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General Category => Programming => Topic started by: freemac on 09:15, 14 October 17

Title: ParaDOS 720KB disk, 4MB RAM, but why not a TARGZ ROM ?
Post by: freemac on 09:15, 14 October 17
(http://www.cpcwiki.eu/imgs/a/a2/Pc_disk_pcfute.jpg)


Was just a stupid morning idea showing back this very old 3.5 floppy...
About a ROM that gzip/gunzip file from/to disk to/from RAM ?
4MB on a single cpc disk, why not ?
Title: Re: ParaDOS 720KB disk, 4MB RAM, but why not a TARGZ ROM ?
Post by: Prodatron on 13:40, 14 October 17
There is UnZip for SymbOS available, which is a very fast and full featured ZIP/GZ file uncompressor:

http://www.symbos.de/appinfo.htm?00008 (http://www.symbos.de/appinfo.htm?00008)

It's based on Grauws (MSX) idea to transfer a huffman tree into executable code, which is much faster compared to the classic approaches, but also requires some additional RAM. The deflate algorithm requires a "dictionary" (something like an uncrunch buffer) with a size of 32KB anyway.
Please note, that the Deflate algorithm is using bit-oriented data, which is of course slower compared to a simple byte-oriented RLE uncompressor.

UnZip for SymbOS is open source, feel free to port it to Amsdos.
Title: Re: ParaDOS 720KB disk, 4MB RAM, but why not a TARGZ ROM ?
Post by: GUNHED on 16:15, 18 October 17
Quote from: freemac on 09:15, 14 October 17
Was just a stupid morning idea showing back this very old 3.5 floppy...
About a ROM that gzip/gunzip file from/to disk to/from RAM ?
4MB on a single cpc disk, why not ?


There are lots of great compression / decompression tools for CP/M and ZCPR including unzip too.
Title: Re: ParaDOS 720KB disk, 4MB RAM, but why not a TARGZ ROM ?
Post by: Prodatron on 19:03, 18 October 17
I would like to try Unzip for CP/M (I read about it in some very old newsgroup posts). Good to know, that it's still available, please tell we where I can download it.
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