70 PERC 3/ DC and PE RC 3 /DCL Fe aturesw w w . d e l l . c o m | s u p p o r t . d e l l . c o m Cache MemoryEither 64 MB or 128 MB of PERC 3/DC and PERC 3/DCL cache memoryreside in a memory bank that uses a 64 MB or 128 MB SDRAM DIMM.PERC 3/DC and PERC 3/DCL support write-through or write-backcaching, selectable for each logical drive. To improve performance insequential disk accesses, the PERC 3/DC and PERC 3/DCL controllers useread-ahead caching by default. You can disable read-ahead caching.PERC 3/DC and PERC 3/DCL BIOSThe BIOS resides on a 1 MB × 8 flash ROM for easy upgrade. The PERC3/DC and PERC 3/DCL BIOS supports INT 13h calls to boot DOS withoutspecial software or device drivers. The PERC 3/DC and PERC 3/DCL BIOSprovides an extensive setup utility that can be accessed by pressing at BIOS initialization. PERC 3/DC and PERC 3/DCL BIOSConfiguration utility is described in Chapter 11 "PERC 3 BIOSConfiguration Utility."Onboard SpeakerThe PERC 3/DC and PERC 3/DCL controller has an onboard tonegenerator for audible warnings when system errors occur. Audible warningscan be generated through this speaker. The audible warnings are listed inChapter 13 "Troubleshooting."Serial PortPERC 3/DC and PERC 3/DCL includes a 3-pin RS232C-compatible serialport connector. This is for manufacturing use only.SCSI BusThe PERC 3/DC and PERC 3/DCL controller has four Wide 160M SCSIchannels that support both LVD and single-ended devices with activetermination. Synchronous and asynchronous devices are supported. PERC3/DC and PERC 3/DCL provides automatic termination disable via cabledetection. The SCSI channel supports up to 15 wide or seven non-wideSCSI devices at speeds up to 160 MB/s.
