Brian Spearing Posted May 20, 2017 Share Posted May 20, 2017 Posted by Geoff Sleath on 20/05/2017 10:57:00 ...... Reverse Polish? I dabbled with a programming language a very long time ago that used it. Can't recall its name and I never used it in anger. Geoff Would that be FORTH? Some HP calculators used RPN, they'd be loved by hipsters these days. Brian Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 20, 2017 Share Posted May 20, 2017 I built the Black Watch as well - the electronics were fine but the mechanical side was rubbish . After a few months I ended up with one of the first digital car clocks - built the internals into the centre boss of my steering wheel...and replaced the dodgy flexible pcb touch contacts with some of my Mum's pins pushed through the boss and wired to the board. Happily, I was never tempted by the C5 - although I did have a go with one round a car park...a bit of fun but a joke as a road vehicle! Quote Link to comment Share on other sites More sharing options...
gangster Posted May 20, 2017 Share Posted May 20, 2017 I had a lot of Sinclair stuff back in the day. I built the Cambridge Scientific from a kit I recall the built up one cost a fortune and the day it came out in kit form I went down to St Ives and bought one. It cost £29 and I thought it a bargain probably the equivalent of over £200. Yes the reverse Polish notation was a pig to work and in reality I checked the answers with a slide rule. Also bought the black watch in kit form I recall you had to trim the crystal frequency to calibrate it it was rubbish and kept loosing the plot and I took it back and they changed it for the latest model. If I recall the black watch fiasco one of the first things that nearly bankrupted Sir Clive. The new black watchworked fine until I lost it. I sold the calculator a bit later and bought the Sinclair Oxford a proper scientific calculator which cost about the same as the old kit but the early ones of those could not deal with trig functions of small numbers. They swapped that for the later model as well. I built the micromatic radio and as someone else said it needed the board filing to fit the case. I recall it only received radio 3. That audio stuff was ok ish but ........ I also had a zx81 hours of programming only for the 15k (50 quid ) ram pack to fall off Yes I did say 15k of ram I understand the spectrum was a success but wasn't that owned by times by then? I still have a Sinclair digital volt meter somewhere Quote Link to comment Share on other sites More sharing options...
gangster Posted May 20, 2017 Share Posted May 20, 2017 Whoops double post deleted. Now if Sinclair had made smart phones! Oh yes I had one of those car clocks too fine if you were parked in the dark and had a magnifying glass to read it Edited By gangster on 20/05/2017 22:05:53 Quote Link to comment Share on other sites More sharing options...
Geoff S Posted May 20, 2017 Author Share Posted May 20, 2017 Posted by Brian Spearing on 20/05/2017 21:12:08: Posted by Geoff Sleath on 20/05/2017 10:57:00 ...... Reverse Polish? I dabbled with a programming language a very long time ago that used it. Can't recall its name and I never used it in anger. Geoff Would that be FORTH? Some HP calculators used RPN, they'd be loved by hipsters these days. Brian It would. I'd totally forgotten the name like a lot of things from my professional career. Geoff Quote Link to comment Share on other sites More sharing options...
Don Fry Posted May 21, 2017 Share Posted May 21, 2017 One I recall was an electronic calculator in a box the size of a shoebox, in an adjoining laboratory. This was about 1970, 72 in the ICI research facility in S Wales. It had some age, and did basic stuff. And the bloke who's lab it was related it cost exactly the same as his MGB would new. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted May 21, 2017 Share Posted May 21, 2017 Posted by Geoff Sleath on 20/05/2017 20:07:46: Yes, but 90% of Sinclair's stuff was absolute rubbish. The radio that wouldn't fit in the case, the Black Watch, the awful class 'D' amplifier as well as the more conventional ones which never approached the claimed performance to say nothing of the disaster that was the C5 electric trike (I was always sorry I never came across one on the road I could have overtaken on my racing pedal trike ) Dad stocked a few of the amplifiers and they sold in small quantities. In the early 70s I worked with a lad who'd worked for Sinclair testing those amplifiers. The rule was to send them out whether they worked or not and replace the ones returned. Of course a significant number weren't returned as the users assumed it was their fault they didn't work as advertised. Sinclair never quite forgave Acorn for getting the BBC contract for the superb (for the time) BBC computer. And of course Acorn when on to be ARM (Acorn RISC Machines) who make the chips found in mobile phones and elsewhere (Taranis I think?). I think Poundland has Sinclair beaten all ends up Geoff Nicely put Geoff - but the ZX Spectrum still got me interested in home computing Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted May 21, 2017 Share Posted May 21, 2017 In about 1965 or 67 I think, I bought a SInclair micro radio kit. I tried to phone them but the number was wrong and I kept getting 999. I gave up in the end. Never did get it working Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted May 21, 2017 Share Posted May 21, 2017 Like John P I did 'A'-levels 1976, we weren't allowed calculators in the exam - just slide rules. The interesting thing is that when I started university and I could use a calulator I actually found that for many calculkations I was faster with the slide rule! Slide rules have other advantages as well in my view: 1. The battery never runs out! 2. You have to have a rough idea what the answer is going to be - you certainly need ro know its order of magnitude. 3. In engineering terms it returns an answer with a sensible and usuable level of precission - tyoically 2-3 sig figs. Later, as a lecturer, students were often amuzed when I would pull a 6" slide rule out of my pocket to do a quick check on a calulation. They felt my method could not be accurate or fast. But the fact is I was constantly uobraiding them for slavishly wroting down the threoretical prediction that the drag force on some 1:50 model of a wing section in a wind tunnel would be 28.98764567 kN!!! When I pointed out that was both a remarkably precise and totally incorrect prediction of about 2.8 tonnes (on a 1:50 model!!) they would look at me and say "surprisingly large eh - goes to show you?" Nope, all it shows is that you can't enter exponents on your calaculator correctly and have absolutely no feel whatsoever for the likely size of the answer! A quick whizz on me slide rule then,...try about 29N (tell you what let's call it 30N) and we might be closer! BEB Edited By Biggles' Elder Brother - Moderator on 21/05/2017 12:36:32 Quote Link to comment Share on other sites More sharing options...
Alex Ferguson 2 Posted May 21, 2017 Share Posted May 21, 2017 HP-35, reverse Polish notation, about $300 ($400?). A year later $20 non-reverse polish scientific calculators were available. At high school those who dared to use a slide rule were looked down on. As soon as I left and started work I had to buy a slide rule and use it. It was a backward school (my opinion), when I started there it only had rugby as a winter sport. My story, I got rid of the headmaster, his story he retired. We then had football as well as other sports. Tradition was "it". Tradition, an excuse for not thinking. A decade after starting work, doing more trade schooling, I asked if power points would be supplied for calculator users in exams. The question was redundant in less than a year. Quote Link to comment Share on other sites More sharing options...
Andy48 Posted May 21, 2017 Share Posted May 21, 2017 Posted by Donald Fry on 20/05/2017 16:29:03: In my day 13 year old stuff. You were really doing stuff like this at 13?????? Note that these logs are not just using base 10. This BTW is one of the easier "A" level questions. Quote Link to comment Share on other sites More sharing options...
Stuart C Posted May 21, 2017 Share Posted May 21, 2017 Are you sure that this is an 'A' level question? It seems too easy insomuch as it is solvable in seconds without pen nor paper. Quote Link to comment Share on other sites More sharing options...
Wihtgar Posted May 21, 2017 Share Posted May 21, 2017 Who cares? I have a slide rule, log tables but best of all my HP scientific RPN calculator. I find it so natural to use and fast without even having to use its programming capabilities. Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 21, 2017 Share Posted May 21, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted May 21, 2017 Share Posted May 21, 2017 Oh groan!!! BEB Quote Link to comment Share on other sites More sharing options...
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