Search found 560 matches

by Coeus
Tue Jan 23, 2018 11:25 pm
Forum: for sale / freebies
Topic: BeebSCSI mini
Replies: 111
Views: 6887

Re: BeebSCSI mini

flynnjs wrote:I think we have interest in 4 so far. I'll do another batch if we get to 10.


I'll take one.
by Coeus
Tue Jan 23, 2018 11:18 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 21
Views: 1045

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

Just as a matter of interest, here are my thoughts on what I think would have been possible in the early 1980s. It would have been possible to design and market a Z80A CPU based home computer that could be compatible with CP/M and which could load some programs from cassette tape. A full CP/M syste...
by Coeus
Tue Jan 23, 2018 2:15 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 21
Views: 1045

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

...A lot of 6502 code ended up being coded to start at &1900 regardless of what machine it actually ended up running on. And presumably this is one of the reasons some don't like ADFS as it raises OWHWM still further compared to DFS, unless you are on a Master. It is also possible, of course, t...
by Coeus
Tue Jan 23, 2018 12:46 pm
Forum: hardware
Topic: BBC Model B and DFS Problem
Replies: 31
Views: 412

Re: BBC Model B and DFS Problem

I will check the connection between Pin 11 8271 and Pin 9 IC27. I just ordered an USB Logic Analyzer (8 Channel), so I can check the Interrupt on Pin 11 8271 at the weekend. My BBC works fine, if the DFS upgrade is out (and the Turbo MMC Rom in). It works fine too, when the DFS upgrade is in and on...
by Coeus
Tue Jan 23, 2018 12:42 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 21
Views: 1045

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

Plus, any properly-written software will use the extended capaibilies of the second processor automatically. Ask the operating system how much memory is available. Use the API to access I/O functions. Use "how much memory have I got?" to find out how much memory you have, not "where ...
by Coeus
Sun Jan 21, 2018 9:46 pm
Forum: hardware
Topic: BBC Model B and DFS Problem
Replies: 31
Views: 412

Re: BBC Model B and DFS Problem

Yeah, I actually knew that (the no interaction part), I just wanted to see if he could get to a state where the DFS can be resident in the machine passively so that we could then see if it correctly responds to *HELP etc. Just some sanity checking steps for his DFS rom as it appears to the machine....
by Coeus
Sun Jan 21, 2018 9:20 pm
Forum: hardware
Topic: BBC Model B and DFS Problem
Replies: 31
Views: 412

Re: BBC Model B and DFS Problem

Ralf - in DFS config (no MMC rom) and whilst it’s hung after switch-on, perform a <Ctrl><T><Break> which should drop you into the prompt with the machine initialised as tape-only. This should work and then, a *HELP should correctly list DFS as one of the roms. Might just help to establish how much ...
by Coeus
Sun Jan 21, 2018 8:35 pm
Forum: hardware
Topic: BBC Model B and DFS Problem
Replies: 31
Views: 412

Re: BBC Model B and DFS Problem

Ralf did say that even with the Turbo MMC ROM out the problem persists. He also said that the behaviour is slightly different with DFS 0.9, which recognises the disk hardware but then locks up, versus DNFS 1.2 which does not find disk hardware that works sufficiently well to finish initialising. So,...
by Coeus
Fri Jan 19, 2018 7:42 pm
Forum: hardware
Topic: Problem BBC Model B and Turbo MMC
Replies: 30
Views: 594

Re: Problem BBC Model B and Turbo MMC

The TL866? I have one & use it to write ROMs for the BBC too. So your ROM should be OK. I am pretty sure that's the same on I have, though I am using it under Linux. So the machine locks up with the DFS ROM installed. If it works with BASIC in the same socket, and if the contents of the ROM are...
by Coeus
Thu Jan 18, 2018 2:36 pm
Forum: hardware
Topic: Fault finding index
Replies: 86
Views: 16951

Re: Fault finding index

O Lucky you have a device like that makes life easy to fault find the problem, and good to hear you got it back on the road :) Peter. I don't know if this was the one Hoglet was using but he had been experimenting with a logic analyser based on a very cheap piece of hardware to actually sample the ...
by Coeus
Wed Jan 17, 2018 10:44 pm
Forum: hardware
Topic: Newbie question regarding first machine
Replies: 16
Views: 458

Re: Newbie question regarding first machine

flaxcottage wrote:8. the Master runs faster


Any idea why?

Also, does anyone have any idea why master motherboards without the case are so common on eBay. Did the cases fall apart? Was there surplus stock? Or were they used in something completely different that had its own case? Or something else?
by Coeus
Tue Jan 16, 2018 11:44 pm
Forum: emulators
Topic: BeebEm ADFS disc access bug?
Replies: 14
Views: 386

Re: BeebEm ADFS disc access bug?

So, after all that try the attached image. This has the sector count back to the original value but has the missing second-side tracks inserted thus: $ i=0 $ while [ $i -le 79 ] > do > dd if=PIAS-ADFS_E.adf bs=4096 count=1 skip=$i > dd if=/dev/zero bs=4096 count=1 > let i=i+1 > done > PIAS-ADFS_E.adl
by Coeus
Tue Jan 16, 2018 11:21 pm
Forum: emulators
Topic: BeebEm ADFS disc access bug?
Replies: 14
Views: 386

Re: BeebEm ADFS disc access bug?

I've tried changing byte offset FD from 0A to 05, and whilst this does indeed allow MENU to be loaded, it creates another problem which is that *RUN !BOOT gives the message "Bad FS map". *DUMP !BOOT has the same effect, in fact just *ADFS does it as well. I realised I had not answered thi...
by Coeus
Tue Jan 16, 2018 11:08 pm
Forum: software: other
Topic: Accessing ROMs from the 6502 second processor
Replies: 14
Views: 518

Re: Accessing ROMs from the 6502 second processor

rharper wrote:Now for paging in the ROMs.
Ray.


Can you do what you need by issuing a service call to the ROM concerned? There's an OSBYTE for that so you may be able to issue that from the 2nd processor and have the OS look after actually running it in the host processor.
by Coeus
Tue Jan 16, 2018 10:25 pm
Forum: emulators
Topic: BeebEm ADFS disc access bug?
Replies: 14
Views: 386

Re: BeebEm ADFS disc access bug?

On anything except BeebEm this will produce a listing. On BeebEm it will generate 'Bad Program' after the LOAD command. Interestingly, on the git master B-Em this also produces "Bad Program". In the log it also produces the following: 16/01/2018 21:56:45 INFO Loaded drive 0 with ... discs...
by Coeus
Tue Jan 16, 2018 12:45 pm
Forum: emulators
Topic: BeebEm ADFS disc access bug?
Replies: 14
Views: 386

Re: BeebEm ADFS disc access bug?

It's reassuring to hear it isn't just me! Just to be clear though, - this bug appears to be totally repeatable (if using this specific floppy image) - and it doesn't actually relate to the hard disc at all. You don't need to switch hd support on to get the bug to appear. I'd switch to using B-Em fo...
by Coeus
Tue Jan 16, 2018 12:25 pm
Forum: software: other
Topic: Accessing ROMs from the 6502 second processor
Replies: 14
Views: 518

Re: Accessing ROMs from the 6502 second processor

Paged ROMs are only in the host (I/O) processor. The 2nd processor has a normal, linear address space with the exception of a small boot ROM at the very top of the address space. That means the latch to select the ROM and its OS copy need to be written on the host processor. At any time the only ROM...
by Coeus
Mon Jan 15, 2018 6:39 pm
Forum: hardware
Topic: BBC B Running slow
Replies: 15
Views: 577

Re: BBC B Running slow

With IRQ being level triggered, if it were held active it would presumably cause the CPU to make no progress at all as, as soon as it executes RTI and the interrupt enable bit is cleared it would respond to the IRQ again. So I would guess that whatever is triggering this is noisy.
by Coeus
Mon Jan 15, 2018 5:39 pm
Forum: archive requests
Topic: BCPL System Disc
Replies: 4
Views: 165

Re: BCPL System Disc

Thanks, guys.
by Coeus
Mon Jan 15, 2018 1:30 pm
Forum: programming
Topic: Many DEFPROC, 1 ENDPROC?
Replies: 17
Views: 1074

Re: Many DEFPROC, 1 ENDPROC?

Of course! But haven't had to do such low-level C hacking for many years now. Also, these days, with such huge advances in compilers and optimization techniques, I doubt if Duff's Device would even be worthwhile any more. The rule these days tends to be: don't micro-optimize - the compiler almost c...
by Coeus
Sun Jan 14, 2018 8:38 pm
Forum: archive requests
Topic: BCPL System Disc
Replies: 4
Views: 165

BCPL System Disc

After expanding the SSD of a BCPL system disc into a directory on VDFS I noticed that it now seemed to have more files in than it did originally. I went to check against the list in the manual and also found the file EXMP3B file missing and even going back to the original SSD it is still not there. ...
by Coeus
Sun Jan 14, 2018 4:17 pm
Forum: programming
Topic: Many DEFPROC, 1 ENDPROC?
Replies: 17
Views: 1074

Re: Many DEFPROC, 1 ENDPROC?

Thinking of Richard's comment about getting used to C and C++ it is interesting to back to BBC BASIC and fine the language that was praised at the time for enabling structured programming allows such as this and lacks features like modern exception handling despite the general approach of the underl...
by Coeus
Sun Jan 14, 2018 3:51 pm
Forum: programming
Topic: Filing system testing, BASIC, line numbers and version control
Replies: 9
Views: 197

Re: Filing system testing, BASIC, line numbers and version control

You could always go with ISO Pascal or BCPL? No line numbers! That's an interesting idea. I do remember years ago being a little frustrated by Pascal primarily, I think, because it didn't have "string" as a data type but used "array of characters" instead and then I seem to reme...
by Coeus
Sun Jan 14, 2018 3:31 pm
Forum: programming
Topic: Filing system testing, BASIC, line numbers and version control
Replies: 9
Views: 197

Re: Filing system testing, BASIC, line numbers and version control

You could try something like E%=0 ON ERROR E%=1 IF E%=0 THEN _command_you_want_to_test ON ERROR OFF IF E%=1 THEN PRINT "Error happened" IF E%=0 THEN PRINT "Command was successful" That looks useful. It had not occurred to me that the statement after the words ON ERROR does not h...
by Coeus
Sat Jan 13, 2018 11:03 pm
Forum: software: other
Topic: What version of Windows is best for running emulators, assemblers etc?
Replies: 5
Views: 277

Re: What version of Windows is best for running emulators, assemblers etc?

Thanks for that, tricky. I'm actually a Mac user, so "kind of" Linux. I'll have a look and see what state beebasm is in currently for Mac. I have not used a modern Mac but AFAIK it is Unix-like enough for many purposes. I'd be surprised if BeebAsm doesn't just compile and work as I don't ...
by Coeus
Sat Jan 13, 2018 8:09 pm
Forum: programming
Topic: Filing system testing, BASIC, line numbers and version control
Replies: 9
Views: 197

Filing system testing, BASIC, line numbers and version control

So, after having asked previously, I think, and not hearing of anything I decided I should write some simple BASIC programs to act as a filing system test suite. This was primarily to replace manual testing in VDFS on B-Em but could potentially be useful for other new/changed filing systems so it oc...
by Coeus
Sat Jan 13, 2018 7:52 pm
Forum: emulators
Topic: Variations on OSGBPB
Replies: 4
Views: 175

Variations on OSGBPB

I found a description on mdfs.net of the OSGBPB call which documents OSGBPB function 9 as, amongst other things, returning the filenames in a directory that has been opened by OSFIND, as opposed to function 8 which returns the names in the current directory. These two also differ in the way the file...
by Coeus
Sat Jan 13, 2018 7:30 pm
Forum: hardware
Topic: Floppy drive ready line.....
Replies: 2
Views: 123

Re: Floppy drive ready line.....

I found this http://www.hermannseib.com/english/synt ... floppy.htm

Interesting here that the behaviour of RDY seems different between IBM and Shugart.
by Coeus
Wed Jan 10, 2018 2:38 pm
Forum: hardware
Topic: Electron cassette counter revolution rate
Replies: 26
Views: 600

Re: Electron cassette counter revolution rate

the missing piece of the puzzle is that the take up spool has a clutch, often comprising a spring and a piece of felt, that enables it to slow down as the circumference of the tape wound into that spool becomes greater I thought cheap decks just used a motor with low enough torque not to stretch th...
by Coeus
Tue Jan 09, 2018 10:11 pm
Forum: programming
Topic: 32k memory management for dummies
Replies: 28
Views: 783

Re: 32k memory management for dummies

If you need to be able to select TAPE/ROM (as the above doesn't work before the Master): DEFPROCfs(Y%):LOCAL X%,A% IF Y%<4:A%=139.5+Y%/2:X%=Y%+1 ELSE A%=143:X%=18 CALL &FFF4:ENDPROC Probably I should have been more explicit. By not a a perfect solution I did mean not able to select TAPE/ROM as ...

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