Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!gatech!ncar!oddjob!mimsy!chris From: chris@mimsy.UUCP (Chris Torek) Newsgroups: comp.arch Subject: Re: numbers Message-ID: <11512@mimsy.UUCP> Date: 16 May 88 06:24:58 GMT References: <11571@ut-sally.UUCP> <28200145@urbsdc> <11618@ut-sally.UUCP> <493@cmx.npac.syr.edu> Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742 Lines: 40 >In article <11618@ut-sally.UUCP> nather@ut-sally.UUCP (Ed Nather) writes: >>Unfortunatly I have found no simple way to get the star to cooperate with >>respect to counting rates. Sometimes 16 bits are enough, sometimes 32 >>aren't, depending on the the star's brightness and the rapidity with which >>it varies. In article <493@cmx.npac.syr.edu> billo@cmx.npac.syr.edu (Bill O) writes: >This is a perfect example of why we need higher-level languages >like lisp. ... [On] overflow ... lisp just converts the representation >to Bignum, and works with it instead -- you may never even be aware >that the conversion has occurred. Lisp is not the only such language, but it does illustrate a certain point. (This point is perhaps stronger with Jack Bonn's glass-slinging machine than with Ed Nather's photon counter.) Imagine the lisp system, counting away: 4 294 967 294 4 294 967 925 Entering GC; please wait. Estimated delay: 7.24s One problem with higher-level langauges is that they may wrest too much control. While there are those with incremental GC, and even some with no GC (although some say `those don't count' :-) ), many of them are not suited for real-time applications. >Yes, we need languages that are close to hardware ... [this left in for balance] >(NOTE: in lisp you actually get the best of both worlds. You can >fully specify types if you choose, to get faster-running code.) But if you specify the type as `integer' you are back to the problem you had with C. You get to decide to which error to commit, but you do not get to overcome both. It may, of course, not be possible to overcome both with a given machine.... -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris