PURPOSE: To shorten the waiting time of a CPU by operating an expansion storage device having a medium speed as an I/O device for a main storage device and as a main storage device for an external storage device and executing MOVE processing if necessary.
CONSTITUTION: When an expansion storage device 5 is to be accessed as an I/O device, a start I/O instruction is generated and the expansion storage device is recognized by a channel and a device address. The initial channel command word is read out by a channel address word in a channel program read out in accordance with the start I/O instruction and the address of the expansion storagedevice is specified by a control command and the reference of a table in the main storage device. When accessing is enabled by said procedure, the main storage device 2 can transfer data to/from the expansion storage device 5 through a control part 3 and a channel device 4.
KANEDA SABUROU
UCHIDA KEIICHIROU
| JPS50115938A | 1975-09-10 | |||
| JPS58102381A | 1983-06-17 | |||
| JPS49116927A | 1974-11-08 |