The card and drive:

I haven't had any problems using an adapter like the one in the EBay link. Mine is attached to a Seagate Cheetah 36GB drive running in my Compaq Prosignia 300 server. It sees it like any other ordinary 50/68pin SCSI drive.

Yes it should. SCSI is usually backwards compatible.

Just make sure that the SCA adapter that you're getting has ID jumpers and termination resistors on it.

Vynix wrote on 2020-04-11, 00:29:

Yes it should. SCSI is usually backwards compatible.
Just make sure that the SCA adapter that you're getting has ID jumpers and termination resistors on it.

Yes ! This SCA adapter will work:
https://www.amazon.com/SCA-SCSI-Adapter-Activ … r/dp/B001TJ45FW
Also double check the drive for a "Force SE" mode jumper. Nearly all SCA SCSI drives are LVD (Low voltage Differential) but most have a jumper to force Single Ended mode which your card is. If the drive does not have a Force SE mode then it will not work with 1542CF.

Please remember that the BIOS of such an old SCSI controller has capacity limits.

Swiego wrote on 2020-04-10, 23:03:

The card is an ISA SCSI card that looks to have a 50 pin connector on it. […]
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The card is an ISA SCSI card that looks to have a 50 pin connector on it.

The drive is I believe an Ultra Wide SCSI using an 80 pin SCA connector which I believe was a hot swap style.

I have found online some options to convert/adapt:
https://www.amazon.com/Micro-SATA-Cables-SCSI … R/dp/B0058V1UWS
https://www.amazon.com/PTC-SCA-Pin-SCSI-Adapt … r/dp/B074TYC7KC
https://www.ebay.com/c/1631507625
(links are examples... not advertising or endorsing any of these!!)

Would one of these kinds of adapters allow these two pieces of hardware to coexist? Am I asking for trouble? Any advice before I jump down this particular rabbit hole?

these adapter will force drive work in Single Ended mode which may compatible with your card.
I tested the same adapter with ultra 320 sca + an old adaptec 50 scsi card (AHA-2930C) and it recognized the drive but with the wrong size (LBA?)
tested the drive + adapter + 50pin to 68pin adapter with the intel SRCU42L recognized the drive with correct size (and with SE speed)
connected the card 68 pin direct to adapter's 68 pin does not work.

Thanks - I bought an adapter (that advertised termination) along with a 50/68 converter and another card with a 68-pin connector. It'll be interesting to see what I'm able to achieve.

I received the adapter and, well, am struggling.

Out of the box, on power up the Cheetah drive seems to repeat a cycle of 1s whir, click and beep. The Adaptec ROM utility, when I select Disk Utilities, scans the bus and hangs. The drive itself doesn’t seem to be spinning outside the repeating sound. I am connecting using the adapter and a 50 pin cable. I have one cable that is simple (only two connectors, one at each end) and another that has several connectors plus what looks like a terminator at one end. Neither work.

I had a 1GB SCSI drive from another computer which I hooked up to the Adaptec... works fine with the simple connector. So the adapter is likely not the issue.

My todo idea list I have not burned through yet:
- I read some reviews that the 50 pin connector on the SCA adapter doesn’t work and to use the 68 pin connector with a 68-50 adapter. One is ordered.
- I haven’t checked the firmware of the 1542cf nor upgraded it
- The Adaptec has some dip switches I should check out
- maybe the drive, a cheap eBay special, is bad?
- I am tossing this in an old Pentium 60... could the psu be too weak to power this?

Any other avenues to explore?

Horun wrote on 2020-04-11, 01:09:

Yes ! This SCA adapter will work: https://www.amazon.com/SCA-SCSI-Adapter-Activ … r/dp/B001TJ45FW Also double check the drive fo […]
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Vynix wrote on 2020-04-11, 00:29:

Yes it should. SCSI is usually backwards compatible.
Just make sure that the SCA adapter that you're getting has ID jumpers and termination resistors on it.

Yes ! This SCA adapter will work:
https://www.amazon.com/SCA-SCSI-Adapter-Activ … r/dp/B001TJ45FW
Also double check the drive for a "Force SE" mode jumper. Nearly all SCA SCSI drives are LVD (Low voltage Differential) but most have a jumper to force Single Ended mode which your card is. If the drive does not have a Force SE mode then it will not work with 1542CF.

Thanks! The drive is a st34501wc which as far as I can tell is a single ended drive. Hope I did not misread this.

Swiego wrote on 2020-04-16, 05:09:

I received the adapter and, well, am struggling. […]
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I received the adapter and, well, am struggling.

Out of the box, on power up the Cheetah drive seems to repeat a cycle of 1s whir, click and beep. The Adaptec ROM utility, when I select Disk Utilities, scans the bus and hangs. The drive itself doesn’t seem to be spinning outside the repeating sound. I am connecting using the adapter and a 50 pin cable. I have one cable that is simple (only two connectors, one at each end) and another that has several connectors plus what looks like a terminator at one end. Neither work.

I had a 1GB SCSI drive from another computer which I hooked up to the Adaptec... works fine with the simple connector. So the adapter is likely not the issue.

My todo idea list I have not burned through yet:
- I read some reviews that the 50 pin connector on the SCA adapter doesn’t work and to use the 68 pin connector with a 68-50 adapter. One is ordered.
- I haven’t checked the firmware of the 1542cf nor upgraded it
- The Adaptec has some dip switches I should check out
- maybe the drive, a cheap eBay special, is bad?
- I am tossing this in an old Pentium 60... could the psu be too weak to power this?

Any other avenues to explore?

I think your hard drive is likely to toasted.

To test:
1. connect the SCA adapter to hdd but don't connect scsi cable, and power it, is it still have the same problem?
2. did you attached the terminal adapter to the other end of the 50 pin cable?
3. or if you are using the 68 pin cable with 50/68 pin adapter, does the cable have the built-in terminal?
4. and did you check the voltage of your power supply? does the 12v line read around 12v? does 5v line read around 5v?

I connected the drive to the SCA adapter, and the adapter to the power supply. On both this vintage PC as well as a modern system (1200W supply) the drive makes similar whir & beep sounds. In the case of the latter system the 12V and 5V lines are spot on. What is the expected behavior... normal spin-up of the drive?

If so, perhaps it's either the drive or the adapter itself. The adapter itself doesn't exactly look like a work of art... none of the adapters I saw on Amazon and eBay did.

ISTM that 10K/15K RPM SCSI HDDs seem to be more fragile, I've had a Hitachi Ultrastar 15K and it didn't work for long before it exhibited the same symptoms (click and whirr before failing altogether).

Some SCA80 drives may need some jumper adjustments to spin up... iirc in servers they were set to spin one after the other to avoid blowing the server's PSU because of the inrush current.

My IBM Ultrastar 9ES (a older drive) also did a similar scare to me, it would flat out not start, I later found out that it's because of a jumper setting.

There's a load of "Gotchas" with SCSI...

There sure is!

I thought I might be getting closer experimenting with different jumper combos governing spin up but ultimately it didn’t make a difference. I also got the 68/50 pin adapter and it did not help either. The drive is not terminated and I am concerned that my one cable with a terminator at the end may not be good so I’ll try to find a fresh cable with a terminator. If not successful then I may have to chalk this up to a bad drive and have to determine if I try to source another and, if so, how to ensure better odds the next time around.

SCSI is such a pain.

FWIW, I got a Maxtor Atlas 10k.4 SCA and it works perfectly.... the Cheetah was a bad drive.

The setup is rather stable once, as other posters said, all the compatibility issues are sorted out.

So, many interesting findings as of late. Ultimately what I'm trying to sort out is:

I have a Pentium 60 with ISA slots and an on-board IDE controller that (a) may or may not be on a proprietary local bus and (b) struggles with the 504MB limit sans mitigations. Therefore, what of the following is best performing:

1) Local IDE controller with an DDO
==> Using OnTrack + DiamondMax Plus 9 80GB, 80GB FAT32 partition (thanks DDO!)
(+) max disk space, no cards
(-) drive won't mount cleanly on other systems due to overlay

2) Local IDE controller with replacement controller BIOS
==> Using a Promise EIDE Max card + DiamondMax Plus 9 80GB, 8GB partition (BIOS limit)
(+) easy to swap drive to modern computer & transfer files w/o overlay causing issues
(-) not utilizing space; Promise BIOS perhaps not as good as XTIDE or others?

3) ISA SCSI with the fastest drive I can find
==> Using an Adaptec 1542CF with 10k, 15k drives, 8GB partition (BIOS limit)
(+) 15k rpm seek times are pretty sweet
(-) hot, hot, still need IDE controller for optical or $$ SCSI optical, hot, performance not better

Looking at max disk throughput (512kb, 1mb transfer size) I end up with:
1) Local controller w/ODD: 1.9MB/sec
2) Local controller w/Promise BIOS: 2.0 MB/sec
3) Adaptec w/36GB 15k U320 + adapter: 1.7 MB/sec

In terms of responsiveness, the SCSI option feels ~ 15% faster in day to day Windows 98SE, which is significant but not mind-bending. But I am not seeing it benchmark faster in sustained transfer rate. It obviously runs hot... unacceptably hot for this vintage computer with limited air flow.

So what I'm gathering is that,
a) this computer (Deskpro XE 560) does not have an on-board IDE controller that has 'local bus' speed advantages
b) given the above, it doesn't matter too much what configuration I use... performance will be similar.
c) at this point, the Adaptec though reliable doesn't unlock a substantially superior level of performance

Anything I should be checking? Now that I have all this hardware, any more robust benchmarks I should run & publish for posterity before tearing all this down?

I vote quit worrying about the heat and rock the SCSI

Swiego wrote on 2020-05-01, 01:55:

So, many interesting findings as of late. Ultimately what I'm trying to sort out is: […]
Show full quote

So, many interesting findings as of late. Ultimately what I'm trying to sort out is:

I have a Pentium 60 with ISA slots and an on-board IDE controller that (a) may or may not be on a proprietary local bus and (b) struggles with the 504MB limit sans mitigations.
So what I'm gathering is that,
a) this computer (Deskpro XE 560) does not have an on-board IDE controller that has 'local bus' speed advantages
b) given the above, it doesn't matter too much what configuration I use... performance will be similar.
c) at this point, the Adaptec though reliable doesn't unlock a substantially superior level of performance

Anything I should be checking? Now that I have all this hardware, any more robust benchmarks I should run & publish for posterity before tearing all this down?

Unfortunately you are most likely stuck. Some socket 4 boards did have "local bus" IDE controllers but it sounds like everything on yours is thru the ISA bus. So no improvement using onboard IDE vereus a fast SCSI drive with an ISA SCSI card. Sort of a waste of a Cheetah drive on a ISA scsi card...

You are never going to get great throughput out of the ISA bus, but you could get better seek times by using an SSD through an IDE to SATA converter or Compact Flash to IDE adapter. As for the 540MB limitation, an XT-IDE BIOS on an ISA network card can take care of that and support up to 127GB . See http://www.xtideuniversalbios.org/

As a matter of intellectual curiosity, is there a max performance anyone has seen from disk I/o through a16 bit ISA slot?

Tweaking some settings and replacing the 15k SCSI disk (some HP branded enterprise drive) with a Maxtor Atlas 10k.4 72gb got me up to ~2.4MB/sec which is the best I’ve seen so far.