DOS ain't dead

I was searching for the latest version of the interesting "624" (Six-2-Four) .COM file packer, and found the following article:

https://codejuggle.dj/analysis-of-the-624-six-2-four-packer/

In that article they give these ideas to improve the compression rate:


1 With the current implementation the first byte is always a literal, therefor the bit in front to mark it as literal is not needed. The unpacking stub could jump at beginning of execution directly to the code to copy the literal to the output buffer

2 A match will probably be followed by a literal. The bit to mark the literal can be skipped and the unpacker adjusted to expect a literal after a match without changing the size of the unpacker stub

3 A run of literals could be encoded with the length of it. The following compressed flag of the match following the literal run would not need to be saved

4 Huffman codes can be replaced by [gamma encoding](https://en.wikipedia.org/wiki/Universal_code_(data_compression)), which would result in a smaller unpacker stub but may depend on the input file to compress to improve the overall compression ratio


The packer versions to download:

Version 1.0:
https://files.scene.org/view/mirrors/hornet//code/compress/plp_624.zip

Version 1.1:
ftp://ftp.sac.sk/pub/sac/pack/624-11.zip


Do any of you dare to improve the 624 packer a bit?

> The packer versions to download:
>
> Version 1.0:
> https://files.scene.org/view/mirrors/hornet//code/compress/plp_624.zip

File date: 2006-08-20 23:09:36

Firefox v102 would not permit me to download from any of the links
claiming they were all security risks.

So, got it with wget.

The contained files are from 28 Feb, 1997

>
> Version 1.1:
> ftp://ftp.sac.sk/pub/sac/pack/624-11.zip
>
>
> Do any of you dare to improve the 624 packer a bit?

Could not get to that one... no anonymous FTP login permitted.

Was able to get it via....

https://www.sac.sk/files.php?d=7

624-11.zip 624 v1.1 - COM program packer 18440 1999-09-24 09:00:18

624.com within that ZIP is dated 24 Aug, 1997
____________________________________________________________________

---
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http://glennmcc.org/

....................

>
> Was able to get it via....
>
> https://www.sac.sk/files.php?d=7
>
> 624-11.zip 624 v1.1 - COM program packer 18440 1999-09-24 09:00:18
>
> 624.com within that ZIP is dated 24 Aug, 1997


Also with FTP client of Total Commander 6.58 for Win 3.x from:

ftp.elf.stuba.sk
anonymous
/pub/pc/pack