Search found 541 matches

by crj
Fri Feb 23, 2018 12:32 am
Forum: hardware
Topic: AP5, Pegasus/AP3-4/EUPURS Metal Case Design
Replies: 12
Views: 487

Re: AP5, Pegasus/AP3-4/EUPURS Metal Case Design

daveejhitchins wrote:Prices are tentative (shouldn't move - just haven't got the proforma from the painters, yet) at:

AP5 £7.16
Pegasus £6.22 - The new AP3/4 will also use this case
EUPURS £7.54
Hmm. that's slightly cheaper than one-off 3D printing, but not massively so.

Good to know, though - thanks.
by crj
Fri Feb 23, 2018 12:12 am
Forum: programming
Topic: Correctly handling EOF when reading with OSGBPB
Replies: 3
Views: 140

Re: Correctly handling EOF when reading with OSGBPB

If you really must, you can check for EOF then if not at file-end perform an OSGBPB, which is guaranteed to return at least one byte. That should cover all circumstances. On the other hand, it'll be slightly inefficient. Very inefficient on NFS. And it still feels as though there has to be something...
by crj
Thu Feb 22, 2018 5:47 pm
Forum: hardware
Topic: AP5, Pegasus/AP3-4/EUPURS Metal Case Design
Replies: 12
Views: 487

Re: AP5, Pegasus/AP3-4/EUPURS Metal Case Design

Just out of interest, what's the ballpark price for this kind of thing, for what kind of quantity? For plastic, injection moulding has a setup fee in the mid-thousands, vacuum forming approaches a thousand, and the cost per unit for 3D printing doesn't decline with volume. I'm wondering how metal co...
by crj
Thu Feb 22, 2018 3:25 am
Forum: general
Topic: little optimistic???
Replies: 28
Views: 892

Re: little optimistic???

Acorn neglected floating point arithmetic support, leaving the A7000+ as their only machine in the Risc PC series (architecturally) that did this in hardware, and that at a much slower clock frequency. Not much help if you're doing MP3-related things towards the end of the 1990s. MP3 decoding, at l...
by crj
Thu Feb 22, 2018 3:21 am
Forum: general
Topic: little optimistic???
Replies: 28
Views: 892

Re: little optimistic???

Of course, there is something else to consider: some computer manufacturers had often discovered previously that bringing out an upgraded machine with improved hardware did not always bring success. Especially if there was some loss of compatibility. It's worth bearing in mind that Acorn's operatin...
by crj
Thu Feb 22, 2018 3:06 am
Forum: hardware
Topic: B+64K - 12k sideways ram working
Replies: 15
Views: 472

Re: B+64K - 12k sideways ram working

However, today I much prefer the Master[...] There are plenty of other reasons to prefer the Master: ⋅ Page at &E00 ⋅ Exploded character set ⋅ Most of the Graphics Extension ROM built in ⋅ More sensible arrangement of the cursor keys ⋅ Break key...
by crj
Thu Feb 22, 2018 2:52 am
Forum: bbcmicro.co.uk
Topic: Dreadnought / Dreadnaught
Replies: 4
Views: 161

Re: Dreadnought / Dreadnaught

Basically, the two words are one and the spelling has diverged. Differently here and in the USA.

Relatedly, it's worth bearing in mind that "naughty" used to mean "worth naught/nought". Several passages of Shakespeare make more sense when you realise this. (-8
by crj
Thu Feb 22, 2018 2:47 am
Forum: off-topic
Topic: This guy made a 'C5' twice as good 70 years earlier...
Replies: 3
Views: 255

Re: This guy made a 'C5' twice as good 70 years earlier...

You see how high the bed of the cargo area is? The entire space under there which isn't wheels, is batteries.
by crj
Thu Feb 22, 2018 2:46 am
Forum: off-topic
Topic: Why did CISC prevail?
Replies: 21
Views: 632

Re: Why did CISC prevail?

This might, or might not, help: Sorry - I was being mainly rhetorical, bordering on bitterly sarcastic. Tone doesn't carry very well online. (-8 Executing Thumb code by mapping it into ARM instructions may have been the thing they managed to patent, but it's a lousy idea in practice. ARM claimed th...
by crj
Thu Feb 22, 2018 2:31 am
Forum: hardware
Topic: Pi Zero Super Interface
Replies: 12
Views: 334

Re: Pi Zero Super Interface

You can arrange for a (complex) circuit sitting in a ROM socket to accept writes to a channel by mapping reads to some page as writes of that value. Indeed you can... The nice thing about a ROM in a host machine is that it can take over the host's RAM The other nice thing about a ROM is that a 28-p...
by crj
Thu Feb 22, 2018 2:19 am
Forum: hardware
Topic: Pi Zero Super Interface
Replies: 12
Views: 334

Re: Pi Zero Super Interface

The problem with any Tube projects for the Compact is that [...] the built-in filing systems have no Tube support Huh? Someone actually went to the trouble of removing that code? I boggle. I mean, I guess they might have been seriously short of space, but I wouldn't have expected that code to be es...
by crj
Thu Feb 22, 2018 2:09 am
Forum: programming
Topic: Correctly handling EOF when reading with OSGBPB
Replies: 3
Views: 140

Re: Correctly handling EOF when reading with OSGBPB

I'm in danger of being corrected, here, but by my recollection... The Beeb's OS isn't like Unix/Posix. OSGBPB is only intended for use on files, not any kind of stream device, and it's only intended for blocking accesses. That means, when you ask to read N bytes, the only reason you might receive fe...
by crj
Thu Feb 22, 2018 1:29 am
Forum: archive submissions
Topic: Billiards - H & H software 1983
Replies: 7
Views: 217

Re: Billiards - H & H software 1983

CMcDougall wrote:I wondered why only 1/4 of sideA was filled, sideB is the same but at 300baud, thats a first! 8)

I thought quite a few games did that?

Or, more precisely, I thought they claimed on their packaging/labelling to have done so. I never actually checked!
by crj
Wed Feb 21, 2018 7:47 pm
Forum: software: other
Topic: Hacking the school Econet
Replies: 15
Views: 476

Re: Hacking the school Econet

Um. On the one hand, our staff were pretty knowledgeable. For example, they physically isolated the fileserver and admin workstation from the rest of the Econet before performing management operations, precisely because they knew passwords were in the clear on the wire. On the other hand, I wrote th...
by crj
Wed Feb 21, 2018 6:35 pm
Forum: adventures
Topic: Text Adventure Games
Replies: 42
Views: 3368

Re: Text Adventure Games

At a guess, because the BBC Micro has MODE 7, which only uses 1K of screen memory, whereas the cheapest mode on the Electron is MODE 6 which uses 8K.
by crj
Wed Feb 21, 2018 6:30 pm
Forum: projects
Topic: Making reasonable progress with a Sudoku solver
Replies: 35
Views: 715

Re: Making reasonable progress with a Sudoku solver

If you want to run in teletext mode, an alternative to using extra spacing to delimit the 3x3 sub-squares is to use the | # = characters. In MODE 7, those come out looking like this:
Image
by crj
Wed Feb 21, 2018 5:55 pm
Forum: off-topic
Topic: High school student building 70's era chip fab in his garage
Replies: 3
Views: 244

Re: High school student building 70's era chip fab in his garage

It is indeed. For me, though, the really big deal is this part: To pattern the circuits on his chips, Zeloof uses a trick not available in the 1970s: He’s modified a digital video projector by adding a miniaturizing optical stage. He can then create a mask as a digital image and project it onto a wa...
by crj
Wed Feb 21, 2018 5:40 pm
Forum: off-topic
Topic: Why did CISC prevail?
Replies: 21
Views: 632

Re: Why did CISC prevail?

Ah, but did Thumb become Thumb-2?

Or did they design something new from scratch and call it Thumb-2?
by crj
Wed Feb 21, 2018 5:32 pm
Forum: off-topic
Topic: Work experience BITD - claims to fame, and infamy
Replies: 15
Views: 813

Re: Work experience BITD - claims to fame, and infamy

You think someone would be stupid enough to walk through a nuclear power station with the lights off? (-8
by crj
Wed Feb 21, 2018 5:20 pm
Forum: emulators
Topic: Double-clicking .SSD overrides VDU 14 ?!
Replies: 13
Views: 355

Re: Double-clicking .SSD overrides VDU 14 ?!

I think that'll delay the program indefinitely in BeebEm But I thought you wanted the program delayed indefinitely? (-8 OKOK, just not at that point in the code. If you really can't get the emulators fixed, an alternative would be to write a small assembly shim which sits on KEYV. I've not tested t...
by crj
Sun Feb 18, 2018 10:38 pm
Forum: wanted
Topic: Wanted: Electron shift key cap
Replies: 1
Views: 118

Wanted: Electron shift key cap

I got hold of an Electron last week, and am looking for a shift key cap.

I can offer a return key cap in part exchange. (-8

Image

(PS: Yes, I've already asked Mark at RetroClinic.)
by crj
Sun Feb 18, 2018 3:27 am
Forum: general
Topic: little optimistic???
Replies: 28
Views: 892

Re: little optimistic???

The 6502 was originally on an 8 micron process. Today, hobbyists can send a file to China. A couple of weeks later, they will receive a PCB which is, in effect, 80 micron. By 2082, you wouldn't even need to use programmable logic to replace any broken chips in a Beeb; you could use discrete componen...
by crj
Sun Feb 18, 2018 3:15 am
Forum: off-topic
Topic: Romance is dead
Replies: 6
Views: 331

Re: Romance is dead

I don't know about anyone else, but what I did for Valentine's Day was take a quick jaunt up the A14 to collect an Electron.
by crj
Sun Feb 18, 2018 3:07 am
Forum: hardware
Topic: Some software to test a Music 500?
Replies: 4
Views: 185

Re: Some software to test a Music 500?

What he said. If you're just wanting to make sure it's working, I really wouldn't bother with the Music 5000 software, though. The first option, the Music 500 one, is way simpler and just as effective. As a slight caution, "Syncron" has some stonking great subsonics in it. Be careful with ...
by crj
Sun Feb 18, 2018 3:02 am
Forum: hardware
Topic: Music 5000 - sound generation
Replies: 12
Views: 391

Re: Music 5000 - sound generation

Careful. As well as the stuff that runs under interrupt (which I believe would be pitch and amplitude envelopes, plus gating, pitch, velocity, tempo and instrument changes taken from a priority queue) there is a co-operative threading system running as the current language. I believe it is mainly th...
by crj
Sun Feb 18, 2018 2:47 am
Forum: off-topic
Topic: Thermionic Valves
Replies: 25
Views: 727

Re: Thermionic Valves

Impressive, but what on earth were they thinking when the chose the shape of the enclosure for some of those? I'm looking especially at the UU5.

Does making it a bizarre shape serve any electronic purpose?
by crj
Sat Feb 17, 2018 3:13 am
Forum: hardware
Topic: Music 5000 - sound generation
Replies: 12
Views: 391

Re: Music 5000 - sound generation

I guess I could rig up some kind of benchmarking and find out, but does anybody happen to know offhand what percentage of CPU time is burned by servicing interrupts for the Music 5000? (It actually used a User VIA timer, didn't it? I don't believe the Music 5000 itself can actually generate interrup...
by crj
Sat Feb 17, 2018 3:09 am
Forum: hardware
Topic: Music 5000 - sound generation
Replies: 12
Views: 391

Re: Music 5000 - sound generation

You could no doubt do something similar with BeebOPL or BeebSID but you are limiting yourself to the capabilities of the original sound chip rather than taking advantages of their extra features. Not necessarily. ENVELOPE wouldn't necessarily be much use, but you could take the stream of notes gene...
by crj
Sat Feb 17, 2018 2:58 am
Forum: software: classic games
Topic: MIA Games on eBay
Replies: 88
Views: 2290

Re: MIA Games on eBay

Almost 5 years! Time flies when you are having fun! Mmm. I know I registered back then. (More exactly, I went on an archaeological dig for my registration details when I tried to register and discovered I already had.) I don't recall why, though. Let the record show my first actual post was on Sept...
by crj
Sat Feb 17, 2018 2:51 am
Forum: general
Topic: Today I received.....
Replies: 4435
Views: 276034

Re: Today I received.....

I actually received these on Wednesday, but have only just got around to taking a photo:

Image

Two model Bs courtesy of Lardo Boffin, and an Electron with Slogger ROM expansion, Slogger disc interface and a floppy drive courtesy of alan50.