bzip2-1.0.1: description + notes
bzip2 compresses files using the Burrows-Wheeler
block-sorting text compression algorithm, and Huffman coding.
Compression is generally better than that
achieved by more conventional LZ77/LZ78-based compressors,
and approaches the performance of the PPM family of
statistical compressors.
The command-line options are deliberately very similar to
those of GNU gzip, but they are not identical.
Compared to gzip -9, bzip2 is slower
and gives a slightly better compression. Decompression
is significantly slower than gzip.
Depending on your case, it may be worth it (or not)
to invest the extra time in compressing/decompressing
with bzip2 instead of the more standard gzip
to gain a small advantage in multiple download times, etc.
The Bzip2
home page has more information.
For the curious, here are some running times and compressed file sizes
numbers for comparison. The input data was a 25765100 byte file,
comprised of roughly 17.5MB of text and 9.5MB of binary data (a copy of
/unix).
| command |
user time |
size |
|
command |
user time |
size |
gzip -1 |
26.770s |
12302784 |
|
bzip2 -1 |
120.584s |
10408869 |
gzip -2 |
27.918s |
12085628 |
|
bzip2 -2 |
124.446s |
10214448 |
gzip -3 |
34.023s |
11877150 |
|
bzip2 -3 |
132.282s |
10155324 |
gzip -4 |
35.784s |
11600827 |
|
bzip2 -4 |
142.633s |
10116976 |
gzip -5 |
43.801s |
11410215 |
|
bzip2 -5 |
152.525s |
10089397 |
gzip -6(*) |
68.693s |
11301849 |
|
bzip2 -6 |
161.633s |
10104382 |
gzip -7 |
80.467s |
11277504 |
|
bzip2 -7 |
171.962s |
10070502 |
gzip -8 |
131.727s |
11248002 |
|
bzip2 -8 |
179.706s |
10097078 |
gzip -9 |
189.888s |
11241577 |
|
bzip2 -9(*) |
189.888s |
10090504 |
|
|
(*) default setting. |
To auto-install this package, go back and click on the respective install icon.
