Diskette Write Verify Function
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
When writing data on magnetic media for permanent storage, it is necessary to verify that the data was correctly written. This is because recovery from a write error is normally feasible only if the write error is discovered at the initial time of writing when the data is still available in an internal buffer. In the past, write verifies have been accomplished by one of these three primary methods: 1) The data compare method, as shown in Fig. 1, consists of a complete read, after which the write buffer is compared to the read buffer. Although this method is totally comprehensive in its verification of the write command, it is costly in terms of diskette, I/O bus, memory, and processor utilization. 2) The cyclic redundancy check (CRC) compare method shown in Fig.