stardot.org.uk

It seems that Colossus 4.0 is the Daddy of them all, basically being an improved version of White Knight. Now a BBC Micro Vs Commodore 64 Colossus 4.0 match may be interesting? With equal thinking time, would that come down to 2MHz (win) vs. 1MHz (lose)? I am planning Chess War - Battle of the 8 bi...

Seriously, though, that's really strange. IIRC I tried it multiple times and it only worked immediately after power-on, and I'm sure someone else reported the same behaviour. I'll be sure to try it again next time I'm in front of hardware. I have three 8271s, too, so I might try it with all of them...

We also tangentially found that the disc-eating test mode is only peckish if no 8271 commands have been executed after power-on. This doesn't match my machine. I just did *. with a disc in drive 0. Then ?&FE82=4 and... awful noises as usual. Actually I have a new favorite drive and it makes a diffe...

BigEd wrote: ↑

Sat Nov 14, 2020 11:19 am

Excellent!

Started a clean new thread for the deliverable:

viewtopic.php?f=3&t=21053


Cheers
Chris

Hi, Here's a blog post describing the 8271 reverse engineering journey a few of us recently went on: https://scarybeastsecurity.blogspot.com/2020/11/reverse-engineering-forgotten-1970s.html Hope you enjoy reading it as much I enjoyed writing it and being part of the team that came together to crack ...

BigEd wrote: ↑

Sat Nov 07, 2020 9:59 am

scarybeasts wrote: ↑

Wed Oct 21, 2020 11:32 pm

... I will be writing a blog post about the journey!

Bump! (Good-natured prompt, of course, no trace of entitlement...)

Almost there!

billcarr2005 wrote: ↑

Mon Nov 09, 2020 7:20 pm

Teenage Mutant Hero Turtles World Tour

It's probably unprotected? But as this is so rare, any chance of a discbeast or flux dump?


Cheers
Chris

So, another Repton game where the original release couldn't be completed.
It's growing to quite a list. So far:

- Repton 2
- Repton 3
- Repton Around the World in 40 Screens
- Life of Repton


Cheers
Chris

Hi, We found a couple of Life of Repton variants, HFEs posted here: https://stardot.org.uk/forums/viewtopic.php?f=32&t=20969 This looks like it could be a very interesting variant: the WORK level data file differs. The best way to differentiate the variants is that one has a file called TEENAGE (151...

Hi,

Couple of different 40T HFEs attached. We think this could be an interesting (gameplay affecting) variant -- separate thread

Thanks to picosonic, billcarr for helping find and identify this variant.


Cheers
Chris

> the Master's built in *FORM command but it just sits there on track 00 and eventually fails with a disk fault 18 Sounds to me like the disk rotation isn't being detected. If that affects several drives, maybe I'd suspect the cable or the host. I could be wrong, but I'd expect no disc rotation to ...

billcarr2005 wrote: ↑

Sun Nov 01, 2020 6:54 am

Needs to have write protect off if editing the levels

Ah, interesting.
The first level of "Alpha" has "HA" written on the screen instead of the diamond shaped formation other versions seem to have. Is it possible someone overwrote the levels that came with the game?


Cheers
Chris

Arcadian wrote: ↑

Sun Nov 01, 2020 2:17 am

Nope, but Gary Partis is on Twitter, and occassionally even replies!

Want me to (attempt to) tip him off about this thread?

Sure, why not? I'm sure he'd remember a re-spin due to a bug!


Cheers
Chris

Hi, Does anyone know much about Impact by Audiogenic? It looks like there are some different releases floating around: 1) bbcmicro.co.uk http://bbcmicro.co.uk/game.php?id=730 Loads up without any levels choice; works. 2) Impact-disk from STH. https://www.stairwaytohell.com/bbc/archive/diskimages/Aud...

Hi,

Attached is an HFE for the disc version of Impact.
There seem to be some variants of this. This variant offers different level sets (Alpha, Beta, Gamma) and actually works when you start the same.

It might convert cleanly to an SSD -- no obvious exotic sectors.


Cheers
Chris

Standing ovation!

CHRISJJ wrote: ↑

Sun Oct 25, 2020 1:22 am

Sorry, copy'n'paste error here. SNG38/D is what I meant. Thanks Chris.

Is there any documentation of these three. E.g. any dates, or just the release order?

With some effort, it might be possible to date a range of discs.

What project is this for?


Cheers
Chris

Hi, Attached! Loads fine in beebjit v0.9.4. Like many Compact titles from Superior, it appears to have a fairly uninspiring disc copy protection that is simply an unformatted track 1. The loader seems to have this extra little reminder screen that I don't see in the beeb version: insert_exile_disc.p...

(also, thanks to Arcadian for supplying the original flux capture in FDI format)

Hi, Attached is Codename Droid for the BBC Master Compact, original protected disc converted to HFE. This goes along nicely with the recent beebjit-0.9.4 release, which is capable of loading this: https://stardot.org.uk/forums/viewtopic.php?f=4&t=20847 It's an interesting disc. It has an ADFS / MFM ...

Hi, I've released beebjit-0.9.4. github: https://github.com/scarybeasts/beebjit Windows build: https://github.com/scarybeasts/beebjit/blob/master/builds/beebjit_win_0.9.4.zip - Master 128 support. Finally! I've been using this to check the compatibility of protected titles on the Master 128. There's...

Or maybe I can set a challenge...the data sheet says it supports (albeit for 8" discs) 15 sectors per track at 256 bytes per sector. That's a 50% increase on DFS disc capacity, and is very close to ADFS capacity. Maybe with a bit of persuasion it could read a 16spt ADFS disc? I don't think this is ...

CHRISJJ wrote: ↑

Wed Oct 21, 2020 9:51 pm

scarybeasts wrote: ↑

Thu Sep 03, 2020 6:20 pm

Three variants are included in the zip.

May I ask are these all from Acornsoft SBG38/C?

scarybeasts wrote: ↑

Thu Sep 03, 2020 6:20 pm

We expect to image at least one more.

Again, from SBG38/C?

Not sure I understand.... I think Acornsoft disc codes are typically SNG??/D

Best I know, all of these would be SNG38/D


Cheers
Chris

Ooo this sounds good - is the code going to be in a form that can be used on a Beeb? I'm curious if there's any particular tooling you'd like to see? I've hacked together a "write track" type of functionality for the 8271. It's incomplete, buggy, and frankly rickety but it did just manage to write ...

Yes I am. Are you testing this stuff with an 8271 in a Beeb, or somewhere else? Or is it even all theoretical as yet? I'm testing in a real model B with 8271. So far, some simple but weird tests I've done are matching results predicted from the ROM source code (i.e. commands with the "wrong" parame...

That's weird. From Diminished's disassembly, I only see it setting CRTC R6 (vertical displayed) to 2 while it redraws the screen - nothing there which would affect VSync, or have that kind of strange effect. It also plays with R5 (vertical adjust) during gameplay, to shake the screen when the playe...

This is interesting. From memory, it does something like reprogram the CRTC to limit the visible screen area to the first few lines (the ones that contain the header text and inventory sprites) while it invisibly redraws the room. Then it switches it back to full screen afterwards. I'm not sure why...

BeebMaster wrote: ↑

Thu Oct 15, 2020 8:30 pm

Ooo this sounds good - is the code going to be in a form that can be used on a Beeb?

Are you referring to making the 8271 do things it "shouldn't" be able to?


Cheers
Chris

My main reservation about this is: do we want to implement a scripting language of sorts in the built-in debugger? Or would it be cleaner to encourage the scripting to be done externally, along the lines of "cat 'command_file' | beebjit -debug" or "python debug.py | beebjit -debug" ? I think you ne...

I'm still working on this and do intend to drive it to some form of resolution. Certainly some blog posts. I did rewrite beebjit's 8271 driver based on the ROM disassembly, and accordingly it now handles things like "bad tracks" correctly. I've managed to get the 8271 to read sectors it cannot norma...