how its possible..such high compression with winrar

A

hi guys i have one winrar file and it contain an iso file of window 6-1 xp 64 bit

now the main thing

size of winrar approx 10 mb
size of iso file approx 3.25 gb

plz tell me how this can be possible

its not of kgb file.just iso n such high compression.how to do this with winrar

I think that is not an ISO file.
It is a simple text file, having lot of repeated text inside to make it large size file & is then saved with .iso extension and then compressed to RAR

I think Raaabo has once told about it. He said it something pertaining to 'patterns'.

Its just an ISO with lots of dummy files filled with 0s in order to create patterns. Compression works this way -

suppose you have a string 54545454555443dfgretttgdftqtqtqltn43hngf43u4905u45 repeated thrice in the file, you store it in an index, and replace all instances of the string with the index number.

Now, look at how repeated zeroes in our case can reduce file size:

take a string 000000000000000000000000000000000000000 which is say 40 zeroes. it is found say 4 times in the file. but notice that this string is a pattern by itself - it has 40 0s. so the compressed form will look something like 40 00 and stored in the index, and each reference to the long string points to the index.

you just compressed 40 characters to 2 characters, and as its found in 4 places, its 160 chars to 8 chars = 95% compression.

Well, afaik highest was KBG doing 1GB to 100MB

But what's the use, when u take a lifetime compressing and decompressing it

A

n2casey said:
I think that is not an ISO file.
It is a simple text file, having lot of repeated text inside to make it large size file & is then saved with .iso extension and then compressed to RAR

no bro its an iso file an i have extracted its content by using alcohal

thanks dheeraj for the xplanation now plz tell me how to do that

here is the link for the file plz check it and tell me

~snipped~

G

it depends on compression algorithm....7z is good but not stable

C

Thanks a lot for that piece of info dheeraj_kumar.

@compaddict- There have been DVD sized files compressed to less than 2 MB using KGB archiver.

BUt, 6 to 7GB of GAME ISOs hv been converted to 1.5GBs or so.. (esp the torrent version of games)
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Its simply this: compress sound files to .ogg format and compress game video files( .bik) into just half of them. Now compress all data with 7zip and rename it with .x extension......

(this is NOT my explaination)..

but this is wat they (ppl like skullptura on torrents) do) maybe its not jus ONLY winrar...

A

thanks alot for your reply but what about the nrg/iso type file

7zip has such a ability to compress files, but not tested myself though...found from google..

C

Yeah. 7zip has a high compression ratio, higher than that of WinRAR. I've tested this myself.

@ashish
First, remove the link. India runs on warez, but its not allowed in digit forum, atleast not in public.
Second, Install it in a virtual machine, my guess is it wont install, or it will, with minimal features only. Try it and post back.

beta testing said:
Yeah. 7zip has a high compression ratio, higher than that of WinRAR. I've tested this myself.

cool, on wat hv u tried?? Musiz files, docs, movies or game ?? plz post..also wat compression u got, i mean the file size b4 7Zipping and the size of file after 7Zipping ??

dheeraj_kumar said:
@ashish
First, remove the link. India runs on warez,

true, very true,lol.. infact the whole world is ditching MS (especially) and running on pirated OS stuff..

C

^^GTA SA original size:: 5.5 GB
Compressed size:: 3.3 GB

And you can get better compression with documents.

^^ hey thats awesome... will try that for all my stuff too.. thanx beta for the update on this..

wat was the time taken for compression (not decom as it hardly takes any huge time)

btw, its free (7zip) isint it ?? like winrar???

C

Yep, 7zip is free. On my system- AMD Athlon 64 1.81 Ghz, 1 GB DDR400 RAM, it took around 2 hrs. The computer was left idle at this time.

Well, ya...so iso's can be compressed to a high level too.

I hav a CD of a game, wanna make an ISO copy of it. Is there any software, good, free, small?

^^ Depends, you might need to use Alcohol 120% depending on the protection.

^^

also, adding to the point, how much RAM u hv and for how much time can u leave ur system idle (wen the compression is goin in progress)

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Also, as beta_testing said, tat it took him 2 hrs wen system was kept idle, well i wud probably stick to the original file size and use a DVD or 2 DVDs than waiting for such time..

but, yes the compression ratio was really good..

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@ dheeraj, nice, enlightening siggy..

A

Its simply this: compress sound files to .ogg format and compress game video files( .bik) into just half of them. Now compress all data with 7zip and rename it with .x extension......

(this is NOT my explaination).. but this is wat they (ppl like skullptura on torrents) do) maybe its not jus ONLY winrar...
__________________

can you explain me more.....i wana my iso's of operating system and movie's to maximum extent without kgb...

Originally Posted by beta testing View Post
Yeah. 7zip has a high compression ratio, higher than that of WinRAR. I've tested this myself.

hey beta testing plz tell me step wise how you did that i too have many iso's n nrg file

Your ISOs are useless to compress. Why? because the unpacking time be quite long. And after that you'll have to mount it or write it to a disk. Thats useless. So my suggestion is, just copy the ISOs to a DVD and be done with it. For your purposes, compression is useless.

A

thanks for your reply dheeraj.....actually i am making copy of my cd/dvd on my hdd because lots of people keep on taking my cd/dvd for their use as we live in hostel so i cant deny them and many times they get broken or get scratched then i have to go n arrange a new one for me so i wana back up them on my hdd so i dont have to get a new one in case of older one get some problem....thats why i need to compress them also so i dont have to loose more space...i dont have any problem regarding time taken to uncompress n burning coz it still very benificial for me then going to download or searching local vendor

but i dont want it to be done with kgb coz it takes lot of time but 1 hr or 2 hr is ok for me to let them uncompress but i didnt have to do that a lot coz only file compressed by me takes that time but the file downloaded by net is far good then mine as they have better compression ratio then mine and takes less time than mine file....this is the reason i wana know how to compress them effectively

ashishstillthere said:
can you explain me more.....i wana my iso's of operating system and movie's to maximum extent without kgb...

well, i saw this reply by a user on torrents site..he didnt disclose the methods used, so i was also left wondering..but as he said, he has been studying this pattern of conmpression done by skullptura (this guys is the master of compression for games on torrents and helping low bandwidth ppl like us to d/load games) since the past 1-2 years..and guess wat, the "he" im referring so much in this post was actually an Indian boy and a B.Tech Computer Science student...similar to me (well im a B.E I.T)..

so this made reading his reply all the more fascinating

will post anything tat i'll come across wen the "he" guy posts anything in future..

@ashishstillthere
No idea, I dont know about the compression methods professional releasers use. I'll tell you what I do, I have lots of software, games and movies, I write them into DVDs as my own copy, and when friends need them, I just copy them back to the hard disk, and write them into other discs for friends. I've been doing that for a long time, and all my master copies are safe for me. Of course, If I had another DVD drive it would be much easier, direct DVD-DVD copying, but I dont

@ashu888ashu888
I have analyzed some rips by Skullptura, and the most of the compression takes place using 7zip, which drastically reduces the file size.

It can't possible iff WinRAR is set to compress at its max. for it has the ability to compress particular files a lot and other very less.

beta testing said:
And you can get better compression with documents.

Only with older Office 2003 format. Compression is almost minimal with ODF & OOXML as they are already compressed using ZIP.

Technically speaking, ODF & OOXML files are a group of XML files compressed with ZIP.

A

any one know other way to get max compression????

Even Windows ntfs Compression Can Achieve Very High Compression But Compression Depends Upon The Structure Of The Data Written In The File.

If U Have pop Ww Original Dvd Then There U Will Find An Single File Of Over 2.xx Gb Size.now Copy That File To Any Drive Which Is Formatted As Ntfs & Drive Compression Is Enabled On That Drive.

Now Right Click The File & Go To Properties. U Will B Amazed To See The Compressed Size.it's just Some Kb I Don't Remember It Now.

The Max Compression Over That File Is Achieved By 7z Format In 7zip, The Best Software For What It Is Meant To Do.

7zip is better

A

can you plz tell me the setting to get that compression in 7 zip.......

Read the command line arguments. I remember seeing a certain chain of arguments that give the max compression some time back.

*www.google.com/search?num=100&hl=en&client=opera&rls=en&hs=V83&q=7zip+command+line+bcj2&btnG=Search

has many argument chains.