Monday, December 21, 2009

ENTERING DEBUG



Debug has been included in every version of MS-DOS as well as Windows. When running any of the debug routines it is recommended that if you have Windows that you exit or shut down to get into a real DOS prompt (unless you're running Windows ME, Windows 2000, Windows XP, or later versions).



Once at the MS- DOS prompt, run through the below example, this example is perfectly fine to run on any PC Computer running MS-DOS / Windows and will not harm anything.
Type debug and press enter.
This should get you to a - (small dash). This is the debug prompt.
At the - type d40:00 and press enter; this will return several lines of information.
After the feedback you will be back to the debug prompt.
To exit out of debug type q and press enter. This will return you back to the MS-DOS prompt.


In some of the below debug routines you will notice that a "g" is typed, then "q". G tells the computer that the code type is not self executing and must be run at this point. If completed, the program will return Program Terminated Normally which indicates you can now quit from the debug program. TESTING PORTS




The below debug routine will check the ports of the computer to allow you to know if ports are being detected or not. Type debug to get to the "-" Type D40:0
You should get several lines; however, the first line is the only important line, which should read the following:
0040:0000 F8 03 F8 02 E8 03 E8 02 - 78 03 78 02 BC 03
F8 03
F8 02
E8 03
E8 02

78 03
78 02
BC 03

COM1
COM2
COM3
COM4

LPT1
LPT2
LPT3


The above graph shows you what the feed back means as far as port, so if you see F8 03, this would be an indication that COM1 is being detected; if you see 00 00, this is an indication that it is not being detected, which could mean that hardware is bad or that it is disabled inCMOS
Once you have finished looking at the information, type Q and press enter to get out of Debug.
CLEAR CMOS




The below debug routine will clear CMOS, BIOS, Passwords, Settings, Viruses, and other items residing in the CMOS. During this process you may get returned characters which are an indication that the string has gone in, if you by chance get ERROR ensure that you have typed the line in correctly, if not retype. Ensure that you do not skip any lines, that it is ALL typed in correctly to help prevent problems. Before running this Debug routine also ensure that you have read the above disclaimer. After typing debug you will get "-" which is were you can begin by typing A and pressing enter. A
MOV AX,0
MOV AX,CX
OUT 70,AL
MOV AX,0
OUT 71,AL
INC CX
CMP CX,100
JB 103
INT 20
Note: Nothing is typed on this line
G By pressing G this will execute the above script, ensure you have read and agree to the above disclaimer.
Q Then reboot and you will get a Setup Checksum Error. Go into setup, correct all the incorrect values, time, date...

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