jimr@maths.su.oz.au (Jim Richardson) (02/14/90)
Am I right in assuming that memory can only be added to a DN2500 in multiples of 4 SIMMS, that is, in multiples of 4 megabytes in the case of 1MB x 9 SIMMS? This is not mentioned in the "Domain 2500 Series Owner's Guide". However, the memory sizing output at boot time suggests that memory is being interleaved, with each of the four bytes in a longword coming from a different SIMM. We would like to add memory to some of our 2500s, because with 4MB they seem to give much slower response than even our previous DN3000s with 4MB. Presumably this is because SR10.2 eats much more memory than SR10.1, though we haven't even started running X yet. We had hoped to compromise between performance and cost by installing an extra 2MB in each node. Is it really an extra 4MB or nothing? Thanks in advance for any information. -- Jim Richardson Department of Pure Mathematics, University of Sydney, NSW 2006, Australia ACSNET: jimr@maths.su.oz Internet: jimr@maths.su.oz.au UUCP: ...!uunet!munnari!maths.su.oz!jimr "When she was dark she was very very dark, but when she was light she was lighter than air." -- J. Crowley
dbfunk@ICAEN.UIOWA.EDU (David B Funk) (02/16/90)
In posting <1990Feb14.101624.5666@metro.ucc.su.oz.au> Jim Richardson asks: > Am I right in assuming that memory can only be added to a DN2500 in multiples > of 4 SIMMS, that is, in multiples of 4 megabytes in the case of 1MB x 9 > SIMMS? This is not mentioned in the "Domain 2500 Series Owner's Guide". > However, the memory sizing output at boot time suggests that memory is being > interleaved, with each of the four bytes in a longword coming from a > different SIMM. You guessed right Jim. The DN2500 needs memory in banks of 4 SIMMs. This is because the bus between the memory & CPU is 32 bits wide to keep the 68030 working at maximum speed. To get 32 bit wide memory you need 4 bytes (4 SIMMs) per "whack". BTW this is also true in the Apple Macintosh '020' & '030' machines. So the next step up from 4 Mbytes is 8 Mbytes, 6 Mbytes is not an option. For what it's worth, we run all our machines at a minimum of 8 Mbytes, if you are going to do a bunch of "X" stuff, 12 Mbytes or more is reccomended. Memory for the DN2500 really isn't very expensive because they use the standard SIMMs. We've seen lots of sources for under $100 US. Dave Funk