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	    ͻ
	                                                       
	                                                       
	                     GOLDEN BOW SYSTEMS                
	                                                       
	                                                       
	                        Vcache 6.00                    
	                                                       
	                                                       
	    ͼ


    This file provides important information which supplements and
    replaces information provided in the Vcache User's Guide:

	Topic                               Page
	New Features . . . . . . . . . . . .   3
	Cache Start-up Options . . . . . . .   4
	Cache Control Options  . . . . . . .   5
	Sharing Cache Memory . . . . . . . .   6
	Buffered and Delayed Writes  . . . .   7
	Loading "high" . . . . . . . . . . .  10
	Windows Operation  . . . . . . . . .  12
	Dos Network Operation  . . . . . . .  13
	Disk Compression . . . . . . . . . .  14
	Batch file control . . . . . . . . .  15
	XMS Managers . . . . . . . . . . . .  16
	DOS Buffers  . . . . . . . . . . . .  16
	Double Buffering . . . . . . . . . .  17
	Applications Interface . . . . . . .  18
	Resident Memory Requirements . . . .  19
	Disktest Program . . . . . . . . . .  20
	Questions, Problems, Solutions . . .  21
	Technical Support  . . . . . . . . .  26



                             NEW FEATURES


    This release of Vcache provides a number of enhancements which
    may not be fully documented in your User's Guide.  The following
    screens provide supplementary information.

    Major enhancements in this release include:

	From 1.5 to 3 times faster than version 5.
	Control table memory overhead reduced by 75%.
	Buffered write mode with optional diskette caching.
	Optional double buffering for non-standard SCSI drives.
	Optional lookAhead buffer placement in low or high memory.

	Load high facility to use upper memory.
	Optional minimum cache size for WINDOWS, etc.
	New control options added for dynamic cache control.
	Optional application interface for advanced cache control
	Full delayed write compatibility forh WINDOWS and DOS networks.

                        CACHE START-UP OPTIONS

    CACHE-AT [nnnn [aaaa]] [/options]      (Extended memory cache)
    CACHE-EM [nnnn] [/options]             (EMS memory cache)
    CACHE [nnnn] [/options]                (Standard memory cache)

    nnnn  maximum cache size.
    aaaa  optional cache address for cache-at.
    low   locate program in low memory.
    d     cache drive "d", where "d" is a DOS drive letter (A - N).
    d*    do not cache drive "d".
    d-    set drive "d" to write-through.
    B=nn  lookAhead buffer size = 4 to 16 kb (default is 16 kb).
    B=E	  lookAhead buffer location = EMS memory (cache-em only).
    B=L	  lookAhead buffer location = low memory (below 640 kb).
    B=H   lookAhead buffer location = high memory (above 640 kb).
    O     locate control tables in HMA or EMS.
    R     suppress enhanced a20 mode (cache-at).
    T=n   set write delay range = 0 to 5 seconds.
    W=nn  set delayed write data limit = 0 to 8192 kb.
    W-    set all drives to write-through.
    X+    do memory diagnostic.
    Z=nn  minimum cache size (cache-at and cache-em).
    ?     display cache command line help.


                        CACHE CONTROL OPTIONS

    These options are effective when a cache command line is executed
    with Vcache already loaded.

    ?     display cache command line help.
    -     flush and disable the cache.
    +     flush and enable the cache.
    d-    set drive "d" to write-through.
    d+    re-enable drive "d" write delay.
    d--   flush and disable drive "d" caching.
    d++   flush and re-enable drive "d" caching.
    Q     quit the cache.
    S     display cache status.
    T=n   set write delay range = 0 to 5 seconds.
    U     quits the cache (same as /q).
    W-    set all drives to write-through.
    W+    re-enable write delay.
    Z-    minimize cache size
    Z+    maximize cache size



                         SHARING CACHE MEMORY

    The /Z= start-up option may be used to specify a minimum cache size
    for cache-at and cache-em.  If you do not enter a minimum size, a
    default minimum cache size will be used as follows:

	Cache size        Minimum
	---------------   -------
	up to 384 kb         0 kb
	up to 512 kb        16 kb
	up to 1 mb          64 kb
	up to 2 mb         512 kb
	up to 4 mb        1024 kb
	up to 6 mb        1536 kb
	6 mb or more      2048 kb

    The /Z- cache control option may be used after the cache is loaded
    to free cache memory for use by other programs.  The /Z+ option
    may be used to restore the cache to full size when not needed by
    another program.



                        BUFFERED AND DELAYED WRITES

    Delayed writes are fully compatible with Windows, Windows enhanced
    mode, DESQview/X, and with mult-tasking and DOS network operation.

    Fixed disk drives normally use delayed writes.  Delayed write data is
    held in the cache for up to several seconds before being written, so
    that duplicate writes (re-writing the same sectors) can be eliminated,
    and to allow Vcache to combine multiple write operations into larger
    single writes for faster operation and less disk activity.

    Diskette drives normally run in buffered write mode.  Buffered writes
    use the lookAhead buffer to combine two or more successive diskette
    writes into a single write, eliminating many duplicate writes and
    increasing write speed substantially in most cases.

    Diskette drives (using buffered write) are temporarily switched to
    write-through mode while Windows is active.



    /W- and /W+ options - The /W- cache control option may be used to
    temporarily switch both buffered and delayed write drives to write-
    through mode.  Buffered and delayed write operation can be restored
    with the /W+ command option.

    /d- and /d+ options - The /d- cache control option may be used to
    temporarily switch drive "d" to write-through mode.  Normal drive
    operation can be restored with the /d+ option.

    /T=n option - This option sets the write delay time.  The value can
    be set from 0 (write-through) to 5 seconds.  For best results, use
    the default value of 5 seconds.  The /T= option may be used both in
    the cache start-up command and in subsequent cache control commands.

    /W=nn (size) option -  This start-up option may be used to limit the
    amount of write data that can be held in the cache as delayed writes.
    For example, /W=2048 would limit the quantity of delayed write data
    to a maximum of 2048 kb.  If you do not set this option, Vcache may
    use the entire cache area for write data as needed.


    If a disk error occurs performing a buffered or delayed write, the
    following message is displayed in the center of the screen:

                       ------------------------
                       Error writing drive d:
                       Retry (R) or Ignore (I)?
                       ------------------------

    Press 'R' to retry the disk operation, or 'I' to ignore the error.



    If you reboot your computer while delayed writes are pending, the
    following message is displayed in the center of the screen:

                       --------------------
                       Shutting-down System
                       --------------------

    This message will remain on the screen until all pending delayed
    writes are completed.  When all data is written to the disk, the
    reboot sequence will be resumed.



                             LOADING "HIGH"

    If Vcache is loaded as a TSR (not as a device driver), Vcache will
    attempt to move the program code into an upper memory block (above
    640 kb) if available.  You can force the program code into low memory
    with the /low command line option.

    If you are using MS DOS or PC DOS, you may also select loading the
    LookAhead buffer in low memory or high memory (above 640 kb) with
    the /B=L or /B=H option, regardless of the cache location.

    If you are using DR DOS and choose to load the cache in high memory
    with "hiLoad" or "hiInstall", Vcache will locate the LookAhead buf-
    fer in low memory unless you use the /B=H specification.  Tests with
    DR DOS version 6.0 exhibit marked degradation in speed when the Look-
    Ahead buffer is in high memory.

    If you load Vcache as a device driver (device=), the /low, /B=L and
    /B=H options are ignored.



   If you are using DOS 5 or above and wish to load Vcache from the
   config.sys file, (rather than the autoexec.bat file), we recommend
   that you use the "install" command in preference to the "device="
   command.

   If you use the "install" command to load Vcache as a TSR from the
   config.sys file, the screen may display a spurious error generated
   by DOS, "Error in line xxxx", where xxxx is the line number of the
   install statement.  This is a normal result when Vcache loads "high"
   from within the install command.



                           WINDOWS OPERATION

    Replacing Windows' Smartdrv with Vcache will improve your system's
    performance.  Do not use both Vcache and Smartdrv!

    We recommend that you use CACHE-AT with Windows.  CACHE-AT cache
    size is AUTOMATICALLY reduced to the minimum (see Sharing Cache
    Memory, above) when windows is started, and restored to the maximum
    size when windows terminates.

    When using CACHE-EM, cache size is uneffected by Windows use, but
    your disk drives will be temporarily switched to write-through mode
    while Windows is active if any other programs are using EMS memory.

    Buffered write drives are ALWAYS temporarily switched to write-
    through mode when Windows is active.

    The /Z- and /Z+ options are ignored while Windows is active.



                         DOS NETWORK OPERATION

    Vcache is fully compatible with DOS network use, provided that
    Vcache is loaded before starting the DOS network.

    You may load Vcache on a workstation to cache local drives.
    Non-local drives will not be cached.

    You may load Vcache on a server to cache server drives.  Non-
    server drives will not be cached.

    Load Vcache BEFORE starting your DOS network.  No other special
    considerations are required for network use.



                           DISK COMPRESSION

    Vcache has been tested with the following disk compression products:

    DoubleDisk - load Vcache BEFORE loading DoubleDisk.

    Stacker - load Vcache AFTER loading Stacker.

    SuperStor - load Vcache BEFORE starting SuperStor.  If you load Vcache
    after SuperStor, do not attempt to force caching of compressed volumes.
    Vcache will normally exclude  SuperStor compressed volumes.  You may
    lose data if you force caching of a SuperStor compressed volume.



                          BATCH FILE CONTROL

    If you wish start, stop, or control Vcache from a batch file, you
    may wish to take different actions depending on whether Vcache is
    loaded or not.  This may be done using the Vcache status option
    followed by the "if errorlevel" command.  The following sample
    batch file statements test cache-at status:

        cache-at /s
	if errorlevel 1 goto noVc
	. . . (the statements you wish to execute if Vcache is loaded)
	goto end
	:noVC
	. . . (the statements you wish to execute if Vcache is NOT loaded)
	:end



                              XMS MANAGERS

    If your system has extended memory, we recommend that you install an
    Extended Memory (XMS) Manager such as DOS HIMEM.SYS, DR DOS MEMMAX,
    386MAX, QEMM, etc.  Use of an XMS manager allows different programs
    to share extended memory without conflict.

    If you do not use an XMS manager, you may have memory use conflicts.
    If no XMS manager is found and if no cache location is specified,
    CACHE-AT will attempt to allocate extended memory top-down from the
    highest address (same as v5.06's /S option).  The cache will be
    allocated bottom-up if either the /O option is selected, or if you
    have 8 megabytes or more of extended memory installed.



                             DOS BUFFERS

    Vcache's lookAhead facility greatly reduces the need for DOS buffers.
    Your CONFIG.SYS file should set BUFFERS=10 or less for best performance.
    The Vcache INSTALL program will make this change for you if needed.


                           DOUBLE BUFFERING

    Some SCSI disk systems do not operate normally in advanced cpu
    configurations, and may display the following symptoms:

      1) System "hangs" when programs are loaded "high", or
      2) Read or write fault errors running Windows, or
      3) Windows fails when a permanent swap file is enabled.

    Any of these symptoms may indicate a need for double buffering of
    disk transfers.  To enable double buffering, insert the line below
    into your CONFIG.SYS file at or near the beginning of thes file,
    BEFORE any lines which enable a memory, network, or task manager:

       DEVICE=[path]DBLBUF.SYS    where [path] is the disk path to
                                  the Vcache install directory

    DBLBUF.SYS must be loaded "low", do NOT use a DEVICEHI= statement.
    You must have an 80286 or above CPU to need or use double buffering.
    For best performance with double buffering enabled, use the cache
    start-up option /B=L (low), to place the cache lookAhead buffer in
    low memory (see Cache Options).

                       APPLICATIONS INTERFACE

    INTERRUPT 2Fh - Function 4Ah, Subfunction 10h

    Registers at call:                             Return registers:
    AX = 4A10h
    BX = request code:
      00h  install check                           AX = 6756h
      01h  complete delayed writes                 none
      02h  flush cache                             none
      03h  do cache function:
           BP = drive number (-1 means all drives)
           DX = command code:
             00h  return status                    AX = BABEh, DL = status*
             01h  enable caching                   AX = BABEh, DL = status*
             02h  disable caching                  AX = BABEh, DL = status*
             03h  re-enable write delay            AX = BABEh, DL = status*
             04h  set to write-through             AX = BABEh, DL = status*
                                                   *status return bits:
                                                     bit 7 on if not cached
                                                     bit 6 on if write-through
                                                     bits 5-0 = driver unit #
             05h  minimize cache		   none
             06h  maximize cache		   none


                       RESIDENT MEMORY REQUIREMENTS


    Resident memory requirments for Vcache are as follows:

      Vcache program:    10 kb

      LookAhead buffer:   4 to 16 kb (/B=size option)

      Control tables:     1 kb plus 3 kb per megabyte of cache

      Double buffering:   2 kb (only if dblbuf.sys is loaded)


    The /low, /B=L, /B=H, /B=E, and /O options affect the placement and
    utilization of resident memory.



                           DISKTEST PROGRAM


    The disktest program included with Vcache simulates the action
    of a typical program creating and accessing a small database.
    Disktest creates a temporary database file on your disk which
    is accessed to obtain example timings.  The temporary file is
    deleted on completion.

    Elapsed times are reported for:

	  Writing (creating) the temporary database file
	  Reading the file sequentially from 1st record to last
	  Reading records randomly from the database
	  Writing records randomly to the database
	  Updating (reading and writing) records randomly

    This program may be executed to compare system performance with
    and without a cache, or to check your system performance with
    different cache versions or cache parameters.



	             QUESTIONS, PROBLEMS, SOLUTIONS


    Problem:  Which cache version should I use?

    Solution: If you have extended memory installed, CACHE-AT is normally
              the best choice.  If you are using EMM386 or a similar pro-
              gram to convert extended memory to EMS memory, modify the
              EMM386 line to allow sufficient extended memory for cache-at.

              If you do not have extended memory but do have EMS memory,
              use CACHE-EM.  If you have neither extended nor EMS memory,
              you must use CACHE.

                               *  *  *

    Problem:  Vcache ignores the /LOW, /B=L, or /B=H options.

    Solution: These options are ignored if Vcache is loaded as a device
              driver.  Replace the device= command in your config.sys
              file with an "install" command.



    Problem:  I cannot load into high memory (above 640 kb).

    Solution: You must have both am XMS manager (such as HIMEM.SYS)
              and a VCPI manager (such as DOS EMM386) to utilize
              upper memory blocks.  See your DOS manual for details.

                               *  *  *

    Problem:  I am having difficulty with correct placement of the
              Vcache start-up command in my config.sys file.

    Solution: Vcache must be started AFTER loading any XMS manager or
              memory conversion programs (e.g. EMM386), but BEFORE any
              network or multi-tasking programs.

              Remember that MS and PC-DOS process the device= programs
              before processing the install= programs, regardless of
              their order in the config.sys file.

                               *  *  *



    Problem:  When loading Vcache as a TSR from the config.sys file,
              the message "Error in line xxxx" appears (where xxxx is
              the line number of the Vcache install statement).

    Solution: This happens when Vcache loads "high" from an install command.
              The spurious error may be ignored.

                               *  *  *

    Problem:  My drive always starts up in write-through mode.

    Solution: Drives with non-standard formats are automatically set to
              write-through mode.

                               *  *  *

    Problem:  I am using DR DOS and loading the LookAhead buffer
              high with the /B=H option.  Disk access is slow.

    Solution: Do not load the LookAhead buffer high with DR DOS.



    Problem:  Sometimes I lose data if I turn off my computer
              immediately after running an application.

    Solution: (1) Wait for the disk access light to turn off before
              turning system power off.

    Solution: (2) Flush or quit the cache before turning power off.

                               *  *  *

    Problem:  CPU halts or "Packed file is corrupt" messages.

    Solution: (1) Run the offending program with DOS 5 LOADFIX
              (see your DOS manual for details).

    Solution: (2) Use the /B=L option to load the buffer "low".

    Solution: (3) Install DBLBUF.SYS to provide double buffering if
              you have an older SCSI disk controller.



    Problem:  CACHE-AT conflicts with other users of extended memory.

    Solution: (1) Install an XMS manager such as DOS HIMEM.SYS
              to resolve conflicts.

    Solution: (2) Specify cache location to avoid conflicts.

                               *  *  *

    Problem:  CACHE-AT CPU halts.

    Solution: Disable Vcache enhanced a20 mode (/R option).




	                   TECHNICAL SUPPORT


	 If you have any questions about using or installing Vcache,
	 please call our technical support line:


	          (619) 298-9349  8:00 AM - 5:00 PM (PST)
	                          Monday through Friday


	 If you do call, be prepared to provide us with the name and
	 serial number of the Golden Bow product (from the label of
	 your master diskette), and the particular computer and name
	 and version number of your operating system.

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      The programs on this diskette are NOT copy protected.  We expect
      they will normally be installed on your hard disk, and this disk-
      ette retained for backup.  This product is licensed for use on a
      single (1) computer and should not be copied for use by others.






	                    GOLDEN BOW SYSTEMS
	               842 Washington Street, Ste B
	                    San Diego, CA 92103
	                      (619) 298-9349
