How to read FAT Table in Assembly Language [closed]

Question

NC - Norton Commander I should write a program like NC. I need to access Fat Table in Assembly to show files and directories in my program. Does anybody know how I can access Fat in assembly( both floppy and Hard Disk ) What Interrupts should I use?

Thanks in advance.

Answer 1

Probably the FAT is protected by the OS for security reasons, so I guess you can't read/write it. You can still use the interrupt #21h (3D - open, 3E - close, 3F - read, 40 - write, 42 - seek, 4E - find first file, 4F - find next file) or the interrupt #13h.

• Int 13h is for low level disk services, so you can directly read or write any (I think) hard disk's (and floppy's) sector you want (functions 2 and 3).

• Int 21h allows you more high level file operations (some of which are listed above). Find first file and first next file find files that match a certain search pattern (just like windows's find, so you can list all files whose name is "ab?c.e?d"). I'm not sure if these functions list the directories too, you should check