How do you control individual pins on a PC's printer port in Java

Question

I know in pascal but cant find out for Java. See below
//// pascal controlling pins in parallel port. Basically 889 is address of the parallel
//// port allowing all pins switch on for '128' or all off '0'
uses CRT;
{ The CRT unit allows the use of "clrscr" and "gotoXY..." and "KeyPressed" }
const
PortAddress = 889; {957 on other machines}
var
InValue : integer;
begin
clrscr; { Clears the screen. }
port[PortAddress-1] := 0; { Turns off any LEDS still on a parallel port circuit }
repeat
InValue := port[PortAddress]; { This is the KEY      line of the program. }
gotoXY(35,12);
write(InValue:4); { The ":4" is used to format the output. }
until KeyPressed;
clrscr;
end.
Someone told me it was not possible because Java is machine independant, thus does not specify direct access of specific ports (because all machines are different)
If anyone knows I would really appreciate some help
Cheers Adrian

Answer 1

Certainly, as far as NT/2000 is concerned, you can't write to any hardware ports form any program running in a user context(except legacy 16 bit applications, whose I/O is virtualised -that will be how your Pascal prgram works, I suspect).
To access the ports, you need a device driver. (written in 'C', I'm afraid.
I have a sample driver for you to modify (it was designed to allow JTAG programming using the prallel port, wher individual pin control is required.
The driver is opened using standard file open protocols, and the I/O is done using DevI/OCtl calls. I think these are accessible from JAVA, but you might need a thin 'C' layer in a DLL.
Hope this helps. I can't think of a simpler way. NT/200 was designed to stop user programs from directly accessing hardware, because of the damage it can do.