18 year old BBC Micros used in retro programming class | Hacker News Reader

18 year old BBC Micros used in retro programming class

bbc.co.uk

20 pointsbensummers32 comments

At university I had to code an emulator in assembly and I thought how much more fun it would have been to use some old 8-bit micros.

I've got a BBC B+128KB and the coolest thing about them is that you can mix BASIC and assembly.

Ah, the '[' trick, I remember when I first found out about that and thought it the neatest trick ever, no need to have a separate assembler. That said, it was mostly useful to speed up basic programs, if you wanted to write a program completely in assembler there were better options (the 'ade' rom for instance).

I still have a 'mostly functional' bbc emulator that I wrote for the ST laying around, there are much better ones available now so there is no point releasing the thing, but it was lots of fun to code that up, the 6502 part is about 1600 loc, the rest of the project another 1600 lines or so.

I never did implement mode 7 (teletext) or sound, but most of the other stuff worked.

Can you still read your old media?

All of my cassettes and most of my 5,25" floppies don't work. My drives are also starting to fail, so I recently got some new 3,5" drives installed and wrote about it here (portuguese only, I'm afraid):

http://alquerubim.blogspot.com/2010/07/upgrade-historico.htm...

The only floppies that still work are those that came in those nice black folders from Acornsoft.

With cassettes the problem is usually copy-through, with one layer influencing the next on the wound up spools so you get pre and post echos of the signal. You can possibly fix that using a bunch of processing.

The disks is a harder problem, surprising though, that they've already degraded that much, I would have expected the 5 1/4" to be readable a bit longer than this.

Well, this is Brazil (hot and humid) and they did have to endure about 10 years in my dad's shed, so I didn't really expect them to still work. The BBC, on the other hand, only requires maintenance on the power source's capacitors every 10 years or so (I've changed them twice so far). It's quite a sturdy machine!

Yes, electrolytic caps tend to dry out over time. There are special ones that are mil-spec that don't have that problem, or you could try your luck with Tantalum.

The Sprague brand used to have fairly affordable long life electrolytic caps, maybe you can find those where you live or order them online. That way it's a one time affair.

On another note, if you open up the power supply you'll find a bunch of coils in there, some of them are fairly loosely wound, eventually the windings will rub their way through the insulation and short out. It's not a bad idea to put some hotmelt on those windings to dampen the vibration. Just a little line on either side will do wonders.

Using '[' to enter the assembler still works in BBC BASIC for Windows, except that of course it accepts IA-32 (x86) instructions rather than the 6502 instructions of the old BBC Micro. The power of being able to mix BASIC and assembler code in the same program is as great as ever.

BBC BASIC for Windows does implement MODE 7 (teletext) and the SOUND statement!

http://www.bb4w.com/

I disagree with that most of these oldies are 'cast aside', they actually fetch good money (if you can find them, they're collectors items) and are still some of the easiest machines to learn with and to teach with.

We should really revive that somehow and make a teaching course around a simulated 8 bit computer that you run as a VM on top of your regular OS.

I'd contribute to an effort like that, both financially and with work.

>I disagree with that most of these oldies are 'cast aside', they actually fetch good money (if you can find them, they're collectors items)

They're collectors items that fetch good money because most of them were cast aside. :)

That's possible but quite unlikely, especially in the case of the machine we're talking about here. The ones that I know about that were bought almost 3 decades ago are either still around or have died in terrible ways, but none were 'cast aside'.

MSX and such, yes, I'd agree with you there.

About 9 years ago my secondary school (in the UK) had finally got fed up of having these lying around, and told the students that if anyone wanted them they could take them home w/ them.

They still had a few left, and so they went in the bin.

that hurts.

I would imagine it's a tale that was repeated up and down the country.

Does anyone know of an "online shell" and tutorial combo that would give a similar kind of learning experience for understanding how computers work at the lower levels, as mentioned at the end of the article:

"The day of study had begun with what must be the ultimate hands-on technology experience: Mr Abrams got the students to be a computer.

They each took on the role of a different part of the machine - CPU, accumulator, RAM and program counter - and simulated the passage of instructions through the hardware.

The five shuffled data around, wrote it to memory, carried out computations and inserted them into the right places in the store."

Through self-study of CS texts and good code that others have written I've been gaining a lot more depth to my OOP programming skills.

I'd love though to get a more ground up, "live action" education on what's happening at the machine level, albeit it would probably need to be based on the simulation of a tiny computer by modern standards, maybe something like Knuth's MixMaster.

I recommend The Element of Computing Systems (http://www1.idc.ac.il/tecs/). It's has no "online shell" but the book is accompanied with hardware simulators

Perfect! Thanks a bunch.

Ordered on Amazon! Really, I feel very excited, just wanted to say thank you again. I had not stumbled across this resource when googling around for such an intro/guide, or maybe it just didn't catch my eye.

Not an online shell, but perhaps playing with Arduino would be a good way to experience basic computing.

I remember a brand of washing detergent running a "Computers for Schools" marketing campaign, here in Ireland around about 1986. Myself and my classmates had to cut out tokens from the packaging and bring them into school. After a year, all the tokens were counted up, and we finally had enough to get one "free" BBC Micro.

All we were missing was a teacher who knew what to do with it.

/doh

28 year old I think you'll find.

Yes, that was a funny mistake there. 18 years ago we were almost a decade in to 'ARM' (Acorn Risc Machine) territory already.

Anybody here remember 'lander'?

edit: maybe they meant the 18 years relative to the date the computer was officially discontinued? But it had already been out of the regular trade for many years at that point.

Oops. Unfortunately, Mathematics degrees don't teach arithmetic. Too late to fix it now. :-(

Some interesting points there about education in the UK

1) using Visual Basic by default (which is obsolete in industry and was never even intended to be a pedagogical language anyway)

2) The reference to "ICT" which is a term that doesn't exist outside of schools.

Depends what A-Level subject they're taking and school; at my school, they're taught Pascal and C (possibly moving into Objective-C this term if I finish installing the Macs into my department before the end of next week!)

At secondary school we had BBC Basic running in an emulator on the RM Nimbus, which had the mysterious 80186 processor. You could run Turbo Pascal if you first ran the 8086 emulator.

If I were designing the curriculum kids would be taught Forth or ML.

"using Visual Basic by default"

I don't believe that is the case. I know some schools teach BBC BASIC (for Windows), which of course was specifically designed for the purpose: http://www.bb4w.com/

I'm amazed they're using BBC Micros for game programming, an awful choice. They should be using ZX Spectrums or C64s.

BBC Basic was easily the best on the 8-bit micros. You can go straight to procedures and functions without ever using GOSUB or GOTO. Plus the OS provided an interface to its internals (e.g. *FX, the OS... routines like OSWRCH, the in-line 2-pass assembler) and vector tables, no need to peek and poke.

Having used a BBC Micro and ZX Spectrums I much preferred the Beeb - everything from the nice keyboard through to the (relatively) pleasant Basic where it was pretty simple to drop down to lower level stuff.

If you want to see what you can achieve using BBC BASIC for games programming these days (on a PC) look here: http://www.bb4wgames.com/

I for one would be intrigued to program a punch card computer. They were before my time and sound like fun.

If you are excellent typist, perhaps. Otherwise, they were a pain.

Reply on news.ycombinator.com