Floppy controller based cartridge for 3b1?

DoN Nichols dnichols at ceilidh.beartrack.com
Fri Feb 22 08:13:41 AEST 1991


In article <1991Feb21.115538.21538 at cbnews.att.com> mvadh at cbnews.att.com (andrew.d.hay) writes:
>In article <1991Feb21.021757.6924 at ceilidh.beartrack.com> dnichols at ceilidh.beartrack.com (DoN Nichols) writes:
>[]
>"	It might work!  Does anyone have access to one of these and the tape
>"controller for the 3B1?  I would be willing to try if someone can lend a
>"drive.  (Or perhaps the pin-out for the drive first, just to check for

	[...]

>
>the 40M qic-40 drive is *completely* different, which is not to say you
>couldn't write a driver for it using the controller card.
>hardware might also not be a big problem, but the drive was meant to plug into
>the floppy-drive ribbon cable, not the controller's db-37.

	But the DB-37 is just the external reflection of the internal 34-pin
edge connector.  Look inside the case of your drive! The three pins at the
pin 1 end of the connector are not used, and the remaining ones map to the
34-pin edge connector used on the drive (just like a floppy drive, except
that (if I remember correctly - I'm not at home where the docs are), some of
the drive select lines are used as additional head select lines.  (Really
head vertical positioning commands, since the head has one track worth of
poles, and is stepped vertically to select tracks on the tape.))

	How is the drive different?  If it works from a floppy interface, it
can't be too different.  The data pins, and most of the control pins will be
the same.  I don't know whether the s4tape diags format to a fixed sector
count, or check for the {beginning,end}-of-tape markers.  We might have to
rewrite the format program in s4tape.  I guess that the "sector number" is
kept in a single byte, which explains the turnaround of the tape at 255
sectors.  The number of tracks could be increased by playing games with more
encoding of the drive/head select lines, or probably could actually use the
"step out" and "step in" lines.

	Do you have the pinout of the qic-40 drive?  We can at least check
if the hardware interface is likely to be compatable.

>my goal is to make it run off the *internal* controller...
>

	I'd actually prefer a replacement controller for the QIC-36/QIC-24
interface, using the Archive drives or equivalent.  (60MB and no need for
pre-formating the tapes. :-) It would be intelligent enough, and have enough
buffer so the system could be building the next buffer with tar or cpio
WHILE the current buffer was being written.  But, that is a more major
project than this could be if we're lucky.

	What I really need is enough disk space on my Tektronix 6130 so I
could ftp a tar image of my disk partitions to that system, then zap the
image onto the Archive tape drive there.  It'd be quicker than the present
system. :-)  (At least till I filled up THAT disk space :-)



-- 
Donald Nichols (DoN.)		| Voice (Days):	(703) 664-1585
D&D Data			| Voice (Eves):	(703) 938-4564
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	--- Black Holes are where God is dividing by zero ---



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