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Groups > sci.electronics.design > #460688
| Subject | Re: [OT] I got a JOB!!! |
|---|---|
| Newsgroups | sci.electronics.design, comp.dsp, comp.arch.embedded |
| References | (4 earlier) <dM6dna6-keoVG4HEnZ2dnUU7-dednZ2d@giganews.com> <SS%SA.62431$ex.41042@fx07.am4> <dM6dnau-kepVFoHEnZ2dnUU7-dednZ2d@giganews.com> <580TA.12225$3w1.6575@fx41.am4> <dM6dnaW-kereC4HEnZ2dnUU7-dednZ2d@giganews.com> |
| From | Tom Gardner <spamjunk@blueyonder.co.uk> |
| Message-ID | <Oc1TA.5102$lb2.833@fx23.am4> (permalink) |
| Organization | virginmedia.com |
| Date | 2017-05-17 20:08 +0100 |
Cross-posted to 3 groups.
On 17/05/17 19:28, Tim Wescott wrote: > On Wed, 17 May 2017 18:55:16 +0100, Tom Gardner wrote: > >> On 17/05/17 18:43, Tim Wescott wrote: >>> On Wed, 17 May 2017 18:36:52 +0100, Tom Gardner wrote: >>> >>>> On 17/05/17 18:21, Tim Wescott wrote: >>>>> On Wed, 17 May 2017 18:11:22 +0100, Tom Gardner wrote: >>>>> >>>>>> On 17/05/17 16:02, Tim Wescott wrote: >>>>>>> On Wed, 17 May 2017 09:12:46 -0400, Randy Yates wrote: >>>>>>> >>>>>>>> Tim Wescott <seemywebsite@myfooter.really> writes: >>>>>>>> >>>>>>>>> Since this is a newsgroup, and this is news... >>>>>>>>> >>>>>>>>> Wescott Design Services is going into remission, while I pursue a >>>>>>>>> day job. Job title is Software Designer 5 at Planar Systems -- >>>>>>>>> so any circuit design or control systems jones will have to be >>>>>>>>> satisfied by hobby work or on the side. >>>>>>>>> >>>>>>>>> In the near term I'll be finishing up current work with current >>>>>>>>> customers; in the longer term I'll probably concentrate on the >>>>>>>>> educational videos and maybe hobby stuff. >>>>>>>>> >>>>>>>>> Lots of embedded Linux work in my near future, and possibly TDD >>>>>>>>> proselytizing. >>>>>>>> >>>>>>>> Congratulations Tim. We'll have to exchange trade secrets >>>>>>>> someday... >>>>>>>> >>>>>>>> BTW, does PS use a specific unit test framework? Have you used it >>>>>>>> yet? >>>>>>>> How do you like it? >>>>>>> >>>>>>> I start next week, so I don't know and no. It's my former coworker >>>>>>> from FLIR who's pushing TDD, and the manager who hired me is kind >>>>>>> of warily standing on the sidelines going "what's the deal here?" >>>>>>> >>>>>>> The guy pushing it is extremely smart and capable, so whatever it >>>>>>> is it's probably good. >>>>>> >>>>>> I expect you'll find it is the codification of many of the >>>>>> development mentality and practices that you have been using for a >>>>>> long time. >>>>>> >>>>>> Be cautious about how TDD applies to bottom-up design (i.e. finding >>>>>> things that work and clagging them together) v.s. top-down design. >>>>>> TDD works naturally with top-down design where all the >>>>>> yet-to-be-implemented are well understood and feasible. >>>>>> >>>>>> Anybody that /thinks/ will realise that sometimes it is beneficial >>>>>> to do a "spike investigation" to quickly validate key concepts from >>>>>> top-to-bottom, and then to use that experience to do it "properly" >>>>>> using full-blown TDD. >>>>> >>>>> It's not magic. I've been geeking out on the COSMAC 1802 lately, >>>>> because it was the first microprocessor I ever owned (I had an ELF-II >>>>> kit). The user's manual has an entire chapter extolling the virtue >>>>> of SUBROUTINES (ooh, ahh) and how to implement them. It's quite >>>>> gushy about how using subroutines make your code better. And yet, >>>>> I've worked on lots of crappy code that has subroutines. >>>> >>>> :) >>>> >>>> The 1802's implementation of subroutines was, um, quirky to the point >>>> of being obtuse. >>>> >>>> I hand built my first computer using a 6800, after having thought long >>>> and hard about the 1802 and 8080. It was a mess, >>>> but worked, I learned a heck of a lot, and prospective employers were >>>> duly impressed. >>> >>> The 1802 is neither a CISC processor nor a RISC processor -- it's a >>> NHISC processor -- "Never Had Instruction Set Computer". >> >> :) >> >>> I wish I had the chops to organize a contest -- I think an annual >>> "build the fastest 1802" contest would be fun to be involved in. >>> Imagine what you could do if the only basic rule was that it had to >>> execute 1802 machine code faithfully, with no constraints on how much >>> happened per clock cycle. Ditch TDA and TDB, keep the I/O command >>> lines, Q, and the flags, and go to town. Prefetch, pipelines, caches, >>> parallel execution, predictive branching, everything -- all with that >>> crazy 1802 instruction set. >> >> I hate all those with a vengeance, since they prevent hard real-time >> software. >> >> I'm currently experimenting with a /small/ XMOS device which >> deliberately avoids all of those techniques so that it can guarantee >> timing. So far I've been able to get the /software/ >> to reliably count the edges on two 20Mb/s input pins, process the >> results and simultaneously shove them up a USB link to a host PC. >> >> Now I've got to understand the algorithms in reciprocal and continuous >> timestamping frequency counters :) > > Some guy has Verilog code for an 1802 in which he claims a 60MHz clock, > one clock per instruction (or perhaps fetch). That would be > deterministic, and fast by some measures. > > All the modern pipeline/predict/prefetch whiz-bang doesn't prevent hard > real time, if only the processor manufacturers would publish the absolute > maximum time it takes to execute any possible instruction, or (better) > provide tools for finding the maximum time-from-interrupt for any given > chunk of code. Then you could just add up all the critical stuff and > make sure it works. > > In my experience there isn't THAT much variation -- you just need to know > how much variation to allow for to meet hard real time criteria. It complicates things enormously, doubly so when all the caches are involved. ISTR someone measuring a 486 with its tiny caches, and finding the mean:max ISR time was somewhere around 1:5. I expect I've still got a paper copy, /somewhere/. The XMOS tools claim to indicate the exact loop/function times, assuming input is available and output can be delivered (Occam channel semantics). The event-driven multicore hardware+software co-implementation looks to be rather nice too. And the I/O is pleasantly high-level too: do i/o on a specific clock cycle, wait until there's a change, etc etc. Makes high speed bit-bashing in software tractable.
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[OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-16 13:49 -0500
Re: [OT] I got a JOB!!! George Herold <gherold@teachspin.com> - 2017-05-16 11:55 -0700
Re: [OT] I got a JOB!!! Tim Wescott <tim@seemywebsite.really> - 2017-05-16 15:13 -0500
Re: [OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-16 17:18 -0500
Re: [OT] I got a JOB!!! Steve Wilson <no@spam.com> - 2017-05-16 19:04 +0000
Re: [OT] I got a JOB!!! Don Y <blockedofcourse@foo.invalid> - 2017-05-16 12:14 -0700
Re: [OT] I got a JOB!!! Tim Wescott <tim@seemywebsite.really> - 2017-05-16 14:41 -0500
Re: [OT] I got a JOB!!! Don Y <blockedofcourse@foo.invalid> - 2017-05-16 14:01 -0700
Re: [OT] I got a JOB!!! mike <ham789@netzero.net> - 2017-05-16 14:42 -0700
Re: [OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-16 17:09 -0500
Re: [OT] I got a JOB!!! Don Y <blockedofcourse@foo.invalid> - 2017-05-16 16:42 -0700
Re: [OT] I got a JOB!!! Clifford Heath <clifford.heath@gmail.com> - 2017-05-17 09:00 +1000
Re: [OT] I got a JOB!!! tabbypurr@gmail.com - 2017-05-16 13:40 -0700
[OT] I got a JOB!!! bulegoge@columbus.rr.com - 2017-05-16 12:27 -0700
Re: [OT] I got a JOB!!! eric.jacobsen@ieee.org - 2017-05-16 20:17 +0000
Re: [OT] I got a JOB!!! Tim Wescott <tim@seemywebsite.really> - 2017-05-16 15:24 -0500
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-16 22:05 +0100
Re: [OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-16 17:11 -0500
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-16 23:51 +0100
Re: [OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-16 18:32 -0500
Re: [OT] I got a JOB!!! Clifford Heath <clifford.heath@gmail.com> - 2017-05-17 09:41 +1000
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 09:35 +0100
Re: [OT] I got a JOB!!! Clifford Heath <no.spam@please.net> - 2017-05-17 19:03 +1000
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 10:31 +0100
Re: [OT] I got a JOB!!! Clifford Heath <no.spam@please.net> - 2017-05-17 23:07 +1000
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 09:41 +0100
Re: [OT] I got a JOB!!! Paul <paul@pcserviceselectronics.co.uk> - 2017-05-17 10:10 +0100
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 10:34 +0100
Re: [OT] I got a JOB!!! Paul <paul@pcserviceselectronics.co.uk> - 2017-05-17 15:59 +0100
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 18:04 +0100
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 18:02 +0100
Re: [OT] I got a JOB!!! Don Y <blockedofcourse@foo.invalid> - 2017-05-16 17:56 -0700
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 09:42 +0100
Re: [OT] I got a JOB!!! Reinhardt Behm <rbehm@hushmail.com> - 2017-05-17 16:57 +0800
Re: [OT] I got a JOB!!! "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-05-16 15:04 -0700
Re: [OT] I got a JOB!!! Don Y <blockedofcourse@foo.invalid> - 2017-05-16 15:30 -0700
Re: [OT] I got a JOB!!! "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-05-18 16:00 -0700
Re: [OT] I got a JOB!!! Don Y <blockedofcourse@foo.invalid> - 2017-05-18 16:18 -0700
Re: [OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-18 19:14 -0500
Re: [OT] I got a JOB!!! "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-05-18 21:40 -0700
Re: [OT] I got a JOB!!! Martin Riddle <martin_ridd@verizon.net> - 2017-05-16 20:02 -0400
Re: [OT] I got a JOB!!! krw@notreal.com - 2017-05-16 20:40 -0400
Re: [OT] I got a JOB!!! Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-17 09:12 -0400
Re: [OT] I got a JOB!!! Tim Wescott <tim@seemywebsite.really> - 2017-05-17 10:02 -0500
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 18:11 +0100
Re: [OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-17 12:21 -0500
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 18:36 +0100
Re: [OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-17 12:43 -0500
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 18:55 +0100
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 18:57 +0100
Re: [OT] I got a JOB!!! Tim Wescott <seemywebsite@myfooter.really> - 2017-05-17 13:28 -0500
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-17 20:08 +0100
Re: [OT] I got a JOB!!! boB K7IQ <boB@everett.wa> - 2017-05-17 21:30 -0700
Re: [OT] I got a JOB!!! Tim Wescott <tim@seemywebsite.really> - 2017-05-18 00:03 -0500
Re: [OT] I got a JOB!!! Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-18 08:18 +0100
Re: [OT] I got a JOB!!! boB K7IQ <boB@everett.wa> - 2017-05-18 22:56 -0700
Re: [OT] I got a JOB!!! Vassilis Spiliopoulos <vassilis@vask1lux.de> - 2017-05-19 14:31 +0300
Re: [OT] I got a JOB!!! Tim Wescott <tim@seemywebsite.really> - 2017-05-19 10:39 -0500
Re: [OT] I got a JOB!!! Vassilis Spiliopoulos <vassilis@vask1lux.de> - 2017-05-19 23:02 +0300
Re: [OT] I got a JOB!!! Don Y <blockedofcourse@foo.invalid> - 2017-05-19 13:12 -0700
Re: [OT] I got a JOB!!! dplatt@coop.radagast.org (Dave Platt) - 2017-05-19 15:00 -0700
Re: [OT] I got a JOB!!! Don Y <blockedofcourse@foo.invalid> - 2017-05-19 16:05 -0700
Re: [OT] I got a JOB!!! boB K7IQ <boB@everett.wa> - 2017-05-21 01:46 -0700
Re: [OT] I got a JOB!!! Vassilis Spiliopoulos <vassilis@vask1lux.de> - 2017-05-21 17:31 +0300
Re: [OT] I got a JOB!!! John S <Sophi.2@invalid.org> - 2017-05-21 13:31 -0500
Re: [OT] I got a JOB!!! krw@notreal.com - 2017-05-21 16:47 -0400
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