vdt=5.4.67 Linux=2.6.36 x86_64=2010/10/05 

Usage : vdt <options> <parameters>
Perform i/o tests.

 basic parameters:

 -b size       alternate i/o buffer size
 -c filename   target file for comparison tests
 -D deadline   run until [[[CC]YY]MMDD]hhmm.ss
 -e seed       random number generator seed
 -f filename   use this file for read/write (compound) tests
 -I 'comment'  (short) information to appear on screen and logs
 -m number     maximum number of operations per test
 -M number     maximum number of passes per test
 -p percent    test area = given % of testsize
 -P pattern    filler for output buffer (0oct|Xhex|Bbin|dec|Rand|Zero)
 -r filename   input(source) file for read-only(comparison) tests
 -s stripes    split test area in given # of stripes
 -t lifespan   [[hh:]mm:]ss = maximum elapsed time per test
 -w filename   use this output file for write-only tests
 -z testsize   test area = just this much
 -Z bulksize   terminate after transfer this much

 basic tests:

 --make        create & fill test (Bunch_of_Sectors at a time)
 --poke        poke test (same as '--writ --sect')
 --read        read test (B.o.S. at a time)
 --seek        seek test (same as '--read --sect')
 --writ        write test (B.o.S. at a time)

 compound tests:

 --aver        ratification test (write, read back, compare)
 --blot        update test (read, stain, write back)
 --comp        comparison test (B.o.S. at a time)
 --cool        freshen test (read, write back)
 --copy        copy test (B.o.S. at a time)
 --stir        shuffle test (read, write somewhere else)

 stress tests:

 --burn        write-only test (1 file,  all addressing modes)
 --cook        read-only  test (1 file,  all addressing modes)
 --mess        read+write test (1 file,  all addressing modes)

 addressing patterns:

 --incr        incrementing addresses (start to end)
 --decr        decrementing addresses (end to start)
 --conv        converging addresses (edges to middle)
 --scat        scattering addresses (middle to edges)
 --gold        'diamond'-pattern (middle to edges and back)
 --spot        'X'-pattern (edges to middle and back)
 --rand        random addresses

 region selection:

 --edge        --head and --tail combined
 --head        select initial portion of test area (default)
 --core        select central portion of test area
 --tail        select  final  portion of test area
 --slab        --edge and --core combined
 --even        divide test area proportionally
 --flip        invert selection of test area

 entropy control:

 --same        yields same random numbers across tests
 --firm        yields same random numbers across platforms
 --fate        same as '--same --firm'
 --whim        extra entropy for unpredictable randomness

 cache illustration:

 --cloy        stops after (default 90) hit limit
 --glib        smooth transition to next round
 --snag        cloggy transition to next round

 operation flags:

 -A            append to log file
 -E            separate error messages into 'vdt.err'
 -F            force overwrite existing files
 -T            timestamped names for log and error files
 -V            show version info and exit
 -v            verbose and additional details

 --si          use powers of 1000 not 1024

 --bias        skip (possibly) cached B.o.S.
 --bang        same as -F above
 --boon        allow last test to end cleanly past deadline
 --daze        full buffer random pattern fill (implies --stew)
 --fast        apply faster algorithms
 --full        random seek within B.o.S.
 --help        show this usage help
 --once        same as --uniq
 --part        compute performance using alt. buffer size
 --raze        flatten (truncate) output file
 --sect        i/o just a single (512-Byte) sector at a time
 --stew        applies '-P Rand' for each B.o.S.
 --sync        synchronous (blocking) output
 --uniq        test each and every random address just once
 --wait        request user interaction to finish
 --wrap        wrap around EOF until timeout

 extra parameters:

 -L lines      override screen's # of lines
 -C columns    ditto for columns