Search found 995 matches

by SarahWalker
Mon Mar 20, 2017 5:57 pm
Forum: other vintage computer hardware, software and games
Topic: IBM PC XT
Replies: 12
Views: 225

Re: IBM PC XT

Very nice!

It might be worth sticking with composite for now - there are quite a few games that support 16 colours on composite CGA.
by SarahWalker
Sun Mar 19, 2017 9:28 pm
Forum: emulators
Topic: Building RPCEmu on Mac OS X
Replies: 11
Views: 200

Re: Building RPCEmu on Mac OS X

Yes, using a modern version of Allegro is a great idea. Although I'm not a developer, I have always wondered why RPCEmu and Arculator used such an old version. I assumed it was more complicated than just changing a few references so that must be the reason. Allegro 5 wasn't available during the ori...
by SarahWalker
Sun Mar 19, 2017 9:25 pm
Forum: emulators
Topic: B-Em and Allegro 5
Replies: 6
Views: 139

Re: B-Em and Allegro 5

The B-Em Linux UI uses the Allegro 4 Menus/Dialogs API, where as the B-Em Windows UI I think bypasses Allegro and uses Windows APIs directly. I'd like to better understand the rationale for that split, as it means the Menus are implemented twice. The Windows native menu is there because the Allegro...
by SarahWalker
Fri Mar 10, 2017 10:46 pm
Forum: projects
Topic: MODE 7 Vertical Rupture
Replies: 29
Views: 559

Re: MODE 7 Vertical Rupture

Actually, that's another question - how does interlaced sync and video work in this case? By ramming two CRTC frames into a single PAL refresh, are you getting odd and even fields in the same refresh, or does the SAA chip also determine odd/even by some other means (e.g. counting VSyncs and alterna...
by SarahWalker
Thu Mar 09, 2017 10:24 pm
Forum: projects
Topic: MODE 7 Vertical Rupture
Replies: 29
Views: 559

Re: MODE 7 Vertical Rupture

I'm still slightly confused as to how interlace applies to the Beeb though, please forgive me. Given that any PAL signal has 625 lines split across two interlaced fields, but the Beeb can only output 312 lines, what exactly is the effect of turning interlace on or off for MODES 0-6? Presumably we'r...
by SarahWalker
Wed Mar 08, 2017 9:25 pm
Forum: emulators
Topic: MAME: Emulating FDC Boards
Replies: 32
Views: 1353

Re: MAME: Emulating FDC Boards

This still doesn't really explain the delay before issuing the Force Interrupt command, though, so I'm suspicious that there's something I'm missing, and/or there's something else I'm still not doing properly. I would guess it's giving time for the FDC to read and check the CRC before cancelling th...
by SarahWalker
Tue Mar 07, 2017 9:15 pm
Forum: software
Topic: Unreleased games
Replies: 13
Views: 377

Re: Unreleased games

Frak 2 is mentioned as a BBC isometric thingy in Stairway To Hell's Lost+Found section.
by SarahWalker
Tue Mar 07, 2017 6:00 pm
Forum: software
Topic: Unreleased games
Replies: 13
Views: 377

Unreleased games

I was digging through some of my old files recently, and found a list of unreleased games that I'd collated from various sources (mainly Usenet), with a view to making a "Games That Weren't" site that never happened. Thought I'd post the list here. Does anyone have any more knowledge about...
by SarahWalker
Mon Feb 27, 2017 5:51 pm
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

That was with the Beeb sound chip playing back samples. A real DAC should be a lot louder!
by SarahWalker
Sat Feb 25, 2017 8:39 pm
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

See attached crap diagram. R is 10k on my DAC.
by SarahWalker
Sat Feb 25, 2017 7:25 pm
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

More than two months since my last release! To make up for it : Here's Zone 66. Another Epic release from 1993, this democoder-authored game uses the CDFM engine, to combine 9 voices of OPL with 4 voices of samples. This is a bit of a stretch for the Beeb, so there are three versions here. The stand...
by SarahWalker
Sat Feb 25, 2017 8:05 am
Forum: emulators
Topic: B-Em
Replies: 219
Views: 5532

Re: B-Em

Apart from file selection, none of the UI needs to be native. Instead of targeting Windows or Linux, why not make it BBC Micro style? Probably worth noting that B-em had a non-native UI prior to v0.8, largely due to DOS still being the primary target. The general feedback I got was that people hate...
by SarahWalker
Sun Feb 19, 2017 10:41 am
Forum: other vintage computer hardware, software and games
Topic: Superior Software's Speech on the Commodore 64
Replies: 4
Views: 223

Re: Superior Software's Speech on the Commodore 64

Yep, you loose ~40 cycles (depending on what sprites are enabled) every 8 lines to VIC-II. This isn't a show-stopper, but I suppose Superior decided that the audio quality was too poor with the display enabled, and that it probably wasn't worth working around it.
by SarahWalker
Sun Feb 12, 2017 3:03 pm
Forum: hardware
Topic: A5000 Overclock
Replies: 4
Views: 172

Re: A5000 Overclock

I did run one at 30 MHz ARM3 + 16.66 MHz memory for a while, and it seemed perfectly stable. There may have been more headroom on the CPU, but I didn't have appropriate oscillators to test. The memory clock was at it's limit though - I tried 17.3 MHz and it had 'issues'.
by SarahWalker
Thu Feb 09, 2017 6:19 pm
Forum: off-topic
Topic: What is the average age on here??
Replies: 192
Views: 10415

Re: What is the average age on here??

Beebs were still in use at my primary school when I left in 1998. They were still in occasional use at my secondary school when I started, but got phased out there after a year or two. There was one used from time to time in my A-level Physics class, about 2003.
by SarahWalker
Wed Feb 08, 2017 8:53 pm
Forum: software: games
Topic: Playing Tetris got me thinking...
Replies: 13
Views: 484

Re: Playing Tetris got me thinking...

Could it be worth looking at the CGA version of Tetris (that I remember well albeit via a monochrome Hercules emulation of CGA) as that is based on a four colour mode with similar(ish) resolutions as the BBC/elec? Possibly worth mentioning that the background graphics on the EGA and Tandy versions ...
by SarahWalker
Mon Feb 06, 2017 5:40 pm
Forum: software: other
Topic: A mathematical demo and the request for help from the hardware owners
Replies: 69
Views: 3014

Re: A mathematical demo and the request for help from the hardware owners

BigEd wrote:??? But the Spectrum is clocked slower than the Amstrad, isn't it?

Amstrad has to deal with memory contention, the Spectrum doesn't outside of the first 16kb. So the Speccy is slightly faster overall.
by SarahWalker
Thu Jan 19, 2017 6:38 pm
Forum: projects
Topic: MODE 7/75
Replies: 19
Views: 531

Re: MODE 7/75

Rich Talbot-Watkins wrote:[*] Or does it just assume characters of 10 scanlines? How does it synchronise the start of the frame in that case?

Looks to be the DEW pin, which is connected to VSYNC on the 6845.
by SarahWalker
Mon Jan 09, 2017 8:08 pm
Forum: general
Topic: the best 8-bit computer...
Replies: 27
Views: 653

Re: the best 8-bit computer...

It's got a bigger palette, 27 colours instead of 8+flashing, or 4096 on the CPC+.

The Commodore 128D has better pixel graphics though - 640x200x16. In terms of colour, the MSX2+ can do 256x212x19268.
by SarahWalker
Sat Jan 07, 2017 7:29 am
Forum: upcoming and recent events & exhibitions
Topic: May 12th-14th 2017 Cambridge ABUG (FULL) & Acorn World event at CCfCH
Replies: 55
Views: 2013

Re: May 12th-14th 2017 Cambridge ABUG & Acorn World event at CCfCH

I'd be up for this again.

I have a prototype ARM3 board the Centre can have, if they don't already have one.
by SarahWalker
Tue Jan 03, 2017 5:38 pm
Forum: emulators
Topic: BeebOPL to Atom (was: Debugging with Atomulator)
Replies: 36
Views: 783

Re: Debugging with Atomulator

oss003 wrote:How does DOSbox do this?

It doesn't. All emulator-side hardware is, well, emulated!

I highly doubt any of the NT-based versions of Windows will let you access IO ports directly from userspace.
by SarahWalker
Sun Dec 18, 2016 10:59 pm
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

And, since it's Christmas, here's a second disc! This is of Wacky Wheels, which I did play a lot back in the 90s, mainly due to not having Mario Kart. It's got some quite good tunes I think. Note that it's the first conversion that doesn't entirely fit in 32k! I had to crop Turbo a bit, and both Tur...
by SarahWalker
Sun Dec 18, 2016 10:55 pm
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

Since I can't say no to an Arcadian request, here's DynaBlaster. I never actually played the PC version of this back in the day. To be honest, I think I prefer the Amiga version...
DynaBlaster_BeebOPL.png
by SarahWalker
Sun Dec 11, 2016 10:16 pm
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

Interesting, thanks for linking to that site! If Dynablaster is using CMF then it should be pretty trivial to convert.
by SarahWalker
Sun Dec 11, 2016 9:30 pm
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

Today's offering is Kiloblaster, another Epic shareware game with music by Dan Froelich. Probably the last one, in fact, as I think I've released them all now! I'd like to offer some commentary on the game, but I've actually never played it. Some nice tunes though.
Kiloblaster_BeebOPL.png
by SarahWalker
Sat Dec 10, 2016 8:28 am
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

Doesn't look like it I'm afraid...
by SarahWalker
Sat Dec 03, 2016 4:12 pm
Forum: programming
Topic: Acorn Electron - Shadow Ram
Replies: 7
Views: 375

Re: Acorn Electron - Shadow Ram

Looking through the Elkulator source, it looks like &FC7F is the MRB control register. Only the top bit seems to be used, and the mapping looks like : FC7F=&80 : 0000-2fff = normal RAM 3000-7fff = normal RAM FC7F=&00, MRB in 'turbo' mode : 0000-2fff = shadow RAM 3000-7fff = normal RAM FC...
by SarahWalker
Wed Nov 30, 2016 6:21 pm
Forum: hardware
Topic: DREM ST506 DRive EMulator
Replies: 7
Views: 287

Re: DREM ST506 DRive EMulator

paulv wrote:Would it be possible to run 4 or more 512MB partitions on an ST506 (or emulated) drive if it had enough capacity? Is the Arc's on board controller up to that job?

I think it maxes out at 64 MB per drive.
by SarahWalker
Sun Nov 20, 2016 9:47 pm
Forum: software: other
Topic: BeebOPL choons
Replies: 42
Views: 1579

Re: BeebOPL choons

Today's music disc is of 1993's Solar Winds, a sort of weird space opera type thing. I seem to remember quite enjoying it, though I never got very far. Anyway, some nice tunes, which did force me to fix a number of bugs in the player...
Solar_Winds_BeebOPL.zip
(22.4 KiB) Downloaded 18 times

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