GENWiki

                              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SUPERCEDED BY:  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.