DOS ain't dead

Adding large disk support to INT13h (Users)

posted by boeckmann, Aachen, Germany, 01.04.2024, 18:41

> For Large Disk support in the BIOS (INT 13h) refer to:
>
> http://www.o3one.org/hwdocs/bios_doc/bios_specs_edd30.pdf
>
> and RBIL (start with INT 13.41).
>
> The extensions support up to 2^64 sectors. A sector can at least
> theoretically be up to 32k bytes (and maybe even 64k bytes, depending on
> the exact inmplementation), though in practice are probably limited 4k
> bytes.

Thanks for the reference. I am aware of this spec, but should have mentioned that my BIOS supports these functions. It sadly only makes available the first 8.4GB. The disk is also reported as 8.4GB disk by the BIOS. But other OS like OS/2 can for example access a 256GB disk without problems with appropriate drivers, so chipset support is given.

Looks like I have to replace the INT13 routines, so I will try to get XT-IDE running from floppy. This will reduce conventional memory by 8-12K. I am wondering if there are other side effects than stealing this memory from DOS, especially with things like EMM, protected mode etc...

Complete thread:

• Adding large disk support to INT13h - boeckmann, 01.04.2024, 11:54 (Users)
  • Adding large disk support to INT13h - RayeR, 01.04.2024, 15:31
    • Adding large disk support to INT13h - boeckmann, 01.04.2024, 18:44
  • Adding large disk support to INT13h - bretjohn, 01.04.2024, 17:28
    • Adding large disk support to INT13h - boeckmann, 01.04.2024, 18:41
      • Adding large disk support to INT13h - bretjohn, 02.04.2024, 16:54
        • Adding large disk support to INT13h - boeckmann, 02.04.2024, 19:23
          • Adding large disk support to INT13h - bretjohn, 04.04.2024, 19:33
            • Adding large disk support to INT13h - boeckmann, 04.04.2024, 23:09
              • Adding large disk support to INT13h - Laaca, 05.04.2024, 06:23
                • Adding large disk support to INT13h - boeckmann, 07.04.2024, 20:21
  • Adding large disk support to INT13h - mceric, 01.04.2024, 22:25
    • Adding large disk support to INT13h - boeckmann, 02.04.2024, 19:31
      • Adding large disk support to INT13h - mceric, 02.04.2024, 20:57
      • Adding large disk support to INT13h - tom, 02.04.2024, 23:16
        • Adding large disk support to INT13h - boeckmann, 04.04.2024, 23:09
        • Adding large disk support to INT13h - Japheth, 05.04.2024, 02:39
      • Adding large disk support to INT13h - ecm, 14.04.2024, 19:19