Disk I/O Support

IOT (I/O Teach)

IOT allows you to change any configurable parameters and attributes of the device. In addition, it allows you to view the controllers available in the system.

IOC (I/O Control)

IOC allows you to send command packets as defined by the particular controller directly. IOC can also be used to examine the resultant device packet after using the IOP command.

BO (Bootstrap Operating System)

BO reads an operating system or control program from the specified device into memory, then transfers control to it.

BH (Bootstrap and Halt)

BH reads an operating system or control program from a specified device into memory, then returns control to 177Bug. It is used as a debugging tool.

Disk I/O via 177Bug System Calls

 

All operations that actually access the disk are done directly or

 

indirectly by 177Bug TRAP #15 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 allow user programs to perform disk

 

I/O:

 

 

.DSKRD

Disk read. Use this system call to read blocks from a disk into memory.

 

 

.DSKWR

Disk write. Use this system call to write blocks from memory onto a

 

disk.

 

 

B

B-17

Page 97
Image 97
Motorola MVME177 manual IOT I/O Teach, IOC I/O Control, BO Bootstrap Operating System, BH Bootstrap and Halt