• Please review our updated Terms and Rules here
  • Exhibitor application for VCF West 2022 is now open! If you are interested in exhibiting, please fill out the form here.
  • Here are the results of the VCF East 2022 Post Event Survey: Survey Results

Connect Ultra Wide SCSI hard drives to 8-bit or 16-bit ISA bus?

arrow_runner

Veteran Member
Joined
Mar 7, 2012
Messages
528
Location
Cincinnati Ohio
There's no real way to do that right? I picked up some really big UW SCSI hard drives and thought about putting them in some older boxes.

47gb_5400_scsi_uw_68p_4mb_st446452w.jpg
 

njroadfan

Veteran Member
Joined
Jan 21, 2011
Messages
1,523
It'll work, you just need an adapter and jumper the drive to run in 8-bit, single ended operation.
 

mbbrutman

Associate Cat Herder
Staff member
Joined
May 3, 2003
Messages
6,237
SCSI drives will revert to slower and narrower buses when they are attached to them. You should be able to put that drive on something like an Adaptec 154x series host bus adapter.

The key is termination. Since you are only using 8 data lines of the 16 on the bus the upper 8 data lines have to be terminated correctly. Some inline adapters do this better than others.

Read up on SCSI termination, using search times like "SCSI wide to narrow". That will get you started.

BTW, who made that drive and what are specs? That looks a little beastly to be a modern drive ...
 

arrow_runner

Veteran Member
Joined
Mar 7, 2012
Messages
528
Location
Cincinnati Ohio
BTW, who made that drive and what are specs? That looks a little beastly to be a modern drive ...

They're Seagate 47GB ST446452W drives. I only grabbed them because they looked so beastly that I thought they would look right if I put them in a 51x0 chassis. At first I thought they were a lot older too until I pulled them out. I picked them up at the local recycler, but I'd imagine that they still work since they were still in a 4 bay tower that was missing it's side(too bad). In hindsight I probably should have left them in the tower because it might have gotten the lower (by the pound) price of a computer rather than the price of bare hard drives.

I'll have to dig through and see what all SCSI adapters I have. Thanks for the tips on termination and such.
 

krebizfan

Veteran Member
Joined
May 23, 2009
Messages
5,340
Location
Connecticut
The Seagate website still has a PDF manual for the drive. Helps to find all the different sets of jumpers.

Don't forget to drop all the SCSI IDs below 8; something easy to miss with drives pre-configured from a loaded out server.

The adapter will make cabling a bit harder on more cramped cases. The extra length results in having to force sharper bends which means you may not be able to fill all drive bays.
 

RWallmow

Veteran Member
Joined
Oct 19, 2006
Messages
1,791
Location
Anoka, MN USA
It works well, I have some 9.1gb and 36gb drives in some older Macintosh computers, that's the good thing about SCSI, I haven't met a drive yet that wont "clock down" to the slowest SCSI bus. Makes up for how much of a pain in the rear it can be to get the right termination settings sometimes, lol.

DX and MonoPrice both have some good prices on the 68 <> 50pin adapters:
68M <> 50M (DX) (plug your 50pin cable into a 68pin drive)
68F <> 50F (DX) (plug your 68pin cable into a 50pin SCSI card)
68M <> 50M (monoprice)
68F <> 50F (monoprice)
 

Unknown_K

Veteran Member
Joined
Sep 11, 2003
Messages
8,508
Location
Ohio/USA

NeXT

Veteran Member
Joined
Oct 22, 2008
Messages
6,754
Location
Kamloops, BC, Canada
I have a small stack of 18/36gb Fijutsu drives that will not clock down that slow. They also lack jumpers to manually force it into slower modes.
 

RWallmow

Veteran Member
Joined
Oct 19, 2006
Messages
1,791
Location
Anoka, MN USA
I think some of the last 320Mbs drives won't work at 20/40 without jumper settings (or at all). Some drives have a SE jumper you need to mess with. Most of the later drives are for servers and are SCA, you need a SCA to 50 pin adapter with a special terminator (SCA drives have no built in termination) to work in 8 bit mode on old macs.

Something like this: http://www.cs-electronics.com/images-large/ADP-9012.jpg

Or this: http://www.geeks.com/imageshare/S/300x300/SCATOSCSI-TERM-unit.jpg

I had a 75gig Maxtor U320 (68pin) drive running on narrow SCSI in my Mac SE/30 at one point, with no jumper config other than ID below 7. I would have to say it depends on the drive though, its sure possible some wont do it, I just haven't run into one yet. Not much experience with SCA drives though other than using them with a SCA backplane in a proliant server, never any adapters.

I didn't keep that 75gb drive in my SE/30, felt like a waste in such an old machine, one now resides in my Beige G3 on a Apple UW SCSI card and the other in a PC on a U320 Adaptec card. SE/30 now runs a more appropriate 9.1GB drive.
 

njroadfan

Veteran Member
Joined
Jan 21, 2011
Messages
1,523
It works well, I have some 9.1gb and 36gb drives in some older Macintosh computers, that's the good thing about SCSI, I haven't met a drive yet that wont "clock down" to the slowest SCSI bus. Makes up for how much of a pain in the rear it can be to get the right termination settings sometimes, lol.

DX and MonoPrice both have some good prices on the 68 <> 50pin adapters:
68M <> 50M (DX) (plug your 50pin cable into a 68pin drive)
68F <> 50F (DX) (plug your 68pin cable into a 50pin SCSI card)
68M <> 50M (monoprice)
68F <> 50F (monoprice)

Make sure those adapters have "upper byte termination". Some of them don't and cause headaches beyond belief. To use a 68pin drive in a Mac, I had to get an upper byte terminated adapter, plus add an additional active SCSI terminator to the end of the chain (Apple CD-ROM drives make lousy bus terminators).
 

RWallmow

Veteran Member
Joined
Oct 19, 2006
Messages
1,791
Location
Anoka, MN USA
Make sure those adapters have "upper byte termination". Some of them don't and cause headaches beyond belief. To use a 68pin drive in a Mac, I had to get an upper byte terminated adapter, plus add an additional active SCSI terminator to the end of the chain (Apple CD-ROM drives make lousy bus terminators).

I am currently using the 68F<>50F one from DX in my Mac SE/30 with an IBM 9.1GB UW SCSI drive, and was using the same adapter when I had the 75GB U320 Maxtor hooked up in it, not sure about the official "upper/high byte termination" capability of that adapter though, but it worked in my SE/30, even when mixed with other SCSI devices on the bus (a external 2GB Jaz drive, and SCSI Ethernet adapter), I do not recall my termination setup in the SCSI chain off hand though so one of the other terminators might be handling it :confused:
 
Top