[comp.lang.apl] Incompatiblity with 386/486 computers

cmercer@helios.lerc.nasa.gov (Carolyn R. Mercer) (02/27/91)

I have been unable to run APL2 on certain 386/486 computers.  The explanation
that I've received from Compaq is as follows:
	
	APL2 reads port 0x92 to see if the mouse is supported.  If the value
read is other than 0x00 or 0xFF, it is assumed that port 0x92 can be used to
enable the A20 line.
	Compaq machines do not support port 0x92, yet they return a value 
other than expected when the port is read.

The result is a locked machine.  This problem also happens on HP's 486, but
not on Dell's.

My question:
Which other computers can not run APL2?  I want to buy a 486, and dont want
any problems.

Thanks,

Carolyn Mercer