Dell DC, 3, User Manual

Page: 61 / 254

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