User`s manual

Disk I/O Support

1-26

Disk I/O via Debugger System Calls

All operations that actually access the disk are done directly or

indirectly by debugger system calls. (The command-level disk

operations provide a convenient way of using these system calls

without writing and executing a program.)

The following system calls are provided to allow user programs to

do disk I/O:

Refer to Chapter 5 for information on using these and other system

calls.

To perform a disk operation, the debugger must present a

particular disk controller module with a controller command

packet which has been prepared for the particular type of controller

module. (This is accomplished in the respective controller driver

module.) Typically, the command packets are different for each of

the controller modules. The system call facilities which do disk I/O

accept a generalized (controller-independent) packet format as an

argument, and translate it into a controller-specific packet, which is

then sent to the specified device. Refer to the system call

descriptions in Chapter 5 for details on the format and construction

of these standardized user packets.

.DSKRD Disk read - system call to read blocks from a disk into

memory

.DSKWR Disk write - system call to write blocks from memory

onto a disk

.DSKCFIG Disk conÞgure - system call to change the

conÞguration of the speciÞed device

.DSKFMT Disk format - system call to send a format command

to the speciÞed device

.DSKCTRL Disk control - system call to implement any special

device control functions that cannot be

accommodated easily with any of the other disk

functions