Fujitsu M2488 manual Command Disconnection, Scsi Reset

M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS

4-4 COMMAND DISCONNECTION

After receiving any command, the controller disconnects if disconnection is not inhibited by the IDEN- TIFY message and the controller requires device activity to complete the request.

The controller reconnects to perform parameter or data transfers or to present command completion sta- tus as required.

Multiple disconnect and reconnect sequences may be performed for a single READ or WRITE com- mand as space or data becomes available in the buffer.

4-5 SCSI RESET

The SCSI Reset is performed in response to a SCSI BUS RESET or a BUS DEVICE RESET Message. The M2488 supports the SCSI hard reset alternative as follows:

•All SCSI I/O processes are cleared; i.e., the SCSI I/O process ends with the BUS FREE phase.

•Any back-end (tape motion or medium changer motion) operation in progress (rewind, synchronize, erase, locate, space, unload, or write filemarks, etc.) is allowed to complete after all of the SCSI I/O processes are cleared.

•Buffered write data is synchronized to tape.

•Buffered write data error is discarded.

•All SCSI device reservations are released.

•Power-on/Reset Unit Attention is generated.

April 1997 CG00000-011503 REV. A 4-153