The following  discussion  is  taken  from  Burton  L.  Alperson.
"Fully Powered  Windows:   Getting  the  Most  Out  of  Your  386
Computer."   (New York:   Brady  Books, 1991).  The text has been
reformatted for electronic distribution.  Footnotes are indicated
by angle brackets (< >).

I grant  permission for  electronic distribution of this material
as long as it is passed along without modification.

Burton L. Alperson

_______________________________________________________________

                         SHARE Problems

DOS 4.x  introduced the  ability to  use hard  disks greater than
32MB in  size.   In  order  to  handle  larger  disk  partitions,
Microsoft borrowed  some of  the functions  of a program normally
used for networks, SHARE.EXE.

When you  have a  partition larger  than 32MB,  DOS  4.x  expects
SHARE.EXE to be loaded.  If it cannot load this program, you will
see an  error message  at boot  time, indicating that the program
must be loaded for large media.

If you  are using DOS 4.x and you have a large partition, you may
be running  SHARE.EXE without  even knowing it.  DOS searches the
root directory  and installs  the program at boot time whether or
not you have given explicit instructions to load it.

This  strategy   produced  few  problems  until  Windows  3  came
along.<1>   Unless you  take special  steps,  you  can  run  into
unexpected conflicts  because of the interaction of SHARE.EXE and
Windows.   Two common  symptoms of  the problem are inappropriate
"Resource busy"  messages  on  networks  and  "Sharing  violation
. . ." messages on stand-alone machines.  At best, these messages
are accompanied  by a  program lock  up.   At worst,  your  whole
machine may freeze.  This is not a happy prospect.

One  solution  you  will  see  frequently  is  simply  to  remove
SHARE.EXE from  your root  directory and ignore the error message
you see  at boot time.  DO NOT FOLLOW THIS ADVICE!  SHARE.EXE is,
in fact,  required for  safe operation  of large  media under DOS
4.x.   Even though  your machine may appear to function normally,
YOU ARE  TAKING A  CHANCE ON CORRUPTING YOUR HARD DISK AND LOSING
ALL YOUR DATA!

There are two parameters you can set for SHARE.EXE, and once they
are set  properly, sharing  problems generally disappear.  If you
install SHARE.EXE  in your AUTOEXEC.BAT file as a TSR, the syntax
is

share [/f:space] [/l:locks]

If you install the program in your CONFIG.SYS file, the syntax is

install=share.exe [/f:space] [/l:locks]

It is  rarely necessary to adjust the /f:space parameter, and you
can usually  omit it.<2>   The /l:locks parameter is the critical
one.   "Each open file . . . requires at least one lock but could
have dozens.   Each  time an  application requests a portion of a
file (such as a record in a database) a lock on only that portion
of the file that contains the desired information is issued.  The
lock remains in effect until the application program specifically
removes it."<3>

The default  value for  /l:locks is 60.  This value is frequently
inadequate for  a stand-alone computer running Windows, and it is
definitely inadequate  for a  network.   If you  are encountering
sharing problems, try issuing the command

share /l:500

in your AUTOEXEC.BAT file or

install=share.exe /l:500

in  your  CONFIG.SYS  file.    If  you  still  encounter  sharing
problems, try changing locks to a higher value (say 1000).
_______________________________________________________________

FOOTNOTES

<1>The discussion of this problem is based on research by Richard
Fink and  reported on  BIX.  The solution to the problem is based
on research by Tom Filliman and reported on CompuServe.

<2>The /f:space  parameter specifies  the amount  of space  to be
reserved for the storage of filepath information.  Each open file
requires space  for the path + 11 bytes.  Microsoft estimates the
average path  length to be 20 characters.  Thus the default value
of 2048  bytes is  sufficient for  66 simultaneously open average
files (2048  / (20  + 11)).   If  your files= statement specifies
more than 66 files, or your average path length is longer than 20
characters, you  may wish to adjust the parameter.  For most, the
default value is more than adequate.

<3>From Tom  Filliman's research,  posted in the MSWIN library of
CompuServe as SHARE.TXT.