Date: Fri, 05 Sep 1997 21:29:46 -0000 (GMT) From: Chris Dillon <cdillon@tri-lakes.net> To: freebsd-hardware@freebsd.org Subject: Tape geometries for the floppy-tape driver Message-ID: <XFMail.970905231516.cdillon@tri-lakes.net>
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I notice that FreeBSD's ft driver has been stagnant for some time. I
noticed this when trying to use some 2120EX and 2120XL tapes in my HP
Colorado Jumbo 350. Apparently the standard 2120 tapes work fine, but
/usr/src/sys/i386/isa/ft.c lists a very short and incomplete tape geometry
table (a whole 6 tapes!). My attempts to find the geometries of these
new, larger tapes has been fruitless so far (I'm assuming thats all I need
to get these tapes to work). I've managed to figure out what some of the
fields mean in the geometry table, but not all of them. Correct me if I'm
wrong, but here is what I gather the table represents, for example:
{ 2, 2, "QIC-80", "307.5/550", 28, 150, 4800, 128, 19200 },
This is a standard DC2120 250MB compressed tape. First two fields just
seem to be some kind of ID tag internal to the driver. The "307.5" is tape
length in feet, and the 550 is the tape coercivity in oersteds. The next
field is the number of serpentine tracks on the tape. The remainder of the
fields elude me. 19200 could possibly be bits/inch, but i think it is
supposed to be 14700 for this particular tape.
Web index searches on the subject of tape geometries didn't get me much. I
found the geometries of the DC2120 and DC2120XL tapes, and thats it.
Basically, the whole point of all this hot air was to ask for some help in
adding new geometries to the tape table. Actually.. anyone have any idea
how hard it would be to port the Linux floppy-tape driver over? (I have no
clue how to do so or I would have started already <grin>) It looks almost
as if it auto-adapts to any tape size as it has no geometry table. If it
did, I would have already copied the relevant data from it. :(
--- Chris Dillon
--- cdillon@tri-lakes.net
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