VirtualA5000 higher resolutions than 1024x768

Perhaps Vivid5000 was always a pay-extra product?

Perhaps it was at one stage though iSV enabled free for personal usage a while back before the whole site went.
What they did not do is allow free to distribute hence why I suggested wayback until hopefully the APDL/iSV site gets resurrected but it appears it is excluded so if it never comes back then they are lost unless someone buys the copyrights and makes them avialable again..hint hint..you never know

Got a good dealer, Doug?

No sorry, so in the same boat as us all but ebay may be your friend at a price.

While VirtualA5000 was an attraktive product for some time, if you want a much more versatile Emu wrt a wide variety of hardware support, I would recommend Arculator. Version 2.1 added emulation of ColourCard and G16. And the AlephOne 386/486 podule. And countless SCSI and IDE and Midi podules.

CJE has a copy of ViViD 20:
https://www.ebay.co.uk/itm/175018387569
http://www.cjemicros.co.uk/micros/individual/newprodpages/prodinfo.php?prodcode=ISV-VIV20V1

but a quote elsewhere says:
“Vivid 5000 offers real resolutions upto 1024 × 536 and emulated hi-resolution virtual desktops upto 2240 × 2016 in 16 colours.”

I’m curious what ‘emulated’ means in this context. Is it simply doing something like the RiscPC’s EX EY setting so the display is scaled (ie more ‘real estate’ by just dropping every other pixel)? Or does it just allow you to pan a small viewport around windows in a larger desktop space (like various OS’ ‘workspaces’ or ‘virtual desktops’ feature)?

so the display is scaled (ie more ‘real estate’ by just dropping every other pixel)?

This, most likely. Stuart says the VIDC can only access 480K. Not sure why that value specifically, perhaps it’s a limit hardcoded into RISC OS as the maximum screen size?
However, if not that, then the problem is that the MEMC’s DMA (as used for video) can only physically access the first 512K.

Not to mention the maximum you’re going to be able to get out of a 36MHz clock.

The 480Kb limit will be from 512Kb-32Kb – a page has to be reserved for sound and cursor DMA use, and as that might be 32Kb on 4Mb systems, 32Kb is always allocated and the rest is used as other workspace.

And, indeed, ScreenMaxSize is defined as 480*1024

Thanks for the explanation.

I’m trying to make sense of the VIDC1 manual, and I’m getting stuck on working out what the largest possible mode actually is. Can’t help but think the limitation, other than memory, is timing. But you know how my maths sucks… ;)

All depends on how slow a refresh rate you can cope with! And 4 colour modes were useful. As were rectangular pixels – who needs square? Peak bandwidth was also an issue – remember ADFS having to screen-blank when accessing floppies in some 256 colour modes?

[Edit: The one with the largest memory use that we did on RISC OS 2 was MODE 21: 640×512, 256 colour, 320Kb. RISC OS 2.01 might have added a few more, given the clock select ability on the later Axxx (it certainly used better timings for the VGA modes). The one I used the most back then was MODE 16 for 132 column text; who cares if circles are ellipses…]

I think you may have hit the nail on the head there, Stuart. I have a feeling that 1152 × 848 probably was our limit for 256 colour modes, and we could get 1600 × 1200 only in 4 colours. Both of which fit in 480k, with square not rectangular pixels.

Memory? I vaguely remember having that…

You mean 16 colour at 1152 × 848 there, Clive?

Memory? That’s what books are for.

None of this helps anyone trying to do what the OP wanted – the solution of which boils down to ‘emulate different hardware’!
“Why doesn’t 65Host or (insert your favourite BBC Micro emulator) support 4k monitors?”

You mean 16 colour at 1152 × 848 there, Clive?

Yup, of course. I’m a mathematician, first and foremost – you don’t expect me to do arithmetic, do you?

Although that said, I keep thinking we had 256 colours and decent resolution on the A5000s and A440s, so I suspect we did get some quite nice graphics podules from Chris Honey, or someone. That shot of the office certainly doesn’t look like 16 colours, and those aren’t lo-res monitors. I’ll see if I can find any actual records of what we were doing!

you don’t expect me to do arithmetic

Nor me, which is why I wrote a ModeMaker program early on to ensure the system hardware constraints were met. But that was no guarantee that its output would display anywhere near correctly! Yoof don’t know how lucky they are with these new-fangled LCD thingies that cope with tiny porches…

And here you have it…look bottom right:

http://clive.semmens.org.uk/024_ROUGOL/PD.html

Memory plays dreadful tricks, doesn’t it!

So the 1600×1200 in more than 4 colours probably only arrived with the RiscPCs (and slow-scanning monitors at that)…

:-)

While VirtualA5000 was an attraktive product for some time, if you want a much more versatile Emu wrt a wide variety of hardware support, I would recommend Arculator. Version 2.1 added emulation of ColourCard and G16. And the AlephOne 386/486 podule. And countless SCSI and IDE and Midi podules.

I added the Colour Card on my config, and I don’t know how to get it to work…

Don’t forget that Acorn was using anti-aliasing and dithering back then that made stuff look loads nicer than just the number of colours and resolution would otherwise imply.

Don’t forget that Acorn was using anti-aliasing and dithering back then that made stuff look loads nicer than just the number of colours and resolution would otherwise imply.

I think that’s clearly the point, isn’t it! That, and my somewhat dodgy memory…

Acorn was using anti-aliasing and dithering back then

I made for my site an eternity ago this:

Which was followed by this:

This was back in the day when ClearType (or whatever Microsoft called it) was not quite right and made things a little fuzzy.
It got better with an add on (or XP SP3), but RISC OS had the font thing sorted a long time before; although I wonder how will it does with modern LCDs. I think FontManager is more aimed at making it look good on CRTs.

Configurations window

Screenshot 2

How do I increase the resolution to 1280×1024?

See https://chrisacorns.computinghistory.org.uk/docs/CC/CC_Colour_Card.pdf

MODE 118 (1280×1024, 4 colours) seems suitable. Might need the Taxan795 module for that. Dunno what comes with Arculator these days.

You are still limited to the VIDC-addressable memory on these early systems, 480Kb.

But I don’t have a copy of the software

I think FontManager is more aimed at making it look good on CRTs.

Indeed so, although it looks absolutely fine on a 43" 4K screen, even at intermediate resolutions and small point sizes.