Retro Computing (on Steroids)

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’ere we go ... **LINK**

http://www.figuk.plus.com/articles.htm

MichaelG.

'Octal' Frances? I used to know that a long time ago - but all I can remember now is '7402' (Halt instruction on a PDP8)

IanT

I just found my old copy. A bit battered but all there.

Now to see if i can make any sense of it

Not as concise as Python but works . ( C#)

On 196 problem , the highest integer before crashing was was 7197636720180367016 , using Int64 and highest value using Int32 is set at 2,147,483,647

I was surprised at the number of integers which became palindrome after only one loop.

Looks good to me, and I think it can be souped up. Never done C# myself, but I believe C# strings can be longer than telephone lines while BigInteger does arbitrarily big arithmetic. Maybe simply substituting BigInteger for Int32 in your declarations will allow the program to generate monster numbers?

After working out how to reverse and add huge numbers the next challenge is to it efficiently which my attempt isn't. Your C# program is likely faster than mine because C# reverses strings directly, whereas I convert between lists and strings, an awful spiralling overhead as the number of digits grows.

Most numbers quickly become palindromic, some take many reversed additions before a palindrome appears, and a few - like 196 - might never produce a palindrome. No one knows! Mathematicians find it an interesting problem, I think it's a good way of stressing computer languages.

Dave

I'm on the case Frances! My comment about Gerard's program is separate. Just that by replacing his Int32 with BigInteger declarations I think it will do big numbers!

I'm musing on how best to code your method: a c++ class (struct on steroids!) feels right, probably with a vector rather than array so it can grow.

Dave

Well, my shared Virtual Reality stuff is in the Canadian Science and Tech museum; I can confirm that by the time I created this stuff, we were well and truly into Hexadecimal.

(I remember the 68008 being released - are you sure about the decade? I would have pegged it later; in the 70s, it was almost all 8 bit processors, if I remember that far back correctly) (no matter, those were the fun days; I loved the 1802 because as a kid, I could single step it and debug the hardware with only a really inexpensive analogue volt meter)

Edited By Frances IoM on 16/12/2020 22:48:37

Ok, that makes more sense - I left high-school (Canada) in 1978 and University in 1982, and a lot changed in that time. That's how I remember time-frames - In high school it was the 1802 and 8080, by the end of University, it was totally changed. Things went quickly back then. (I guess they do today, too).

Many years ago, I was on an overnight train (would have been autumn/winter 1982, maybe spring 1983) I went on an overnight train here in Canada (almost 9 hours long journey), almost nobody on it. My task was to further a S-100 bus-based 1802/8085 computer, wire-wrapped. The old crusty conductor (they were all crusty old conductors back then) came by and said in the typical gruff voice "What you building, a Bomb??" I said "Yeah", his answer "Good luck" and kept on walking, checking to see if anyone was likely going to give him trouble.

These days, that cocky little kid would be taken down by a SWAT team or something equivalent.

Sigh!

Memory's unreliable but I think you're both right. Late 70's I was a data processing department customer focussed on the future of microcomputers as office tools. The machines of the day were useful, but puny, but I saw no reason why they wouldn't eventually rule the world. (Mainframe colleagues disagreed violently!)

I was much taken with the promise of the Motorola 68000 family but they existed on paper long before hitting the street. Motorola must have had trouble making them in volume because they took years to arrive, and cost more than expected. Delayed so long that Intel grabbed the PC market by releasing the 8088 and successors, running MS-DOS and Windows. Intel's chips may have been technically inferior, but they worked and you could buy them.

The computing world would be very different had Motorola delivered the powerful 68000 family on time: we would all have gone UNIX, and Microsoft would never have existed!

Dave

Edited By Frances IoM on 17/12/2020 10:03:06

@SOD, liked the palindrome, put it into my list of pythons. Reminded me of back pages of Sci Am way back.

Anyone know how the CMM2 produces VGA. Is it some kind of fast loop does it use dma? Just curious, not really sure if I want to spend too much time on a VGA gadget, but I have a vga screen that has been kicking round the shop for too long.

Hi Roger,

The VGA graphics are generated by the underlying hardware but much of the 'programable' functionality is built into the BASIC engine. The CMM2 is built around a single 'Waveshare' MCU chip, which uses a Cortex-M7 32-bit RISC CPU core, running at 480Mhz and producing 1027 DMIPS. The MCU also has a double-precision FPU and Chrom-ART graphic accelerator. So just about every 'hard' feature of the CMM2 is on the MCU chip with just a few external components to enable connections to the real world.

Waveshare - Core 743i

MM Basic is closely coupled to this hardware platform, meaning that it has direct access to the 'metal' and whilst firmware upgrades have been happening pretty regularly, the MCU provides a well defined (e.g. fixed) hardware reference to base these upgrades upon. The VGA graphics are a good example, with a combination of very fast hardware combined with firmware designed to get the best out of it.

In many ways I think that's why the "Retro" guys like the CMM2 so much - it's like the 80's consoles (such as C64, Atari and Amiga etc) which were specific (e.g. stable) hardware platforms that could be explored and further 'tweeked'. There are disadvantages to devices like the RPi where both the OS and underlying hardware are constantly evolving - for some, they also present a constantly moving target...

Not really my thing but the retro-gamers are re-coding old 80's games (in Basic) and getting 30 frames per minute performance (it was originally half that). They've also recently introduced 3D graphics commands into the CMM2's Basic which are based on advanced MATH functions that I (frankly) don't understand but which apparently have all sorts of other useful applications.

The key thing is that MMB is implemented to get the best from it's platform - be that a tiny 28 pin MicroMite or the CMM2. There's nothing in-between to suck performance away. Many might see that as a major disadvantage but clearly some do not - and that is who this little box of tricks is for.

With regards VGA/HDMI - there are a lot of adapters around ranging from a fiver upwards. CMM2 owners seem to like the GANA boxes which are a bit more (about £12 on Amazon). I've got several older VGA monitors that still work very well and in fact I use an HDMI to VGA converter to connect my Pi 3B to one.

Regards,

IanT

Edited By IanT on 18/12/2020 16:56:35

I'll pass this on as an interesting video

The Art of Code

Program like a rockstar...

Wow! Thanks for that/ Trouble is, it made me feel stupid. I knew about Game of Life the time, but just thought it was just an interesting novelty. Ditto Mandlelbrot. Forty years later I find out clever chaps have taken computer science to a whole new level, whilst I was plodding along...

I'm not musical but Sonic Pi has got to be tried! (The website implies it's only available for Mac, Windows, and Raspian: not so - it's in the standard Ubuntu repository.)

Dave

"sound of code". Anyone else remember attaching an amp to chip select lines to get a feel for whether the computer was accessing the right bits of memory?

Interesting that despite the advances in computing people inventing new programming systems still resort to stilted syntax. Nowadays their simple example 'haunted bells' should, instead of several awkward code phrases, be an English sentence like "play random bell sounds". Roll on AI.