Jon -

As I indicated, I'm looking at a very old version of the DT, but it (Oct96) was a straight DOS program. My understanding was that a Windows "front end" had been added, but the basic database was probably not recompiled.

Even a lot of programs rewritten/recompiled specifically for Windows have significant "memory leaks," which is frequently the cause of "lock-up" behaviour.

Windows has "very large" memory available, through paging of memory segments to hard drive - but it does this, essentially, by writing lots of "temp" files to the drive. Using Word as an example, selecting a 200 page document full of one line paragraphs, and sorting "by paragraphs" will probably work once. A similar operation would be a "global replace" all the periods with commas, or some such. If you immediately try to "sort reverse order," or change all the "a" to "t"s, you're fairly likely to "bog down." If you do a full save, you clear some of the temps, but they tend to hang in there so that eventually you need to exit and restart Word.

Doing massive global replace or sort operations on large documents will eventually lead to where even closing and restarting Word doesn't clear things. You have to go into Explorer and delete *.tmp in the Windows Temp directory - at least - or reboot the machine.

Even Word97/Word7 has rather massive "leaks" for some kinds of operations.

Windows 95, in its original incarnation, required contiguous free space for its temp directory, so a fragmented drive could almost eliminate your virtual memory. Windows 98, and possibly 95 with the right SR patches, is supposed to be able to use non-contiguous free space for temp files, but my experience has been that a fragmented drive will cut down on what is "usable," - and, by design, the default limits temp files to 10 percent (?) of drive free space.

John