Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Paul Rubin Newsgroups: comp.lang.forth Subject: Re: I'm so conflicted... Date: Sun, 20 Nov 2016 11:15:37 -0800 Organization: A noiseless patient Spider Lines: 14 Message-ID: <87twb2arom.fsf@nightsong.com> References: <89c407af-410f-4089-9032-7552ac91736b@googlegroups.com> <17d77571-5f23-4b3b-a55e-8a66bfe8aa92@googlegroups.com> <7fb7eebf-32f2-4061-8bc3-1720674ce7c2@googlegroups.com> <5d84a748-6d02-4133-bd34-4601fe7a44cf@googlegroups.com> <65f97f06-8302-411f-b001-afbd6f890d6c@googlegroups.com> <281d7b0a-992e-4e18-96f9-e389848eb5e8@googlegroups.com> <36fdf559-726d-48f1-a15d-c37683ed2d7c@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: mx02.eternal-september.org; posting-host="4a8e12b9b1b368f8d5b968032e549542"; logging-data="13780"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19zapRDJ7gd7s9ZRcpA2JX9" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) Cancel-Lock: sha1:jszpZiNamrJXPppziH0Plc4rgyU= sha1:P1gwEFysYFqOYaaTxiE2tdBnNlk= Xref: csiph.com comp.lang.forth:52773 Mark Wills writes: > The PLC I used to use (Allen Bradley ControlLogix) had 32 megabytes of > RAM. They are capable of millions of instructions per second, and have > fully typed languages (booleans,bytes,ints, dint, reals, floats,... Interesting -- is that still different from what we would usually call a computer instead of a PLC? I had thought the original PLC's were implemented with relays or simple switching elements and were programmed with ladder logic, which persisted into the microprocessor era because control engineers understood it, it had good verification methods, and it was hard to go wrong because its range was so limited. Once you get away from that, are you not doing just ordinary programming?