DOS ain't dead

Video BIOS shadowing on modern systems. (Users)

posted by Zyzzle, 02.02.2023, 10:54

I remember back in the days of American Megatrend, and Awarf BIOSes, there was often an option to "shadow" the video BIOS into low memory in DOS, to greatly speed up vBIOS routines and calls in DOS.

Now, we are in an age of SOC chips and "Intel Graphics" onboard video embedded in all modern core i3/i5/i7 systems. As a technical point, is it possible to "shadow" the ~60 to 64kb "VGA video BIOS" ROM code portion of such onboard Intel graphics which contains the relevant 16-bit DOS video routines into low DOS memory, so that the code may be modified and corrected of the many bugs and limitations which have occurred in the DOS VBIOS portion of the Intel Graphics chipsets (such as UHD 620, Intel HD 5500-series, etc)? After 2020, Intel sadly removed *all* legacy BIOS support, and this also included all 16-bit DOS VBIOS code.

DOS programs such as DEBUG are capable of finding and dumping the video BIOS code in DOS.

Does the fact the "integrated" graphics on the Intel core i are already "on the chip" mean that the concept of "shadowing" the BIOS in fast RAM is obsolete?

I'm sure there were some DOS utilities from 30+ years ago on Simtel and other sites which could do this "shadow" RAM trick with video BIOSes. However, none of those allowed you to *modify* the code which was shadowed into RAM, nor were there any built-in optimizations.

Scitech did this "optimizing" VGA and VESA support 25 years ago. I'm wondering, for example, if one could "replace" the onboard vBIOS of one Intel Graphics (eg, UHD 620) with another (eg, Intel HD5500 series) which *does* correct some of the bugs introduced with Onboard UHD 620 Graphics (VBE 2.0 errors / black screen at 640x480 and above, lack of 320x240 Mode 13, etc).

Any suggestions, pointers or advice on to "shadow" modern Intel vBIOSes into lower RAM, for modification?

Complete thread:

• Video BIOS shadowing on modern systems. - Zyzzle, 02.02.2023, 10:54 (Users)
  • 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