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visits member for 2 years, 8 months
seen Aug 23 at 2:15

Mostly harmless.


Sep
24
awarded  Autobiographer
Aug
18
awarded  Yearling
Aug
31
comment Why does RAM have to be volatile?
The accepted answer doesn't actually answer the question, whereas this one does.
Mar
29
revised What is the equivalent unix command to a Mac OSX “Compress” menu action?
added 4 characters in body
Mar
29
answered What is the equivalent unix command to a Mac OSX “Compress” menu action?
Mar
29
comment What is the equivalent unix command to a Mac OSX “Compress” menu action?
The command-line zip (and the Compress menu item) use the same compression method as gzip, i.e. deflate. The "better compression" you're thinking of could only be with respect to compressing a tar file as one thing with gzip, as opposed to the zip approach of compressing each file individually. In any case, both gzip and Info-ZIP zip are not encumbered by any patents.
Mar
21
comment What is the advantage of using 'tar' today?
By the way, your workflow discussion is about something no one ever does, which is to write a tar file to a disk and then compress it. tar is always used either calling the compression program directly, or directly into a pipe to a compression program.
Mar
21
comment What is the advantage of using 'tar' today?
Um, ok. Whatever you'd like to think is fine. Your answer nor any other answer seems to address whether there is a performance penalty. Your answer does not address the noticeable compression difference, though others do. Since yours does not actually address performance (your performance section is actually about workflow, nothing about performance), no other answer answers everything in one place. It is interesting that you wrote the performance penalty question, but you did not answer it! Go figure.
Mar
18
comment What is the advantage of using 'tar' today?
Since there seems to be no limit to the amount of misinformation you can fabricate, this is no longer productive. I am done commenting on this answer and related comments. Thank you and good night.
Mar
18
comment What is the advantage of using 'tar' today?
The deflate dictionary is strictly limited to 32K. It does not "grow" once you're at least 32K into the stream. From there on it is always exactly 32K. bzip2 certainly does have a limit of 900K of history, which is not a sliding dictionary but rather a block on which the BWT transform is applied. Each block is compressed independently, and cannot make use of the information in previous blocks.
Mar
18
comment What is the advantage of using 'tar' today?
No, you cannot start decompressing at any CFDATA block. Read the specification, which is very clear on this point. Within a folder, each CFDATA block can and does use the previous CFDATA blocks as history for compression. The folder is the only abstraction in the specification that defines where you can start decompressing, so it is not only useful, but essential for the random extraction application you are calling attention to in your answer.
Mar
18
revised What is the advantage of using 'tar' today?
Added another not-tar reason.
Mar
18
comment What is the advantage of using 'tar' today?
An amusing exception is that the gzip source code is available as a naked tar, for obvious reasons.
Mar
17
awarded  Critic
Mar
17
answered What is the advantage of using 'tar' today?
Mar
17
comment What is the advantage of using 'tar' today?
Your edited answer has improved, but is still chock full of misinformation. zip does not compress in 32K chunks, and does not provide access to parts of files without having to decompress the entire file. "It also prevents the compressor from building up a very large dictionary before it is restarted." is nonsensical. There is no building up of anything. The deflate dictionary is simply the 32K bytes that precede the next byte to be compressed. Once you get past the first 32K, the dictionary is always the same size, there is no "building up", and the compression speed does not change.
Mar
17
comment What is the advantage of using 'tar' today?
When working on the CAB format, it might have been a good idea to spend some time studying the cab format specification. The 32K CFDATA blocks are not random access entry points. The random access points are at the start of CAB "folders", which consist of a series of CFDATA blocks. From the specification: "By default, all files are added to a single folder (compression history) in the cabinet." So a non-default option would be needed for CAB file to have any random access midpoints at all.
Mar
16
comment What is the advantage of using 'tar' today?
Also Info-ZIP's zip supports compression to a stream.
Mar
16
comment What is the advantage of using 'tar' today?
You need to either make corrections to your answer or delete your answer.
Mar
16
comment What is the advantage of using 'tar' today?
The zip format can store both the uid and gid.