assembly question.

I Came across this script a few years ago when I had a problem with a hdd formatting. Its using the dos debug command. It worked that time and a few times with viruses. Now I'm being told it does'nt work. Even though I dont know how to explain it I know it works. Can anybody explain to me whats going on. Here is the script.

-F 200 L1000 0 (ENTER)
-A CS:100 (ENTER)
xxxx:0100 MOV AX,301 (ENTER)
xxxx:0103 MOV BX,200 (ENTER)
xxxx:0106 MOV CX,1 (ENTER)
xxxx:0109 MOV DX,80 (ENTER) <-- "80" for hd 0, "81" for hd 1 >
xxxx:010C INT 13 (ENTER)
xxxx:010E INT 20 (ENTER)
xxxx:0110 (ENTER) <---BLANK LINE - IMPORTANT! >
-G (ENTER)
Program terminated normally
-(CTRL)-(ALT)-(DEL)

Of course this is ran after booting to a dos or startup disc. I know it deletes all partions causer after I run it when I go to format it says there is no partions. Any help is appreciated.

I believe I got it broke down:

-f 200 L1000 0-calling for 512 mb of 0's to be written at off set 200

-a cs 100- start assembly

mov ax,301- Is calling on bio to write sector and calling for 1 sector to be written.

mov bx,200- points to where to be written

mov cx, 1-tells which cly and sector

mov dx,80-which drive

int 13- calls bios disc fuctions read/write

int 20- I'm not real sure right here I believe int 13 is getting turned back over to debug

this blank line ends the code

go,run, commands to do it.

I wouldn't mess with that-use DBAN instead. That will well and truly remove any and all partitions on a disk in a secure fashion.

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