Path: utzoo!attcan!uunet!lll-winken!ames!mailrus!cornell!uw-beaver!rice!sun-spots-request From: anderson@sapir.psy.jhu.edu Newsgroups: comp.sys.sun Subject: Wren IV (?cabling) Problem Message-ID: <8901201904.AA00222@sapir.> Date: 27 Jan 89 15:51:14 GMT Sender: usenet@rice.edu Organization: Sun-Spots Lines: 65 Approved: Sun-Spots@rice.edu Original-Date: Fri, 20 Jan 89 14:04:40 EST X-Sun-Spots-Digest: Volume 7, Issue 125, message 4 of 16 I'm trying without success to attach a CDC Wren IV drive to a 4/110. Sun tells me that the famous pin-26 problem on 4/110's is no longer a problem as of the rev level of my machine, and nobody's power supply appears to have fried, so that seems not to be what's wrong. The Sun itself doesn't seem to be the culprit, since it recognizes a Sun SCSI shoebox snarfed from another machine with no problem. What happens is that when the drive is cabled to the SCSI connector on the machine, it won't even spin up, though it does spin up when not attached to the 4/110. Letting it spin up and then attaching it to the machine, the Sun reports that it can't find any sd device. One theory: the drive unit itself is cabled to its DB-50 SCSI connector with a straight fifty-line ribbon cable. This appears to yield the following physical arrangement of its pinouts: ------------------------------------------------------------- \ 49 46 43 40 ............... 10 7 4 1 / \ / \ 48 45 42 39 ............ 12 9 6 3 / \ / \50 47 44 41 ............... 11 8 5 2/ --------------------------------------------------- According to Sun, however (and also according the numbers on a 50-pin male-to-male connector I'm using between the drive and the Sun), the physical configuration of the Sun SCSI connector has the following pinouts: ------------------------------------------------------------- \ 17 16 15 14 ............... 4 3 2 1 / \ / \ 33 32 31 30 ........... 21 20 19 18 / \ / \50 49 48 47 ............... 37 36 35 34/ --------------------------------------------------- If the logical interpretation of "1, 2, 3," etc. on the drive is the same as that on the Sun, it stands to reason I need a cable to map the one onto the other, rather than the 50-pin straight through cable I have. Does this make sense? I'm having a hard time convincing the supplier I need a new cable to do this, but I don't know what else to try. The drive is jumpered to identify as drive 0 (i.e., no jumpers on the SCSI id block), to tie ground to both signal and physical ground, and to get terminator power from the supply in its box. As far as I can tell, these are the only settings available to tweak, and they seem right. If my cabling theory isn't right, what is? One (not generally very helpful or knowledgeable seeming) person at 800-USA-4SUN suggested "the 4/110 doesn't support embedded SCSI". Is this plausible, explanatory, and (perhaps most important) correct? If you're technically sophisticated about such things, it's probably quite clear to you by now that I'm not. Help and/or advice would be very welcome (apart, perhaps, from the suggestion that I trash the Wren and buy something from Sun, at their prices....). Please send mail to me at the address below (which your mailer will probably be able to find, as opposed to my return address above). If information that looks more broadly useful arrives, I'll summarize to Sun-Spots. Thanks, Steve Anderson Cognitive Science Center The Johns Hopkins University