LSI Series 518 4.10.5 Serial Port, 4.10.2 Cache Memory, 4.10.3 MegaRAID BIOS, 4.10.4 Onboard Speaker

transfers, RAID processing, drive rebuilding, cache management, and error recovery.

4.10.2 Cache Memory

Cache memory resides in a single 72-bit DIMM socket that requires one unbuffered 3.3 V SDRAM single-sided or double-sided DIMM. Possible conﬁgurations are 32, 64, 128, or 256 Mbytes.

MegaRAID supports write-through or write-back caching, which can be selected for each logical drive. To improve performance in sequential disk accesses, MegaRAID does not use read-ahead caching for the current logical drive. The default setting for the read policy is Normal, meaning no read-ahead caching. You can disable read-ahead caching.

Warning: Write caching is not recommended for the physical drives. When write cache is enabled, loss of data can occur when power is interrupted.

4.10.3 MegaRAID BIOS

The BIOS resides on a 1 MB or 2 MB 8 ﬂash ROM for easy upgrade. The MegaRAID BIOS supports INT 13h calls to boot DOS without special software or device drivers. The MegaRAID BIOS provides an extensive setup utility that can be accessed by pressing <Ctrl> <M> at BIOS initialization. The MegaRAID Conﬁguration Utility is described in the MegaRAID Conﬁguration Software Guide.

4.10.4 Onboard Speaker

The MegaRAID SCSI 320-2 has an onboard tone generator for audible warnings when system errors occur. Audible warnings can be generated through this speaker. The audible warnings are listed in Appendix B.

4.10.5 Serial Port

The MegaRAID SCSI 320-2 has a 3-pin RS232C-compatible serial port connector, which is used for test purposes only.

MegaRAID Components

4-9