| 摘要 |
PURPOSE:To easily judge whether a fault relating to DMA transfer is caused by hardware or software at the step of system development by providing this device driver with three kinds of transfer modes. CONSTITUTION:A user process 1 (or 2 or 3) issues a system call to an OS, either one of switch tables is referred in accordance with the contents of the system call, i.e., a block type I/O request or a character type I/O request, and a disk driver routine corresponding to the I/O request is called. Each routine in the disk driver 14 which is called by a switching table 12 executes processing inherent in the routine itself, and when it is necessary to control a disk controller 30 or a DMA controller 40, an interface driver 16 arranged as a slave device driver of the disk driver 14 is called. |
