Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!sdd.hp.com!decwrl!parc!cutting From: cutting@parc.xerox.com (Doug Cutting) Newsgroups: comp.lang.lisp Subject: Re: Is this the end of the lisp wave? Message-ID: Date: 25 Jan 91 00:41:16 GMT References: <17374@csli.Stanford.EDU> <1991Jan24.153322.1307@cs.mcgill.ca> Sender: news@parc.xerox.com Organization: Xerox PARC, Palo Alto, CA Lines: 27 In-Reply-To: dean@cs.mcgill.ca's message of 24 Jan 91 15:33:22 GMT In article <1991Jan24.153322.1307@cs.mcgill.ca> dean@cs.mcgill.ca (Dean NEWTON) writes: In article cutting@parc.xerox.com (Doug Cutting) writes: >No, Garbage collectors don't make storage management a non-issue, they >just make it less of an issue (unless you don't care about performance). Compilation, virtual memory management, and garbage collection are entirely mechanical processes, and, as we have already seen in the case of compilers, computers can become better at them than most programmers. This is a naive point of view. Virtual memory does not really provide infinite, fast, memory. Data structures and algorithms which acknowlege this can achieve vastly superior performance, e.g. B-trees, which underly most database systems. Similarly, garbage collectors cannot always do a satisfactory job of storage management. Usually they can, but there are programs whose memory usage patterns cause their performance to become dominated by GC. In these cases one can often make an otherwise unusable system quite by manual storage management. A (rather weak) example is the use of RECONS in the PCL code walker. Sure, PCL will run without it, but your compilations would run much slower. To claim otherwise is akin to claims one sometimes hears that memory usage or CPU speed is no longer an issue. While these are indeed less of an issue, they're still core concerns of computer science. Doug