FileForums - SREP parameter

shazzla
Bat
srep -a8 -m5f -l512 -d8g -dh4gb -dl32 -dc8
Code:
SREP 3.93a beta: huge-dictionary LZ77 preprocessor   (c) Bulat.Ziganshin********com

October 11, 2014    homepage: http://freearc.org/research/SREP39.aspx



Usage: SREP [options] infile [outfile]

   infile/outfile can be specified as "-" for stdin/stdout

   "SREP [options] somefile" compresses data from somefile to somefile.srep

   "SREP [options] somefile.srep" decompresses data back to somefile

   "SREP [options]" compresses and "SREP -d [options]" decompresses data from stdin to stdout



Options are:

   -m0: only in-memory compression (REP algorithm)

   -m1: fixed-window content-defined chunking with matches checked by VMAC

   -m2: order-1 content-defined chunking with matches checked by VMAC

   -m3: check matches by VMAC digest (compression memory = 7-8% of filesize)

   -m4: check matches by rereading old data (compression memory = 3-4% of filesize)

   -m5/-mx: rereading with byte-accurate matches (compression memory = 7-9% of filesize)

   -l: minimum LZ match length, default 0

   -c: size of hash chunk, by default as small as required to find all these LZ matches

   -aX[/Y]: alloc X bytes of those Y bits will be set per L input bytes for compression accelerator

            Y=0/1/2/4/8/16/32/64, -a0 is slowest but requires least memory

   -ia-: disable I/O acceleration to reduce memory usage (-m5* only)

   -tN: use N compression threads (only for -m1/-m2)

   -dBYTES: dictionary size for in-memory compression (REP algorithm), default 512mb

   -dhBYTES/-dcN/-dlN: size of hash / size of hash chunk / minimum match length for in-memory compression



   -m1..-m5: index-LZ - list of matches saved at the end of compressed file

   -m1f..-m5f: future-LZ - decompression dictionary will hold only future matches

   -m1o..-m5o: I/O LZ - output file used as decompression dictionary

   -memBYTES: amount of RAM used by future-LZ/index-LZ decompression (extra goes into VM file)

      -mem75% AKA -mem75p means "use no more than 75% of RAM" - that's by default

      -mem600mb means itself

      -mem75%-600mb means "use no more than 75% of RAM minus 600 mb"

   -mBYTES: don't store matches larger than BYTES on future-LZ/index-LZ decompression



   -d: decompression (for -m0o..m5o requires only 24 mb of memory besides of OS I/O buffers)

   -i: print info about compressed file: srep -i datafile.srep

   -delete: delete source file after successful (de)compression

   -sBYTES: explicitly specify filesize (for compression from stdin), default 25gb

   -bBYTES: change compression block size, default 8mb

   -index=FILENAME: read/write index of compressed data into separate file

   -temp=[FILENAME]: keep uncompressed data in the file in stdin-to-stdout mode, default srep-data.tmp

   -vmfile=FILENAME: temporary file used by Virtual Memory manager, default srep-virtual-memory.tmp

   -vmblock=BYTES: size of one block in VM temporary file, default 8mb



   -hash=vmac(default)/siphash/md5/sha1/sha512: store hash checksums in every block

   -hash-: don't store/check block checksums

   -mmap: use memory-mapped files for match checking

   -slp[+/-/]: force/disable/try(default) large pages support (2mb/4mb)

   -pc[max_offset]: display performance counters [for matches closer than max_offset]

   -s: save printed stats from overwriting; -s+/-s-/-sX.Y: update stats every X.Y seconds

   -v[0..2]: verbosity level

   -rem...: command-line remark