24 Oct
2004
24 Oct
'04
9:58 a.m.
On Sun, 24 Oct 2004, der Mouse wrote:
"Under any UNIX system"? Have you tried them all? No, but, over the past
20 years, a good selection of them.
True... half-inch (and most other fixed-block) drives didnt
do the tapemark thing.
What I forgot to mention was: teh tape-marking "standard" was mostly
a software-based, voluntary standard, to prevent programs from reading
past EOT. Of course, pretty much nothing prevented people from doing
a <TM><TM> sequence, and then writing more data :)
--f
Ah... I have never used that facet of 'mt'
before
You dont need 'mt' (under any UNIX system) to read non-local tape
formats. This depends on the drive hardware and the driver.
Some tape drives
really do have fixed hardware block sizes. Even if setting a variable
Yes, such as
the half-inch ones, most DAT (DDS1/2 .. /3?) drives
and, I believe, 8mm drives.
where usually,
a length of 0 indicates an EOF (end of logical file,
aka "first tape mark detected") or EOT (end of tape, aka "second
consequtive tape mark detected") situation.
If you are using real half-inch tapes, detecting EOT is hard. I've run
into tapes with a dozen consecutive tape marks and data after them;
with some hardware, if you keep reading you'll eventually run off the
*physical* end of the tape - I've done it, and on the less friendly
drives it's a mess to re-thread the tape enough to rewind it onto the
original reel.