Document 1502
I.T.T. Extra 286


Description:

Several users have reported that DR DOS memory management
features do not work properly on I.T.T. Extra 286 machines.
These machines are no longer in production.

On investigation, it appears that the A20 line which controls
HMA access was not properly implemented at the hardware level on
these machines. Therefore, DR DOS 6's HIDOS.SYS cannot use the
HMA for memory management. Since there is no LIM memory
capability on this computer, DR DOS utilizes this machine as a
640K 286 computer.