Ref: 19880003
Title: Error "Insufficient Buffer Space (IDP)" Due to 3OPT Setting
Date: 5/18/90

Copyright 3Com Corporation, 1991.  All rights reserved.

When making changes that affect the total amount of memory used
by the services installed on a server, make sure that you leave
enough memory left over.  3OPT approximates the amount of "extra"
memory.  Once DOS and the 3+ services load, they may actually use
more memory than is shown in 3OPT.

For example, when another hard disk drive was added to the server,
more memory was required by CIOSYS.  3OPT showed 2 KB extra, but when the
server was booted, it hung loading 3+ Backup.  The LASTBOOT record showed
the error "Insufficient Buffer Space (IDP)."  To work around the problem,
3+ Start was disabled, leaving 14 KB extra as reported by 3OPT.  But after
the server booted successfully, the LCD reported only 10 KB left.  The 4 KB
difference is what was needed in 3OPT as extra memory.

Always leave at least 10-12 KB of extra memory available to account for
the difference between the approximation done by 3OPT and the memory
actually used by the services after loading.  If you find yourself having
to tune down parameters to get all of your services to load, consider
increasing the amount of memory in your server.  Or, if you already have
done that, consider adding another server to allow growth of your user
base, added services, and increased performance.
