Search found 1698 matches

by BigEd
Mon Mar 12, 2018 4:03 pm
Forum: archive submissions
Topic: Unidentified BBC B service Manual Extract
Replies: 7
Views: 356

Re: Unidentified BBC B service Manual Extract

Some of the document's text is also found on Chris Richardson's page "Inside the BBC"
http://8bs.com/inbbc.htm
by BigEd
Mon Mar 12, 2018 2:08 pm
Forum: projects
Topic: Making reasonable progress with a Sudoku solver
Replies: 75
Views: 2492

Re: Making reasonable progress with a Sudoku solver

Found a thread to help with PAGE: On the topic of memory I'm going to have a small rant. It's boggling that Acorn chose to set PAGE=&1900 by default for DFS when the vast majority of simple file load/save operations can be undertaken quite safely / happily with PAGE=&1100 If you start as a B...
by BigEd
Mon Mar 12, 2018 12:54 pm
Forum: archive submissions
Topic: Literacy Project Provisional copy
Replies: 3
Views: 152

Re: Literacy Project Provisional copy

OK thanks, and done:
https://archive.org/details/BBCComputer ... rovisional

(Let me know if you want named credit for the scan.)

The OCR output is of course patchy.
by BigEd
Mon Mar 12, 2018 12:35 pm
Forum: archive submissions
Topic: Unidentified BBC B service Manual Extract
Replies: 7
Views: 356

Re: Unidentified BBC B service Manual Extract

Looks like some of the text is found in "Microprocessor systems servicing" / "Servicing the BBC Micro" / "Hardware and simple test programs" (pdf) (which turns out to have quite a nice block diagram) although it's not the same document. Perhaps the same publisher? (Micr...
by BigEd
Mon Mar 12, 2018 12:24 pm
Forum: archive submissions
Topic: Literacy Project Provisional copy
Replies: 3
Views: 152

Re: Literacy Project Provisional copy

Nice! Are you OK for me to upload this to the Internet Archive and get it OCRd?
(Four pages of typewritten text describing the content of 10 proposed television programmes.)
by BigEd
Sun Mar 11, 2018 5:36 pm
Forum: other vintage computer hardware, software and games
Topic: ZX Spectrum next... Anybody backing ?
Replies: 102
Views: 6674

Re: ZX Spectrum next... Anybody backing ?

As I understand it, the Vega was a successful project, the Vega+ a disaster. The Spectrum Next appears to be going reasonably well - uncased boards were shipped many months ago, but the cased version is running a bit late. I assume if there was any big problem with the design, I would have heard, an...
by BigEd
Sun Mar 11, 2018 4:46 pm
Forum: projects
Topic: Making reasonable progress with a Sudoku solver
Replies: 75
Views: 2492

Re: Making reasonable progress with a Sudoku solver

I'm pretty sure you'd find Page can be lowered a bit if you're not doing explicit file i/o - load and save are cheap, I think, needing no buffer space. There's probably a recipe for lowering Page but I don't know it offhand. Loading to &1900 is pretty safe, I think. With some cleverness, if you ...
by BigEd
Sun Mar 11, 2018 4:11 pm
Forum: projects
Topic: Making reasonable progress with a Sudoku solver
Replies: 75
Views: 2492

Re: Making reasonable progress with a Sudoku solver

And that looks very good too! If RAM isn't much of a constraint then this might be best. How about using inverse video for the clue numbers? Ideally they'd be somehow different.
by BigEd
Sun Mar 11, 2018 1:45 pm
Forum: general
Topic: BBC Micro Tech spec Issue 3
Replies: 5
Views: 275

Re: BBC Micro Tech spec Issue 3

Ahem, I should have searched: it's already scanned here.

Although, that's showing as 41 pages so if you have extra, that could be interesting.
by BigEd
Sun Mar 11, 2018 12:12 pm
Forum: general
Topic: BBC Micro Tech spec Issue 3
Replies: 5
Views: 275

Re: BBC Micro Tech spec Issue 3

very interesting - are you able and willing to scan it?
by BigEd
Sun Mar 11, 2018 12:08 pm
Forum: projects
Topic: Making reasonable progress with a Sudoku solver
Replies: 75
Views: 2492

Re: Making reasonable progress with a Sudoku solver

Looks good to me! And Mode 7 is especially clear and readable. (But note that the Electron doesn't have a Mode 7)
by BigEd
Sat Mar 10, 2018 5:29 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 47
Views: 2721

Re: Acorn's Second Processors and the Tube - what, and why

Just out of interest, do you - could you - compile them on the ARM Native?
by BigEd
Sat Mar 10, 2018 2:07 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 47
Views: 2721

Re: Acorn's Second Processors and the Tube - what, and why

Quite so - in the context of PiTubeDirect, the Tube ULA emulation is written in assembly (initially in ARM and then in VideoCore for a performance and reliability win), and is very time-critical so it must be, whereas the second processor emulation is generally written in C - it's only the very high...
by BigEd
Sat Mar 10, 2018 9:52 am
Forum: general
Topic: Maplin Electronics in administration
Replies: 79
Views: 3107

Re: Maplin Electronics in administration

I found this (warning, lots of depressing news within): Members of the company’s pension schemes need not panic. When schemes collapse they fall into the hands of the PPF , who have the responsibility for paying workers’ pensions. Those who already reached the scheme’s normal pension age will receiv...
by BigEd
Fri Mar 09, 2018 8:46 am
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 47
Views: 2721

Re: Acorn's Second Processors and the Tube - what, and why

It was an interesting demo JGH, and I appreciated it!

NorthernBob, if you want something more like a sales pitch, you may have to make it yourself... it turns out to be difficult to make a slick and self-explanatory video. I know I can't do it.
by BigEd
Fri Mar 09, 2018 8:22 am
Forum: other vintage computer hardware, software and games
Topic: PiZeroSCSI
Replies: 3
Views: 178

Re: PiZeroSCSI

That would be well worthwhile!
by BigEd
Wed Mar 07, 2018 9:51 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 120
Views: 4769

Re: SpectROM - Speccy emulator for the Pi co-pro

It's almost like you were in the room with us! It would be nice to know of a free location - or, could it perhaps be left on the stack? We also noted there's an environment-reading mechanism, so for example the information could be left after the zero-terminated command line. (Like Unix, where the c...
by BigEd
Tue Mar 06, 2018 10:42 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 120
Views: 4769

Re: SpectROM - Speccy emulator for the Pi co-pro

Rob, I was round at Dave's this afternoon, and were able to determine that - for your special case of an application running on native ARM - your application can indeed do some bitbanging on unused Pi GPIOs just by knowing the addresses of the memory-mapped peripherals. Possibly a good choice of pin...
by BigEd
Tue Mar 06, 2018 8:53 am
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 47
Views: 2721

Re: Acorn's Second Processors and the Tube - what, and why

zxhost sounds like just the thing: the effect will be running CP/M or GEM on a Speccy. So long as you boot into the Speccy prompt and type some Basic to start with, it'll remain clear that it's a Speccy, but acting as a portal into something else - something with lots of software. CP/M easier of cou...
by BigEd
Mon Mar 05, 2018 6:38 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 43
Views: 2549

Re: Electron ULA Schematics

Great - do please keep us updated!

(I think Dave's code allowed itself to creep off the true vertical or horizontal, according to the patterns it recognised - so it didn't need a perfectly aligned scan.)
by BigEd
Mon Mar 05, 2018 2:29 pm
Forum: projects
Topic: Making reasonable progress with a Sudoku solver
Replies: 75
Views: 2492

Re: Making reasonable progress with a Sudoku solver

All good then! I just tried and failed to solve the 17clue problem myself... but I will not resort to guesswork!
by BigEd
Mon Mar 05, 2018 2:17 pm
Forum: projects
Topic: Making reasonable progress with a Sudoku solver
Replies: 75
Views: 2492

Re: Making reasonable progress with a Sudoku solver

Ah right... is there merit in showing at the end how many cells were found by recursing vs inference? Or is that already there?
by BigEd
Mon Mar 05, 2018 1:48 pm
Forum: projects
Topic: Making reasonable progress with a Sudoku solver
Replies: 75
Views: 2492

Re: Making reasonable progress with a Sudoku solver

I was just thinking... there are two extreme cases of solver design. One is purely a recursive backtracking thing (may be rather slow), and the other is purely using inference rules and has no backtracking (may fail to solve.) As this program is a bit of both, would it be interesting for the program...
by BigEd
Mon Mar 05, 2018 11:57 am
Forum: for sale / freebies
Topic: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 603
Views: 58035

Re: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro

I think you need to tap the second-hand market now - try posting in Wanted.
by BigEd
Sun Mar 04, 2018 3:28 pm
Forum: off-topic
Topic: Thermionic Valves
Replies: 51
Views: 2153

Re: Thermionic Valves

Found this re: Mullard: https://www.youtube.com/watch?v=-GgWIlvyEL8 By coincidence just came across this story of the EF50 , a wartime essential. It seems Philips, the parent company, were now regarded as the enemy, or in enemy territory, and Mullard was at risk of compromise... With the number of ...
by BigEd
Sun Mar 04, 2018 8:58 am
Forum: software: new games
Topic: Thoughts on StarWars for the beeb
Replies: 20
Views: 728

Re: Thoughts on StarWars for the beeb

I'm going to have to be vague here, but as I recall PiTubeDirect needed to do something special to support the multiple accesses of a RMW instruction on the host. It hangs around after an access in case there's a followup, and as a consequence there's something it couldn't do... which turns out not ...
by BigEd
Sat Mar 03, 2018 6:42 pm
Forum: hardware
Topic: Pi Zero Super Interface
Replies: 22
Views: 1175

Re: Pi Zero Super Interface

Here's an interesting thing: a bare metal library for the Pi which supports USB, SDCard, FAT, TCP/IP.
https://github.com/rsta2/circle
(Via ZXbaremulator at http://zxmini.speccy.org/, via José Luis Sánchez on G+)
by BigEd
Sat Mar 03, 2018 4:01 pm
Forum: other vintage computer hardware, software and games
Topic: ZX Spectrum next... Anybody backing ?
Replies: 102
Views: 6674

Re: ZX Spectrum next... Anybody backing ?

It's fine for you not to enjoy the same things that some other people do enjoy. It's fine for people to spend their time in ways which you wouldn't.

But what positive outcome could there be from challenging people to justify their interests?
by BigEd
Sat Mar 03, 2018 3:55 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 43
Views: 2549

Re: Electron ULA Schematics

It might be that the recent photo stitch by revaldinho is already enough for a circuit extraction attempt - watch this space before taking action! There might be other ULAs which would be worth capturing, but I'm not sure if there are others with metal lids.