NEC Express5800/120Rd-2, Service Manual

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1-18 System Overview
SAF-TE LOGIC
NOTE:
SAF-TE Logic is in systems that include the hot-swap SCSI disk
drive cage. SAF-TE Logic is not available in systems that include the
standard SCSI disk drive cage.
The SCSI backplane includes SAF-TE (SCSI Accessed Fault Tolerant Enclosure) logic that
provides an interface to the disk subsystem that supports status signals, hot swapping drives, and
enclosure monitoring.
The transport mechanism for the standardized alert detection and status reporting is the SCSI
bus. Disk drives, power supplies, cooling fans, and temperature are continually monitored and
the conditions then reported over the SCSI bus to the system. When used with RAID
management software the user can be alerted of impending or imminent disk conditions
requiring attention. This allows the user to react to conditions that could normally go unnoticed
until data loss.
SYSTEM BOARD FEATURES
The following subsections describe the system board major components.
Processor
The system board accommodates one or two Intel Pentium III processors with 512k cache in the
FC-PGA2 package. This processor uses the .13 micron technology and offers advanced
performance. The processor external interface operates at a maximum of 133 MHz.
Memory
The system board contains six 168-pin DIMM slots each supporting 72-bit ECC (64-bit main
memory plus ECC) registered SDRAM DIMMs (PC-133 compatible). Memory is two-way
interleaved and partitioned in three banks. You may install a minimum of 256 MB (128MB × 2)
and as much as 6 GB.
The controller automatically detects, sizes, and initializes the memory array, depending on the
type, size, and speed of the installed DIMMs, and reports memory size and allocation to the
server via configuration registers.
NOTE:
Use DIMMs that have been tested for compatibility with the
system board.
Contact your sales representative or dealer for a current list of approved
memory modules.