DOS ain't dead

Combined .com executable/DOS driver (Announce)

posted by Ninho , 12.06.2010, 14:37

snippety-snip... Just an detail which you may or may not remember

>> The reason is that an FFFFFFFFh value denotes the LAST driver in the DOS
>> driver list.
> Indeed like Zbikowski's "Z" on MCB's.

Actually, when loading a driver, MS-DOS (others ?) check only the segment part (high word) of this double word for the special value FFFFh. This behaviour (by design?) will allow us to make a dual device driver/ dot com executable, using the first two bytes as a short jump over the rest of the driver header. Of course, the init routine for the 'sys' specific part of the init code should replace FFFF at offset zero before giving back control to the DOS system initialisation routines...

Cheers

--
Ninho

Complete thread:

• "That Will Be ALL!" For UIDE and USB! - Jack, 06.06.2010, 20:37 (Announce)
  • "That Will Be ALL!" For UIDE and USB! - Rugxulo, 07.06.2010, 04:20
    • Re: UIDE Unloading And Cache-Sizes. - Jack, 07.06.2010, 05:30
      • Re: UIDE Unloading And Cache-Sizes. - Rugxulo, 08.06.2010, 01:35
        • Re: UIDE Unloading And Cache-Sizes. - marcov, 08.06.2010, 23:18
          • Re: UIDE Unloading And Cache-Sizes. - Rugxulo, 09.06.2010, 04:23
  • "That Will Be ALL!" For UIDE and USB! - Japheth, 07.06.2010, 07:51
  • TSR vs DEVICE= - DOS386, 07.06.2010, 08:01
    • TSR vs DEVICE= - RayeR, 08.06.2010, 15:46
      • TSR vs DEVICE= - Arjay, 08.06.2010, 19:30
        • TSR vs DEVICE= - RayeR, 09.06.2010, 02:00
        • TSR vs DEVICE= - Japheth, 09.06.2010, 09:50
          • TSR vs DEVICE= - RayeR, 09.06.2010, 16:15
        • TSR vs DEVICE= - roytam, 09.06.2010, 18:18
      • TSR vs DEVICE= - DOS386, 27.06.2010, 14:30
    • TSR vs DEVICE= - bretjohn, 18.06.2010, 21:50
      • TSR vs DEVICE= - Jack, 18.06.2010, 23:29
        • TSR vs DEVICE= - bretjohn, 19.06.2010, 01:18
        • Nothing Against You! - Jack, 19.06.2010, 01:52
      • TSR vs DEVICE= - Japheth, 19.06.2010, 09:02
        • TSR vs DEVICE= - Arjay, 19.06.2010, 19:13
        • TSR vs DEVICE= - bretjohn, 19.06.2010, 20:33
          • TSR vs DEVICE= - Japheth, 20.06.2010, 09:04
            • TSR vs DEVICE= - Arjay, 20.06.2010, 12:48
            • TSR vs DEVICE= - bretjohn, 20.06.2010, 16:32
              • TSR vs DEVICE= - Ninho, 20.06.2010, 17:34
  • "That Will Be ALL!" For UIDE and USB! - marcov, 08.06.2010, 22:41
    • "Capital Letters". - Jack, 08.06.2010, 23:15
      • "Capital Letters". - marcov, 08.06.2010, 23:19
        • No "Rants", But ... - Jack, 09.06.2010, 00:24
        • "Capital Letters". - Arjay, 09.06.2010, 00:37
          • "Capital Letters". - Jack, 09.06.2010, 00:48
            • Seeking the middle ground: thinking re flexibility+realibity - Arjay, 09.06.2010, 02:29
              • Bret's USB driver bugs - I was testing v0.11 by accident - Arjay, 09.06.2010, 02:50
              • Seeking the middle ground ... - Jack, 09.06.2010, 04:29
                • giving back a block of HMA - Ninho, 10.06.2010, 16:03
                  • Giving Back HMA ... - Jack, 10.06.2010, 17:03
                    • Giving Back HMA ... - Ninho, 11.06.2010, 09:48
                      • Giving Back HMA ... - Jack, 11.06.2010, 16:43
                        • Giving Back HMA ... - Ninho, 12.06.2010, 20:30
                • Seeking the middle ground ... - Arjay, 11.06.2010, 19:29
                  • Seeking the middle ground ... - Jack, 11.06.2010, 21:42
                    • Seeking the middle ground ... - Arjay, 12.06.2010, 01:12
                      • Combined .com executable/DOS driver - Ninho, 12.06.2010, 14:37
                        • Combined .com executable/DOS driver - Arjay, 12.06.2010, 15:13
                          • Combined .com executable/DOS driver - Ninho, 12.06.2010, 15:49
                            • Combined .com executable/DOS driver - Arjay, 12.06.2010, 16:33
                              • Combined .com executable/DOS driver - RayeR, 13.06.2010, 10:41
                                • Combined .com executable/DOS driver - Arjay, 13.06.2010, 16:11
                              • Combined .com executable/DOS driver - Ninho, 13.06.2010, 13:24
                                • Combined .com executable/DOS driver - Arjay, 13.06.2010, 18:54
                          • Combined .com executable/DOS driver - Arjay, 13.06.2010, 20:42
                            • Combined .com executable/DOS driver - Rugxulo, 14.06.2010, 04:27
                              • Combined .com executable/DOS driver / RJDUMP - Arjay, 19.06.2010, 15:08
                            • Combined .com executable/DOS driver - Matjaz, 20.06.2010, 11:58
                              • Combined .com executable/DOS driver - Turbo pascal example - Arjay, 20.06.2010, 13:06
                                • Combined .com executable/DOS driver - Turbo pascal example - Arjay, 20.06.2010, 13:39
                        • Combined SYS device drivers - more than 1 driver in a file - Arjay, 21.06.2010, 17:48
                        • Combined .com executable/DOS driver, multi-header drivers - ecm, 10.08.2010, 18:49
                          • Combined .com executable/DOS driver, multi-header drivers - Arjay, 10.08.2010, 19:41
                            • Combined .com executable/DOS driver, multi-header drivers - ecm, 10.08.2010, 20:21
  • No "Removable" HARD Disks Supported By UIDE! - Jack, 08.06.2010, 23:57
  • "That Will Be ALL!" For UIDE and USB! - bretjohn, 15.06.2010, 22:47
    • Further Comments ... - Jack, 16.06.2010, 01:35
    • "That Will Be ALL!" For UIDE and USB! - Rugxulo, 17.06.2010, 12:07
      • "That Will Be ALL!" For UIDE and USB! - bretjohn, 17.06.2010, 16:53
        • "That Will Be ALL!" For UIDE and USB! - Rugxulo, 17.06.2010, 17:45