rmk@snowhit.att.com (05/02/90)
In my preparation for future growth in SPARCstation 1 memory, above the 16 Meg limit with 1 Meg SIMMS, I prepared the following chart to help us all with this growth. It's been my experience that at least two banks of four SIMMS slots have to be populated, even if one bank is 4 Meg SIMMS. It doesn't seem to matter which bank is filled next. They can be filled in any order, only 4 SIMMS at a time. +----------------------------------------------+ | SPARCstation 1 Memory Growth | +------+---------+---------+---------+---------+ | Size | One | Two | Three | Four | +------+---------+---------+---------+---------+ | 8 Meg| 4x1 Meg| 4x1 Meg| | | |12 Meg| 4x1 Meg| 4x1 Meg| 4x1 Meg| | |16 Meg| 4x1 Meg| 4x1 Meg| 4x1 Meg| 4x1 Meg| |20 Meg| 4x4 Meg| 4x1 Meg| | | |24 Meg| 4x4 Meg| 4x1 Meg| 4x1 Meg| | |28 Meg| 4x4 Meg| 4x1 Meg| 4x1 Meg| 4x1 Meg| |32 Meg| 4x4 Meg| 4x4 Meg| | | |36 Meg| 4x4 Meg| 4x4 Meg| 4x1 Meg| | |40 Meg| 4x4 Meg| 4x4 Meg| 4x1 Meg| 4x1 Meg| |48 Meg| 4x4 Meg| 4x4 Meg| 4x4 Meg| | |52 Meg| 4x4 Meg| 4x4 Meg| 4x4 Meg| 4x1 Meg| |64 Meg| 4x4 Meg| 4x4 Meg| 4x4 Meg| 4x4 Meg| +------+---------+---------+---------+---------+ Richard Kurtz (816)995-3204 rmk@snowhit.att.com AT&T ..!att!snowhit!rmk
sanders@uunet.uu.net (Jeremy Sanders) (05/04/90)
From article <7336@brazos.Rice.edu>, by rmk@snowhit.att.com: > It's been my experience that at least two banks of four SIMMS slots have > to be populated, even if one bank is 4 Meg SIMMS. What happens when you fill only one? Has anyone done this? Jeremy Sanders sanders@shearson.com
eggert@uunet.uu.net (Paul Eggert) (05/04/90)
Richard Kurts <rmk@snowhit.att.com> writes about the SPARCstation 1: |It's been my experience that at least two banks of four SIMMS slots have |to be populated, even if one bank is 4 Meg SIMMS. This doesn't match our experience. We've run a SPARCstation 1 with just one bank of 4 Meg SIMMs, for 16 MB total.
jeremy@bbird4.prime.com (Jeremy Nussbaum) (05/05/90)
In article <7336@brazos.Rice.edu> rmk@snowhit.att.com writes: | In my preparation for future growth in SPARCstation 1 memory, above the 16 | Meg limit with 1 Meg SIMMS, I prepared the following chart to help us all | with this growth. |... | +----------------------------------------------+ | | SPARCstation 1 Memory Growth | | +------+---------+---------+---------+---------+ | [table deleted] This is all correct. HOWEVER, there is a 32 Mb limit on the amount of physical memory that the mmu on the SS's can map at any one time. While I do not know the details of what happens when you would really like to have more than 32 Mb active at one time, it seems that currently you get a full page fault and lose track of the page thrown out of the mmu mapping to make room. In other words, more than 32 Mb or so (+ any unmapped memory) does not get you anything. I was told by email from someone at Sun that they are working on a software cache solution to the problem. I presume that means that the page that gets thrown out of the mmu mapping stays in some unmapped page in memory, and a table is kept of valid pages in non-mmu mapped memory. On mmu faults some code is executed to check for the existence of the requested page in unmapped memory, and if it's there, only the mm table entry needs to be written; no disk read. Someday soon, I hope Jeremy Nussbaum (jeremy@jeremy.prime.com, ...!harvard!primerd!jeremy!jeremy) Prime Computer (508)879-2960 x3516