Chapter 1
Introduction
4
Adapter Hardware and Battery-backed Cache
IOP: The I/O processor (IOP) directs all functions of the adapter, including
command processing, PCI and SCSI bus transfers, RAID processing, drive
rebuilding, cache management, and error recovery.
•
The IOP for the HP NetRAID-1M adapter is the Intel i960RM
®
Intelligent
I/O RISC processor running at 100 MHz.
•
The IOP for the HP NetRAID-2M adapter is the Intel i960RN
®
Intelligent
I/O RISC processor running at 100 MHz.
The HP NetRAID-1M adapter has a 32-bit, 33 MHz PCI Bus Interface. The
HP NetRAID-2M adapter has a 64-bit, 66 MHz PCI Bus Interface.
Cache: All HP NetRAID-1M and 2M adapters have cache memory.
•
For the HP NetRAID-1M adapter, cache memory resides in a 32-MB
SDRAM DIMM with ECC.
•
For the HP NetRAID-2M adapter, cache memory resides in a 64-MB or
128-MB SDRAM DIMM with ECC, depending on the model purchased.
The HP NetRAID-1M or 2M adapters support Direct and Cached I/O and Write
Through or Write Back caching, which can be selected for each logical drive. To
improve performance in sequential disk accesses, the HP NetRAID-1M and 2M
adapters use Adaptive Read Ahead caching by default, but it can be disabled to
Normal or set to simple Read Ahead caching.
Battery: Battery backup of the cache is standard for the HP NetRAID-2M
adapter. It is not available with the HP NetRAID-1M.
Alarm: A tone generator on the HP NetRAID-1M and 2M adapters provides
audible warnings (alarms) when RAID system errors occur.