Slashdot Mirror
FEAD Compressing Compressed Files by 50-75%?
An anonymous reader asks: "I just installed Acrobat Reader and found that it was using FEAD which claims - 'FEAD© Optimizer© significantly reduces the size of application programs on average by 50% (in some cases up to 75%, depending on the specific software), even when they are already compressed with common compression technology like ZIP or CAB.' . It seems that they optimize each application individually at thieir labs. But an average of 50% compression on already compressed binary files seems to be too good to be true. Anyone familiar with how someone may be able to achieve this?"
The thing they tout as FEAD is basically a load-over-network-on-demand thingy. They haven't actually developed anything that does compression, they're just storing some of the app on a server somewhere to be downloaded on demand. The hype at their site mislead you, like it was meant to do.
11*43+456^2
It's decompressing the file that's hard.
You can compress all your files down to a single bit using this patented two step process:
1. Discard all zeros.
2. Use one to represent any length sequence of ones.
This is as reliable a compression scheme as most backups to tape I've ever seen, and you can fit a huge number of files onto a single floppy.
Some people have a way with words, and some people, um, thingy.
I think that it reads as you interpret: if you put some stuff in a .ZIP, it will further compress it. But, on a very close reading, they are only comparing sizes, and not necessarily saying they are compressing the zip file.
From the article: "Netopsystems specialists combine and customize these tools and processes for each individual software product so that optimal size reduction results are achieved."
Note the following from the whitepaper: "Usually software producers compress their data by generating cabinet files or the like...Applying a conventional compression tool like WinZip or WinRAR on such data does not lead to appreciable - often negative - results."
Read strictly, this says what we know: compressing a compressed file generally doesn't work. They aren't saying they compress the compressed file here.
Note that towards the bottom, they are comparing 'lossless compressed' data to what they do.
So, here's my bet: they probably do something like crack open a cab or zip, parse a PDF, for example, for 'magic things' that can be ignored without changing the functionality ('lossy' but nothing of significance lost), or take an HTML file and strip all spaces and newlines between tags. Similar things could be done for other file types: Removing quotes and instead, magic-quoting commas in a CDF. Etc, ad inifinitum.
All in all, it's lame, but so is most software.
If you have a gigantic amount (hundreds of gigs terabytes) of different files to back up or move around, with so many file formats that you can't keep them straight, then it might be worth it. If you are lazy and it's cheap, it might be worth it. Other than that, I fail to see the real utility here - disk is cheap, bandwidth is getting cheaper, and reasonably assuming the bulk of this data is generated (an adequate assumption), you can do very similar things by fiddling around with the the output formatting in code.
J
"Lying through one's teeth" comes to mind...
by employing the latest in smoke and mirrors technology. they've invented a new mirror that reflects 110% of all light. neat huh?
Difficult (c) to Read (c).
It may be difficult to read, but it sure is easy to FEAD© !!!
"Can of worms? The can is open... the worms are everywhere."
Difficult to read, but easy to compress.
When you use an executable compressor, like PKLITE, on an executable file, it can't compress all the data. This is because EXEs will dynamically load more data, and if that data is compressed, the code can't read it.
I suspect these guys are going in and manually altering the code to perform a decompression. This would certainly produce a benefit.
Here's something for you to try: Take an executable and zip it. If it compresses, then there's probably SOME give in it. And most executables I see are compressable.