BACON@MTUS5.BITNET (Jeffery Bacon) (07/05/90)
I know the first is common knowledge, but not for I: What's the diff between the Wren VII and the Wrenrunner? Right now we have a bunch of Wren VI's; they've had a colorful life with us, but now that they're older and more settled down (and we've culled out the flakey drives), they're doing fine. Nice and fast too. But we're looking at buying some more big drives, and I'd like to get the lowdown on the rest of the Wren line. (For various political and other reasons, we're probably gonna stay Wren pern.) Next: There's been some talk in the past on Suns and differential scsi (I don't think it was here...) and possibly getting it enabled. Is this truly possible? I've hacked a little code in the kernel and found the scsi_options symbol, and found various include files, etc...and I've also heard that the Wren drives are capable of diff scsi...and I'd like to put 1+1 together and get some real throughput, but...has anyone done this? Does it work? Is it possible even? Or am I just california dreamin'? (My test bed: SS1 or 1+, 1xQuantum 105MB internal, 1xWren VI, 2xSun 150MB tape) Thanks all. Jeffery Bacon -- Computing Technology Svcs., Michigan Technological University email- bacon@mtus5.bitnet voice: (906)487-2110 fax: (906)487-2787 alternate- uucp: <world>!itivax!anet!bacos domain: bacos%anet@itivax.iti.org
BACON@MTUS5.BITNET (Jeffery Bacon) (07/06/90)
Ah, yes, someone pointed out to me that I really meant synchronous scsi, not differential...thanks Chris. (We're also dealing with getting an exabyte onto a Multimax, the scsi cards on which are differential synch...got confused.)
chris@com50.c2s.mn.org (Chris Johnson) (07/10/90)
In article <90185.225056BACON@MTUS5.BITNET> BACON@MTUS5.BITNET (Jeffery Bacon) writes: > >Next: There's been some talk in the past on Suns and differential scsi (I >don't think it was here...) and possibly getting it enabled. Is this truly >possible? I've hacked a little code in the kernel and found the scsi_options >symbol, and found various include files, etc...and I've also heard that the >Wren drives are capable of diff scsi...and I'd like to put 1+1 together >and get some real throughput, but...has anyone done this? Does it work? Differential SCSI is an electrically different way of driving and connecting the SCSI bus. There's nothing in the software involved. In fact, I've never seen a device capable of doing both differential and single-ended (the "other" kind), without at least some hardware jumper changes. Usually, it requires different chips to be stuffed. As far as I know, none of the standard Sun SCSI interfaces are available in differential form -- at least, I've never or heard of such. However, many peripheral makers manufacture both differential and single-ended versions of their devices. When you buy a single-ended disk, though, it will most likely always be single-ended only. The user won't be able to change to differential without replacing a component board. Differential SCSI also has no effect on throughput or data rates, at least not directly. It does lower the effects of noise on the bus, perhaps enabling more reliable performance at higher rates. Mostly, however, it just allows you to run a longer bus. A single-ended SCSI bus is not longer than 6 meters in length while if I recall correctly, a differential SCSI bus may be up to 25 meters in length. -- ...Chris Johnson chris@c2s.mn.org ..uunet!bungia!com50!chris Com Squared Systems, Inc. St. Paul, MN USA +1 612 452 9522