Multiple Data Transfer Request
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Feb-09
When data is transferred to or from I/O device 100 (Fig. 1), the data is first stored in data storage 60 of I/O controller (IOC) 50. If data is being transferred from I/O device 100 to channel 30, the microcode of IOC 50 requests a channel transfer and the channel interface circuitry 55 transfers the data from data store 60 to channel 30. After a block of data has been transferred from data store 60 to channel 30 the microcode of IOC 50 must check the status of that transfer. If I/O device 100 has transferred another block of data into data storage 60, the microcode of IOC 50 would request another data transfer to channel 30. The data transfer arrangement just described is effective, but there is a burden of having the microcode check the status of the completed transfer and setting up and requesting the next data transfer.