home *** CD-ROM | disk | FTP | other *** search
- 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.
-