user manual

Debugger General Information
B-16
B
The device probe mechanism utilizes the SCSI commands
ÒInquiryÓ and ÒMode SenseÓ. If the specified controller is non-SCSI,
the probe simply returns a status of Òdevice present and unknownÓ.
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 Òdevice presentÓ status
(pointer to the device descriptor).
Disk I/O via 177Bug Commands
The 177Bug commands listed in the following paragraphs 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 177Bug so that the
next disk command defaults to use the same controller and device.
IOI (Input/Output Inquiry)
This command probes the system for all possible CLUN/DLUN
combinations and displays inquiry data for devices which support
it. The device descriptor table has space for a maximum of 16 device
descriptors. Use the IOI command to view the table or clear it if
necessary.
IOP (Physical I/O to Disk)
IOP allows you to:
❏ Read blocks of data
❏ Write blocks of data
❏ Format a specified device in a certain way
IOP creates a command packet from the arguments you have
specified, then invokes the proper system call function to carry out
the operation.