STBLOCKSIZE(8)STBLOCKSIZE(8)NAMEstblocksize - Set the block transfer size of a SCSI tape device.
SYNOPSIS
usretcstblocksize [ -v ] [ -s size ] device_pathname
DESCRIPTIONstblocksize determines the maximum and minimum number of bytes that a
SCSI tape device is capable of transfering to or from the computer in a
single hardware-level transaction. If the maximum and minimum are
the same value, stblocksize places the device in fixed-block mode and
will use that value for all data transfers. Otherwise, it sets the
device to variable-block mode.
This command is called by the etcrc script that is invoked during the
bootup sequence. This means that tape drives connected to the system
have their block size set automatically.
Note that stblocksize controls the size of low-level data transfers in
hardware. It should not be confused with the block sizes used in other
commands like tar or dd which control the format of data as seen by the
software at a higher level.
OPTIONS-v Verbose mode. Print the maximum and minimum block size
reported by the device to standard output.
-s size Set block size to size, regardless of what the device
reports.
EXAMPLES
The following command causes the maximum and minimum block sizes for
/dev/rst0 to be displayed on the output device:
stblocksize-v /dev/rst0
This command sets the transfer block size for /dev/rst0 to 512 bytes:
stblocksize-s 512 /dev/rst0
SEE ALSOst(4),mt (1)
DIAGNOSTICSstblocksize returns a status of 0 for normal execution. It returns -1
and prints a diagnostic message if it is unable to interpret the
command line, open the tape device, or retrieve or set the device's
block size.
BUGSstblocksize cannot correct automatically for tape drives that report
their block sizes incorrectly. For such devices, you must execute the
command with the -s option each time the system is booted (e.g., by
modifying the command line in etcrc).
NeXT Computer, Inc. August 9 1994 STBLOCKSIZE(8)