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diff --git a/Documentation/ftape.txt b/Documentation/ftape.txt new file mode 100644 index 00000000000..7d8bb338403 --- /dev/null +++ b/Documentation/ftape.txt @@ -0,0 +1,307 @@ +Intro +===== + +This file describes some issues involved when using the "ftape" +floppy tape device driver that comes with the Linux kernel. + +ftape has a home page at + +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 +======== + +A minus 1: Ftape documentation + +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. Formatting + 5. Interchanging cartridges with other operating systems + +B. Debugging Output + 1. Introduction + 2. Tuning the debugging output + +C. Boot and load time configuration + 1. Setting boot time parameters + 2. Module load time parameters + 3. Ftape boot- and load time options + 4. Example kernel parameter setting + 5. Example module parameter setting + +D. Support and contacts + +******************************************************************************* + +A minus 1. Ftape documentation +============================== + +Unluckily, the ftape-HOWTO is out of date. This really needs to be +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://ftape.dot-heine.de/ + +******************************************************************************* + +A. Changes +========== + +1. Goal + ~~~~ + 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. + + The concept of a fixed block size for read/write transfers is + rather unrelated to this SCSI tape compatibility at the file system + interface level. It developed out of a feature of zftape, a + block wise user transparent on-the-fly compression. That compression + support will not be dropped in future releases for compatibility + reasons with previous releases of zftape. + +2. I/O Block Size + ~~~~~~~~~~~~~~ + 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 + (i.e. do "mt -f /dev/qft0" setblk #BLKSZ). A block size of 0 + switches to variable block size mode i.e. "mt setblk 0" switches + off the block size restriction. However, this disables zftape's + built in on-the-fly compression which doesn't work with variable + block size mode. + + The BLKSZ parameter must be given as a byte count and must be a + multiple of 32k or 0, i.e. use "mt setblk 32768" to switch to a + block size of 32k. + + The typical symptom of a block size mismatch is an "invalid + argument" error message. + +3. Write Access when not at EOD (End Of Data) or BOT (Begin Of Tape) + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + 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. + +4. Formatting + ~~~~~~~~~~ + 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://ftape.dot-heine.de/ + + `ftformat' is contained in the `./contrib/' subdirectory of that + separate ftape package. + +5. Interchanging cartridges with other operating systems + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + + The internal emulation of Unix tape device file marks has changed + 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. + + However, it isn't possible to extract the data dumped to the tape + 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 already + provides all kernel level support necessary to do that. + +******************************************************************************* + +B. Debugging Output + ================ + +1. Introduction + ~~~~~~~~~~~~ + The ftape driver can be very noisy in that is can print lots of + debugging messages to the kernel log files and the system console. + While this is useful for debugging it might be annoying during + normal use and enlarges the size of the driver by several kilobytes. + + To reduce the size of the driver you can trim the maximal amount of + debugging information available during kernel configuration. Please + refer to the kernel configuration script and its on-line help + functionality. + + The amount of debugging output maps to the "tracing" boot time + option and the "ft_tracing" modules option as follows: + + 0 bugs + 1 + errors (with call-stack dump) + 2 + warnings + 3 + information + 4 + more information + 5 + program flow + 6 + fdc/dma info + 7 + data flow + 8 + everything else + +2. Tuning the debugging output + ~~~~~~~~~~~~~~~~~~~~~~~~~~~ + To reduce the amount of debugging output printed to the system + console you can + + i) trim the debugging output at run-time with + + mt -f /dev/nqft0 setdensity #DBGLVL + + where "#DBGLVL" is a number between 0 and 9 + + ii) trim the debugging output at module load time with + + modprobe ftape ft_tracing=#DBGLVL + + Of course, this applies only if you have configured ftape to be + compiled as a module. + + iii) trim the debugging output during system boot time. Add the + following to the kernel command line: + + ftape=#DBGLVL,tracing + + Please refer also to the next section if you don't know how to + set boot time parameters. + +******************************************************************************* + +C. Boot and load time configuration + ================================ + +1. Setting boot time parameters + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Assuming that you use lilo, the LI)nux LO)ader, boot time kernel + parameters can be set by adding a line + + append some_kernel_boot_time_parameter + + to `/etc/lilo.conf' or at real boot time by typing in the options + at the prompt provided by LILO. I can't give you advice on how to + specify those parameters with other loaders as I don't use them. + + For ftape, each "some_kernel_boot_time_parameter" looks like + "ftape=value,option". As an example, the debugging output can be + increased with + + ftape=4,tracing + + NOTE: the value precedes the option name. + +2. Module load time parameters + ~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Module parameters can be specified either directly when invoking + the program 'modprobe' at the shell prompt: + + modprobe ftape ft_tracing=4 + + or by editing the file `/etc/modprobe.conf' in which case they take + effect each time when the module is loaded with `modprobe' (please + refer to the respective manual pages). Thus, you should add a line + + options ftape ft_tracing=4 + + to `/etc/modprobe.conf` if you intend to increase the debugging + output of the driver. + + +3. Ftape boot- and load time options + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + + i. Controlling the amount of debugging output + DBGLVL has to be replaced by a number between 0 and 8. + + module | kernel command line + -----------------------|---------------------- + ft_tracing=DBGLVL | ftape=DBGLVL,tracing + + ii. Hardware setup + BASE is the base address of your floppy disk controller, + IRQ and DMA give its interrupt and DMA channel, respectively. + BOOL is an integer, "0" means "no"; any other value means + "yes". You don't need to specify anything if connecting your tape + drive to the standard floppy disk controller. All of these + values have reasonable defaults. The defaults can be modified + during kernel configuration, i.e. while running "make config", + "make menuconfig" or "make xconfig" in the top level directory + of the Linux kernel source tree. Please refer also to the on + 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 + ft_fdc_irq=IRQ | ftape=IRQ,irq + ft_fdc_dma=DMA | ftape=DMA,dma + ft_probe_fc10=BOOL | ftape=BOOL,fc10 + ft_mach2=BOOL | ftape=BOOL,mach2 + ft_fdc_threshold=THR | ftape=THR,threshold + ft_fdc_rate_limit=RATE | ftape=RATE,datarate + +4. Example kernel parameter setting + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + To configure ftape to probe for a Colorado FC-10/FC-20 controller + and to increase the amount of debugging output a little bit, add + the following line to `/etc/lilo.conf': + + append ftape=1,fc10 ftape=4,tracing + +5. Example module parameter setting + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + To do the same, but with ftape compiled as a loadable kernel + module, add the following line to `/etc/modprobe.conf': + + options ftape ft_probe_fc10=1 ft_tracing=4 + +******************************************************************************* + +D. Support and contacts + ==================== + + Ftape is distributed under the GNU General Public License. There is + absolutely no warranty for this software. However, you can reach + the current maintainer of the ftape package under the email address + given in the MAINTAINERS file which is located in the top level + directory of the Linux kernel source tree. There you'll find also + the relevant mailing list to use as a discussion forum and the web + page to query for the most recent documentation, related work and + development versions of ftape. + + Changelog: + ========== + +~1996: Original Document + +10-24-2004: General cleanup and updating, noting additional module options. + James Nelson <james4765@gmail.com> |