DOS ain't dead

UPX (Announce)

posted by lucho, 31.10.2007, 15:40

> > As fas as I know, the UPX default NRV algorithm has a very fast unpacking,
> > so the delay it causes should be unnoticeable even on slow machines. The
> > new LZMA method unpacks very slowly though. Perhaps the executables are
> > packed with it?
>
> Andris used "upx --brute". (see gcc422s2.zip\diffs\install.gcc\makepkg.pl) So no LZMA.

Wrong. I just tested how UPX 3.0 compresses COFF executables with --brute. The result is the same as if I added --lzma explicitly. That is, it assumes --lzma not only with --ulra-brute, but also with --brute. If you use --best instead of --brute, it uses NRV and the executable is larger but then unpacks much faster. For 16-bit executables, --brute and --ultra-brute don't assume --lzma (you must specify it explicitly if you want it), but for 32-bit executables, they do.

So, it's better to replace --brute with --best to avoid LZMA. Adding --nrv2e (default is --nrv2d as far as I know) may reduce file size slightly, but it's still NRV, not LZMA.

You may want to let Andris know this.

Complete thread:

• GCC 4.2.2 for DJGPP released - Rugxulo, 25.10.2007, 06:58 (Announce)
  • GCC 4.2.2 for DJGPP released - RayeR, 25.10.2007, 10:54
    • GCC 4.2.2 for DJGPP released - RayeR, 26.10.2007, 02:28
      • GCC 4.2.2 for DJGPP released - rr, 26.10.2007, 11:19
        • GCC 4.2.2 for DJGPP released - RayeR, 27.10.2007, 01:54
          • GCC 4.2.2 for DJGPP released - RayeR, 27.10.2007, 03:07
            • GCC 4.2.2 for DJGPP released - Rugxulo, 27.10.2007, 14:26
              • GCC 4.2.2 for DJGPP released - RayeR, 28.10.2007, 23:17
                • GCC/DJGPP --masm=intel (plus YASM, GCC speed) - Rugxulo, 30.10.2007, 05:42
                  • GCC/DJGPP --masm=intel (plus YASM, GCC speed) - RayeR, 30.10.2007, 13:09
                    • GCC/DJGPP --masm=intel (plus YASM, GCC speed) - Rugxulo, 31.10.2007, 00:26
                      • GCC/DJGPP --masm=intel (plus YASM, GCC speed) - Rugxulo, 31.10.2007, 09:31
                        • UPX - lucho, 31.10.2007, 10:08
                          • UPX - RayeR, 31.10.2007, 12:15
                            • UPX - rr, 31.10.2007, 17:12
                            • UPX - gcc - benchmark - RayeR, 01.11.2007, 02:27
                              • UPX - gcc - benchmark - Rugxulo, 01.11.2007, 02:47
                                • UPX - gcc - benchmark - RayeR, 01.11.2007, 11:10
                                  • UPX - gcc - benchmark -- LZMA can save a lot (sometimes) - Rugxulo, 03.11.2007, 03:32
                                    • UPX - gcc - benchmark -- LZMA can save a lot (sometimes) - RayeR, 03.11.2007, 11:25
                          • UPX - rr, 31.10.2007, 13:11
                            • UPX - lucho, 31.10.2007, 15:40
                              • UPX - rr, 31.10.2007, 15:48
                                • UPX - lucho, 31.10.2007, 16:51
                              • UPX - RayeR, 31.10.2007, 17:47
                                • UPX - lucho, 31.10.2007, 18:43
                                  • UPX - RayeR, 01.11.2007, 02:07
                                    • UPX - rr, 01.11.2007, 11:04
                                • UPX - Rugxulo, 01.11.2007, 03:33
                                  • UPX - RayeR, 01.11.2007, 10:49
                                    • UPX - rr, 01.11.2007, 10:58
                                      • UPX - version detect - RayeR, 01.11.2007, 22:18
                          • UPX - Andris, 31.10.2007, 19:30
                        • GCC/DJGPP --masm=intel (plus YASM, GCC speed) - Rugxulo, 01.11.2007, 03:27