asked on

computer's BIOS date

how can i retrieve the computer's BIOS date with Delphi Pascal (16 bits version)?

I tried memory location Mem[$FFFF:$0005] but this gives a general protection error.

I made a DOS-program in Turbo Pascal 4.0 about 6 year's ago which retrieves 8 bytes starting at memory location $FFFF:$0005. This 8 bytes contain the BIOS date of the computer. The program worked well with the three generations of computers i owned (286, 486 Pentium 166).

But in Delphi i get a general protection failure at run time in the line marked with {*} in the function below.

function
BiosDate: string;
var
Offset: Word;
begin
Result := '';
for Offset := $0005 to $000C do
Result := Result + Char(Byte(Ptr($FFFF, Offset)^)); {*}
end;

peter_vc

I think I have an easy solution, but I need to know if $FFFF:$0005 is really the correct location. The Undocumented PC and Undocumented DOS don't seem to have that info.

ASKER

Edited text of question

ASKER

i expanded my question about biosdate with some more info.

ASKER CERTIFIED SOLUTION

peter_vc

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

ASKER

Thanks for your answer. You're a real expert.
I added your source to my project and it worked!

I have just one question: what is the meaning of the assembler line in your source (asm MOV sel,DS end;)? I tried to run without this line and this gave also the same result.

bye, robbert-jan

peter_vc

It stores the data segment register into the variable sel. It just ensures that its using the proper parameters to allocate the selector. You should leave it in.

As you are testing it, put a call to it in a loop a few thousand times and let me know what happens. I'm wondering if a call to FreeSelector is needed. I think you'll need to free it once your done with the pointer. I really should have done this, but ...

Credit for this actually goes to Andrew Shulman, author of Undocumented Windows and many other titles.

ASKER

Hi,
I rewrited your code according to my programming standards. (see below). I tested the code with and without the FreeSelector command, calling the routine 30000 times. Without FreeSelector the program is crashing leaving Windows in an instable state. With the FreeSelector command there is no problem. So I think your advise on using FreeSelector is a right one.

I have rated your solution as excellent! I also had dropped my question in the Pascal topic area, sou you can get another 200 pionts by locking this question in that area.

If you have more comments, please contact me at RJM@XS4ALL.NL

(* begin of code *)

uses
WinProcs;

function
fBiosDate: string;
{this routine returns the BIOS-date of the computer}
var
Selector: Word;
CharacterIndex: Integer;
begin
Result := '';

asm {this assembler code ensures a proper allocation of the Selector}
MOV Selector, DS;
end;

Selector := AllocSelector(Selector);
try
SetSelectorBase(Selector, 16*$FFFF + $0005);
SetSelectorLimit(Selector, 8 - 1);

for CharacterIndex := 0 to 7 do
Result := Result + Chr(Byte(Ptr(Selector, CharacterIndex)^));
finally
FreeSelector(Selector);
end;
end;

(* end of code *)