A SIMM Reference

This appendix is provided as a convenient collection of reference materials presented elsewhere in this manual. Use this appendix to:

Set jumpers on NVSIMMs

Find or choose SIMM and NVSIMM slot locations

A.1 NVSIMM Battery Jumper

Before installing NVSIMMs, move the jumper to the battery ON position. See Figure A-1.

Caution -

Never move the jumper after the battery has been turned on, or data contained in the NVSIMM will be lost.

Figure A-1 NVSIMM Jumper Location

A.2 SIMM and NVSIMM Locations for SPARCserver 1000 Systems

A.2.1 Replacing SIMMs

If a SIMM or NVSIMM fails, the power-on selftests (POST) will specify the location number (also know as the U-number or J-number) of the failing device. See Figure A-2.

Do not mix SIMM sizes within a group.

Figure A-2 SIMM Groups on the SPARCserver 1000 System Board

A.2.2 Adding SIMMs

On SPARCserver 1000 boards, install SIMMs in groups of four. The SIMM slots on each board are divided into four groups of four slots each. The SIMM groups are numbered from 0 to 3.

The SIMM slots are listed by groups in Table A-1.

Table A-1 SIMM Groups on SPARCserver 1000 System Boards

---------------------------------------

         
Group    Location
---------------------------------------

         
Group 0  2800, 2900, 3000, 3100
         
Group 1  3200, 3300, 3400, 3500
         
Group 2  3600, 3700, 3800, 3900
         
Group 3  4000, 4100, 4200, 4300

---------------------------------------

These are the rules for adding memory devices to a SPARCserver 1000 board:

Fill the lowest numbered groups first on every system board.

Do not mix SIMM sizes within a group.

To optimize memory performance, keep the numbers of memory groups balanced across boards, in multiples of two or four boards (This allows the system to interleave memory across boards.) For example, if there are three boards in the system, and a total of four SIMM groups, fill both group 0 and group 1 on the first two boards. Memory added to the third board is usable, but it cannot be interleaved with memory on the first two boards (unless a fourth board with memory in a matching group location is also added.) If this memory is accessed often, performance will suffer.

Install SIMMs in groups of four in the SPARCserver 1000 system.

A.3 SIMM and NVSIMM Locations for SPARCcenter 2000 Systems

A.3.1 Replacing SIMMs

If a SIMM or NVSIMM fails, the power-on selftests (POST) will specify the location number (also know as the U-number or J-number) of the failing device. See Figure A-2.

Do not mix SIMM sizes within a group.

Figure A-3 SIMM Groups on the SPARCcenter 2000 System Board

A.3.2 Adding SIMMs

On SPARCcenter 2000 boards (which have two buses), always install eight SIMMs at a time, four in group x (where x = 0 or 1) on bus 0 and four in the same group number on bus 1.

Figure A-2 and Table A-2 show how the groups are organized.

Table A-2 SIMM Groups on SPARCcenter 2000 System Boards

-------------------------------------------------------

                                 
Group    XDBus 0                 XDBus 1
-------------------------------------------------------

                                 
Group 0  4000, 4100, 4200, 4300  4800, 4900, 5000, 5100
                                 
Group 1  3600, 3700, 3800, 3900  4400, 4500, 4600, 4700

-------------------------------------------------------

Note - Fill the lowest-numbered SIMM groups first. For multiple-board configurations, fill group 0 on each board before filling group 1 (but see below for rules for optimizing system performance.)

The rules for adding memory to a SPARCcenter 2000 board are as follows:

Always install eight SIMMs at a time, in two groups of four.

Install one group on bus 0, and install the second group on in the matching group number on the other bus. For example, fill group 0 on bus 0 and group 0 on bus 1. (Although it is not mandatory that both groups must be on the same board, to avoid confusion it is best to put both groups on the same board.)

Install SIMMs in both group 0 locations on every board (in groups of two or four boards), before adding SIMMs to any group 1 location.

A minor exception to the above rule is that to optimize memory performance, you should keep the numbers of memory groups balanced across multiples of two or four boards. (This allows the system to interleave memory across two or four boards.)

For example, if a system has five boards, and group 0 is filled on all five boards, performance will not be optimal. Memory addresses will be interleaved across the first four boards, but not across the fifth. If this memory is accessed often, performance will suffer.

Ideally (for the case of five boards), populate group 0 across four boards, then populate group 1 across four boards. The next most optimal case would be to populate group 0 across four boards, then populate group 1 across two boards. Both cases allow for interleaving across group 0 memory and separate interleaving across group 1 memory.

Do not mix SIMM sizes within a group.