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From: tleylan@pegasus.com (Tom Leylan)
Newsgroups: comp.databases,comp.dcom.lans
Subject: Re: Convert Clipper app to network, other network questions
Message-ID: <1991Jan29.064906.26316@pegasus.com>
Date: 29 Jan 91 06:49:06 GMT
References: <1991Jan28.005022.9930@csn.org>
Organization: Pegasus,  Honolulu
Lines: 47

In article <1991Jan28.005022.9930@csn.org> haverlan@tramp.colorado.edu (HAVERLAND MARC BRADLEY) writes:
>
>I'm looking for a utility that will ease the task of converting a large
>Clipper Summer '87 application to a network version.  It seems like a 
>process that could be automated, but I haven't seen anything like this.
>Any leads you could provide would be great.
>
>A couple other related questions:
>
>The application in question is broken into many overlays. My client is
>getting a Lantastic network.  Any known problems with this?
>
>Does Clipper 5.0 leave more memory available in general?  I'm currently
>having out of memory problems, and it will get worse with the addition
>of a network driver.

Marc,

There is at least one product that claims to convert dBASE code from single
user to multi-user but I won't even mention it because it would probably
do you more harm than good.  The problems are not trivial as records should
be locked for as little time as possible but not so little that integrity
problems creep in.

First move is to SET EXCLUSIVE OFF and Clipper will require you to handle
the RLOCK() and FLOCK() situations or you'll be given a fatal error.  More
than the physical mods are required however.  Logical mods may be called
for to avoid deadlock situations (the conversion software wouldn't detect
this).

Lantastic has no known problems with Clipper.

Clipper 5.0 eliminates memory problems altogether.  Currently there are some
bugs with the VMM system but they will be fixed.  Even with the bugs one can
now create (for example) a 10MB array in 640K of RAM.  The virtual memory
manager will use expanded memory if it is available and then the disk drive
to store it totally transparent to the developer.

Dynamic overlaying linkers will control the code size and you can use
BLINKER or WARPLINK for Clipper S'87.  From a code standpoint you should
not run out of memory though with S'87 you can still run out of memory
for data.

Hope that does it...

tom leylan
ex-Senior Systems Analyst / Nantucket Corp.