Motorola MVME166IG/D2 - Manual (Page 62)

Debugger General Information
3-16 MVME166 Single Board Computer Installation Guide
3
Device Probe Function
A device probe with entry into the device descriptor table is done whenever a
specified device is accessed; i.e., when system calls .DSKRD, .DSKWR,
.DSKCFIG, .DSKFMT, and .DSKCTRL, and debugger commands BH, BO,
IOC
, IOP, IOT, MAR, and MAW are used.
The device probe mechanism utilizes the SCSI commands "Inquiry" and
"Mode Sense". If the specified controller is non-SCSI, the probe simply returns
a status of "device present and unknown". The device probe makes an entry
into the device descriptor table with the pertinent data. After an entry has
been made, the next time a probe is done it simply returns with "device
present" status (pointer to the device descriptor).
Disk I/O via 166Bug Commands
These following 166Bug commands are provided for disk I/O. Detailed
instructions for their use are found in the Debugging Package for Motorola 68K
CISC CPUs User’s Manual. When a command is issued to a particular
controller LUN and device LUN, these LUNs are remembered by 166Bug so
that the next disk command defaults to use the same controller and device.
IOI (Input/Output Inquiry)
This command is used to probe the system for all possible CLUN/DLUN
combinations and display inquiry data for devices which support it. The
device descriptor table only has space for 16 device descriptors; with the IOI
command, you can view the table and clear it if necessary.
IOP (Physical I/O to Disk)
IOP allows you to read or write blocks of data, or to format the specified
device in a certain way. IOP creates a command packet from the arguments
you have specified, and then invokes the proper system call function to carry
out the operation.
IOT (I/O Teach)
IOT allows you to change any configurable parameters and attributes of the
device. In addition, it allows you to see the controllers available in the system.