
I have two SCSI hard drives, each has 512KB of 'cache'.

There several reasons for this :-

When the drive has read requested data from the disk the SCSI bus may be
busy. This data needs to be stored some where until the bus is free and
the data can be transmitted.

When the drive receives data to be written, the data can come down the bus
faster than the drive can write it to the disk. It needs to be stored
somewhere while the disk is writing it out.

In these situations the memory is being used as a buffer NOT a cache!

May be the drive does some read-adead caching as well...


Guy