7Zip - v3.10


G

Gordon Darling

http://www.7-zip.org/

The main features of 7-Zip:
7-Zip is free software distributed under the GNU LGPL Highest compression
ratio in new 7z format Supported formats: 7z, ZIP, CAB, RAR, ARJ, GZIP,
BZIP2, TAR, CPIO, RPM and DEB For ZIP and GZIP formats 7-Zip provides
compression ratio that is 2-10 % better than ratio provided by PKZip and
WinZip Self-extracting capability for 7z format Integration with Windows
Shell
Powerful File Manager
Powerful command line version
Plugin for FAR Manager
Localizations for 40 languages

Regards
Gordon
 
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J

john p.

http://www.7-zip.org/

...7-Zip provides
compression ratio that is 2-10 % better than ratio provided by PKZip and
WinZip

Interesting stats on their web site. How, for instance, do you achieve
100% (and greater) compression? Wouldn't that be compressed to
nothingness? The black hole of compression utilities!
 
A

Aaron

john p. wrote in
Interesting stats on their web site. How, for instance, do you achieve
100% (and greater) compression? Wouldn't that be compressed to
nothingness? The black hole of compression utilities!

??? 100% is the file size when compressed using 7z format, it's the basis
they are using to compare.

Aaron
 
B

Blinky the Shark

john said:
On Mon, 29 Sep 2003 19:56:49 +0000 (UTC) Gordon Darling
Interesting stats on their web site. How, for instance, do you achieve
100% (and greater) compression? Wouldn't that be compressed to
nothingness? The black hole of compression utilities!

Sounds like it's a file shredder, too. :)
 
S

Simon Whitaker

john p. wrote in
Interesting stats on their web site. How, for instance, do you achieve
100% (and greater) compression? Wouldn't that be compressed to
nothingness? The black hole of compression utilities!

Maths not your strong point then. Comparison chart is perfectly obvious to
me and balancing my cheque book is about my limit.

7zip is a good program, give it a go.
 
S

Simon Whitaker

Sounds like it's a file shredder, too. :)

Look at the site, read the table and make your own mind up. You're giving
the impression that using the program risks losing your files. Especially
as the comment came from a regular contributor to a.c.f. It's a shame as
it's a good program.
 
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R

Romain Petges

Sounds like it's a file shredder, too. :)
Look at the site, read the table and make your own mind up. You're giving
the impression that using the program risks losing your files. Especially
as the comment came from a regular contributor to a.c.f. It's a shame as
it's a good program.

Take a look at the smilie ... I think he referred to the impressive
compression ratio of the 7z format (at least, I hope so). I use this
application sine a year now, and it works great !

Romain
 
V

Vic Dura

7zip is a good program, give it a go.

It seems to require installation. Does the installation make registry
changes, or just de-compress into a directory?
 
R

REMbranded

Simon Whitaker <[email protected]> wrote:
john p. wrote in news:[email protected]:
Maths not your strong point then. Comparison chart is perfectly obvious to
me and balancing my cheque book is about my limit.

Math is not a strong suit for me either, but it "looks" like the
compression ratios are in error. I might well be wrong, but...

27,128,826 bytes:

7-Zip (7z format) 5,445,402 100%
WinRAR 3.10 6,004,155 110%
WinAce 2.3 6,242,424 115%
CABARC 1.0 6,455,327 119%
7-Zip (zip format) 9,461,621 174%
PKZIP 2.50 9,842,800 181%

Take the first one (7z format) and divide the original file size by
the compressed file size and move over two decimal places.

It is easy to see the compressed size is close to 1/5 the original
size. The compression rate is 498.20%. (very nice!)

Look at the last one, (PK 2.50) and see that it is "nearly" twice as
large as the first. How can it have a higher rate of compression?
The rate of compression is 275.62%, or "nearly" twice less than the
original 7z format.

The usage of % in a ratio kinds skews things up. A higher "%" score is
bad, not good in this table. I think ratio should be abandoned in the
table and the percentage "original/compressed" be inserted myself.

Better:

27,128,826 bytes:

7-Zip (7z format) 5,445,402 = 498.20% (compression rate)
WinRAR 3.10 6,004,155 = 451.83%
WinAce 2.3 6,242,424 = 434.59 %
CABARC 1.0 6,455,327 = 420.25%
7-Zip (zip format) 9,461,621 = 286.72%
PKZIP 2.50 9,842,800 = 275.62%

7z compresses ~498 bytes into one, (498:1) where PK compresses ~275
into one, (275:1), which are the "ratios" of compression for
compressing this particular archive. As is pointed out, the results
vary depending on what is compressed. Gimp might be very favorable to
7z and not so to PK.
7zip is a good program, give it a go.

It sounds like a great program! Maybe PK will finally go freeware.

I still use online banking to balance my check book though <G>.
 
R

REMbranded

(e-mail address removed) wrote:


27,128,826 bytes:
7-Zip (7z format) 5,445,402 = 498.20% (compression rate)
WinRAR 3.10 6,004,155 = 451.83%
WinAce 2.3 6,242,424 = 434.59 %
CABARC 1.0 6,455,327 = 420.25%
7-Zip (zip format) 9,461,621 = 286.72%
PKZIP 2.50 9,842,800 = 275.62%

Le whoops. The decimal points go back in when converting to a ratio:
7z compresses ~4.98 bytes into one, (4.98:1) where PK compresses ~2.75
into one, (2.75:1), which are the "ratios" of compression for
compressing this particular archive. As is pointed out, the results
vary depending on what is compressed. Gimp might be very favorable to
7z and not so to PK.


It sounds like a great program! Maybe PK will finally go freeware.

I still use online banking to balance my check book though <G>.

For darned good reason! <G>
 
B

Blinky the Shark

Look at the site, read the table and make your own mind up. You're giving
the impression that using the program risks losing your files. Especially
as the comment came from a regular contributor to a.c.f. It's a shame as
it's a good program.

See smilie. I was responding to someone's report about it claiming 130%
compression on some file, IIRC. That's been snipped, to force my
comment to be taken out of context; that's a shame.
 
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B

Blinky the Shark

Take a look at the smilie ... I think he referred to the impressive
compression ratio of the 7z format (at least, I hope so). I use this
application sine a year now, and it works great !

Yes, I think someone mentioned it showed "130%" compression on a file.
:)

Simon's doing the "quote out of context" trick, to make my comment look
like something it's not.
 
S

Simon Whitaker

See smilie. I was responding to someone's report about it claiming
130% compression on some file, IIRC. That's been snipped, to force my
comment to be taken out of context; that's a shame.

You responded to a poster mistakenly claiming that 7zip must compress it
self to nothing, with a quick 'one liner' about it being the equivalent
to a file shredder. I pointed out that your sparkling retort could
denigrate a very good program. People don't like ambiguity when it comes
to file archival.

I accept I may have over reacted to your post but the way you are trying
to deflect my point by using spurious counter claims dose you no credit.
As a regular contributor to this group your posts carry a little
credence. Please be mindful of this the next time you feel a 'funny'
comming on.
 
B

Blinky the Shark

You responded to a poster mistakenly claiming that 7zip must compress it
self to nothing, with a quick 'one liner' about it being the equivalent
to a file shredder. I pointed out that your sparkling retort could

That I did. Chuckle a little, for crissakes. This isn't
alt.brain.surgery. Watch a funny TV show. Take the splint outta your
neck, perhaps.
denigrate a very good program. People don't like ambiguity when it comes
to file archival.
I accept I may have over reacted to your post but the way you are trying

Now we're talkin'.
to deflect my point by using spurious counter claims dose you no credit.

I've never had a dose. I've always been careful where I put it.
As a regular contributor to this group your posts carry a little
credence. Please be mindful of this the next time you feel a 'funny'
comming on.

I shan't abandon humor for your sake, Simon. It's something that many
people have a sense of.
 
B

Blinky the Shark

Blinky said:
I shan't abandon humor for your sake, Simon. It's something that many
people have a sense of.

Make that, "it's something of which many people have a sense."
 
L

Loki Harfagr

Math is not a strong suit for me either,

For sure :)
but it "looks" like the
compression ratios are in error. I might well be wrong, but...

Nope, the ratio are relative to the 7-Zip comp ratio :

just test with the first case and do :
6004155 / 5445402

Can you read the chart now ?-)
 
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M

Matt

(e-mail address removed) wrote in

For sure :)


Nope, the ratio are relative to the 7-Zip comp ratio :

just test with the first case and do :
6004155 / 5445402

Can you read the chart now ?-)

Other compression reviews vary too...

The table being discussed out of context is Percent of BEST compressed
file size, with 7-Zip's result as the 100% reference point.


Looking at other compression reviews, "percent removed" or
"percent remaining" are common styles, and one is the reverse of the
other, as are JPEG compression settings which aree scaled in QUALITY
or COMPRESSION.

www.compression.ca - a rather out of date set of tests now, though you
could download some of the file sets used and see where the new
version would come in.
 

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