cmdbyk@pmvax.weeg.uiowa.edu (Karl Boyken) (04/25/91)
In article <1991Apr24.192424.23745@kestrel.edu>, gyro@kestrel.edu (Scott Layson Burson) writes... >.... This is very definitely a concern I have about C++: that when people >start manipulating 60 Mb worth of objects in one program (and I have >already seen 30 Mb process sizes), that the locality problem is going >to bring their machines to their knees, even though they would have >had no trouble running the same algorithms on the same data in Lisp. >I don't know of any allocation algorithms for C++ that pay any >attention to locality, nor do I really see how there *can* be any, >because the information about what other objects an object X points to >or is pointed to by is not available at the time X is created. >Furthermore, there is no way of doing compaction of live objects. > >As I say, I am very concerned about this. I think the C++ community >is not prepared for the magnitude of the problem.... As someone who's participated in writing a large object-oriented application in a C++-like language, I agree with you. I helped write a large Turbo Pascal 5.5 application, with 9 other programmers. Since the program was so large, we had to use overlays, and we had to split the overlay file into 3 parts to distribute the app on floppies. We discovered that object-oriented programming caused us to hit the overlay manager frequently; juggling the modules among the three files so that disk swaps were minimized was a large undertaking. ** _My_ views, no one else's--except those I plagiarize. ** Karl Boyken, Project Analyst | "It's so easy to slip, it's State Health Registry of Iowa | so easy to fall and let your Iowa City, IA | memory drift into nothing Internet: cmdbyk@pmvax.weeg.uiowa.edu | at all." -- Lowell George