Compressing ratio

[miracle]

It looks that WinZIP is useless to compress big EXE files. For example, it
almost cannot reduce size of big setup file, the compressed file size
remains the same(almost).
Looks like using WinZIP is useless for compressing big executable files. Am
I correct?

 

[Pegasus \(MVP\)]

It looks that WinZIP is useless to compress big EXE files. For example, it
almost cannot reduce size of big setup file, the compressed file size
remains the same(almost).
Looks like using WinZIP is useless for compressing big executable files.
Am I correct?

Sorry, you aren't. If you cannot compress certain files then it's
usually because they are already compressed. I'm sure you know
that trying to compress a file twice won't reduce the size any
further on the second attempt.

However . . . many years ago there was a tool called pklite.exe,
issued by PKWare. It was specifically designed to compress
executable files. Its successor was pklite32.exe. Maybe it still
exists and maybe it can do a better job than WinZIP.

 

[miracle]

can the compressing a file twice with WinZIP cause any problems? (damaging
file integrity, etc)

 

[Pegasus \(MVP\)]

can the compressing a file twice with WinZIP cause any problems? (damaging
file integrity, etc)

No, but the file will grow . . . (as a quick experiment
would show you).

 

[Ken Blake, MVP]

It looks that WinZIP is useless to compress big EXE files. For example, it
almost cannot reduce size of big setup file, the compressed file size
remains the same(almost).
Looks like using WinZIP is useless for compressing big executable files. Am
I correct?

This has little to do with Winzip. It has to do with the file. How
much a file *can* be compressed depends on what type of file it
is, as well as what it contains.

It's primarily the file itself that determines how much it can be
compressed, not so much the program that's doing the compressing. You
might find a program that did a *slightly* better job, but that's all.

 

[Tim Slattery]

can the compressing a file twice with WinZIP cause any problems? (damaging
file integrity, etc)

You won't do any harm, but the product of the second ZIP will probably
be larger then the product of the first ZIP. And you'll have to unzip
it twice, of course. The first time will yield a zip, the second time
whatever was zipped in the first place.

 

[Big_Al]

You won't do any harm, but the product of the second ZIP will probably
be larger then the product of the first ZIP. And you'll have to unzip
it twice, of course. The first time will yield a zip, the second time
whatever was zipped in the first place.

The overhead to record the zip directory, normally stored at the end of
the file, and other header info causes the 2nd and successive files to
grow larger. The files themselves in the 2nd zip will not be any
different probably.

 

[HeyBub]

It looks that WinZIP is useless to compress big EXE files. For
example, it almost cannot reduce size of big setup file, the
compressed file size remains the same(almost).
Looks like using WinZIP is useless for compressing big executable
files. Am I correct?

Some EXEs are compressed by the program's developers who add an uncompress
program to the front of the file. When the resulting "program" loads, it
executes in two stages: the first uncompresses the remainder and transfers
control to the result.

Inasmuch as these programs are already "compressed," further compression
attempts are usually futile.

 

[Ken Blake, MVP]

can the compressing a file twice with WinZIP cause any problems? (damaging
file integrity, etc)

Three points:

1. Any time you manipulate a file in any way, there is *always* a
potential for file corruption or other problems. That said, the great
majority of the time when we manipulate files, we don't have problems,
and there's no reason to expect one here either. Any such occurrence
should be extremely rare.

2. Compressing a compressed file can not possibly make it any smaller
than it already is. The compressing program doesn't suddenly get
smarter and do a better job.

3. In fact, compressing an already-compressed file will actually make
it slightly bigger. That's because you add the overhead of the extra
compression.

 

[Twayne]

Sorry, you aren't. If you cannot compress certain files then it's
usually because they are already compressed. I'm sure you know
that trying to compress a file twice won't reduce the size any
further on the second attempt.

However . . . many years ago there was a tool called pklite.exe,
issued by PKWare. It was specifically designed to compress
executable files. Its successor was pklite32.exe. Maybe it still
exists and maybe it can do a better job than WinZIP.

Since that's PKWare, and the forerunniner to WinZip, probably not. exe
files just don't contain much compressible data, period. The process of
making an executable file already has it pretty well compressed. Only
the text portions of the file would compress at all, and they make up a
very small part of an exe file.
WinZip does have sort of a "super" compression scheme, but it's
unique and proprietary, so be forewarned there.

 

[Twayne]

can the compressing a file twice with WinZIP cause any problems?

(damaging file integrity, etc)

No, most compression programs are good at reassembling whatever they
compressed. Shouldn't be a problem, but no benefit to compressing a
second time either.

 

[Pegasus \(MVP\)]

Since that's PKWare, and the forerunniner to WinZip, probably not. exe
files just don't contain much compressible data, period. The process of
making an executable file already has it pretty well compressed. Only the
text portions of the file would compress at all, and they make up a very
small part of an exe file.
WinZip does have sort of a "super" compression scheme, but it's unique
and proprietary, so be forewarned there.

It depends entirely on the executable. Just for fun I compressed
xiv32.exe (a binary editor), using pklite32.exe. It compressed to
about 60% of its original size. Other executables were almost
incompressible.