM AT otherwise operate normally and pass various diagnostic tests?

We still need to know exactly what model of SCSI card this is. Some ISA SCSI cards - usually meant for scanners - do not have a BIOS, and can not boot hard disks.