DOS ain't dead

AHCI CD-ROM driver for DOS (Developers)

posted by DOS386, 19.12.2009, 04:08

Thanks.

> 1) there are no longer IO ports to access the drive. (1f0-1f7, 170-177, etc)

Above are legacy ports, but there are also "native" IDE/SATA ports ...

> so the drive does not appear as a standard hard drive anymore.

So PIO / UDMA code won't find anyting ...

> 2) all of the access to the drive is done through DMA through the AHCI
> controller itself. essentially the "driver" or int 13 interface takes a
> command, even identify device, which is PIO, and you build a bunch of
> tables in memory that tell the controller what the command is, where
> to get/put the data, etc, then you hit the "go" bit, and the controller
> takes care of the actual drive communication through DMA.

> The performance of AHCI comes through a parallel interface in these
> tables you can build. You can have 32 outstanding requests at the
> same time, each with their own scatter/gather tables and buffers in
> memory. You build the tables of the commands you want to issue,
> hit that go bit and sit back and wait for your data to be read or
> written to/from the drive. (I think you can do up to 32mb sized
> transfers, and have 32 of them at a time.)

COOL

> 3) my assumption would be that when using the INT13 interface, they
> probably don't open up 32 channels, as that becomes a big memory
> hog and could require memory access >1mb. My guess is that it's only
> 1 channel ever being used, and thus with 1 channel going, you'd end
> up with the exact same performance as issuing commands to a
> standard SATA port.

What performance do you get using INT $13 (IDECHECK) ?

So since it works well (just not very fastest) in DOS, the need for a
driver is not "that bad" (not as bad as for sound) for now

---
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Complete thread:

• AHCI projects? - DOSferatu, 14.12.2009, 20:30 (Developers)
  • AHCI CD-ROM driver for DOS - Rugxulo, 15.12.2009, 02:10
    • AHCI CD-ROM driver for DOS - RayeR, 16.12.2009, 01:37
      • AHCI CD-ROM driver for DOS - RayeR, 16.12.2009, 01:45
      • AHCI CD-ROM driver for DOS - DOS386, 18.12.2009, 02:09
        • AHCI CD-ROM driver for DOS - DOSferatu, 18.12.2009, 16:04
          • AHCI CD-ROM driver for DOS - DOS386, 19.12.2009, 04:08
            • AHCI CD-ROM driver for DOS - DOSferatu, 21.12.2009, 16:45
              • AHCI CD-ROM driver for DOS - DOS386, 22.12.2009, 17:11
        • AHCI CD-ROM driver for DOS - RayeR, 19.12.2009, 20:27
          • AHCI CD-ROM driver for DOS - DOS386, 20.12.2009, 08:05
  • AHCI projects? - Maybe Jack R. Ellis!! - swf, 16.12.2009, 01:05
  • AHCI projects? - Khusraw, 16.12.2009, 11:54
    • AHCI projects? - DOSferatu, 16.12.2009, 15:56
      • AHCI projects? - RayeR, 16.12.2009, 18:10
        • AHCI projects? - DOSferatu, 16.12.2009, 22:21
        • AHCI projects? - marcov, 17.12.2009, 10:25
          • AHCI projects? - RayeR, 19.12.2009, 20:37
            • AHCI projects? - marcov, 17.01.2010, 14:34
              • AHCI projects? - Laaca, 08.03.2010, 09:41
                • AHCI projects? - DOSferatu, 10.03.2010, 16:57
                  • AHCI projects? | Sound - DOS386, 17.03.2010, 05:53
                    • AHCI projects? | Sound - DOSferatu, 17.03.2010, 22:34
                      • AHCI projects? | Sound | Mail theft - DOS386, 18.03.2010, 09:36
      • AHCI projects? - Gabiz_ro, 27.03.2010, 22:45
        • AHCI projects? - DOSferatu, 31.03.2010, 15:59
          • AHCI projects? - Gabiz_ro, 01.04.2010, 19:00
      • AHCI projects? - Gabiz_ro, 07.04.2010, 22:58
      • AHCI projects? - kladno, 06.05.2010, 08:40
  • AHCI projects? - mcluskyism, 06.05.2023, 09:37
    • AHCI projects? - glennmcc, 07.05.2023, 21:04
      • AHCI projects? - mcluskyism, 08.05.2023, 17:28
    • AHCI projects? - mcluskyism, 13.05.2023, 13:27