Int 21h Function 440Dh Minor Code 41h (FAT32)
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what is this and how can i use it Int 21h Function 440Dh Minor Code 41h (FAT32) Writes data from a buffer to a track on the specified device. mov bx, Drive ;See below mov ch, DeviceCat ;See below mov cl, 41h ;Write Track on Logical Drive mov dx, seg WriteBlock ;See below mov ds, dx mov dx, offset WriteBlock ;ds:dx points to RWBLOCK structure mov ax, 440Dh ;IOCTL for block device int 21h jc error_handler ;carry set means error
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what is this and how can i use it Int 21h Function 440Dh Minor Code 41h (FAT32) Writes data from a buffer to a track on the specified device. mov bx, Drive ;See below mov ch, DeviceCat ;See below mov cl, 41h ;Write Track on Logical Drive mov dx, seg WriteBlock ;See below mov ds, dx mov dx, offset WriteBlock ;ds:dx points to RWBLOCK structure mov ax, 440Dh ;IOCTL for block device int 21h jc error_handler ;carry set means error
while programming dos, we have to program interrupts. These interrupts are like 10h, 13h, 21h etc, each made for a pre-specified purpose. 21h is called a DOS interrupt. This is a general-purpose interrupt. I guess I can't tell you the whole thing here or perhaps you will not be able to catch up with these things. You need to learn a little bit of System Programming in DOS and Assembly to exactly grab these. Well, any way, I should continue. Every interrupt is/can be called with a major and minor code. This is like passing arguments to a function. And every major and minor code is for something specific. In this case, I guess major code of 440DH is telling DOS to communicate with the Disk and Minor Code must also be something specific. Now, you will have to check yourself what these codes do and how are these being handled in the next assembly statements. Think Negatively, It makes you creative :confused: