User`s guide

Chapter 2: System Processor Board Description

Memory

Main memory resides on an add-in board, called a memory module, designed

speciﬁcally for the SGI 1400 server. The memory module contains slots for 16 DIMMs,

each of which must be at least 64 MB, and is attached to the processor board through a

242-pinconnector. Memory amountsfrom256 MB to4GB of DIMMare supported, with

a 64/72-bit four-way-interleavedpathway tomain memory,which is alsolocated onthe

module. The 16slots are dividedinto fourbanks of fourslots each, labeled AthroughD.

These banks support 4:1 interleaving. The memory controller supports EDO DRAMs.

The ECC used for the memory module is capable of correcting single-bit errors (SBEs)

anddetecting100percentofdouble-biterrorsoveronecodeword.Nibbleerrordetection

is also provided. Figure 2-2 shows the installation sequence for the memory modules.

Figure 2-2 Memory Module DIMM Installation Sequence

J16

J15

J12

J11

J14

J13

J10