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fblckgen - Fast block generator
fblckgen
[-a|-r] [-q] [-v] [-b blocksize] [-c count]
fblckgen generates blocks
of data, either a repeating ascii sequence which is very compressible,
or a pseudo- random binary sequence, which, although very simple, does not
compress. Very handy for benchmarking tape drives, or just making a sized
lump of data. By using double buffering and either pthreads or multiple
processes, it can generally keep a tape drive busy.
Data is written directly
to a copy of the standard output file descriptor. Shell redirection must
be used to output to an alternate destination.
Before exiting, fblckgen
writes a single summary line to standard error, containing statistics from
the run.
- -a
- Instructs fblckgen to generate blocks of a repeating ASCII
sequence, from octal 040 (` ', space), through octal 176 (`~', tilde). The sequence
repeats, without newlines. This the default mode of operation.
- -b blocksize
- Writes blocks of size blocksize to standard output. If not specified, a
blocksize of `1s', 512 bytes, is used.
- -c count
- Writes count blocks, or until
error if count is zero. If not specified, a default of `1k', 1024, is used.
- -q
- Quiet operation, suppresses the printing of the summary line.
- -r
- Instructs
fblckgen to generate a pseudo-random sequence, based on an inlined copy
of rand(3).
- -v
- Verbose: regularly prints a status line showing current progress.
All numeric arguments may take an optional letter suffix, similar to the
strsuftollx(3) function introduced in NetBSD.
- s
- sector; multiply by 512.
- k
- kibibytes; multiply by 1024 or 2^10.
- m
- mebibytes; multiply by 1048576 or
2^20.
- g
- gibibytes; multiply by 2^30.
- t
- tebibytes; multiply by 2^40.
- p
- pebibytes;
multiply by 2^50.
- e
- exbibytes; multiply by 2^60.
fblckgen exits
0 on success, and >0 if an error occurred.
Filling an LTO1 tape with
pseudo-random data:
sh$ fblckgen -rb 64k -c 0 > /dev/nrst1
Write failed: Input/output error
105722740736 bytes written in 7064.506 secs (14614.590 KB/sec)
iohammer(1), mbdd(1)
fblckgen and the rest of the iotools
were developed by Paul Ripke, <stixpjr@gmail.com>. See <http://stix.id.au/wiki/iotools>
for the current version.
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