Multi-Port Data Cache Directory
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-29
The data directory is used to hold the address for the data stored in the data cache. In a typical environment such as the 9370 MOD 60, one processor unit is allowed at any one time. This may be the CPU or the I/O processor. In order to handle the I/O, a synchronization mechanism was designed, which usually shuts down the processor access to cache for a few cycles regardless of whether the I/O has any data in (Image Omitted) cache or not. A two-port read directory will allow the I/O to peek at the directory without shutting down the CPU unless I/O data is in cache.