umb.doc

DriverStudio V2.70

UMB.DOC
Using UMB.SYS to Activate DOS Upper Memory Blocks

Microsoft with MS-DOS 5.0 and its associated HIMEM.SYS has defined a standard
mechanism for loading T&SRs and	loadable drivers into the free memory
address	space between 640K and 1 Megabyte.  These free memory areas
are called UMBs	(Upper Memory Blocks).

UMB.SYS	supports the standard UMB protocol as defined in the Microsoft
XMS specification.  This is useful if you are debugging	a program that
uses UMBs or if	you wish to use	other load high	utilities than the ones
supplied by Nu-Mega Technologies, Inc.	(DOS 5 LH and DEVICEHIGH for example.)

To activate these UMBs with a NU-MEGA driver (S-ICE.EXE, BC.SYS	or
NU-MEGA.SYS) you must use an additional	driver named UMB.SYS. This
driver has no parameters and must be placed after HIMEM.SYS in your
CONFIG.SYS file.  The following	example	using Soft-ICE as the driver
shows the order	that the EMM driver, HIMEM.SYS and UMB.SYS must	be placed
in your	CONFIG.SYS:

	DEVICE = S-ICE.EXE
	DEVICE = HIMEM.SYS /M:1
	DEVICE = UMB.SYS

Notes:	1. The order is	critical.
	2. The /M:1 parameter should be	used with DOS 5.

Defining UMBs

Before using UMB.SYS you must direct the Nu-Mega EMM driver to place memory 
in the holes between 640K and 1	megabyte.  For S-ICE.EXE and NUMEGA.SYS	you 
must first run EMMSETUP.EXE (use the syntax EMMSETUP S-ICE.EXE or EMMSETUP 
NUMEGA.SYS to be sure the correct memory manager is changed). For BC.SYS 
you must run BCSETUP.EXE.  In each case	you must choose	to have	high memory 
support	and you	must make sure that there are one or more H's in the memory 
page map.  See the manual for the specific product in question for details.

Using UMB.SYS with DOS 5

If you are using MS-DOS	5.X then UMB.SYS allows	you to load device
drivers	and T&SRs high using the DOS built-in commands;	LH & DEVICEHIGH.
You should put the command:
	dos = high;umb
as the first line in your CONFIG.SYS. See the DOS 5 documentation for details.