Dell 3 User Manual

Page 61

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PERC 3/SC Features

59

PCI Bridge/CPU

PERC 3/SC uses the Intel i960RM PCI bridge with an embedded i960RM
RISC processor running at 100 MHz. The RM bridge handles data transfers
between the primary (host) PCI bus, the secondary PCI bus, cache memory,
and the SCSI bus. The DMA controller supports chaining and unaligned
data transfers. The embedded i960JT CPU directs all controller functions,
including command processing, SCSI bus transfers, RAID processing, drive
rebuilding, cache management, and error recovery.

Cache Memory

32 MB of PERC 3/SC cache memory resides in a memory bank. PERC 3/SC
supports write-through or write-back caching, selectable for each logical
drive. To improve performance in sequential disk accesses, the PERC 3/SC
controller uses read-ahead caching by default. You can disable read-ahead
caching.

SCSI controller

One SCSI controller for 160M and Wide support

SCSI data transfer rate

Up to 160 MB/s per channel

SCSI bus

Low-voltage differential (LVD) or single-ended

SCSI termination

Active

Termination disable

Automatic through cable and device detection

Devices per SCSI channel

Up to 15 wide or seven narrow SCSI devices

SCSI device types

Synchronous or asynchronous

RAID levels supported

0, 1, 5, 10, and 50

SCSI connectors

One 68-pin internal high-density connectors for

16-bit SCSI devices. One ultra-high density 68-

pin external connectors for 160M and Wide

SCSI.

Serial port

3-pin RS232C-compatible connector (for

manufacturing use only)

Ta b l e 4 - 7 . P E R C 3 / S C S p e c i f i c a t i o n s

(continued)

Parameter

Specification

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