Quadra 950 SCSI

[QuillOmega0]

I'm having a terrible time hooking up harddrives to my Quadra 950. I'm trying to redo the cable layout to prevent any damage or strain to the cabling but I don't have anything to really go off of, can anyone post a picture of the SCSI cabling of their Quadra 900/950?

I also checked the continuty of my SCSI Cable, Pin 1 on both ends has continuity from end to end on the cable. However Port 49 or Port 50 don't have any continutity.

This is a 590-0528 Apple SCSI Cable. The break seems to be between Position B and Position C:

MOBO------------------------------------------------POS A-----------POSB-------------------- -----------------------POS C---------POSD----TERM

or does this cable have an odd setup where there is a break in pin 49 and 50 between those positions. I'm looking for replacement cables but would like someone's opinion on the state of my cable first.

Thanks.

 

[ojfd]

Google for "quadra 950 service manual' It's all in there.

 

[sunder]

Not sure about this model, but with SCSI generally you want motherboard->internal-drives->terminator, then the last device at the end of the external chain gets a terminator. You need to make sure there's no conflicts in IDs as well. You'll want something like SCSI probe to help you debug.

With some weirdo setups, it helps to have a device in the middle have a terminator. Not sure if this was an old wives tale or real, but it can't hurt to try.

Beware that some SCSI devices are differential, so be sure you know what kind you have, as you can't mix differentials with regulars. I think off the top of my head that the IIfx used differentials, so needed special terminators and all differential SCSI devices.

http://www.openbsd.org/38.html OpenBSD has a song about SCSIs. Sort of.

 

[Trash80toHP_Mini]

With some weirdo setups, it helps to have a device in the middle have a terminator.

The recommended SCSI Disk mode cable setup for the PB100 and Duos would be a prime example of this.

Active termination block circuitry helps tremendously for strange SCSI Voodoo situations.

 

[QuillOmega0]

There's a terminator on the end of the cable. What I've read though is that Quadras 950 are terminated on the motherboard and hard drives should not be terminated. http://support.apple.com/kb/TA47480?viewlocale=en_US

I've ordered a replacement cable. I have a 76gb sca scsi drive with a adapter I did get the Mac to see on Position A of the cable (Positions B-D do not work).

 

[CelGen]

I think off the top of my head that the IIfx used differentials, so needed special terminators and all differential SCSI devices.

The IIfx does NOT use differential.

I never understood what was so special about the infamous black terminator.

 

[QuillOmega0]

Got the replacement SCSI cable, drives are seen just fine. Now to deal with partitioning a 76gb drive. (Apple's tool won't allow me to create more then 8 partitions ).

 

[johnklos]

Mac OS 8.1 is one option (normal HFS from which to boot, HFS+ for the rest). System 7.6.1 allows for HFS partitions to exceed 4 gigabytes even if the disk usage per file is ridiculous.

 

[QuillOmega0]

Yea. I figured out the partition problem. I was booting off of a custom boot disk with Disk Setup 1.5 (unable to boot from cd) which can't format bigger then 4gb. So I will work around it by booting into a temporary install on a separate hard drive and formatting the drive there.

 

[johnklos]

A neat trick is that you can make a RAM disk, copy a system onto that, then reboot onto that if you need to swap media to get access to run other programs.