68 pin SCSI in Amiga

[Zac67]

Wide cable terminators are usually no problem to obtain and once the bus is terminated in whole there's no need for 'half-terminators' any more. You can also use built-in terminators on the end drives instead of cable terminators. OTOH most wide drives run fine on a narrow bus, there are few refusing to (esp. IBMs).

[amigadave]

I have just recently purchased several 68pin & 80pin SCSI hdd's of 36GB & 74GB sizes to use as replacement drives for old failing and noisy 9.1GB full height hdd's, but I have been having a heck of a time getting the cabling and terminators set up right so the Toaster/Flyer Tools can see the drives, so they can be formatted to be used as Flyer drives.  Any help would be greatly appreciated.  I have adapters and all different kinds of terminators, but still no luck, even with LVD terminators when using LVD u320 drives.

Help!

[mdivancic]

Wide cable terminators are usually no problem to obtain and once the bus is terminated in whole there's no need for 'half-terminators' any more. You can also use built-in terminators on the end drives instead of cable terminators. OTOH most wide drives run fine on a narrow bus, there are few refusing to (esp. IBMs).

I've not been able to get any IBM drives to work yet here. I got a bunch of drives from work when we switched from SCSI to newer formats. I was only able to get about one in four to work.

Note: I get my adaptors from eBay.

Here's the one I'm using:

http://cgi.ebay.com/SCA-80-to-SCSI-1-2-3-68-50-Pin-Converter-Card-Adapter_W0QQitemZ310147836256QQcmdZViewItemQQptZPCA_Cables_Adapters?hash=item4836406960&_trksid=p3286.c0.m14&_trkparms=65%3A1%7C66%3A2%7C39%3A1%7C293%3A2%7C294%3A50

Found this with a quick ebay search for SCSI Adaptor.

[Zac67]

Those are simple SCA adaptors, so any drive requiring full termination won't work.
When you can put the SCA drive at the chain end there's a trick: simply plug a wide terminator into the spare 68pin connector. That way the drive sees full termination and cooperates.

@amigadave
You can't use "LVD" terminators on an Amiga - there's no U2W+ controller supporting it. "LVD/SE" or "SE" or unlabeled terminators do work however. Amiga controllers are pre-Fast/Async or Fast (most), Ultra (few) or UltraWide (some late accelerators) but they're all single ended.

[amigadave]

Note: I get my adaptors from eBay.

Here's the one I'm using:

http://cgi.ebay.com/SCA-80-to-SCSI-1-2-3-68-50-Pin-Converter-Card-Adapter_W0QQitemZ310147836256QQcmdZViewItemQQptZPCA_Cables_Adapters?hash=item4836406960&_trksid=p3286.c0.m14&_trkparms=65%3A1%7C66%3A2%7C39%3A1%7C293%3A2%7C294%3A50

I have the same adapter and have been able to get some 4GB hdd's to work on a Warp Engine 040 accelerator SCSI-2 controllers.  I can't seem to get it to work on my CSPPC SCSI-2 wide controller, or the Flyer 50pin SCSI controllers.  I have tried all types of termination, both LVD/SE and non-LVD active terminators.  Still no luck.

I now have 3x 73GB 80pin SCA hdd's and 3x 36GB 68pin U320 hdd's plus 1x 73GB 68pin U320 hdd and have yet been able to get any of these large hdd's recognized on any of my SCSI controllers using both 50pin or 68pin cables and all types of terminators and jumper combinations on the drives themselves.

I am really stumped as to why I am having so much trouble and see now why some other members have cursed so loudly about having SCSI configuration problems.  This is my first experience with such difficulty in getting SCSI drives working.

@Zac67,

The drives and terminators I am trying to use are all marked LVD/SE and I have enabled the SE jumpers on the drives.  The first terminators I tried did not have the LVD/SE designation written on them, so I ordered and received and tried the LVD/SE terminators and have seen no difference.

Very frustrating!

[save2600]

I'd like to mirror what AmigaDave and mdivancic have said and are experiencing. I too inherited a combination of IBM and Seagate drives from an old Dell server. Out of 4, I was only able to get ONE to ever work! And I've got the adapters w/ termination everyone else is talking about. I chalked it up to bad drives (I kept them all anyway), but am somewhat "relieved" to hear others have experienced the same things. I am currently using the working 16gb Seagate drive in my A2500 with zero problems however. When SCSI works, it works real well  :-)

But I guess my next question is: why is SCSI so seemingly picky or flaky? Combination of things I guess - but frustrating when you know how to troubleshoot, but are left with no real answers.

[spaceman88]

Hi,
Will an Amiga work with a 68 pin SCSI hard drive (2.1 Gig, Seagate) if you use a 68 to 50 pin adaptor? A shop about 50 miles away is giving a couple away, if I go pick them up!

Ok, I picked up the drives. I downloaded the new(er) HDtoolbox, when I run it this is what it says.... "Compaq   ST32171w     0940     unsupported" and all the buttons are grayed out.
If I use the 3.1 install disk it usually locks up when scanning for drives, but once it got to the partitioning stage and I think it was asking me to enter data like # of cylinders, size , sectors etc. It seemed to think I had a 20meg hard disk. Is there any other software I can use that might support it? Also I'm using a 2091 rev. 6.6 card that is working with a Quantum drive (40meg), would it make difference if I used a GVP, ICD or Fastlane card?
Len

[spaceman88]

Ok,
I tried the GVP faaastprep program. Unfortunatly all it says is "Can't open GVPSCSI.device", the file is in the Expansion drawer.

[RiP]

My GVP A2000-HC+8 doesn't detect Hitachi 73GB SCSI 68pin
I used SCSI 68 Male to IDC 50 Male Adapter. I enabled TP/Force SE but they didn't help.

[BozzerBigD]

Weird as it should work fine! Have you checked the jumpers? Unit ID, termination, etc

[QuikSanz]

Ok,
I tried the GVP faaastprep program. Unfortunatly all it says is "Can't open GVPSCSI.device", the file is in the Expansion drawer.

If using OS3.1 throw faastprep in the bin, useless!

[RiP]

Weird as it should work fine! Have you checked the jumpers? Unit ID, termination, etc

Yes, enabled termination power, different ID and Force Single End jumpers but no luck.

[Oldsmobile_Mike]

If using OS3.1 throw faastprep in the bin, useless!

+1

[BLTCON0]

My GVP A2000-HC+8 doesn't detect Hitachi 73GB SCSI 68pin
I used SCSI 68 Male to IDC 50 Male Adapter. I enabled TP/Force SE but they didn't help.

Since it has a "force SE" jumper (force Single-Ended mode) it means it's an LVD (low voltage differential) drive.
These drives never have onboard termination. The "termination power" jumper is just to provide power to a standalone terminator, plugged at the end of the cable.
This also brings another implication into play:

Wide-SCSI bus (= 68 pin = 16 bit) is conceived as an extension to the older narrow-SCSI bus (=50 pin = 8 bit) standard. Actually, commands are still transferred in 8-bit 5 MHz async mode, regardless of advertised bus speed. The wide transfers (16 bit) or faster transfers (10 mhz Fast, 20 Mhz Ultra) are purely for data transfers.

So a 16-bit bus is more or less an 8 + 8 bit bus, with a low-byte (corresponding to operation in 50 pin narrow SCSI mode) and a high-byte (used in 68-pin wide SCSI mode).

Most 68-pin drives do require the presence of so-called bias-voltage on ALL the scsi lines (both low byte and high byte ones) in order to successfully init. This means that when in narrow mode, they require a special 50-68 adapter with high-byte active termination, which (as a side effect) will provide said bias voltage (assuming Termination Power exists, of course, but this can be set).

Alternatively, in lack of such an adapter, one can place the 68-pin drive with a simple (passive) 68-50 adapter LAST in the chain and enable its onboard terminator, which will have an identical side-effect.

Unfortunately, LVD drives by design don't have onboard termination, so this trick can't be used in your case. Using a wide active external terminator will not have the desired effect. Your safest bet is a (more expensive) high-byte terminated 68-50 adapter, plus (of course) active 50-pin terminators at both ends of the controller's 8-bit bus, with the drive (again of course) in SE mode.

Seagate wide drives were a distinguished exception - they universally worked fine in narrow mode, without requiring bias-voltage.

[LoadWB]

You'll need to shed for an expensive high-byte terminated 68-50 adapter.

They're not really that expensive.  The Datamate 5000-5068-13 can be found relatively cheaply and has high-byte termination.  I first found these in Dells with UW-SCSI adapters and narrow tape drives.  Bought several of them a while back just to have on-hand (one of which I just demolished to prove the high-byte resistors are actually present.)

Check here:

https://ebay.com/itm/222653979494

It's more than I paid for mine but still not a bad price.

[BLTCON0]

@LoadWB
Yes indeed, back in the day (when I was all about SCSI) they were about 3x the price of regular ones, so indeed they aren't 'expensive' but just 'more expensive'.
I actually corrected it right away but you posted faster than your shadow :-)

Furthermore, as today SCSI is mostly gone, I guess they can occasionally be found dirt-cheap as stock surplus or whatever - the culprit (most often) being with the seller unable to distinguish between passive and terminated ones.