rrw@naucse.UUCP (Robert Wier) (01/26/89)
We are looking for information on how compatible are devices designed for SCSI, *really*? For example, could you buy a HD being marketed for the Macintosh, and use it on an HP workstation which has a SCSI port? I have heard (I can't remember where exactly), that Apple's use of the SCSI is somewhat non-conforming to the standard. Is this true? How about other devices? Is everyone else compatible? Any comments would be greatly appreciated. Feel free to respond by E-Mail if you wish not to post comments here, and I will summarize. Many thanks- -Bob Wier at Flagstaff, Arizona Northern Arizona University ...arizona!naucse!rrw | BITNET: WIER@NAUVAX | *usual disclaimers*
rrw@naucse.UUCP (Robert Wier) (01/26/89)
In my request for information on SCSI "standard" devices, I have found such a discussion already going on under comp.arch, with the most recent message being numbered here as #7960, "Decstation 3100 info". I would be interested in any other comments in addition, though. thanks -Bob Wier at Flagstaff, Arizona Northern Arizona University ...arizona!naucse!rrw | BITNET: WIER@NAUVAX | *usual disclaimers*
billkatt@sol.engin.umich.edu (Steve Bollinger) (01/26/89)
In article <1138@naucse.UUCP> rrw@naucse.UUCP (Robert Wier) writes: > > We are looking for information on how compatible are devices designed > for SCSI, *really*? For example, could you buy a HD being marketed > for the Macintosh, and use it on an HP workstation which has a > SCSI port? I have heard (I can't remember where exactly), that > Apple's use of the SCSI is somewhat non-conforming to the standard. > Is this true? How about other devices? Is everyone else compatible? There are really two ways in which the mac is non-standard. First, they only use a 25-pin connector. This is not an issue because the 25 pins they omitted are all grounds, and most SCSI cables just split the ground which is available out to 26 different lines. There is no standard connector for SCSI, Apple uses a centronics type (except on the back of the Plus, SE, and I series), and Sun uses a D-shell connector. The other way that Apple is non-standard is that it requires a driver for its SCSI drives. This is good because that way both standard and non-standard drives can be supported, however, I would rather that they used direct SCSI calls and required standard drives. The important factor is that with the correct cable and driver, you can use any standard (and many non-standard) SCSI drive on a Mac. On the other hand, we have a Maxtor drive which works on a Mac but not a Sun. I repeat: any drive which works on a NeXT or a Sun will work on a Mac, so stop yer gripin' B-) +----------------------+----------------------------------------------------+ | Steve Bollinger | Internet: billkatt@caen.engin.umich.edu | | 4297 Sulgrave Dr. +------+---------------------------------------------+ | Swartz Creek, Mi. 48473 | "My employer doesn't take my opinion any | +-----------------------------+ more seriously than you do." | | "You remember the IIe, it +---------------------------------------------+ | was the machine Apple made before they decided people didn't need | | machines with big screens, color, or slots." | | - Harry Anderson (from NBC's Night Court) | +---------------------------------------------------------------------------+
ts@cup.portal.com (Tim W Smith) (01/31/89)
There most certainly is a standard SCSI connector. Many boring pages of the ANSI SCSI standard are devoted to describing in excruciating detail what standard SCSI connectors look like. Tim Smith ps: the main problem that one is likely to encounter trying to use a standard SCSI drive on the Mac is the various bugs in the Mac plus ROM. Here are some of the problems that can cause serious trouble: 1. ROM SCSI Manager can't read more than one block at a time safely. 2. Blind transfers can't be used safely. 3. Original plus ROM can't deal with drives that do UNIT ATTENTION on reset. Problems 1 and 2 can be worked around in software ( simply don't do blind or multiblock transfers until the SCSI Manager patches are loaded ). Problem 3 is more of a problem. Either get the later plus ROMs, or convince your drive not to do UNIT ATTENTION ( many have such on option ).