Dynamic Usage of Varying Cache Size
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-29
An adapter card utilizes a data cache which provides the system device driver software with the ability to read data ahead of system requests. The performance of this adapter is directly related to the size of the data cache. The cache size of the first release of the adapter card was fixed at 16k bytes. This allowed for reasonably good performance for single sequential requests. The introduction of additional competing sequential requests caused a performance degradation due to the small cache size. This was due to a steal effect whereby one request would steal cache space from the other request. When swapping between competing requests, data that was read ahead but not used immediately would be discarded and therefore would require another read later.