Newsgroups: comp.lang.smalltalk,comp.lang.c++,comp.databases.object
Path: cantaloupe.srv.cs.cmu.edu!das-news2.harvard.edu!oitnews.harvard.edu!yale!yale.edu!spool.mu.edu!howland.reston.ans.net!swrinde!sdd.hp.com!hplabs!hplextra!hplb!gw
From: gw@hplb.hpl.hp.com (Gunther Walther)
Subject: Re: Question re: Global Positioning (GPS) technology in a railroad app
Sender: news@hplb.hpl.hp.com (Usenet News Administrator)
Message-ID: <DJsy36.DHw@hplb.hpl.hp.com>
Date: Mon, 18 Dec 1995 21:52:17 GMT
References: <perform.64.00231B88@iu.net> <1995Dec14.201432@venus>
Nntp-Posting-Host: gwalther.hpl.hp.com
Organization: Hewlett-Packard Laboratories, Bristol, England
X-Newsreader: TIN [version 1.2 PL0.7]
Followup-To: comp.lang.smalltalk,comp.lang.c++,comp.databases.object
Lines: 34
Xref: glinda.oz.cs.cmu.edu comp.lang.smalltalk:32317 comp.lang.c++:165576 comp.databases.object:8604

: In article <perform.64.00231B88@iu.net>, perform@iu.net (PERFORMANCE Software Services, Inc.) writes:
: [deleted]
: > 
: > Their desire is to do this development in an OO paradigm and
: > are thinking smalltalk would not be appropriate due to the
: > "real-time" nature of the app.  Any thoughts on this?
: > 

Depends on what you want to get out of the GPS system and how
you interface to it. Using RS-232 would indicate that "real-
time" is quite relative.

A) If you want accurate time, then maybe Smalltalk is not a
good idea, same goes for RS-232.

B) If you want just position, then maybe Smalltalk is a good idea.
In the real world, you will not always see enough satellites, and imho,
a system that goes away and comes back all the time, is
unlikely to be hard-real time. But then, this depends on whether
you back GPS somehow up with a different technology.

C) If you want velocity, then you have to sit down and look at the
   errors. Questions to ask would be: what is your required accuracy
   and the length of the measurement interval.

D) Is it a prototype? Does it need to fit later into a tiny bit
   of h/w?

gunther

-------------------------------------------------------------------
These answers are worth 0.02 Euros. If they don't buy you anything
today, you have to wait until 1999...
-------------------------------------------------------------------
