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:
 tem****ary 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-****ts (01F0../0170..)]

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