sekoppenhoef@rose.waterloo.edu (Shawn E. Koppenhoefer) (10/13/89)
The following was a small part of a text file I pulled off of SIMTEL. Does anyone know anything about this? I have 512 in my machine but I am using an EMM card to bring me up to 640... can I use the info in the following text file (I *do* have the complete file but...) : WHAT IS HIGH MEMORY, WHY DO I CARE, AND HOW CAN I USE IT? : BY CY ATKINSON : The 8088 chip, the engine in the PC and XT, can address one meg in 16 : 64K segments numbered 0 thru F. IBM has designed the hardware of the PC : and XT to make the first 640K available to PCDOS and the user, and : reserved the upper 360K for various hardware functions such as ROS and : screen buffers, etc. This upper portion of the 1 meg address capability : is refered to as HIGH MEMORY, and it is available for the user in 64K : segments IF THE SPECIFIC HARDWARE WHICH USES THAT SEGMENT IS NOT : INSTALLED. : A COUPLE OF MONTHS AGO, A DISCUSSION WAS ENTERED IN AN INTERNAL IBM BBS : as to how storage addresses are decoded on the IBM PC XT motherboard. : The idea was advanced that it should be possible to replace all four : banks of 64K chips with 256K chips, plug in a "custom" prom at U44, and : depending on the system's hardware configuration, have up to 256K of : additional HIGH MEMORY available for ramdisk, print spooler, DOS : extensions, or whatever. : Well, it's been done. IT WORKS! IT'S EASY! IT INVOLVES NO SOLDERING : OR MODIFICATIONS TO THE MOTHERBOARD EXCEPT REPLACING SOCKETED CHIPS --- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| _ _ KLEIN BOTTLE for sale... Shawn E. Koppenhoefer | | enquire within. ...watmath!rose!sekoppenhoef | - ~~~~~~~~~~~~~~~~~sekoppenhoef@rose.uwaterloo.ca sekoppenhoef@rose.uwaterloo.edu