[<<Previous Entry]
[^^Up^^]
[Next Entry>>]
[Menu]
[About The Guide]
INT 26h (38) Absolute Disk Write
Writes one or more sectors on a specified logical disk.
On entry: AL Drive number (0=A, 1=B)
CX Number of sectors to write
DX Starting sector number
DS:DX Address of sectors to write
Returns: AX Error code (if CF is set; see below)
Flags DOS leaves the flags on the stack
For DOS 4.+ >32MB disk access:
On entry: AL Drive number (0=A, 1=B,...)
CX 0FFFFH . indicates extended format
DS:BX Address of Control Packet (see below)
Control Packet:
DD SECTOR ;Logical sector number (0 origin)
DW COUNT ;Number of sectors to write
DD BUFFER ;DS:Offset of data buffer
Returns: AX Error code (if CF is set; see INT 25h)
Flags DOS leaves the flags on the stack
--------------------------------------------------------------------------
This interrupt reads one or more sectors from a disk drive, and is
comparable to the service provided by the ROM BIOS in Interrupt 13h.
See the descrition on INT 25h for the full details.
For extended disks under DOS 4+, you pass the address of a Control
Packet in DS:BX. This extended support is offered because DOS 4+ can
support disks with media larger than 32MB.
The control packet is made up of the following fields:
Control Packet:
DD SECTOR ;Logical sector number (0 origin)
DW COUNT ;Number of sectors to write
DD BUFFER ;DS:Offset of data buffer
You pass a doubleword logical sector number, followed by a one-word count
of sectors to write, and then the doubleword address of the data buffer.
If you use conventional parameters and try to access media greater than
32MB, the error returned in AX is 0207H.
Before you use INTs 25h or 26h, DOS 4+ must know how a disk or diskette
is formatted. With hard disks, this is not a problem, but if you are
using a diskette, you should call INT 21h, function 47h (Get Current
Directory) before using INTs 25h or 26h.
See Also:
INT 25h
INT 13h, 03h
This page created by ng2html v1.05, the Norton guide to HTML conversion utility.
Written by Dave Pearson