File Compression

[hyunkeru]

I have downloaded a zip file from a website. The size of the file is about 15mb. I extracted it the size is over 150mb. I tried to use winzip or winrar to compress a iso. I used the maximum compression. The compressed file is still about 90% of the original size. How can they compress it? Do I have to get any special compression program to do it or only work for certain kind of iso. Anyone knows. Thanks.

[XtremeMaC]

u can use UHARC compression to do that....

[Datalore]

Sometimes it really just depends on the file type and it's contents. Things like exe's usually have a good compression rate (mind you, not exceptional) but there's some formats that compress very easily. I can't remember any off the top of my head.

[Chaosratt]

Text and excatuables (lines of code) compress very well, I have some files that have 80% compression (ie. the file is 20% of what it used to be).

Multimedia does not compress very well at all. a 715mb video would only compress down to 702 with winrar at maximum. While a 300mb program file was compressed down to 80mb. All depends on the file.

[Ausmith1]

7-Zip has the best compression ratio that I have seen so far. It can compress executables to 1/3 the size that WinZIP/RAR typically can. Mind you it does take a _long_ time to compress and it works best in cases where there are lots of small files, you also have to use its proprietary 7z compression format to get the ultra compression rates (it can create SFX 7z files though). Decompression times for 7z archives are relatively fast though.

While 7-Zip is not perfect I've been happy enough with it to replace WinZIP and WinRAR on all my systems. That it's GNU LGPL open source is an added bonus.

i.e. 7-ZIP 3.13 can compress the SQL Server 2000 Enterprise edition installer (plus service packs and patches) from about 600MB to about 90MB, this takes at least an hour to compress on my dual Xeon 2.4GHz system and less than a minute to decompress.

[Datalore]

i.e. 7-ZIP 3.13 can compress the SQL Server 2000 Enterprise edition installer (plus service packs and patches) from about 600MB to about 90MB, this takes at least an hour to compress on my dual Xeon 2.4GHz system and less than a minute to decompress.

Holy crap. That's amazing. Thanks for the info on 7-zip.

[R600]

i.e. 7-ZIP 3.13 can compress the SQL Server 2000 Enterprise edition installer (plus service packs and patches) from about 600MB to about 90MB, this takes at least an hour to compress on my dual Xeon 2.4GHz system and less than a minute to decompress.

wow.. dual xeon takes over an hour to compress this. I wonder how long it would take for us home users to compress such a thing.. lol

[Chaosratt]

1.35gb isos take me around 45min-1hour to compress with my processor, and about 10-15 seconds to unpack.

[ramian]

how big are the ISOs after you compress them?

[Chaosratt]

like many people have already stayted, it depends on whats in the ISO, if its a lot of code, it iwll compress very well, if its full of textures, then not much at all.

I have had some ISOs (like windows) get compreesed down to 30% of their original size, while some games i can only get down to 85-90%.