Back to home page

DOS ain't dead

Forum index page

Log in | Register

Back to the forum
Board view  Mix view

Heatshrink compressed drives? - Tamp ISO compression test (Announce)

posted by mceric, Germany, 31.01.2025, 23:33

Data news, everybody :-)

I made a little histogram counter for CDH files and ran it on some ISOs I had around, after "tampisoing" them. Enjoy, or something ;-)


File fdbasecd_2007-09-06.cdh compressed 8333312 to 6699576 bytes
4069 sectors, 19.6% saved, 80.4% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         4.7%  4.1%  2.1%  3.1%  1.8%  1.7%  1.8%  1.6%   3.1%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
  4.5%   2.6%   1.3%   1.6%   1.6%   1.5%   1.0%   1.4%  69.6%

File fdbootcd_0.9.BETA.cdh compressed 10291200 to 8758719 bytes
5025 sectors, 14.9% saved, 85.1% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         3.9%  2.5%  1.9%  2.8%  1.9%  1.3%  1.5%  1.9%   2.1%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
  3.2%   1.8%   1.1%   1.2%   1.1%   1.3%   1.2%   1.0%  77.3%

File fdbootcd_0.9rc5.BETA.cdh compressed 11599872 to 9563353 bytes
5664 sectors, 17.6% saved, 82.4% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         3.5%  2.3%  1.3%  3.3%  2.0%  1.5%  1.6%  4.1%   3.9%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
  3.9%   2.6%   1.1%   1.4%   1.1%   1.3%   1.3%   1.4%  71.3%

File fdoslite_0.9pre.cdh compressed 36026368 to 22294142 bytes
17591 sectors, 38.1% saved, 61.9% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         2.2%  2.3%  2.5%  3.3%  2.7%  3.3%  4.0%  5.5%   7.8%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
 11.3%  13.4%   9.8%   8.6%   6.4%   3.6%   2.2%   1.8%  18.2%

File freedos_1.0_fdfullcd.cdh compressed 160184320 to 147371512 bytes
78215 sectors, 8.0% saved, 92.0% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         0.8%  1.1%  1.0%  1.2%  1.1%  1.2%  1.6%  1.8%   2.5%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
  2.9%   2.2%   1.3%   1.6%   1.3%   1.0%   0.8%   1.1%  84.4%

File kramers_nederlandse_taal.cdh compressed 147781632 to 73337302 bytes
72159 sectors, 50.4% saved, 49.6% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         0.9%  0.6%  0.5%  0.8%  1.1%  2.7% 13.7% 28.7%  21.8%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
 14.3%   7.9%   3.0%   2.4%   1.4%   0.9%   1.0%   0.9%   6.5%

File hp_windows_print_drivers.cdh compressed 478834688 to 430721071 bytes
233806 sectors, 10.0% saved, 90.0% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         1.0%  0.8%  0.7%  0.6%  1.7%  1.5%  1.7%  1.9%   2.3%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
  3.0%   3.4%   4.6%   3.3%   1.5%   0.9%   1.0%   3.3%  75.8%

File logox_3.5.cdh compressed 514738176 to 476102193 bytes
251337 sectors, 7.5% saved, 92.5% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         0.6%  0.7%  1.2%  1.5%  1.2%  1.3%  1.7%  1.8%   1.5%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
  1.3%   1.5%   1.4%   1.7%   2.0%   2.8%   5.6%  11.2%  70.1%

File encyclopedie.cdh compressed 580093952 to 517457387 bytes
283249 sectors, 10.8% saved, 89.2% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         0.8%  0.8%  0.9%  3.7%  2.0%  1.6%  1.9%  1.5%   1.4%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
  2.0%   3.8%   2.0%   1.8%   1.4%   1.6%   1.6%   3.9%  76.5%

File thesis.cdh compressed 735221760 to 513439278 bytes
358995 sectors, 30.2% saved, 69.8% remaining
Histo:  Empty ..128 ..256 ..384 ..512 ..640 ..768 ..896 ..1024
         0.6%  0.8%  6.8%  0.9%  1.7%  3.1%  2.1%  3.5%   5.7%
..1152 ..1280 ..1408 ..1536 ..1664 ..1792 ..1920 ..2047 ==2048
  7.9%  10.5%  11.2%  10.5%   6.1%   2.4%   1.9%   1.9%  31.4%


I also considered doing some Linux install/live CD, but those already do not compress well in solid compression, so trying to TAMP them seems a bit pointless. Example: Ubuntu 6.10 still takes 98.1% of the original space after BZIP2 of the ISO as a whole. For a classic Debian 3.0, more than two decades old, BZIP2 compresses the first CD ISO to 95.5%.

Even a 2016 Svarog386 DOS ISO only BZIP2 compresses to 99.0% of the original size. I guess I should have tested some DOS live CD with a lot of pre-installed stuff, but still UPX etc. will mean that many files already are compressed anyway.

It is interesting that quite a few sectors either do not compress at all and get stored as-is, or do not contain any data at all. I am not sure what the latter means. Does TAMP compress zero-filled arrays to zero-sized results, no matter how long they are?

---
FreeDOS / DOSEMU2 / ...

 

Complete thread:

Back to the forum
Board view  Mix view
22208 Postings in 2050 Threads, 396 registered users, 117 users online (0 registered, 117 guests)
DOS ain't dead | Admin contact
RSS Feed
powered by my little forum