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┌─────────────────────────────────────────────────────────────────────────┐ │ │ │ SCSI TAPE BACKUP for OS/2 2.0 │ │ ───────────────────────────── │ │ │ │ Version 2.12 │ │ │ │ Author: Andreas Kaiser │ │ Danziger Str. 4 │ │ D-7000 Stuttgart 70 │ │ Germany │ │ │ │ Fidonet: 2:241/7220.9 │ │ Internet: ak@ananke.stgt.sub.org │ │ Voice: 49-711-766116 │ │ │ │ IF YOU CAN USE ELECTRONIC MAIL, PLEASE DO SO. DON'T CALL │ │ BY VOICE UNLESS ABSOLUTELY UNAVOIDABLE. │ │ │ └─────────────────────────────────────────────────────────────────────────┘ $Id: readme.os2,v 1.27 1993/02/22 12:08:32 ak Exp $ Legal notices: -------------- BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Der alternative Device-Driver SCSITAPE.SYS unterliegt nicht dem GNU Copyleft. Der Quellcode dieses Treiber ist nicht erhältlich. Sie können SCSITAPE.SYS in kommerzieller Umgebung nutzen, Sie dürfen ihn jedoch nicht verkaufen oder auf andere Art Geld oder andere Gegenleistungen dafür erhalten. Sie dürfen diesen Treiber nicht als Basis eines kommerziellen Produktes einsetzen, auch nicht als Beigabe. English translation of the sentences about SCSITAPE.SYS (the german version has priority): The alternate device driver SCSITAPE.SYS is not governed by the GNU Copyleft. It's source code is not available. You can use SCSITAPE.SYS within a commercial environment, but you may not sell it or make profit in other ways. You may not use it as a base for a commercial product or as an add-on to a product. ───────────────────────────────────────────────────────────────────────── Thanks to Kai Uwe Rommel for beta test, several fixes and enhancements and to Eberhard Mattes for his great OS/2 development environment. ───────────────────────────────────────────────────────────────────────── Contents: --------- Binaries: ......... TAR.EXE Modified GNU-TAR 1.10 for OS/2 2.0 and tape driver. 32-bit version using EMX 0.8f. No EMX.DLL required. TAPE.EXE Tape control utility. COMPRESS.EXE A file compression program for OS/2, invoked by the "-z" tar option. The compression rate is not as good as LHARCs and it is not as fast as PKZIP -es, but COMPRESS can be used with pipes on both ends. It is an OS/2 port of the well known Unix compress program. It supports 16-bit compression mode, of course. BUFFER.EXE Pipe buffer & reblock program for OS/2. Invoked by the "-z" option when operating on character devices. SCSITAPE.DMD Tape device driver for OS/2 2.0, based on an ADD SCSI base device driver (such as AHA154X.ADD). SCSITAPE.SYS Alternate device driver, based on OS2SCSI.DMD. ASPITAPE.SYS Alternate device driver, based on ASPI (OS2ASPI.DMD). README.ABS An overview description. README.OS2 This file. 1.10/TAR.TEX TeXinfo documentation of original TAR. Sources: ........ 1.10/* GNU tar 1.10. TAPE/*: Tape control program. UTIL/*: compress.d, buffer.c LIBX/*: Some OS/2 utility functions and library replacements. OS2-ADD/*: Tape device driver based on the ADD interface. OS2-ASPI/*: Tape device driver based on the ASPI interface. OS2-DD/*: OS/2 device driver support library . ───────────────────────────────────────────────────────────────────────── The drivers: ------------ There are three alternate versions of the device driver. SCSITAPE.DMD is based on the ADD driver, SCSITAPE.SYS is based on OS2SCSI.DMD and ASPITAPE.SYS is based on Adaptecs ASPI interface definition which is implemented by OS2ASPI.DMD. Prerequisites: SCSITAPE.DMD: - SCSI ADD driver like AHA154X.ADD. SCSITAPE.SYS - SCSI ADD driver like AHA154X.ADD. - Installed OS2SCSI.DMD. - SCB support built into the SCSI adapter (IBM PS/2) or driver. OS2SCSI.DMD emulates the required SCB commands starting with syslevel 2.00.1, but nevertheless it crashed with an AHA1542. ASPITAPE.SYS - SCSI ADD driver like AHA154X.ADD. - Installed OS2ASPI.DMD. - Syslevel >= 2.00.1 (service pack). If you run a SCSI adapter not listed below, you may try all versions in the order SCSITAPE.DMD -> ASPITAPE.SYS -> SCSITAPE.SYS. But be prepared for immediate or delayed system crashes. Note that a SCSI driver fault can damage filesystems, so backup your filesystems before. ───────────────────────────────────────────────────────────────────────── Tested: ------- Host adapters, tested with SCSITAPE.DMD: Good: AHA1542B, AHA1742 DPT2011 (Mark Leidecker - 2:241/5111.3@fidonet) Future Domain TMC-885 OS/2 SYSLEVEL >= 2.00.1 (Service Pack) (Rob Prikanowski - rpr@oce.nl) Future Domain TMC-1650 The tape's SCSI ID must be set to 7 (toy@alydar.crd.ge.com) Future Domain TMC-1670 Service Pack required (manne@minsk.docs.uu.se) Bad: IBM PS/2 SCSI AHA1522 (Wolfgang Franke - wfranke@blabel.ppp\ .informatik.uni-muenchen.de) Host adapters, tested with ASPITAPE.SYS: Good: AHA1542B OS/2 SYSLEVEL >= 2.00.1 (Service Pack) Future Domain TMC-1670 Service Pack required (manne@minsk.docs.uu.se) Host adapters, tested with SCSITAPE.SYS: Good: IBM PS/2 SCSI 32-bit version Bad: AHA1542B Tape devices: With QFA (Quick File Access) using SCSI-2 commands: Tandberg TDC4200 SCSI-2 Tandberg TDC4120 SCSI-2 Tandberg TDC3820 SCSI-2 (Manfred Huber - 100021.3416@compuserve.com) HP DAT 35470A/80A (Martin Vorlaender - 2:241/3420.1@fidonet) With QFA (Quick File Access) using the Tandberg SCSI-1 commands: Tandberg TDC4120 SCSI-1 Tandberg TDC3820 SCSI-1 Tandberg TDC3660 SCSI-1 Wangtek 5150ES, depending on the firmware revision Archive Viper 2150S (Clemens.Beckstein@informatik.uni-erlangen.de) Sankyo CP150 (manne@minsk.docs.uu.se) Archive Python DAT SCSI-2 - uses SCSI-1 QFA even though it claims to be a SCSI-2 device (mark@mystic.ucdavis.edu) No QFA: Wangtek 5150ES, depending on the firmware revision No information about QFA: Sankyo, equivalent to Wangtec 5525ES (Mark Leidecker - 2:241/5111.3@fidonet) If you are successful and your SCSI adapter or tape device is not listed above, please send a note to one of my email addresses. ───────────────────────────────────────────────────────────────────────── Installation: ------------- SCSITAPE.DMD: ------------- Copy SCSITAPE.DMD into the root or \OS2 directory (preferably) of your OS/2 boot partition (the only places where a BASEDEV driver is recognized). Add the following lines to CONFIG.SYS: set TAPE=+++TAPE$<id> BASEDEV=SCSITAPE.DMD TAPE$<id> A<ano> <id> S<mode> SCSITAPE.SYS: ------------- SCSITAPE.SYS can be placed anywhere on your disks, as long as you specify its full path in CONFIG.SYS. set TAPE=+++TAPE$<id> DEVICE=your_path\SCSITAPE.SYS TAPE$<id> <unit> S<mode> Note that this driver installs successfully, even if there is no tape present in the system and no tape configured in the system setup (PS/2). This is a bug. ASPITAPE.SYS: ------------- ASPITAPE.SYS can be placed anywhere on your disks, as long as you specify its full path in CONFIG.SYS. set TAPE=+++TAPE$<id> DEVICE=your_path\ASPITAPE.SYS TAPE$<id> A<ano> <id> S<mode> all: ---- <mode> 2 for SCSI-2 devices, like TDC 3820 and TDC 4120 1 for Tandberg SCSI-1 devices (TDC 3660, TDC 3820, TDC 4120) 0 for other SCSI-1 devices Note that there are both SCSI-1 and SCSI-2 versions of Tandberg TDC 3820 and TDC 4120 available, with no visible difference. Run "tape inq" and look for "ANSI 1" or "ANSI 2" to know what SCSI level your device supports. Use a <mode> of 0 for this purpose. <ano> Adapter number, starting with 0. Only required if you have multiple SCSI adapters with the same (!) ADD driver. If you have several tape devices connected to different host adapters, use different SCSI ID's to reduce the chance of confusion. <id> SCSI ID <unit> 1 for the first sequential device, 2 for the second and so on. The driver's <mode> argument determines the way, how both the driver and the tape interface interpret and print SCSI error codes. If your device supports the QFA commands of Tandberg SCSI-1 (some Wangtek and Archive 150MB models) and the extended sense data conforms to SCSI-1 (Tandberg's does not), you should set <mode> to 0. Example: set TAPE=+++TAPE$4 BASEDEV=SCSITAPE.DMD TAPE$4 4 S2 The leading "+" characters in the file/device name signal TAR to use the tape device interface instead of the standard file interface. If you like to sort your CONFIG.SYS: The environment variable can be specified anywhere, only the programs TAPE and TAR use it to determine the default tape device name. The tape device must be present and powered on when OS/2 boots. This is enforced by the ADD interface. A device driver on top of an ADD driver can only access SCSI devices which are known at the time when the ADD driver is initialized. If you have more than one tape device, install the driver once for each device, using different SCSI IDs and different device names (TAPE$x). Hint: You may be tempted to use TAPE$0 for the first and TAPE$1 for a possible second tape device, but this way you are unable to specify the TAR tape device in short form as -4 or -5, since the options -0 and -1 are reserved for floppy access. Add C<x>, where <x> is the device type code, to the driver command line if you want to use the driver and the TAPE program to access non-tape devices. This way you can run any arbitrary SCSI command on the device, unless it is locked by another driver. If the device is locked by OS2DASD.DMD (disks are), add /!DM:<id> to the SCSI ADD line - note that you will have to boot from floppy if this is your boot disk. ASPITAPE.SYS does not care about device types, the option C<id> is ignored in ASPITAPE.SYS. SCSITAPE.DMD: If you have a seperate monochrome video card in your machine, you may want to add the option D3 to the BASEDEV=SCSITAPE.DMD line. The driver will display all available BASEDEV device driver info on the monochrome screen at system boot time. Remove this option after getting this info once because it will seriously slow down operation. As a side effect, you will definitely know which of your device drivers supports more than 16MB of memory. Do *not* add /!SM:<id> to the SCSI driver's command line as this option disables the tape driver too. If the device is locked by OS2SCSI.DMD (e.g. CDROM), comment out OS2SCSI.DMD. ASPITAPE.SYS: If the device is locked by OS2SCSI.DMD, add /SM:<id> to the ADD driver command line. ───────────────────────────────────────────────────────────────────────── Add SCSI tape support to your OS/2 boot disk: --------------------------------------------- You may want to create a boot diskette with SCSI tape support, to be able to restore your files in case of a damaged hard disk. Make a boot diskette using the REXX program MAKEBOOT or IBMs SE20BOOT (available on many FTP servers and BBSs). Copy the device driver and its prerequisites (see above) to the diskette and replace the line BASEDEV=IBMINT13.I13 by BASEDEV=AHA154X.ADD (or whatever you are using). Add the configration statements as shown above. Caution: an unmodified MAKEBOOT disk as well as the standard OS/2 boot disks will probably not allow any SCSI device access except for the first two BIOS disks, since there is no SCSI driver installed. When booting non-IBM machines from unmodified diskettes, OS/2 runs the INT13 driver instead of the SCSI driver. The INT13 driver does not allow SCSI device access except for the two BIOS mapped harddisks. ───────────────────────────────────────────────────────────────────────── GNU TAR: -------- This is not an introduction into TAR. Look into the TeX file or a good Unix book to learn more about the usage of TAR. If TAR is invoked without explicit archive specification or with a archive filename beginning with "+", it always positions to end-of-tape before data is written to the tape and it automatically appends a filemark after writing all data. This way TAR never erases existing tape contents when you accidentally forget the -f switch on the command line (or if you pressed the wrong key - remember that "c" is close to "x"). If you want to rewrite the tape from the beginning, either erase the tape (TAPE ERASE, see below) or write an empty filemark at the beginning of the tape (TAPE REWIND MARK). If you write an empty filemark, you have to skip the first tape file (TAPE FILE) when reading the tape. Multi-volume archives will probably not work when the tape reaches its limit - it takes too long to test it. If you need multi-volume archives, use the option -L (--tape-length) to split the data in chunks of a size somewhat less than the maximum tape capacity. TAR uses whatever block size is preset in the tape device. If the block size is set to variable, the actual block size is the TAR block size (usually 10K). Use TAPE BLOCKSIZE to set the tape's blocksize. Get help with tar --help New/changed options: -0 -1 Alias for "-f a:" and "-f b:" Writing diskettes in this way wipes out the DOS format. You have to reformat such a diskette before reuse with DOS/OS2 files. Such diskette archives can be used to exchange files with most Unix systems. Not recommended for 360/720KB diskettes in 1.2MB/1.44MB drives. -2 .. -7 Alias for "-f +++TAPE$2" .. "-f +++TAPE$7" -E Similar to "-v", but prints directory names only as they (and the files within them) are processed. -D --tape-dir filename Use and maintain a tape directory. New data is appended to the (text) file if it already exists. This option allows fast random access to single files (QFA, Quick File Access), provided the device supports the random access commands of SCSI-2 or Tandberg TDC3600/3800 SCSI-1 series. Many 60-150MB streamers do not support these commands, so there is no way for a fast random access on these models. This is a deficiency of the SCSI command set prior to the SCSI-2 specification. This option is not usable with compression mode. NOTE: The format of the tape directory has changed. Version 1 tape directories should not be used. -g --incremental filename The backups will be done incremental. Implies --all-timestamps and --all-files. If --generation is not specified, it defaults to "incremental". Directories archived with -g contain info about all files located in this directory. On restore, all files, which exist in the directory on disk but not in the directory on the archive, are removed from the disk, since they are left over from previous incremental restores. Standard tar programs will complain about or ignore such directories on the archive. The specified file is the dumpfile. The dumpfile is not used on restore. Nevertheless it has to be specified on the commandline, for syntactic reasons. -G --generation O Specifies the state and the strategy of incremental backups. When O is "f[irst]" The first generation of incremental backups. The dumpfile is overwritten, all files are archived. Directories are archived in special GNU dump format. When O is "s[econd]" All files and directories, which were changed since the last update of the dumpfile, are archived. Directories are archived in special GNU dump format. The dumpfile is *not* updated. If only first and second generation incremental backups are used, each second generation backup archives all files changed since the last first generation backup. You no longer need previous second generation backup media, once a new one is written. When O is "i[ncremental]" All files and directories, which were changed since the last update of the dumpfile, are archived. Directories are archived in special GNU dump format. The dumpfile is updated to reflect the current state of the archived filesystems. All future second and incremental generation backups are based on latest run. -L <n>[B|K|M] You can append B or K or M now, for B=blocksize (TAR block size, not tape block size), K=KB, M=MB. Example: -L 145M Split archive into chunks of 145 MB. Note that TAR does not account for the current tape position. If there is less space on the remaining tape than specified in -L, TAR will run until it hits the physical end of the tape. -p --all-files Include extended attributes, SYSTEM and HIDDEN files on backup. Account for extended attributes, SYSTEM and HIDDEN file attributes on list and restore. The SYSTEM and HIDDEN attributes are encoded in the group and world execute bits of the Unix style file mode. NOTE: The format of archived extended attributes has changed. Version 2 does not restore (ignores) EAs saved with version 1. -pp --all-timestamps Archive and restores all time stamps, including access and creation time stamps of HPFS files. This is the default for GNU dumps. -Y --no-recursion Save only the files specified on the command line. Do not save contents of directories. --fat Convert long (i.e OS/2 HPFS or Unix) filenames to FAT 8.3 filenames if required. Use this option if you extract archives with filenames that exceed the 8.3 FAT restrictions onto HPFS file systems but want to convert to 8.3 names unconditionally. If you extract onto FAT file systems, names which do not fit into 8.3 are converted in any case, if --fat is used or not. -Z Was alias for -z. Now forces buffered pipe compression mode. This is automatically done when the archive is a character device (tape or floppy). --archive Archive only those files, where the "archive" bit is set. This bit is reset afterwards. If you create a new file or modifiy a file in DOS or OS/2, this bit is automatically set, so this is OS/2's "official" way of running incremental backups. --reset-archive Reset the "archive" bit for every file archived. Use this option in a full backup, if you intend to later use incemental backups via --archive. This is software designed for (and ported from) Unix systems, so don't expect all options and features to work. And don't be too much confused by some warnings, which may occur when TAR tries to set attributes or filetimes at times when this is not allowed under OS/2. This TAR automatically saves and restores Extended Attributes when -p is given. Path and filename specifications are sensitive to upper/lower case and forward/backward slash convention. Since the TAR format is standardized and available on every UNIX system, you can use TAR to exchange data with UNIX systems. Even compressed data is compatible with 32-bit Unix systems. If you intend to exchange tapes or diskettes with standard Unix tar programs, avoid the GNU TAR specific options -V, -g and the OS/2 specific option -p. Paths and filenames should be specified with forward slashes as path separators. On extract, paths and filenames must be specified exactly as shown by "TAR t" except for the trailing "/" of directories, which should be omitted. Hint: GNU TAR removes leading absolute path indicators such as drive letters and leading slashes (verbose) on create and extract, unless -P or --absolute-paths is specified. If put save several partitions into the same archive, you may not be able to distinguish files with the same path and filename on restore. Use separate archives (run TAR seperately) for each logical disk or specify --absolute-paths. You can still extract files to a relative path even when it was written with an absolute path. Hint: Although the output of the -v option looks nice, it may be wise not to use it for large backups. When a large number of small files is written to tape, the big amount of screen output may slow down the tape output, forcing the tape into inefficient stop-and-go mode. Use the -E option instead, if you like to get feedback about the progress of backups. Examples: tar cp . Backup the current directory and all subdirectories including extended attributes, hidden and system files. tar tpv List all files on the archive. tar xpv Restore whole archive. Restore extended attributes and set attributes of hidden and system files. tar x path/file Restore a single file or a directory tree. Filenames are case sensitive. Always use forward slashes. tar -c -v -D c:/tar_maps/tape.dir c:/ Backup logical disk c: and append a tape directory to the specified file. tar -x -v -D c:/tar_maps/tape.dir this/is/a/single/file Restore "this/is/a/single/file" using the random access commands of SCSI-2 or Tandberg SCSI-1 models. OS/2 compressed backup performance: A 486 33MHz equipped with a 5MB/min streamer provides a compression rate of about 1.5 on a whole disk with 90MB binaries and an effective disk data throughput of about 85 KB/sec and a tape data throughput of about 55 KB/sec. When storing the backup on a diskette (a way to exchange HPFS files), compressed and buffered (-Z, default if raw diskette) data throughput is faster than the diskette data throughput. Therefore compressed mode can be considerably faster than uncompressed mode, depending on the machine's speed and the data throughput of the backup device. WARNING: If a compressed archive contains a bad block, all data of the archive starting with the bad block is lost. Uncompressed archives are recoverable by manually skipping beyond the bad block, compressed archives are not recoverable. COMPRESS was not written with tape backups in mind. - - - Once again, due to some complaints - PLEASE READ: If used with the dedicated tape interface, this version of TAR always appends to all existing data on the tape, it skips existing tape data before new data is written to the tape. It does not erase existing tape contents. If there already was some data on the tape before (even if cpio, Sytos, ...), this is what you get when reading the tape from the beginning. If this data does not have the same archive format (compressed archive or another backup program), you'll get an error message like "doesn't look like a tar archive". If you want to rewrite the tape from the beginning, either erase the tape ("tape erase", see below, which is slow but recommended since it also retensions the tape in the case of a QIC tape device), or write an empty filemark at the beginning of the tape ("tape rewind mark"). If you write an empty filemark to erase the tape, you have to skip the first tape file ("tape file") when reading the tape, else you get an error message. You may consider this stuff irritating, but the letters "c" for "create a tape archive" and "x" for "extract" are too close to each other. If you accidentally hit "c" instead of "x", you won't kill previous tape contents since the new data appends to logical EOT instead of killing your data. If you don't know if you tape drive supports QFA, run tape tell tape seek 1 If both commands are accepted, you can be pretty sure it supports QFA. If you get something like "Illegal request", the device doesn't know about the QFA commands used in the mode you've choosen by the S<x> option (S0 and S1 use Tandberg's SCSI-1 commands, S2 uses the standard SCSI-2 commands). ───────────────────────────────────────────────────────────────────────── Tape utility - TAPE: -------------------- Just run it without any arguments to get usage information. You can specify multiple verbs in a single call, unless the -Nowait option is given. Mostly case-insensitive, except for some dangerous commands which have to be specified in upper case. Examples: -0 .. -7 Device TAPE$0 .. TAPE$7 rew Rewind tape. ret Retension tape. file Skip until next filemark. end Position to end of written data. mark Write filemark. erase Erase tape. read <file> Read tape to file, write to stdout if <file> is "-". write <file> Write file to tape, read from stdin if <file> is "-". speed <n> TDC4120: <n>=1: slow (200KB/sec) <n>=2: fast (300KB/sec) (recognized at beginning of tape only) ───────────────────────────────────────────────────────────────────────── A few words on blocks and sizes: -------------------------------- Most tape devices with a capacity of at least 525MB can be used with different blocksizes. Both with fixed length blocks of 512 and 1024 bytes as well as with variable length blocks. The default setting varies. The default setting of TAR is 512 bytes. If the default tape blocksize differs, you have to set the blocksize before running TAR, using tape blocksize 512 or tape blocksize 1024 or tape blocksize 0 -- for variable length blocks You can get the current setting of the tape device with "tape mode 0". But note that there are devices, which do not show a valid value until the tape is read. Additionally, this value may depend on the type of the inserted tape. Tapes for QIC-24 (DC600A 60MB), QIC-120 (DC600XTD 120MB) and QIC-150 (DC6150 150MB, DC6250 250MB) must be used with a blocksize of 512 bytes. If DC6150/6250 tapes work and DC6320 or higher do not work, the tape device is probably set to a blocksize of 1024 bytes and switches down to 512 bytes when it recognizes a DC6150/6250 tape (Wangtec 525MB). TAR works with block sizes of 512 and 1024 bytes (it should work with any reasonable fixed block size if it is a multiple of 512) as well as with variable block sizes. Don't confuse the TAR block size ("tar -b<n>") with the tape block size ("tape blocksize <n>"). Unless variable length tape blocks are used, the TAR blocksize can be any value which is an exact multiple of the tape blocksize (default: 10KB). If variable length blocks are used, a tape block equals a TAR block. Note that TAR also knows about a "record size" which is the TAR file header and file alignment size and is fixed to 512 bytes by the TAR archive format. ───────────────────────────────────────────────────────────────────────── Pipe buffer - BUFFER: --------------------- Command line options: -s <number> Buffer size, 64K..4096K. -b <number> Reblock to a multiple of <number> bytes per output block. Pad output with 0 if necessary (<number> <= 32768). -i <number> Refill buffer when <number> % empty. -o <number> Flush buffer when <number> % filled. Default for -i and -o is 100. When called with "-/" (or any other invalid option) as argument, BUFFER prints a small usage info. This usage shows the default buffer size as second number in the line corresponding to "-s". BUFFER is multi-threaded. If the buffer fill ratio permits according to the input and output tresholds, it will be active on both ends at the same time. If the buffer size is not specified on the command line, the default size can be specified with the environment variable BUFFER in KB. If not specified, the default buffer size depends on the version of the operating system: 1.3: The size of the largest contiguous area (DosMemAvail) minus 1MB. 2.0: 2MB. When copying a large file from one partition to another, BUFFER can considerably reduce the effects of disk positioning times by using: buffer < input-file > output-file ───────────────────────────────────────────────────────────────────────── Incremental backups: -------------------- There are 3 alternatives: (1) To make incremental backups, where every increment is based on the previous increment: full backup: tar --create --incremental=dumpfile --generation=first ... increment: tar --create --incremental=dumpfile --generation=incr ... To restore such backups, you have to restore the full backup first, then all increments in the order they were created. The info saved with each directory ensures, that no files will be left over which have been erased before the last increment was created. (2) To make incremental backups, where the increments are based on the last full backup (this is an extension to original GNU tar 1.10, where the option -G is outdated and next to unusable): full backup: tar --create --incremental=dumpfile --generation=first ... increment: tar --create --incremental=dumpfile --generation=second ... To restore such backups, you have to restore the full backup first, then the last increment. You do not have to restore other increments. (3) To make incremental backups using the filesystem's "archive" bit: full backup: tar --create --reset-archive ... increment: tar --create --archive ... You can combine both (1) and (2). In this case, second or incremental generation backups will archive all files which were changed since the last first or incremental generation backup. You have to restore the full backup first, then all incremental generation backups in the order they were created, then the last second generation backup if it is newer than the last incremental generation backup. ───────────────────────────────────────────────────────────────────────── Known bugs: ----------- When there are multiple archives on the same tape and you read them sequentially using tar, you may get an error message like "I/O error" on every second run. Ignore this error message and continue. The reason for this message is TAR's own end-of-file mark which causes TAR to stop reading before having encountered the tape's filemark. The next run of TAR gets nothing but this filemark which results in the mentioned error message. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . --tape-length doesn't know about the current tape head position. If you append to a tape with existing contents, specifying the full tape length in --tape-length will not save you from a tape overrun. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The device driver r/w interface (file access to TAPE$<id>) will not always correctly sense the current device block size, so run "tape blocksize <n>" before, to synchronize driver and device. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The driver SCSITAPE.SYS installs successfully, even if there is no tape drive connected or configured. Reason: I have not found out how to call OS2SCSI.DMD in init phase, the corresponding DosDevIOCtl calls never return. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . There is no support for the "quick erase" option supported by some drives (HP 35480A) in this release. Although the changes are trivial, the current state of my source-code management votes against it. Use tape CMD cdb=19,0,0,0,0,0 instead (don't mistype or your system may hang!). If your drive accepts this command, you can erase a tape in a few seconds instead of an hour. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . When a tape is inserted, the very first TAPE command fails with "Unit Attention" or alike. This is no a bug but a feature of SCSI tape drives. TAR itself ignores it using a dummy command but TAPE is intended as a direct device interface, so it does not make attempts to hide informations from the user. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . When writing to a Wangtek or equivalent (Sankyo) drive, you may get "Seek to end of tape failed", when the tape is empty or the head is already positioned to end-of-tape at the time TAR is started. This is a bug/feature of Wangtek tape drives, you can ignore this message. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TAR commands, which have to backspace or have to overwrite previous archive contents, are not supported when operating on tapes. Such as --append, --update, --delete, --verify. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . When you backup a FAT partition, TAR loudly complains about not being able to backup the file "ea data. sf". This is perfectly ok, since extended attributes are saved with each file individually. It makes no sense to save it, since the sole reason of this file is to cover the disk space used by extended attributes so that DOS CHKDSK doesn't complain about wasted disk space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TAR does not archive files starting with the character '#'. This is a bug in OS/2, not in TAR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . After change of media, TAPE displays a message like "Unit attention". This is not a bug but a feature of SCSI devices. TAPE could skip this message just as TAR does, but TAPE is intended as a transparent low-level utility. ───────────────────────────────────────────────────────────────────────── Changes since 2.01: ------------------- 2.02: SCSITAPE.DMD: Debug mode was accidentally enabled by default. 2.03: TAR: Fixed a GNU tar bug. If access/creation times were not written to the archive ("-g" but not "-p"), tar nevertheless extracted dates from the header fields where the dates were expected. The result were funny dates such as xx.xx.2098 or xx.xx.1970, depending on your timezone. If you have such files on your disk, archive them and restore them using TAR (but avoid --all-timestamps). The access and creation dates will show the current date afterwards. Archiving access and creation dates when -p was given, wasn't the brightest idea anyway. If you want to make a system backup with all dates, use --all-timestamps or twice -p. Gnu dumps enable it by default. Specify --all-timestamps or twice -p to archive/extract access and creation timestamps (implicitly enabled for gnu dumps). Except in the case of a system backup/restore, restoring the creation timestamp isn't a very good idea as it disturbs future incremental backups. TAR: On extract, tar now correctly creates all required subdirectories in the path of a file. Previously only the trailing component was created (the corresponding code in tar relies on getting a specific error code from mkdir, but every system or library seems to behave differently in this respect). Removed -G aka --incremental. Renamed --listed-incremental to --incremental. Added a new -G aka --generation. The functionality of a plain -g hasn't changed though. OS/2 only: Added --all-files as an additional long option name for -p: -g aka --incremental now implies --all-files and --all-timestamps. 2.10: Added SCSITAPE.SYS, since SCSITAPE.DMD doesn't run on IBM PS/2 machines. Note that this driver has a different license statement as all other programs and drivers distributed in this package. The Service Pack (2.00.1) contains a valid ASPI driver, so you now have to choose between 3 different tape device drivers :-). Due to a bug in OS/2 syslevel 2.00.1, earlier version of TAR may fail to backup extended attributes or may even crash. You can use the filesystem's archive bit for incremental backups now (thanks to Kai Uwe Rommel). See --archive and --reset-archive. QFA now works with a variable blocksize. 2.11 Bugfix release. 2.10 didn't accept EAs when reading an archive. 2.11 now creates correct archives and is able to read archives creates with 2.10. 2.12 TAR: Had to fix the very same bug again since the library function mkdir() changed in EMX 0.8f. It returns the unix-like error code now, when the dir already exists, so TAR once again failed to create the proper directories on extract. ───────────────────────────────────────────────────────────────────────── Notes: ------ I've got questions of the kind "I'm desperately seeking the command to format the tape.". Well, neither QIC (DC6xxx) nor DAT not Video8 tapes have to be formatted before use. Only floppy tapes have to be formatted because of a limitation of the used floppy controller. Although this version is compiled using EMX 0.8f, it's extended attribute support is not yet used. The EA representaion in the archive is still an aligned image of what OS/2 returns in its API. Things might change in future releases though. ─────────────────────────────────────────────────────────────────────────