STAC ELECTRONICS TECHNICAL SUPPORT BULLETIN NUMBER: 015 SUBJECT: DOS5.0 DATE: June 28, 1991 TIME: 7:24 AM SOURCE: Tech Support, MS DOS 5.0 Documentation SUPERCEDES/ SUPERCEDED BY: RELEASE STATUS: Public TITLE: Loading STACKER into upper memory ("loading high") with MS-DOS 5.0 OVERVIEW: MS-DOS 5.0 comes equipped with a memory manager which may be used to load device drivers into the upper memory area between 640K and 1MB. STACKER is one such driver. ISSUES/COMMENTS: 1) DEVICE=C:\DOS\HIMEM.SYS provides access to extended memory and ensures that no two programs use the same portion of it at the same time. 2) DOS=UMB tells DOS to maintain a link to the upper memory area; DOS=HIGH,UMB also loads the kernel of DOS into the high memory area (HMA). 3) DEVICE = C:\DOS\EMM386.EXE NOEMS causes extended memory to simulate expanded memory so that programs and device drivers may be loaded into the upper memory area. Specifying RAM instead of NOEMS will establish a 64K page frame for expanded memory, and the reduced number of upper memory blocks may be insufficient to allow the driver to be loaded high; in this case, a commercial memory manager (QEMM386, 386MAX) may be needed. If the STACKER coprocessor card is installed, it will also be necessary to exclude its address range (e.g., x=CC00-CFFF). 4) DEVICEHIGH=C:\STACKER\STACKER.COM... does the actual loading of the STACKER device driver into the upper memory area. If there is insufficient memory available, DOS will load the driver into conventional memory with no warning message. 5) The DOS command MEM/C lists the order and size in which drivers and programs have been loaded. RECOMMENDED ACTIONS: 1) Ensure that the statements are executed in CONFIG.SYS in proper order. (Note that they need not be consecutive, and the paths may differ from system to system): DEVICE=C:\DOS\HIMEM.SYS DOS=HIGH,UMB DEVICE=C:\DOS\EMM386.EXE (NOEMS or RAM) (X=exclude range if applicable) DEVICEHIGH=C:\STACKER\STACKER.COM... 2) If boot drive is SSWAPped, ensure that a copy of HIMEM.SYS and EMM386.EXE reside in the \DOS directory on the host volume; for instance, if C: and D: are SSWAPped, then a copy of the files must reside in D:\DOS.