Date: Fri, 18 Sep 87 14:22:57 EST From: Dwight D. McKay (The Moderator) Reply-To: Suns-at-Home@mckay.UUCP Subject: Suns-at-Home Digest V1 #25 To: Suns-at-Home-List Suns-at-Home Digest Fri, 18 Sep 87 Volume 1 : Issue 25 Today's Topics: Memory in Sun-2/120s (intermittent parity errors) SCSI disks +--------------------------------------------------------------------+ | Submissions: suns-at-home \ @ea.ecn.purdue.edu | | Requests: suns-at-home-request > -- or -- | | Archives: suns-at-home-archives / ...rutgers!pur-ee!mckay!... | +--------------------------------------------------------------------+ ---------------------------------------------------------------------- Date: Mon, 12 Sep 88 16:57:23 EDT From: Alexander Dupuy Subject: Memory in Sun-2/120s (intermittent parity errors) To: suns-at-home Having a few Sun-2/120s here (including one on my desk) with memory upgrades, I can give a few words of advice on your memory problems. The Sun-2 memory runs with no wait states, but it does this by pushing the chip technology to the edge. If the memory board doesn't have the bytes ready when the CPU wants them the CPU gets no wait state noise. As a result of this, Multibus Sun-2s are cantakerous, tending to die with parity errors, which, as I'm sure you've noticed, also hang the machine for a good minute or so, depending on memory size, while the PROM scans memory looking for the offending byte(s). Some things which you can do to help: 1 2 3 1 2 3 4 5 | | | | | | | | v v v v v v v v M C M M M C M M e P e e e P e e m U m m m U m m 1. Put the cpu board in the middle of the memory. Amazingly enough, those few centimeters can make all the difference for those bytes. 2. Make sure the memory boards and cpu are *firmly* seated. Your thumbs may be bleeding when you're done, but every little bit of capacitance matters. You might want to check the edge connectors for corrosion wile you're at it. 3. If you get third party memory, get rid of your old Sun memory. We got memory from Helios a few years ago, and were never able to get it to coexist happily with Sun memory. We ended up getting two 4M boards, and moved all the Sun memory into two other machines, so that we upgraded a total of four machines to 4M. You can go above this, but I'm not sure it's worth the $$ or the hassle. I did all this well over a year ago to our Sun-2s, and they have been running happily (thought slowly, relative to Sun-3s and -4s) ever since. We still get parity errors once every few months, but much less frequently than before. @alex ------------------------------ Date: Mon, 12 Sep 88 06:51:48 PDT From: pur-ee!Sun.COM!kevin (Kevin Sheehan {Consulting Poster Child}) Subject: SCSI disks To: Suns-at-Home@mckay.uucp Uhhh, having worked on the sun2 boot proms, I can assure you they support SCSI disks - at least the ones Sun supported at the time... They work great at my house! l & h, kev ------------------------------ End of Suns-at-Home Digest ******************************