Commit 63104fcc authored by James Nelson's avatar James Nelson Committed by Linus Torvalds

[PATCH] ftape documentation fixes

Description: Cleanup and update to Documentation/ftape.txt

Signed-off by: James Nelson <james4765@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c1a23528
......@@ -2,26 +2,21 @@ Intro
=====
This file describes some issues involved when using the "ftape"
floppy tape device driver that comes with the Linux kernel. This
document deals with ftape-3.04 and later. Please read the section
"Changes" for the most striking differences between version 3.04 and
2.08; the latter was the version of ftape delivered with the kernel
until kernel version 2.0.30 and 2.1.57. ftape-3.x developed as the
re-unification of ftape-2.x and zftape. zftape was developed in
parallel with the stock ftape-2.x driver sharing the same hardware
support but providing an enhanced file system interface. zftape also
provided user transparent block-wise on-the-fly compression (regard it
as a feature or bug of zftape).
floppy tape device driver that comes with the Linux kernel.
ftape has a home page at
http://www-math.math.rwth-aachen.de/~LBFM/claus/ftape
http://ftape.dot-heine.de/
which contains further information about ftape. Please cross check
this WWW address against the address given (if any) in the MAINTAINERS
file located in the top level directory of the Linux kernel source
tree.
NOTE: This is an unmaintained set of drivers, and it is not guaranteed to work.
If you are interested in taking over maintenance, contact Claus-Justus Heine
<ch@dot-heine.de>, the former maintainer.
Contents
========
......@@ -31,9 +26,8 @@ A. Changes
1. Goal
2. I/O Block Size
3. Write Access when not at EOD (End Of Data) or BOT (Begin Of Tape)
4. MTBSF - backspace over file mark and position at its EOT side
5. Formatting
6. Interchanging cartridges with other operating systems
4. Formatting
5. Interchanging cartridges with other operating systems
B. Debugging Output
1. Introduction
......@@ -58,7 +52,7 @@ changed. Up to date documentation as well as recent development
versions of ftape and useful links to related topics can be found at
the ftape home page at
http://www-math.math.rwth-aachen.de/~LBFM/claus/ftape
http://ftape.dot-heine.de/
*******************************************************************************
......@@ -70,7 +64,7 @@ A. Changes
The goal of all that incompatibilities was to give ftape an interface
that resembles the interface provided by SCSI tape drives as close
as possible. Thus any Unix backup program that is known to work
with SCSI tape drives should also work with ftape-3.04 and above.
with SCSI tape drives should also work.
The concept of a fixed block size for read/write transfers is
rather unrelated to this SCSI tape compatibility at the file system
......@@ -81,14 +75,8 @@ A. Changes
2. I/O Block Size
~~~~~~~~~~~~~~
The probably most striking difference between ftape-2.x and
ftape-3.x with the zftape file system interface is the concept of a
fixed block size: data must be written to or read from the tape in
multiples of a fixed block size. The block size defaults to 10k
which is the default block size of GNU tar. While this is quite
usual for SCSI tapes (block size of 32k?) and the QIC-150 driver
`./drivers/char/tpqic02.c' ftape-2.x allowed data to be written in
arbitrary portions to the tape.
The block size defaults to 10k which is the default block size of
GNU tar.
The block size can be tuned either during kernel configuration or
at runtime with the MTIOCTOP ioctl using the MTSETBLK operation
......@@ -109,53 +97,41 @@ A. Changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
zftape (the file system interface of ftape-3.x) denies write access
to the tape cartridge when it isn't positioned either at BOT or
EOD. This inconvenience has been introduced as it was reported that
the former behavior of ftape-2.x which allowed write access at
arbitrary locations already has caused data loss with some backup
programs.
4. MTBSF - backspace over file mark and position at its EOT side
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ftape-2.x didn't handle the MTBSF tape operation correctly. A MTBSF
call (i.e. "mt -f /dev/nqft0 bsf #COUNT") should space over #COUNT
file marks and then position at the EOT tape side of the file
mark. This has to be taken literally, i.e. "mt -f /dev/nqft0 bsf 1"
should simply position at the start of the current volume.
5. Formatting
EOD.
4. Formatting
~~~~~~~~~~
ftape-3.x DOES support formatting of floppy tape cartridges. You
need the `ftformat' program that is shipped with the modules version
of ftape-3.x. Please get the latest version of ftape from
ftape DOES support formatting of floppy tape cartridges. You need the
`ftformat' program that is shipped with the modules version of ftape.
Please get the latest version of ftape from
ftp://sunsite.unc.edu/pub/Linux/kernel/tapes
or from the ftape home page at
http://www-math.math.rwth-aachen.de/~LBFM/claus/ftape
http://ftape.dot-heine.de/
`ftformat' is contained in the `./contrib/' subdirectory of that
separate ftape package.
6. Interchanging cartridges with other operating systems
5. Interchanging cartridges with other operating systems
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The internal emulation of Unix tape device file marks has changed
completely. ftape-3.x now uses the volume table segment as specified
completely. ftape now uses the volume table segment as specified
by the QIC-40/80/3010/3020/113 standards to emulate file marks. As
a consequence there is limited support to interchange cartridges
with other operating systems.
To be more precise: ftape will detect volumes written by other OS's
programs and other OS's programs will detect volumes written by
ftape-3.x.
ftape.
However, it isn't possible to extract the data dumped to the tape
by some MSDOG program with ftape-3.x. This exceeds the scope of a
by some MSDOS program with ftape. This exceeds the scope of a
kernel device driver. If you need such functionality, then go ahead
and write a user space utility that is able to do
that. ftape-3.x/zftape already provides all kernel level support
necessary to do that.
and write a user space utility that is able to do that. ftape already
provides all kernel level support necessary to do that.
*******************************************************************************
......@@ -200,7 +176,7 @@ B. Debugging Output
ii) trim the debugging output at module load time with
insmod ftape.o ft_tracing=#DBGLVL
modprobe ftape ft_tracing=#DBGLVL
Of course, this applies only if you have configured ftape to be
compiled as a module.
......@@ -240,7 +216,7 @@ C. Boot and load time configuration
2. Module load time parameters
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Module parameters can be specified either directly when invoking
the program 'insmod' at the shell prompt:
the program 'modprobe' at the shell prompt:
modprobe ftape ft_tracing=4
......@@ -277,6 +253,12 @@ C. Boot and load time configuration
line documentation provided during that kernel configuration
process.
ft_probe_fc10 is set to a non-zero value if you wish for ftape to
probe for a Colorado FC-10 or FC-20 controller.
ft_mach2 is set to a non-zero value if you wish for ftape to probe
for a Mountain MACH-2 controller.
module | kernel command line
-----------------------|----------------------
ft_fdc_base=BASE | ftape=BASE,ioport
......@@ -316,10 +298,10 @@ D. Support and contacts
page to query for the most recent documentation, related work and
development versions of ftape.
Changelog:
==========
~1996: Original Document
LocalWords: ftape Linux zftape http www rwth aachen LBFM claus EOD config
LocalWords: datarate LocalWords BOT MTBSF EOT HOWTO QIC tpqic menuconfig
LocalWords: MTIOCTOP MTSETBLK mt dev qft setblk BLKSZ bsf zftape's xconfig
LocalWords: nqft ftformat ftp sunsite unc edu contrib ft MSDOG fdc
LocalWords: dma setdensity DBGLVL insmod lilo LI nux ader conf txt
LocalWords: modprobe IRQ BOOL ioport irq fc mach THR
10-24-2004: General cleanup and updating, noting additional module options.
James Nelson <james4765@gmail.com>
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