IBM CD Showcase

home *** CD-ROM | disk | FTP | other *** search

/ IBM CD Showcase / OS2_CD_ROM.iso / smce0001 / sware / utility.exe / diskutil / gtak / gtak100 / readme.ak < prev next >

Wrap

Text File | 1992-06-24 | 11.9 KB | 306 lines

┌─────────────────────────────────────────────────────────────────────────┐ │ │ │ SCSI TAPE BACKUP for DOS and OS/2 │ │ ───────────────────────────────── │ │ and Adaptec Host Adapter │ │ ──────────────────────── │ │ │ │ Version 1.0 │ │ │ │ Autor: Andreas Kaiser │ │ Fido: 2:241/7220.9 │ │ Subnet: kaiser@ananke.stgt.sub.org │ │ Voice: 49-711-766116 │ │ │ └─────────────────────────────────────────────────────────────────────────┘ Legal notice (german): ---------------------- Ich übernehme für die Programme keinerlei Gewährleistung für korrekte Funktion oder irgendwelche Folgeeffekte. Es liegt in der Natur eines derartigen Programms, dass Fehlbenutzung oder darin enthaltene Fehler den Inhalt der Festplatte zerstören können. Dafür übernehme ich keinerlei Haftung. ───────────────────────────────────────────────────────────────────────── Contents: --------- GTAR.EXE Modified GNU-TAR for DOS and ASPI4DOS. TAPE.EXE Tape control utility for DOS and ASPI4DOS. GTARP.EXE Modified GNU-TAR for OS/2 1.3 / 2.0 and ASPI manager. TAPEP.EXE Tape control utility for .. COMPRESS.EXE A file compression program for OS/2, invoked by the "z" switch. Bound executable for DOS and OS/2. 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 a DOS port of the well known Unix compress program. Supports 16-bit compression mode. BUFFER.EXE Pipe buffer & reblock program for OS/2. Invoked by the "z" switch when operating on character device. ASPITAPE.SYS Tape device driver for OS/2 1.3 / 2.0, sitting on top of ASPI. README.AK This file. README.TAR README from original TAR distribution. TAR.TEX TeXinfo documentation of original TAR. ───────────────────────────────────────────────────────────────────────── Installation: ------------- DOS Version: ------------ Requires ASPI4DOS (ASW-1410) or equivalent ASPI manager. set TAPE=+++TAPE$4 For streamer target ID 4 set TAPEMODE=0 Tape sense mode (see below) OS/2 1.3 Version: ----------------- Requires an ASPI manager. ASPI managers usually are included in the DISK01.SYS or ASPI4OS2.SYS drivers (ASW-1420) for Adaptec SCSI host adapters. If you are not sure if your device driver contains an ASPI manager, look for a present character device named SCSIMGR$. Under OS/2, the tape device can be accessed like any other sequential character device, using standard read and write calls (caution: restricted to multiples of 512!). It is possible to COPY whole volumes from tape to disk. DEVICE=<path>\ASPITAPE.SYS TAPE$4 4 S0 ASPITAPE command line: <1st word> device name, in uppercase A<digit> host adapter number (0..1, default is 0) digit streamer target ID (0..7) S<digit> tape sense mode (0..2, see below) set TAPE=+++TAPE$4 Same device name as above. The leading "+" signs signal GTAR to use the tape interface instead of the standard file interface. Tape sense modes: 0 Sense key, should be ok for most SCSI streamers 1 Tandberg TDC3600 series, prints more status information 2 SCSI-2 (not tested) ───────────────────────────────────────────────────────────────────────── 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 GTAR is invoked without explicit archive specification, it always positions to end-of-tape before data is written to the tape will automatically append a filemark. This way GTAR never erases existing tape contents when you accidentally forgot the -f switch on the command line. 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). I'm quite sure multi-volume archives won't work when the tape reaches its limit since it is very time-consuming to test such a behaviour (30min per trial). If you need multi-volume archives, use the option -S to split the data in chunks of a size somewhat less than the tape capacity. Get help with gtar -help New options: -S <n>[B|K|M] Split archive, B = type block, K = 1024 bytes M = 1024 * 1024 bytes. The tape block size depends on option -b, the default is a block size of 10KB. Example: -S 140M Split into chunks of 140 MB. -F filename 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, provided the streamer supports the random access commands of Tandberg TDC3600. Most streamers (like Wangtek) do not support these commands, so there is no chance for a fast random access on these models. This is a serious fault of the SCSI command set prior to SCSI-2. This option is not usable with compression mode. -p Include SYSTEM and HIDDEN files on backup. Account for SYSTEM and HIDDEN file attributes on list and restore. These attributes are encoded in the group and world execute bits of the Unix style file mode. -Y Don't recurse. Do not include files within subdirectories. It does include the names of the first subdirectory level but not the contents. -Z Was alias for -z. Now forces buffered pipe compression mode even if the archive is not a device. 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 might occur when GTAR tries to set attributes or filetimes at times when this is not allowed under DOS or OS/2. The OS/2 version automatically saves and restores Extended Attributes. The length of paths and filenames is limited by the standardized TAR format to a maximum of 100 bytes. 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 GTAR to exchange data with UNIX systems. Even compressed data is compatible with 32-bit Unix systems. Paths and filenames should be specified with forward slashes as path separators. On extract, paths and filenames must be specified exactly as shown by "GTAR t". Hint: On archive creation GTAR removes leading absolute path indicators such as drive letters and leading slashes (verbose). If you save several partitions on the same tape volume (a tape volume is a single tape file - consecutive tape data until end-of-tape or filemark), you might not be able to distinguish files with the same path and filename on restore. Use a seperate volume (run GTAR seperately) for each logical disk. Hint: Although the output of the "v" option looks nice, it might be wise to drop it for large backups. When a large number of small files is written to tape, the screen output might slow down the tape output, forcing the tape into inefficient stop-and-go mode. Hint: A disk cache with write caching enabled will greatly improve performance of restore operation under DOS and OS/2. Disk writes using OS/2 1.x FAT filesystem are very slow, so if you have to restore whole OS/2 FAT filesystems, restore them to HPFS and later move the data, to avoid stop-and-go mode. Or restore them using DOS with a good write-cache like HyperDisk. OS/2 only: There will be no trailing filemark if the tape is written as via filename (e.g. "-f TAPE$4") or via explicit pipe (see BUFFER below). Examples: gtar cp . Backup the current directory and all subdirectories including hidden and system files. gtar tpv List all files on the volume. gtar xpv Restore whole volume. gtar x path/file Restore a single file or a directory tree. Filenames are case sensitive. Always use forward slashes. gtar -c -v -F c:/tar_maps/tape.dir c:/ Backup logical disk c: and append a tape directory to the specified file. gtar -x -v -F c:/tar_maps/tape.dir this/is/a/single/file Restore "this/is/a/single/file" using Tandbergs random access commands. OS/2 compressed backup performance on a 486 33MHz equipped with a 5MB/min streamer is a compression rate of 1.5 over a whole disk with 90MB binaries, achieving an effective disk data throughput of 85 KB/sec and a tape data throughput of 55 KB/sec. When storing the backup on diskette (a way to exchange HPFS files), compressed data throughput is faster than the diskette data throughput. Therefore compressed mode can be considerably faster than uncompressed mode, depending on speed of the machine and the data throughput of the backup device. Warning: If a compressed backup volume contains a bad tape block, all data of the volume (tape file) starting with the bad block is lost. Uncompressed volumes are recoverable by skipping beyond the bad block, compressed volumes are not recoverable. COMPRESS was not written with tape backups in mind. ───────────────────────────────────────────────────────────────────────── Tape utility: ------------- Just run it without arguments to get usage information. You can specify multiple verbs in a single call, unless the -Nowait option is specified. Case-insensitive. Examples: tape rew Rewind tape. tape ret Retension tape. tape file Skip until next filemark. tape end Position to end of written data. tape mark Write filemark. tape erase Erase tape. ───────────────────────────────────────────────────────────────────────── Pipe 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 corresnponding to "-s". 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. This is subject to change, but there seems to be no reliable way to obtain the free memory size on OS/2 2.0 without loosing compatibility to 1.3. DosMemAvail is of little use. Examples: --------- buffer -s1024 < tape$4 | gtar xvf- gtar cf- . | compress | buffer -i0 -o90 -b512 > tape$4 The second example will *not* append a filemark and will *not* seek to end of tape. TAPE END should be called to seek to end of tape, TAPE MARK should be called to append a filemark. The command gtar cz . is essentially the same as the second example above, except that GTAR seeks to end of tape and a filemark is appended to the end of the data. When copying a large file from one disk to another, BUFFER can considerably reduce position times by using: buffer < input-file > output-file ───────────────────────────────────────────────────────────────────────── Source: ------- Source code for GNU-TAR, the utilities and the OS/2 device driver is available on request. The specification of my OS/2 tape driver IOCtl interface is available on request. But you should already have SCSI command set documentation.