Search found 1392 matches

by Coeus
Fri Nov 15, 2019 10:22 pm
Forum: software & utilities for the pc, mac or unix
Topic: Proposal for BBC BASIC 'FOR lists'
Replies: 25
Views: 704

Re: Proposal for BBC BASIC 'FOR lists'

My difficulty with that argument is that several other 'modern' languages do use FOR to indicate general iteration rather than just a sequence: I think in many languages in which this appears you could say that this is syntactic sugar in that it does not enable you to do anything that you could not...
by Coeus
Sat Nov 02, 2019 10:24 pm
Forum: software: other
Topic: Saving with wildcards
Replies: 1
Views: 129

Saving with wildcards

I thought I'd try saving a file with wildcards in the name and got some surprising, at least to me, results. I don't know if these are well known or documented. First for DFS 0.9 (8271): dfs8271.png So this expands the '*' into hashes as if it was about to do some wildcard matching but then saves wi...
by Coeus
Thu Oct 31, 2019 2:49 pm
Forum: hardware
Topic: Master - Hangs on disk command
Replies: 10
Views: 329

Re: Master - Hangs on disk command

Its a little annoying, because if you accidentially mistype a star command, it then tried to access the disk and hangs - you then have to press break. If you don't have a disc drive connected then it is probably best to *UNPLUG the DFS and ADFS filing systems so the system will make no attempt to a...
by Coeus
Wed Oct 30, 2019 8:00 pm
Forum: hardware
Topic: Master - Hangs on disk command
Replies: 10
Views: 329

Re: Master - Hangs on disk command

Is there any reason to suppose the behaviour with no disc drive connected should match the behaviour with the drive connected but no disc in it? I would be surprised to find any emulator having set out to emulate the drive disconnected condition. When the disc has been ejected it will almost certain...
by Coeus
Wed Oct 30, 2019 7:47 pm
Forum: software & utilities for the pc, mac or unix
Topic: Greaseweazle - £2 disc archiver!
Replies: 9
Views: 834

Re: Greaseweazle - £2 disc archiver!

I checked the project linked to but it is not immediately obvious what is done in hardware and what in software. Do the flux level archivers have a common mode of operation? How does it differ from the obvious of take the signal from the head of a disc drive, amplify it, feed it through a suitable A...
by Coeus
Wed Oct 30, 2019 7:20 pm
Forum: off-topic
Topic: LOLPRICE
Replies: 2950
Views: 276753

Re: LOLPRICE

Is it worth much that? Cos i've got the same record somewhere Exactly the same? There's more to it than which piece of music is on the record. Like anything it's about rarity so if you have a copy where there's a mistake on the label where only a few leaked out before it was corrected then that's m...
by Coeus
Mon Oct 28, 2019 9:24 pm
Forum: software & utilities for the pc, mac or unix
Topic: Acorn files on a PC/Mac, attributes and transfer software
Replies: 4
Views: 164

Re: Acorn files on a PC/Mac, attributes and transfer software

They've been around since forever, probably the late 1980s. Thanks, Jonathan. So to parse the first bit in C is easy enough. void parse_inf(const char *fn) { unsigned load = 0, exec = 0; char name[13]; size_t len = strlen(fn)+5; char *inf = alloca(len); snprintf(inf, len, "%s.inf", fn); FILE *fp = ...
by Coeus
Mon Oct 28, 2019 5:45 pm
Forum: software & utilities for the pc, mac or unix
Topic: Acorn files on a PC/Mac, attributes and transfer software
Replies: 4
Views: 164

Acorn files on a PC/Mac, attributes and transfer software

The attributes kept with Acorn files on their native filing systems don't really fit into the native attributes on Windows/Linux/MacOS with the load and exec addresses being the biggest mismatch. There seems to be a convention to write these to a sidecar file with the .inf extension. Certain this is...
by Coeus
Mon Oct 21, 2019 5:28 pm
Forum: hardware
Topic: Screen shadow memory
Replies: 35
Views: 2017

Re: Screen shadow memory

I don't mean it shadows SWR but the address map can go past 0x8000 so can be used as SWR. The 32K block "overlaps" &8000... Yes, this extra piece of RAM is not sideways RAM in the usual sense in that it is not selected by writing to ROMSEL and can thus not participate in the OS scheme for sideways ...
by Coeus
Mon Oct 21, 2019 5:12 pm
Forum: hardware
Topic: Screen shadow memory
Replies: 35
Views: 2017

Re: Screen shadow memory

I'm well aware of how sideways banking works, but this cannot be the case for this board. The full 32K is paged in with a write to &FFFC, which is performed in ROM (which is only 8K and can be in any bank). If you overlay the extra 12K as sideways RAM then the code that triggered the switch is no l...
by Coeus
Mon Oct 21, 2019 5:00 pm
Forum: software: other
Topic: ADFS Compaction
Replies: 1
Views: 152

ADFS Compaction

I have been thinking about possible approaches for compacting an ADFS filing system, i.e. closing up the gaps between files so all the free space is in one chunk. So firstly, does anyone know what algorithm the ADFS ROM uses to do this? What about thinking with a clean sheet instead? The first thing...
by Coeus
Sun Oct 20, 2019 7:25 pm
Forum: software: other
Topic: Short and sweet prime numbers in Basic
Replies: 24
Views: 822

Re: Short and sweet prime numbers in Basic

Indeed I'd be surprised if there were any "simple and elegant" solutions left. Trial division is the really obvious way to find primes. The sieve seemed simple and elegant to me when I thought of doing it that way in response to a competition run by our local radio station for a program to finding p...
by Coeus
Fri Oct 18, 2019 1:57 pm
Forum: software: other
Topic: *GRAPHICS command
Replies: 4
Views: 382

Re: *GRAPHICS command

Thinking of the RM Nimbus takes me back to their 380Z and 480Z machines. As best I remember these machines had video overlayed from two sources: a character mapped display used for text and a bitmapped display. The machine would start by printing text only and the bitmapped display may have needed t...
by Coeus
Fri Oct 18, 2019 9:40 am
Forum: hardware
Topic: Multiple programs on ROMs using tl866ii plus programmer
Replies: 3
Views: 256

Re: Multiple programs on ROMs using tl866ii plus programmer

On the question of how you use the presumably Windows software to load multiple files into the same EPROM at different places you'll have to wait for someone who has used the Windows software for that programmer. I have a TL866 but I am using minipro on Linux to drive it. On Linux I simply use the '...
by Coeus
Wed Oct 16, 2019 1:03 pm
Forum: software: other
Topic: Serial port BASIC commands
Replies: 16
Views: 562

Re: Serial port BASIC commands

As well as project designs for a MIDI interface there was a commercial one, the M2000, as part of the Hybrid music system.

Thinking of which, the Hybrid software can act as a MIDI sequencer too.
by Coeus
Mon Oct 07, 2019 8:54 pm
Forum: emulators
Topic: Request for testers for quick but fascinating test case
Replies: 36
Views: 1379

Re: Request for testers for quick but fascinating test case

Ok, I don't think you've had this one in the results yet.

BBC B, Issue 7, but with a R65C02 in place of the usual NMOS 6502: 2/2
On my Master with VTI 6845: 255/255
by Coeus
Sat Oct 05, 2019 12:07 am
Forum: hardware
Topic: BBC Micro PSU blanking plate
Replies: 5
Views: 299

Re: BBC Micro PSU blanking plate

So does this mean this is probably not the PSU that originally came in that case?

Or maybe when a new issue came out the stock of old PSUs ran out before/after the stock of cases?
by Coeus
Thu Oct 03, 2019 3:23 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

Apologies if this is what you’re already saying, but thinking laterally from this, if the first thing MMFS finds on startup is the 12k spare ram, left over from setting up shadow ram, does this happen in a consistent, reliable manner (ie same ram area every time)? If so, and that location can be kn...
by Coeus
Wed Oct 02, 2019 11:21 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

But we still need to get SWMMFS to enable writing to its own sideways RAM bank before it would work with this board. Dave, Just looking at the code, do you think the subroutine PageIn12K for the Bplus would be the key to this, i.e. for a Solidisk version, everywhere the B+ version would need to pag...
by Coeus
Wed Oct 02, 2019 10:46 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

So, if I understand you correctly, you’re saying that ZMMFS isn’t giving the “No sideways ram banks available” error because it can’t find any at all, but because it does find one but it’s too small and the error message is actually because the first bank it finds is too small and its copy fails? C...
by Coeus
Wed Oct 02, 2019 10:33 pm
Forum: emulators
Topic: Multiple concurrent BeebEm for Unix instances?
Replies: 6
Views: 232

Re: Multiple concurrent BeebEm for Unix instances?

And, because B-Em didn't have this quite right, I have added it to this branch: https://github.com/stardot/b-em/tree/sf/disclock This goes beyond simply making sure data is committed to file on spindown and uses record locking to make a second instance of B-Em with the same disc mounted wait, i.e. i...
by Coeus
Wed Oct 02, 2019 10:21 pm
Forum: emulators
Topic: Multiple concurrent BeebEm for Unix instances?
Replies: 6
Views: 232

Re: Multiple concurrent BeebEm for Unix instances?

It was really just for even faster development :D The more Beebs I can have running at a time, the quicker I can try new ideas :) I could also try the same program on different targets at the same time. That was one of the ideas behind VDFS, which b-em supports. Unlike the usual filing systems wher...
by Coeus
Wed Oct 02, 2019 8:06 pm
Forum: emulators
Topic: Multiple concurrent BeebEm for Unix instances?
Replies: 6
Views: 232

Re: Multiple concurrent BeebEm for Unix instances?

Can you run multiple instances of BeebEm together, and mount the same disc images in each one? I think there are two separate things here. One applies to emulators in general, the other is emulator-specific. For Acorn DFS there some caching going on within DFS itself. Essentially, because floppies ...
by Coeus
Wed Oct 02, 2019 7:53 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

Coeus wrote:
Wed Oct 02, 2019 7:44 pm
So I think what needs to happen is to also write to &FE36 to move the mapping of that 32K bank up so it goes from &4000 to &C000.
I suspect this is what you mean by enabling the sideways RAM. Before doing that the RAM bank is there, but too short.
by Coeus
Wed Oct 02, 2019 7:44 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

Does the fact that the eprom version reports that it can't find any sideways ram suggest that it's looking too early in the startup cycle, before the board has actually allocated any? Whereas the same rom running from sideways ram must, by definition, be waiting until the sideways ram is available ...
by Coeus
Wed Oct 02, 2019 6:52 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

Or finally, I had assumed that, as this board sits in the CPU socket, they had you put the NMOS 6502 you removed into a socket on the board. Did they, perhaps, include a 65C02 on the board? That may make these well-defined instructions. I am now thinking it is probably this one. If I have B-Em emul...
by Coeus
Wed Oct 02, 2019 6:44 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

Boydie, Thanks for posting that. I thought I had a look at some of the service calls and see what I could learn and this ROM seems to be doing some very weird things. The first thing to note is that this appears to be two logical ROMs glued together into the one actual ROM as the service entries are...
by Coeus
Wed Oct 02, 2019 11:30 am
Forum: off-topic
Topic: Lardo's Atari 800
Replies: 30
Views: 470

Re: Lardo's Atari 800

The cheap multimeters give very misleading results when switched to AC and testing ANY DC systems, even a 9V PP3 battery! My suspicion is that the cheap multimeters are feeding the AC input signal through a diode, i.e. half-wave rectifying it and then doubling the answer in software to compensate (...
by Coeus
Tue Oct 01, 2019 1:04 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

The 2m128 and 4m256 were totaly different boards. I have a 2m128 (and wrote a manager ROM to fix all the bugs in the STL version), and the 4m256 is... different. With the 2M128 ACCCON (FE34) determined shadow/buffer modes So do they use different manager ROMs, then? Boydie, perhaps you could check ...
by Coeus
Mon Sep 30, 2019 10:30 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 949
Views: 67039

Re: MMFS Development and Support

Going slightly off-topic but I have been looking at what this ROM does at start-up and I think I have found two bugs already. In response to service call 2 it claims the NMI space with ROM service call &C and then copies this routine into the NMI space, leaving the RTI: 0D01: A5 F4 LDA F4 0D03: 48 P...