DOS ain't dead

Video BIOS shadowing on modern systems. (Users)

posted by tom , Germany (West), 12.02.2023, 12:00

> > Maybe I’m missing something, but why does loading a BIOS font take
> extra
> > memory or interaction with a memory manager?
>
> Some people use a TSR that catches interrupt 10h and after changing the
> video mode reloads their font which is stored in conventional memory. At
> the expense of XMS memory, using a memory manager (eg JEMM) you can make a
> video copy of the BIOS (see memory mapping and paging) and store the font
> there (function 10h.1130.es:bp) which the BIOS will load itself. In this
> case, the TSR program becomes redundant and we have more free conventional
> memory (an 8x16 font takes up 16*256=4K).

this font - and probably most of the TSR's code - should be swapped out to XMS.

actually - as this INT 10 is never called from the kernel - the code and font data could be reloaded from disk.

Complete thread:

• Video BIOS shadowing on modern systems. - Zyzzle, 02.02.2023, 10:54
  • Video BIOS shadowing on modern systems. - tom, 02.02.2023, 14:24
    • Video BIOS shadowing on modern systems. - bretjohn, 02.02.2023, 18:02
      • Video BIOS shadowing on modern systems. - Zyzzle, 03.02.2023, 02:53
        • Video BIOS shadowing on modern systems. - CandyMan, 06.02.2023, 00:26
          • Video BIOS shadowing on modern systems. - bretjohn, 07.02.2023, 15:47
            • Video BIOS shadowing on modern systems. - Zyzzle, 10.02.2023, 05:25
              • Video BIOS shadowing on modern systems. - CandyMan, 10.02.2023, 09:52
                • Video BIOS shadowing on modern systems. - Oso2k, 11.02.2023, 23:54
                  • Video BIOS shadowing on modern systems. - CandyMan, 12.02.2023, 09:24
                    • Video BIOS shadowing on modern systems. - tom, 12.02.2023, 12:00
                • Video BIOS shadowing on modern systems. - Zyzzle, 22.02.2023, 10:24
                  • Video BIOS shadowing on modern systems. - CandyMan, 26.12.2023, 19:48