xmame  

Re: use of tar.gz to compress the roms

Tomi Ollila
Mon, 27 Nov 2000 23:39:24 -0800

Tuesday Nov 28 01:28:01 -0500 2000 theGREENzebra <[EMAIL PROTECTED]> wrote:
> > About the saved space, I think that gz compress about 30% more than zip,
> 
> I think this figure is a little out there. If I compress with maximum
> compression using zip, and maximum compression using gzip, I get about 5-10%
> (tops) savings. It is, however, standardised across platforms..

Nowadays zip usually uses the same compression algorithm than gzip, but zip 
compresses each file invidiually -- in tar.gz -file files are first tarred
and then the whole archive is compressed, therefore the compression ratio
is a bit better (in tar.gz deflate algorithm can re-use the "strings" found
in previous files for the current one). 

> 
> > and bz2 about 20-30% more than gz. 

Usually -- sometimes I get even worse compression than with gzip (usually
with text files).

> 
> This, however, is no lie. Bzip2 is the bomb. I get a minimum of like 10-15%
> over gzip every time I compress something with bzip2. Not everyone has bzip2,
> although the support couldn't hurt.

There is /usr/lib/libz.so, and then there is /usr/lib/libbz2.so. The former
has been used in xmame, and usage of the latter is quite similar...

> 
> > And the gz and bzip2 are open formats. The zip not.

... zip format is pretty simple, but perhaps not documented very well...

> 
> Being an open source freak, I'll go with this one too. Hooray for source code!
 
... There is lgpl'd software (check zziplib on freshmeat) that can read
zipped files quite easily...


> just a few cents for me to add in.


So. IMHO the .tar.gz and/or .tar.bz2 formats could go in, those are easy to 
do and so on. Just write the code in nice and clean manner so that the
XMAME maintainers can include it in...

... but there is no reason to lower the need for zip, it is good and free
archiving method to be used and I am happy if that is the only available.

> 
> *  [EMAIL PROTECTED]  *  http://switch.orotech.net  *  ICQ# 1107012  *  IRC: P2E  *  
>AIM: theGREENzebra

Tomi
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