Accessing the ctc on a 3B2/400 from a program ?

[Kim F. Storm]

We have to port a program to backup large files (and disks) on the
23 Mbyte cartridge tape on the 3b2/400.

There is no problems in moving the code (isn't C+UNIX wonderful),
but we cannot get any good performance out of the tape drive, because
we cannot make it stream.

We have no information about the programming of this beast, so we are
left with guessing from what we can find in sys/ct.h which is not
much.  It seems that some combination of open flags and ioctls is
needed, using the following defines:

	#define O_CTSPECIAL	0200

	#define	STREAMON	's'

Most attempts have resulted in the following error:

	ENOTOPN  (205)	sub-device not open 

(Which "sub-device" ?)


We are completely stuck, so if you know how it is node, please let us
know.  Any help will be received with gratitude.

--
Kim F. Storm, storm at ambush.dk (or ..!mcvax!diku!ambush!storm)
AmbraSoft A/S, Rojelskaer 15, DK-2840 Holte, Denmark.  tel: +45 2424 111

		No news is good news, but nn is better!