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vol(1) [minix man page]

VOL(1)							      General Commands Manual							    VOL(1)

vol - split input on or combine output from several volumes SYNOPSIS
vol [-rw1] [-b blocksize] [-m multiple] [size] device DESCRIPTION
Vol either reads a large input stream from standard input and distributes it over several volumes or combines volumes and sends them to standard output. The size of the volumes is determined automatically if the device supports this, but may be specified before the argument naming the device if automated detection is not possible or if only part of the physical volume is used. The direction of the data is automatically determined by checking whether the input or output of vol is a file or pipe. Use the -r or -w flag if you want to specify the direction explicitly, in shell scripts for instance. Vol waits for each new volume to be inserted, typing return makes it continue. If no size is explicitely given then the size of the device is determined each time before it is read or written, so it is possible to mix floppies of different sizes. If the size cannot be deter- mined (probably a tape) then the device is assumed to be infinitely big. Vol can be used both for block or character devices. It will buffer the data and use a block size appropriate for fixed or variable block sized tapes. Vol reads or writes 8192 bytes to block devices, usually floppies. Character devices are read or written using a multiple of 512 bytes. This multiple has an upper limit of 32767 bytes (16-bit machine), 64 kb (32-bit), or even 1 Mb (32-bit VM). The last partial write to a character device is padded with zeros to the block size. If a character device is a tape device that responds to the mtio(4) status call then the reported tape block size will be used as the smallest unit. If the tape is a variable block length device then it is read or written like a block device, 8192 bytes at the time, with a minimum unit of one byte. All sizes may be suffixed by the letters M, k, b or w to multiply the number by mega, kilo, block (512), or word (2). The volume size by default in kilobytes if there is no suffix. OPTIONS
-rw Explicitly specify reading or writing. Almost mandatory in scripts. -1 Just one volume, start immediately. -b blocksize Specify the device block size. -m multiple Specify the maximum read or write size of multiple blocks. The -b and -m options allow one to modify the block size assumptions that are made above. These assumptions are -b 1 -m 8192 for block devices or variable length tapes, and -b 512 -m 65536 for charac- ter devices (32 bit machine.) These options will not override the tape block size found out with an mtio(4) call. The multiple may be larger then the default if vol can allocate the memory required. EXAMPLES
To back up a tree to floppies as a compressed tarfile: tar cf - . | compress | vol /dev/fd0 To restore a tree from 720 kb images from possibly bigger floppies: vol 720 /dev/fd0 | uncompress | tar xfp - Read or write a device with 1024 byte blocks: vol -b 1k /dev/rsd15 Read or write a variable block length tape using blocking factor 20 as used by default by many tar(1) commands: vol -m 20b /dev/rst5 Note that -m was used in the last example. It sets the size to use to read or write, -b sets the basic block size that may be written in multiples. SEE ALSO
dd(1), tar(1), mt(1), mtio(4). VOL(1)

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tz(4)							     Kernel Interfaces Manual							     tz(4)

       tz - SCSI magnetic tape interface

       VAX NCR 5380:
	 adapter      uba0    at nexus?
	 controller   scsi0   at uba0	 csr 0x200c0080  vector szintr
	 tape	      tz0     at scsi0	 drive 0

       VAX DEC SII:
	 adapter      ibus0   at nexus?
	 controller   sii0    at ibus?	 vector sii_intr
	 tape	      tz0     at sii0	 drive 0

       RISC DEC SII:
	 adapter      ibus0   at nexus?
	 controller   sii0    at ibus?	 vector sii_intr
	 tape	      tz0     at sii0	 drive 0

       RISC DEC KZQ:
	 adapter      uba0    at nexus?
	 controller   kzq0    at ibus? csr 0761300vector sii_intr
	 tape	      tz0     at kzq0	 drive 0

       RISC NCR ASC:
	 adapter      ibus0   at nexus?
	 controller   asc0    at ibus?	 vector ascintr
	 tape	      tz0     at asc0	 drive 0

       The SCSI tape driver provides a standard tape drive interface as described in This is a driver for any Digital SCSI tape device.

       For  the  TZK10	QIC  format tape drive, the densities supported are QIC-24 (read only) block size of 512 byte blocks, QIC-120, and QIC-150
       read/write block size of 512 byte blocks, and QIC-320 read/write block size of 1024 byte blocks.  With QIC format style tapes all reads and
       writes  must  be  in  multiple  of the block size.  This is a requirement of fixed block tape drives because record boundaries are not pre-
       served.	The QIC densities are selected using the following special device names:

	 QIC-24 Fixed block size.
	 QIC-120 Fixed block size.
	 QIC-150 Fixed block size.
	 QIC-320 Fixed block size.

       With all fixed block tape devices a of a file to the tape must be padded out.  An example of this is a of which has a size of approximately
       3800 bytes.
       dd if=/etc/gettytab of=/dev/rmt0h bs=10k conv=sync
       dd if=/etc/gettytab of=/dev/rmt0l bs=512 conv=sync
       The option of pads the output to block size.

       This  driver  also  supports  n-buffered  reads	and  writes  to the raw tape interface (used with streaming tape drives).  See for further

Tape Support
       TZ30, TZK50, TLZ04, TSZ05, TKZ08, TZK10

       All diagnostic messages are sent to the error logger subsystem.

See Also
       mtio(4), nbuf(4), SCSI(4), MAKEDEV(8), uerf(8), tapex(8)
       Guide to the Error Logger

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