DOS ain't dead - LZ-DOS 7.1

LZ-DOS 7.1 (Miscellaneous)

posted by sol, 21.11.2007, 00:36

> BTW if I remember well, io.sys from windows contains fullscreen VGA logo.
> Is it also included and compressed in LZ-DOS? :)

I don't know. The logo takes about 100k. It's possible to remove it, or at least write over it with something that is compressible like a 'nop' instruction (I've done it in the past, playing around).

I'd have to decompress it to determine if they removed it, or just altered the check for 'bootgui' to behave as though it were always 0.

> I agree that recompiling of slightly changed source may produce big
> changes in binary. As I readed you revealed a same part at the beginning
> of io.sys. Do you know how to decompress whole file? It would be
> interesting. If it's UPX compression there should be some group of bytes
> same in other UPXed files.

Decompressing the whole file would be a matter of continuing the work I did earlier. This is either:

a) Step through a pile of assembly until you find something that looks like a decompression routine.

or

b) Skim through the file for something that looks like code, rather than compressed data, and then step through it.

Neither of those are particularly appealing to me, especially since I've already proven this is the MS-DOS kernel (or the 0.0000001% chance that it's merely reverse engineered & stolen code, which is no better).

Thread locked

Complete thread:

LZ-DOS 7.1 & booting previous DOS version - RayeR, 19.11.2007, 10:43 (Miscellaneous)
- LZ-DOS 7.1 & booting previous DOS version - sol, 19.11.2007, 17:56
  - LZ-DOS 7.1 & booting previous DOS version - sol, 19.11.2007, 17:59
    - LZ-DOS 7.1 - lucho, 19.11.2007, 19:05
      - LZ-DOS 7.1 - Steve, 19.11.2007, 19:36
        LZ-DOS 7.1 - lucho, 19.11.2007, 20:11
        LZ-DOS 7.1 - Steve, 20.11.2007, 18:29
        Canadian - lucho, 20.11.2007, 19:20
        Canadian - sol, 20.11.2007, 19:43
        Canadian - Steve, 21.11.2007, 02:11
        Canadian - Steve, 21.11.2007, 02:09
      - LZ-DOS 7.1 - sol, 19.11.2007, 20:06
        LZ-DOS 7.1 - lucho, 19.11.2007, 20:24
        LZ-DOS 7.1 - sol, 19.11.2007, 20:26
        LZ-DOS 7.1 - lucho, 19.11.2007, 20:38
        LZ-DOS 7.1 - sol, 19.11.2007, 20:45
        LZ-DOS 7.1 - lucho, 19.11.2007, 20:49
        LZ-DOS 7.1 - sol, 19.11.2007, 21:32
        LZ-DOS 7.1 - sol, 19.11.2007, 21:39
        LZ-DOS 7.1 - sol, 19.11.2007, 21:55
        LZ-DOS 7.1 - sol, 19.11.2007, 21:58
        LZ-DOS 7.1 - sol, 19.11.2007, 22:00
        LZ-DOS 7.1 - lucho, 20.11.2007, 07:35
        LZ-DOS 7.1 - sol, 20.11.2007, 08:13
        LZ-DOS 7.1 - lucho, 20.11.2007, 09:43
        LZ-DOS 7.1 - RayeR, 20.11.2007, 12:52
        LZ-DOS 7.1 - lucho, 20.11.2007, 13:25
        LZ-DOS 7.1 - RayeR, 20.11.2007, 14:51
        LZ-DOS 7.1 - lucho, 20.11.2007, 15:28
        LZ-DOS 7.1 - RayeR, 20.11.2007, 18:15
        LZ-DOS 7.1 - sol, 20.11.2007, 19:04
        LZ-DOS 7.1 - sol, 20.11.2007, 19:09
        SOL comes from StoOL-pigeon - lucho, 20.11.2007, 19:54
        SOL comes from StoOL-pigeon - sol, 20.11.2007, 20:22
        "Forking" is much worse than copying - lucho, 21.11.2007, 11:00
        LZ-DOS 7.1 - lucho, 20.11.2007, 19:30
        LZ-DOS 7.1 - sol, 20.11.2007, 19:34
        LZ-DOS 7.1 - RayeR, 20.11.2007, 19:51
        LZ-DOS 7.1 - sol, 21.11.2007, 00:36
        LZ-DOS 7.1 - lucho, 21.11.2007, 10:32
        LZ-DOS 7.1 *IS* MSDOS 7.1 - tom, 22.11.2007, 12:39
        LZ-DOS 7.1 - Rugxulo, 22.11.2007, 16:58
        LZ-DOS 7.1 - rr, 22.11.2007, 21:28
        LZ-DOS 7.1 - rr, 20.11.2007, 10:58
        LZ-DOS 7.1 - lucho, 20.11.2007, 12:45
      - LZ-DOS 7.1 - sol, 19.11.2007, 20:10
        LZ-DOS 7.1 - lucho, 19.11.2007, 20:33
        LZ-DOS 7.1 - sol, 19.11.2007, 20:37
        LZ-DOS 7.1 - lucho, 19.11.2007, 20:46
        LZ-DOS 7.1 - Rugxulo, 20.11.2007, 00:07
        About the Best Kept Top Secret of this forum, again - lucho, 20.11.2007, 07:46
        I apologize. - Japheth, 20.11.2007, 12:01
        I apologize. - lucho, 20.11.2007, 12:49
        anger shortens one's life - Rugxulo, 21.11.2007, 09:28
        anger shortens one's life - lucho, 21.11.2007, 10:03
        anger shortens one's life - Japheth, 21.11.2007, 10:09
        About the Best Kept Top Secret of this forum, again - Rugxulo, 21.11.2007, 09:25
        About the Best Kept Top Secret of this forum, again - lucho, 21.11.2007, 12:10
        About the Best Kept Top Secret of this forum, again - Steve, 21.11.2007, 12:32
        About the Best Kept Top Secret of this forum, again - lucho, 21.11.2007, 12:38
        About the Best Kept Top Secret of this forum, again - Steve, 21.11.2007, 13:17
        About the Best Kept Top Secret of this forum, again - lucho, 21.11.2007, 13:22
        About the Best Kept Top Secret of this forum, again - Rugxulo, 21.11.2007, 12:46
        Useless to argue - Japheth, 21.11.2007, 13:11
        Useless to argue - lucho, 21.11.2007, 13:17
        About the Best Kept Top Secret of this forum, again - lucho, 21.11.2007, 13:12
        About the Best Kept Top Secret of this forum, again - sol, 21.11.2007, 16:29
        Pravetz-16, etc. - lucho, 21.11.2007, 18:20
        Pravetz-16, etc. - RayeR, 21.11.2007, 18:45
        1980s - lucho, 21.11.2007, 19:11
        1980s - RayeR, 22.11.2007, 00:58
        Pravetz-16, etc. - Steve, 22.11.2007, 05:35
        Saul Hudson -- nice guy - Rugxulo, 21.11.2007, 13:02
        Book author? - lucho, 21.11.2007, 13:26
        Book author? - Rugxulo, 22.11.2007, 14:59
  - LZ-DOS 7.1 & booting previous DOS version - Japheth, 19.11.2007, 22:41
    - LZ-DOS 7.1 - lucho, 20.11.2007, 08:06
      - LZ-DOS 7.1 - Japheth, 20.11.2007, 08:57
        The pot calls the kettle black - lucho, 20.11.2007, 09:26
        The pot calls the kettle black - Japheth, 20.11.2007, 10:22
        The pot calls the kettle black - lucho, 20.11.2007, 13:18
        "Five of Good" - agreed - Japheth, 20.11.2007, 14:05
        The pot calls the kettle black - Rugxulo, 21.11.2007, 09:43
        Depression - lucho, 21.11.2007, 10:18
        The pot calls the kettle black - Japheth, 21.11.2007, 10:19
        The pot calls the kettle black - lucho, 21.11.2007, 10:25
        The pot calls the kettle black - Japheth, 21.11.2007, 10:42
        Udo confirmed it was you - lucho, 21.11.2007, 11:05
        The FOG is speaking - Japheth, 21.11.2007, 12:43
        The FOG is speaking - Steve, 21.11.2007, 13:28
        Five of Good vs. Gang of Four - lucho, 21.11.2007, 13:42
        2 innocent questions - Japheth, 21.11.2007, 14:05
        2 innocent questions - lucho, 21.11.2007, 14:44
        2 innocent questions - Steve, 21.11.2007, 14:56
        2 innocent questions - lucho, 21.11.2007, 15:34
        None selected - Japheth, 21.11.2007, 17:45
        None selected - Steve, 21.11.2007, 17:58
        ... the game must go on ... - Japheth, 21.11.2007, 15:38
        ... the game must go on ... - Matjaz, 21.11.2007, 19:14
        A small riddle - Japheth, 21.11.2007, 19:39
        Farewell! - lucho, 21.11.2007, 20:06
        Failed! - Japheth, 21.11.2007, 20:30
        A small riddle - Matjaz, 21.11.2007, 20:19
        Solved! - Japheth, 21.11.2007, 20:26
        Solved! - Matjaz, 21.11.2007, 20:37
        Solved! - Japheth, 21.11.2007, 22:07
        Solved?? - Rugxulo, 22.11.2007, 14:56
        a one man play ... no, not about my hooha - Rugxulo, 21.11.2007, 10:51
- LZ-DOS 7.1 & booting previous DOS version - rr, 20.11.2007, 11:24
  - LZ-DOS 7.1 & booting previous DOS version - RayeR, 20.11.2007, 12:07
    - LZ-DOS 7.1 & booting previous DOS version - lucho, 20.11.2007, 13:27
      - LZ-DOS 7.1 & booting previous DOS version - Rugxulo, 21.11.2007, 09:15
        Boot managers, Vista - lucho, 21.11.2007, 09:40
        Boot managers, Vista - Rugxulo, 21.11.2007, 09:57
        METAKERN by Eric Auer - lucho, 21.11.2007, 12:46
        OS boot managers -- comparison requested - Rugxulo, 21.11.2007, 12:57
        OS boot managers -- comparison requested - lucho, 21.11.2007, 13:32