Re: int 0x13 utility


JJ "João Jerónimo" asked:

Wolfgang Kern wrote:
But if you write your own HD-driver, the physical CHS-limit is:
16 heads, 255 sectors, 65536 tracks(cylinders), and this gives
us 267386880 sectors (= 127.5 GB).
So if the the hardware can handle it then it works almost like LBA28
(max= 128 GB), ...except for the unconvenient calculation needs.

But is this a DOS or a BIOS level driver?

You will encounter I/O-permission issues if you try this on windoze
or in a winDOS-box. My first disk-editor ran on DOS 3.0, and had its
own HD-routines, so bypassing all limits from DOS and BIOS int13.

All it did:
temporary replace HD-IRQ vectors (just to not confuse DOS)
fill the HDC-registers as desired (incl. command-byte as the last)
wait for acknowledge
read or write sector(s)
[find all required details in RBIL-ports (01F0../0170..)]

I kept this very rare now used CHS functions in my PM32 Os, just for
the opportunity to read from old drives when they become replaced.
__
wolfgang


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Relevant Pages

  • Re: int 0x13 utility
    ... 16 heads, 255 sectors, 65536 tracks, and this gives ... So if the the hardware can handle it then it works almost like LBA28 ... But is this a DOS or a BIOS level driver? ...
    (comp.lang.asm.x86)
  • Re: int 0x13 utility
    ... Wolfgang Kern wrote: ... 16 heads, 255 sectors, 65536 tracks, and this gives ... So if the the hardware can handle it then it works almost like LBA28 ...
    (comp.lang.asm.x86)
  • Re: Fedora Core 5 + WinXP Pro
    ... At the spindle you have the lowest sectors per ... rim of the hard drive; which is where the boot sector is too btw. ... for the heads to get to the right bit of the disk. ...
    (Fedora)
  • Re: C/H/S from user space
    ... ULONG SectorsPerTrack) ... ULONG offset, cylinders, head, sector; ... More than 8 heads ... Sectors = 1 ...
    (Linux-Kernel)
  • Re: Fedora Core 5 + WinXP Pro
    ... At the spindle you have the lowest sectors per ... rim of the hard drive; which is where the boot sector is too btw. ... for the heads to get to the right bit of the disk. ...
    (Fedora)