SuperREP Publisher's description
from Bulat Ziganshin
LZ77 compressor that supports dictionaries larger than RAM available
The SuperREP application was developed to be the first LZ77 compressor that supports dictionaries larger than RAM available. Default settings (-l512) allows to process files that are 20x larger than RAM size. Memory requirements are proportional to 1/L, so by increasing -l value it's possible to process even larger files.
When compressing, memory usage for hash: filesize/L*20 + filesize/L*4 + roundup(filesize/L*4 * 5/4) + roundup(filesize/(L*8) * 4) where roundup() rounds up to the next power of 2 and first memory block (i.e. *20) used only in -m1 mode. So, overall, hash includes 3 or 4 chunks. Besides hash, compression uses 3*8mb buffers.
Decompression uses only 2*8mb buffers and no hash. Repeated data copied directly from output file, though, so you need to have enough RAM used for disk cache in order to make decompression fast.
What's New in This Release:В· -m1: old method (compression memory = 6-7% of filesize, check matches by SHA1 digest)
В· -m2: new, default method (compression memory = 2-3% of filesize, check matches by rereading old data)
В· -index option - keep index of compressed data in separate file in order to improve compression ratio
В· 64-bit executable that\'s still 100% compatible but faster than 32-bit one
System Requirements:No special requirements.
Program Release Status:
Program Install Support: Install And Uninstall