					1megXT

	If you are upgrading a 256-640k motherboard or if you have already upgraded to 640k on a 64-256 motherboard, skip to next paragraph.  For stock 64 to 256k motherboard, install a Multiplexer chip (74LS158) in empty U84 socket.  Replace all 4 banks of ram with 256k DRAM.  Find the empty solder pads at E2 (right edge of board near power connector) and connect pads 1 and 2.  The preferred method is to use a four pin header and a shunt.  Or just solder a wire across. 
 
	For a 256-640k motherboard, you'll need to desolder the PROM at U44 and install a socket.  Save the old PROM so that you can return to stock configuration.  

	For both types of motherboards, install the GAL with adapter in the U44 socket with the notch toward the rear of the motherboard so that pin 1 on the GAL lines up with pin 1 of the U44 socket.  Four of the pins at the other end of the adapter have been shortened and will hang over beyond the socket toward the front of the motherboard.  Make sure all of the remaining pins engage the socket.  
	Set motherboard switches 3 and 4 off for 640k of base memory and 128k of upper memory at segments D and E (make sure no other devices have thier roms using these segments).  There are other configuations availlable and those can be found in the original 1megXT.txt document.  More upper memory may be available depending on other devices in the system.  I.E. Video card, HDD adapter etc.

	Copy USE!UMBS.SYS to C:\UMBDRIVR.  
	Copy DOSMAX.EXE to c:\UMBDRIVR
	Edit config.sys as follows (you'll need dos 5.0 or higher);

		device=c:\umbdrivr\use!umbs.sys D000-F000
		dos=high,umb
		devicehigh=c:\umbdriver\dosmax.exe /r+ /p-
		
	Dosmax will load DOS into UMB simular to loading dos high on a 286 or higher processor machine. The down side is it will leave less upper memory available for other drivers.  When you execute MEM/c/p you'll only see about 91k of upper memory instead of 128k.  That's because Dosmax stole some of that to load DOS high.  Devicehigh and Loadhigh your other drivers and tsr's and there you have it.  UMBs on an IBM XT without any aditional cards!!  And you'll see more of that preciuos 640k of base memory available for other stuff.