Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ukc!dcl-cs!aber-cs!athene!pcg From: pcg@cs.aber.ac.uk (Piercarlo Antonio Grandi) Newsgroups: comp.lang.lisp Subject: Re: Memory Management in Lisp? Message-ID: Date: 6 Mar 91 21:51:11 GMT References: <1991Mar5.040348.25396@Think.COM> Sender: pcg@aber-cs.UUCP Organization: Coleg Prifysgol Cymru Lines: 41 Nntp-Posting-Host: aberdb In-reply-to: barmar@think.com's message of 5 Mar 91 04:03:48 GMT On 5 Mar 91 04:03:48 GMT, barmar@think.com (Barry Margolin) said: barmar> In article barmar> pcg@cs.aber.ac.uk (Piercarlo Antonio Grandi) writes: pcg> I have this idea that a very large, very large part of Computer Science pcg> is simply the consequence of dealing with this gap. Certainly most of OS pcg> and DBMS design is centered around it. Minimizing IO operations and pcg> memory usage is a large and important worry of any programmer's work. barmar> And if we didn't have OSes hiding these details then a large barmar> part of Computer Science would be programming I/O and memory barmar> management routines. Just a moment, this is not a fair comment; I don't regret that OSes and other sw layers give programmers a highger level view of certain things, because what is being abstracted over is details. In the view of some this is indeed the same thing as abstracting over essential things like the performance profile of the available assets, but surely not to me. barmar> And we'd still have to worry about minimizing I/O operations, barmar> because they are still orders of magnitude slower than in-memory barmar> operations. No, no. With more abstract interfaces (like VM and memory mapped files) we can *concentrate* just on minimizing IO operations. Unless we are Lisp programmers, that is :-). I really don't see why so many people would die tomorrow for reducing by 10% the time complexity of their code, but are indifferent to reducing the space or IO complexity by an order of magnitude. If your attitude were right, then why bother with any sort algorithm other than bubble sort? It gets the job done, and if it is too slow, add more CPUs (actually a quadratic number of CPUs :->). -- Piercarlo Grandi | ARPA: pcg%uk.ac.aber@nsfnet-relay.ac.uk Dept of CS, UCW Aberystwyth | UUCP: ...!mcsun!ukc!aber-cs!pcg Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@aber.ac.uk