Mylex DAC960PG, Installation Manual

Page: 26 / 106

Controller Components
2-2 DAC960PG Installation Guide
Cache Memory Subsystem
The DAC960PG requires a minimum of 4 MB of on-board cache memory
to operate and up to 128 MB of memory can be installed. The physical
memory configuration for the DAC960PG is one 72-pin SIMM.
The DAC960PG supports EDO (Extended Data Out) RAM. EDO RAM is a
type of DRAM that has a performance level approaching that of Static RAM.
The maximum amount of EDO RAM is 128 MB.
The memory subsystem supports the ECC (Error Correction Code) form of
error protection. ECC requires the use of 40-bit EDO RAM SIMMs.
The cache memory is controlled by a Mylex MYL-86138 RAID
Coprocessor ASIC.
Cache memory write policy can be configured by software as either Write
Through or as Write Back.
Cache memory data can be protected in the event of a power outage by an
optional battery backup unit.
,
WARNING
Do not attempt to install, remove, or change a
cache SIMM on the DAC960PG with the IBBU
installed. Serious damage to the SIMM and/or the
battery backup unit will occur if this precaution is
not followed.
Controller Firmware
The DAC960PG firmware contains the programs executed by the i960RP
CPU. The Firmware resides in the on-board Flash EEPROM and operates
from DRAM after the firmware is uncompressed and downloaded from the
EEPROM. The EEPROM retains information after power is off and can also
be re-written, to allow the controller firmware to be upgraded without the
need to replace any hardware chips.