

                                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  SUPERCEDED BY:  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.