QIC-24 to QIC-150

[Dave Olson]

In <1991Jun26.124823.11846 at thunder.mcrcim.mcgill.edu> panisset at thunder.mcrcim.mcgill.edu (Jean-Francois Panisset ) writes:

| I have some tapes which were written to by a QIC-24 tape drive. Now, these
| tapes are "high-density" (12500 ftpi), and I would now like to re-use them
| in a QIC-150 drive. Unfortunately, the drive detects that these tapes were
| written to at low density, and thus refuses to write to them. So my question
| is: what is the best way to force a QIC-150 drive to write to such a tape,
| or do I have no choice but to use a powerful magnet? For reference, I
| am using a Personnal Iris under IRIX 3.3.2.

This is due to a bug in the tape drive firmware.  The problem is that
the firmware detects the qic24 format, and confuses it with a qic24
cartridge.  Newer firmware fixes the problem.  The newer firmware should
start shipping shortly, but there is no plan to do field upgrades, since
the drive needs to be almost completely taken apart to get to the PROM.
There are no other problems that affect SGI systems that are fixed by
the newer PROMs.

The workaround is pretty straightforward.  The problem ONLY occurs
when you insert a qic120 or qic150 cartridge, written in qic24 format,
and then try to read it before writing it.  The solution is to simply
insert the cartridge, and then start writing it, without trying to
read it first.