3B2 internal floppy diskette ioctl handling

Larry Lippman larry at kitty.UUCP
Mon Jan 5 14:55:24 AEST 1987


	I am attempting to write a custom device driver to permit reading
(only) of a non-3B2 diskette on the 3B2 internal floppy diskette drive.
For the moment, I am referring to 3B2-300's running Sys V Rel 2.2 which
use the Western Digital 2797 controller and Tandon diskette drive.  I have
some questions:

1.	In if.h there are three ioctl commands mentioned: IFFORMAT, IFBCHECK,
	and IFCONFIRM.  Which structures (like ifdev, ifformat, ifccmd,
	ifpreamfmat, etc.) are affected by which ioctl command?
	
2.	The above three ioctl commands do not seem to be enough (or at least
	the names are not that intuitive); are there more?  If so, what are
	they, and what is the bitwise operation on FIOC to derive them?

3.	How do I get the same semaphore key as the winchester driver is
	using?  Or, if I have to set IPC_CREAT to make a key, how is the
	the winchester driver supposed to know about it?  Also, how about
	a bit more information on the five semaphore flags (than disclosed
	by the if.h comments)? 

4.	What, if anything, do I do with the controller command IFFRCINT
	and the four defined interrupts?

	While I have previous experience writing device drivers and have
Sys V source code, unfortunately neither pertains to the 3B2 - so any help
will be appreciated!

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
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