Re: OS/2 i dyski pod DOSem

Autor: Jan Stożek (jasio_at_nowhere.pl)
Data: Thu 06 May 1999 - 14:21:45 MET DST

On Thu, 6 May 1999 07:23:45, stachnie_at_alf.ifj.edu.pl (Sˆawomir
Stachniewicz) wrote:

> On Mon, 3 May 1999 03:33:39, "Tomasz Szczesniak"
> <tszczesn_at_elka.pw.edu.pl> wrote:
>
> > Wie ktoś może dlaczego w sesji DOSa korzystając z fukcji 2
> > przerwania 13h (odczyt fizycznych sektorów z dysku) w
> > odniesieniu
> > do dyskietki najpierw brzęknie stacja A, potem B, następnie
> > chwila
> > przerwy i dopiero jest odczytywany żądany sektor?
>
> Nie wiem, dawno się takimi rzeczami nie bawiłem. Może
> coś jest na ten temat w "Interrupt List" Ralpha Browna?

        Nie ma, chyba że nie wprost.

Notes: errors on a floppy may be due to the motor failing to spin up
quickly
          enough; the read should be retried at least three times,
resetting
          the disk with AH=00h between attempts
        most BIOSes support "multitrack" reads, where the value in AL
          exceeds the number of sectors remaining on the track, in
which
          case any additional sectors are read beginning at sector 1
on
          the following head in the same cylinder; the MSDOS
CONFIG.SYS command
          MULTITRACK (or the Novell DOS DEBLOCK=) can be used to force
DOS to
          split disk accesses which would wrap across a track boundary
into two
          separate calls
        the IBM AT BIOS and many other BIOSes use only the low four
bits of
          DH (head number) since the WD-1003 controller which is the
standard
          AT controller (and the controller that IDE emulates) only
supports
          16 heads
        AWARD AT BIOS and AMI 386sx BIOS have been extended to handle
more
          than 1024 cylinders by placing bits 10 and 11 of the
cylinder number
          into bits 6 and 7 of DH
        under Windows95, a volume must be locked (see INT
21/AX=440Dh/CX=084Bh)
          in order to perform direct accesses such as INT 13h reads
and writes
        all versions of MS-DOS (including v7 [Win95]) have a bug which
prevents
          booting on hard disks with 256 heads, so many modern BIOSes
provide
          mappings with at most 255 heads 

-- 
Pozdrawiam,
Jan.
PS. Mój adres: nowhere = Polbox.

To archiwum zostało wygenerowane przez hypermail 2.1.7 : Tue 18 May 2004 - 15:22:10 MET DST