

                                STAC ELECTRONICS
                           TECHNICAL SUPPORT BULLETIN

  NUMBER:     005
  SUBJECT:    STACKER-MISC

  DATE:       May 24, 1991
  TIME:       2:57 PM

  SOURCE:         Engineering, User's Manual
  SUPERCEDES/
  SUPERCEDED BY:  
  RELEASE STATUS: Public

  TITLE:
      The STACKER device driver's memory requirements.

  OVERVIEW:
      The STACKER device driver is a resident program.  It loads from the
      CONFIG.SYS file at boot-time, mounts the compressed STACKER volumes, then
      shrinks down and remains in RAM until powered off.

      Starting sizes in bytes, without STACKER cache (/M=0)

                                  Coprocessor             Software
                                    Version               Version

      1st volume  (with 4KB clusters):21,504                30,720
                  (with 8KB clusters):25,600                38,912
                      add'l volumes:   3,072 each            3,072 each

      When STACKER loads at boot time, the size of the driver (both initial and
      resident) is displayed.

  ISSUES/COMMENTS:
      1) The amount of memory used by STACKER may prevent the launching of
      programs which ran properly before STACKER was installed.  "Insufficient
      memory" messages may result.

      2) When loading both the driver and the STACKER cache into high memory,
      there may not be a sufficiently large contiguous block of memory.  This
      may result in an error message from the memory manager and failure to
      load the driver high.

      3) In the coprocessor version, 9 Kbytes are allocated for internal
      buffers by default.

  RECOMMENDED ACTIONS:
      1) If the STACKER cache has been specified, try lowering the /M=xx switch
      in the "DEVICE=C:\STACKER\STACKER.COM..." line for a smaller cache (see
      User's Manual, "STACKER Utilites/Commands").  If errors persist even with
      the driver as small as possible, use a memory manager to load the STACKER
      driver (and cache, if present) into high memory.

      2) Lower the size of the STACKER cache, as in (1), until the driver fits
      into high memory.  Most memory managers include a utility for optimizing
      the organization of device drivers; optimizing high memory may allow the
      STACKER driver and cache to fit better.

      3) To free up the 9 Kbytes of internal buffers, insert an /M=0 switch to
      the STACKER device driver line in CONFIG.SYS, as in (1).