The Ftape Installation Guide - Loading ftape
zftape can be used with the kerneld
daemon safely.
The driver simply locks itself in memory under the following
conditions:
man 2 open
') and not yet been
closed (see `man 2 close
').
MTWEOF
has to be considered as a special means to write data (i.e. file marks,
see MTWEOF) to the tape, whereas MTERASE
is uncritical in
this context as it takes care of the header segments itself.
MTFSF
, MTBSF
,
MTBSFM
, MTFSFM
, MTFSR
, MTBSR
, MTSEEK
and MTEOM
. See MTIOCTOP for more information about these tape
operations.
MTSETBLK
operation (see Setting the block size).
MTCOMPRESSION
tape
operation when using the non-compressing devices.
see zftape devices. See MTCOMPRESSION.
MTRESET
command or remove and reinsert the tape cartridge and
open the tape device again. Issuing the MTRESET
command should be
preferred. See MTRESET.
Most of the above module locking situations can be cleared by simply
rewinding the tape device when it isn't needed any more. However, please
remember that this is not the case when the tape block size has
been changed using MTSETBLK
. In this case one has to restore the
default block size of 10k:
mt -f /dev/nqft0 10240
Other situations might require to send a MTRESET
command to the
driver, especially if a tape operation has been interrupted before
completion. Think for example of removing the tape cartridge during a
formatting procedure. The MTRESET
command has the same effect (or
should have) as re-inserting the tape cartridge and opening the tape
device (see MTRESET).
The following is an example of what could happen when the driver would not lock itself in memory:
claus@anaxagoras:claus$ mt -f /dev/nqft0 eom claus@anaxagoras:claus$ sleep 120 claus@anaxagoras:claus$ tar -cvvf /dev/nqft0 /usr/src/ftape-3.04d
When ftape would be unloaded in between this would result in erasing the entire cartridge and then writing the new volume starting at BOT but as ftape is not unloaded this does not result in erasing the entire cartridge.
Keep in mind that the ftape driver is quite large. Compiling the driver with full debugging support and loading ftape and zftape consumes roughly 250kb (including the 3 dma buffer the driver needs for the data transfer) so it might be a good idea to not keep it constantly in memory.
Please refer also to the documentation included in the `modules
'
(or `modutils
') package on how to configure the modules utilities
for use with the kerneld
program (see Requirements). There is
a short example how to modify /etc/conf.modules for use with
ftape. See Insmod ftape.
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