Hard Disk handling using 32-bit system call in assembly language - windows

Question

friends, I need help regarding Harddisk handling using 32-bit system call. I am new to assembly language and I am using MASM assembler. I have tried some example codes but they are in 16-bit mode, and also i gives me error, while compling. I want to write in 32-bit. and i also read in a book that 32-bit is complicated, Is there any another procedure for 32-bit system call.
Example Code!
; This program calls INT 21h Function 7303h, to get free space information
; on a FAT-type drive volume. It displays both the volume size and free space.
; Runs under Windows 95/98/Me, but not under Windows NT/2000/XP.
; Last update: 12/11/01
INCLUDE Irvine16.inc
.data
buffer ExtGetDskFreSpcStruc <>
driveName BYTE "C:\",0
str1 BYTE "Volume size (KB): ",0
str2 BYTE "Free space (KB): ",0
str3 BYTE "Function call failed.",0dh,0ah,0
.code
main PROC
mov ax,#data
mov ds,ax
mov es,ax
mov buffer.Level,0 ; must be zero
mov di, OFFSET buffer ; ES:DI points to buffer
mov cx, SIZEOF buffer ; buffer size
mov dx, OFFSET DriveName ; ptr to drive name
mov ax, 7303h ; Get disk free space
int 21h
jc error ; Failed if CF = 1
mov dx,OFFSET str1 ; volume size
call WriteString
call CalcVolumeSize
call WriteDec
call Crlf
mov dx,OFFSET str2 ; free space
call WriteString
call CalcVolumeFree
call WriteDec
call Crlf
jmp quit
error:
mov dx,OFFSET str3
call WriteString
quit:
exit
main ENDP
;-------------------------------------------------------------------
CalcVolumeSize PROC
; Calculate and return the disk volume size, in kilobytes.
; Receives: buffer variable, a ExtGetDskFreSpcStruc structure
; Returns: EAX = volume size
; Remarks: (SectorsPerCluster * 512 * TotalClusters) / 1024
;--------------------------------------------------------------------
mov eax,buffer.SectorsPerCluster
shl eax,9 ; mult by 512
mul buffer.TotalClusters
mov ebx,1024
div ebx ; return kilobytes
ret
CalcVolumeSize ENDP
;-------------------------------------------------------------------
CalcVolumeFree PROC
; Calculate and return the number of available kilobytes on the
; given volume.
; Receives: buffer variable, a ExtGetDskFreSpcStruc structure
; Returns: EAX = available space, in kilobytes
; Remarks: (SectorsPerCluster * 512 * AvailableClusters) / 1024
;--------------------------------------------------------------------
mov eax,buffer.SectorsPerCluster
shl eax,9 ; mult by 512
mul buffer.AvailableClusters
mov ebx,1024
div ebx ; return kilobytes
ret
CalcVolumeFree ENDP
END main

Answer 1

Trying to assemble this program...
also i gives me error
Firstly, it cannot assemble because the struct ExtGetDskFreSpcStruc in the line
buffer ExtGetDskFreSpcStruc <>
is not defined before - not in this file and not in (the only) include file(s), in this case "Irvine16.inc", which doesn't contain the definition. Therefore all attempted accesses to "buffer.xxx" will throw errors.
Secondly, if you are trying to assemble this program for 32-bit, you are including a 16-bit include file in a 32-bit assembly file. You should use the 32-bit version "Irvine32.inc", because otherwise all indirect addressing like mov al, [si](16-bit) in the subroutines will fail.
Thirdly, you are calling DOS-legacy-interrupts, which are available only in Win95/98/Me, because their kernels are based on DOS. The newer NT kernel in Win2000 and above does not provide them, because it was a different OS architecture/codebase without/with reduced legacy code. The DOS-interrupt(21h) is 16-bit, because DOS was 16-bit. I don't know if there are implemented 32-bit versions of old DOS-interrupts in Win95/98/Me. A quick search yielded no indications of this having been realized. The BIOS interrupts used in "Irvine16.inc" are surely 16-bit and therefore unusable(without very complicated workarounds) in a 32-bit executable probably crashing the program.
Is there any another procedure for 32-bit system call[?]
Yes. Use the Win32-API, which is available in Win95 till Win8/10(?).
The easiest way to do this would be using the MASM-package by Hutch found at MOVSD.COM and then include kernel32.inc/lib from it. Then you can call the GetFreeDiskSpace function to get the desired result with a line similar to this:
invoke GetFreeDiskSpace,
offset driveName,
offset buffer.lpSectorsPerCluster, ; adjust to actual buffer layout names
offset buffer.lpBytesPerSector, ; "
offset buffer.lpNumberOfFreeClusters, ; "
offset buffer.lpTotalNumberOfClusters ; "