Compukit UK101 core

[danielb]

Hi DanielB, et al.

I really need to find out exactly what the differences were between the UK101 and the OSI machines, and also the differences between the different OSI models,

Main differences:

Default Screen size: UK101 = 48x16, OSI C1p = 32x32, OSI c2,c3,c4,c8 = 32x32 or 64x32
(Normally 24x24 would be visible with a C1p, as it doesn't account for the front/back porch area in the video signal).
32x32 mode on the C1p is addressed differently to that on the bigger end models too.

Keyboard addressing:
UK101 and OSI C1p are the same.
OSI C2,C3,C4,C8 all have the bits inverted. (Check my keyboard code)

Monitor roms:
Different variations of the monitor. Individual 256 byte routines can be addressed anywhere between $F000 and $FFFF in the bigger models.
This is a minefield
check out the discussions on this topic in the forums at osiweb.org

ACIA addressing.
Large models have the serial/parallel chips addressed at different locations to the C1p/UK101.
Again, this doesn't help compatibility between OSI models at all.

Probably a few other minor things, but nothing of note I don't think.
Manuals for all models are on osiweb.org

Hope that helps.

Red

Thanks

D.

[EeDee]

- Floppy disk system. This would be very difficult, at least for me. To do this, you would need precise documentation of the actual interface, and the original DOS ROMS. Some of this does exist for the Superboard, but even so, I suspect this is beyond my FPGA coding skills. There are some disk images on the web for the Superboard, but I don't know whether they would even theoretically work on the UK101.

Not just for you I think: https://stardot.org.uk/forums/viewtopic.php?t=13550 (3rd post down and Link in the last one)

Wow, there are some pretty hardcore UK101 people on that forum

Meanwhile I have been messing about with the OSI emulator on this site http://osi.marks-lab.com/index.php. It supports the UK101, and several different models of OSI computer. It also comes packaged with quite a lot of software, including disk images. My original intention was to try to use the emulator to export files from the disk images and see if I could get them to run on the core. I was able to export a couple of files, but they were for a more advanced OSI model and didn't run properly.

This got me wondering what it would take to get them running...

D.

Read this:
"The 40 pin expansion socket opened up the world to the UK101. It also mated with all Superboard extras. One could attach a dual 5.5-inch floppy disk controller and a memory expansion card (40K max) to allow faster and reliable save/load of programs/data. Later on Compshop recommended not using discs with the UK101. The original intention was to use Ohio Scientific discs, however they were made to work with the original version but did not work with later versions."
Here: http://www.computinghistory.org.uk/det/ ... UK101-(2)/

[EeDee]

From same page: http://www.computinghistory.org.uk/det/ ... UK101-(2)/

This example of the UK 101 is mounted in a proprietary box and is complete with the following printed notes:
6502 Assembler / Disassembler
Toolkit for UK 101 and OHIO systems
Basic 4 notes
Memory Display and modification
CEGMON A new monitor for OSI and UK101 BASIC-In-ROM systems
Real Time Clock for Compukit UK101

Appears it could have a Real Time Clock added

[danielb]

Not just for you I think: https://stardot.org.uk/forums/viewtopic.php?t=13550 (3rd post down and Link in the last one)

Wow, there are some pretty hardcore UK101 people on that forum

Meanwhile I have been messing about with the OSI emulator on this site http://osi.marks-lab.com/index.php. It supports the UK101, and several different models of OSI computer. It also comes packaged with quite a lot of software, including disk images. My original intention was to try to use the emulator to export files from the disk images and see if I could get them to run on the core. I was able to export a couple of files, but they were for a more advanced OSI model and didn't run properly.

This got me wondering what it would take to get them running...

D.

Read this:
"The 40 pin expansion socket opened up the world to the UK101. It also mated with all Superboard extras. One could attach a dual 5.5-inch floppy disk controller and a memory expansion card (40K max) to allow faster and reliable save/load of programs/data. Later on Compshop recommended not using discs with the UK101. The original intention was to use Ohio Scientific discs, however they were made to work with the original version but did not work with later versions."
Here: http://www.computinghistory.org.uk/det/ ... UK101-(2)/

That's interesting, especially as the later Cegmon has the "D" option at startup, while the earlier monitor doesn't. The UK101 emulator doesn't seem to support disks, while the OSI emulators do.

D.

[RedskullDC]

Hi EeDee, et al.

@RedskullDC
You seem to have an interest in this line of computers

Yes, you could say that

The OSI Superboard II was the first machine I bought as a school kid way back when.

Currently have a Suberboard II, C1P + 610 expansion board, and a C4P built with reproduction PCBs.

(User "glitchwrks" makes the repro boards: https://www.ebay.com.au/sch/glitchwrks/m.html)

Cheers,
Red

[EeDee]

Hi EeDee, et al.

@RedskullDC
You seem to have an interest in this line of computers

Yes, you could say that

The OSI Superboard II was the first machine I bought as a school kid way back when.

Currently have a Suberboard II, C1P + 610 expansion board, and a C4P built with reproduction PCBs.

(User "glitchwrks" makes the repro boards: https://www.ebay.com.au/sch/glitchwrks/m.html)

Cheers,
Red

Ah I see! An interesting choice I think

[danielb]

After a little bit of fiddling, I managed to hack together a version of the core that runs OSI Basic, and uses the OSI character set. It runs OSI Invaders, showing off the correct characters.
At this stage, I made no changes to the screen resolution, and it's running the same monitor as before.
It's pretty hilarious that all the characters are reversed, until you reverse them back.

D.

[EeDee]

After a little bit of fiddling, I managed to hack together a version of the core that runs OSI Basic, and uses the OSI character set. It runs OSI Invaders, showing off the correct characters.
At this stage, I made no changes to the screen resolution, and it's running the same monitor as before.
It's pretty hilarious that all the characters are reversed, until you reverse them back.

D.

Good job!!

[danielb]

Thanks

For some reason, the famous Easter egg does work in this version of Basic, unlike in the standard version.

D.

[EeDee]

I feel great things afoot
Until Mister came along there were emulators, which work fantastically and are very handy, but I've never really got into them as, for me, there is something missing. Mister on the other hand....

[danielb]

After a bit more fiddling, I managed to get one of the OSI ROMs to work.

It seems to default to 64x32 characters. I haven't yet attempted to change this, although I did tweak the video output a bit to get a 60hz refresh rate. Not sure if this actually matters or not.

Anyway, almost all of the OSI-specific games that I tested now work. I have attached some pictures of some examples.

@RedskullDC: Thanks very much for your help, your code has been very useful in getting this to work.

D.

[danielb]

Hi,

Here is another pre-release version.

This one allows switching between UK101 and OSI machines.

Compatibility with UK101 games seems to be the same as before.

Tested OSI games include Galaxia, Pacdude, OSIInvaders, SuperDefender, Universe, TimeTrek, Pinball and OSI Grand.

Caterpillar and RidgeCruiser do not work. NightRider seems to work with glitches.

OSI mode is only 64x32 ATM. This is what the ROM seems to want to default to, and I don't yet have a 32x32 or 24x24 mode.

D.

[danielb]

Hi all,

I managed to get 32-column mode to work. Not quite ready for the big time yet, but coming soon.

Using the same principle, I could add other resolutions, like 32x16 (already working...), 48x32 or whatever. Is there any use for these?

D.

[EeDee]

Hi,

Here is another pre-release version.

This one allows switching between UK101 and OSI machines.

Compatibility with UK101 games seems to be the same as before.

Tested OSI games include Galaxia, Pacdude, OSIInvaders, SuperDefender, Universe, TimeTrek, Pinball and OSI Grand.

Caterpillar and RidgeCruiser do not work. NightRider seems to work with glitches.

OSI mode is only 64x32 ATM. This is what the ROM seems to want to default to, and I don't yet have a 32x32 or 24x24 mode.

D.

Thanks. There are a couple of OSI games (Aardvark Berrrzerrk and Blockade) working which didn't, properly, on the 101.

[EeDee]

Hi all,

I managed to get 32-column mode to work. Not quite ready for the big time yet, but coming soon.

Using the same principle, I could add other resolutions, like 32x16 (already working...), 48x32 or whatever. Is there any use for these?

D.

They were available in those screen configurations so there'd be software for them somewhere so why not? The more configurable, if it's possible, the better. At least it can't hurt

[danielb]

Hi,

Here is another pre-release version.

This one allows switching between UK101 and OSI machines.

Compatibility with UK101 games seems to be the same as before.

Tested OSI games include Galaxia, Pacdude, OSIInvaders, SuperDefender, Universe, TimeTrek, Pinball and OSI Grand.

Caterpillar and RidgeCruiser do not work. NightRider seems to work with glitches.

OSI mode is only 64x32 ATM. This is what the ROM seems to want to default to, and I don't yet have a 32x32 or 24x24 mode.

D.

Thanks. There are a couple of OSI games (Aardvark Berrrzerrk and Blockade) working which didn't, properly, on the 101.

Hi,

Excellent! Are those games downloadable anywhere?
EDIT: Never mind I found them

D.

[danielb]

Hi,

Here's another pre-release version. This one adds selectable screen resolution in the OSI mode.

D.

[EeDee]

Hi all,

I managed to get 32-column mode to work. Not quite ready for the big time yet, but coming soon.

Using the same principle, I could add other resolutions, like 32x16 (already working...), 48x32 or whatever. Is there any use for these?

D.

Thanks for the update
I can understand why screen resolution choice may seem unnecessary to many as it can be changed at system start. But I suppose the point is, among others, that it loses something when done like that. For example a basic 4K machine with a 25x25 screen resolution and a pimped 40K machine with a 64x32 resolution. The latter can perform as the former but you lose the experience of struggling with the limitations of the former. Like, what's the point of a 1K ZX81 when you can have a 48K version? Someone wrote a 1K chess game I think. Be nice to experience what that was like.
We all see things differently though don't we?

[EeDee]

It appears to me that all the models OSI produced had the same basic architecture but that elements, such as sound, colour, RTC, floppies, Hard Drives, ect, were bolted on. If so then brilliance in it's simplicity. The Challenger 3 being the basis for Grant Searle's Multicomp

[danielb]

Hi,

OSI mode is now "official". In addition to this, input files may now have the .bas and .lod extensions, which seem to be fairly standard for Basic and machine code programs.

@Eedee: I was wondering what the Multicomp was based on, although it seems to be a less precise simulation than the UK101-specific one. The Z80 Multicomp is apparently based on the Nascom, which is another machine that it might be worth porting to the MiSTer.

D.

[EeDee]

Hi,

OSI mode is now "official". In addition to this, input files may now have the .bas and .lod extensions, which seem to be fairly standard for Basic and machine code programs.

@Eedee: I was wondering what the Multicomp was based on, although it seems to be a less precise simulation than the UK101-specific one. The Z80 Multicomp is apparently based on the Nascom, which is another machine that it might be worth porting to the MiSTer.

D.

Love to receive this core's updates. It's developing nicely thanks to you.
Yes the Uk101 is more a copy whereas the Multicomp seems to be Grant's own work.
@Moondandy opened a thread, with that same thought as yours in mind, regarding a port of the Nascom and I agreed. There are some Links there which you may find interesting.
I've been trying the WinOSI Emulator. Feature rich or what?! It's great! Much prefer the Mister version though for some reason or other
Thanks again. I'm going to give it a try now

[danielb]

I've been trying the WinOSI Emulator. Feature rich or what?! It's great! Much prefer the Mister version though for some reason or other
Thanks again. I'm going to give it a try now

It's great for giving an idea of what's possible and how it should work.

I was very happy to see that a couple of games that don't work on the core, don't work on the emulator either.

The only game that does work on the emulator, and should, as far as I know, work on the core, but doesn't, is Caterpillar. Not sure what's going on there...

BTW, I found this: https://archive.org/details/OSI_Aardvar ... s/mode/2up. It's a very interesting little historical document about a game that does run on the core. I especially like "don't look at the screen while the game is loading"

D.

[EeDee]

It's great for giving an idea of what's possible and how it should work.

I was very happy to see that a couple of games that don't work on the core, don't work on the emulator either.

The only game that does work on the emulator, and should, as far as I know, work on the core, but doesn't, is Caterpillar. Not sure what's going on there...

BTW, I found this: https://archive.org/details/OSI_Aardvar ... s/mode/2up. It's a very interesting little historical document about a game that does run on the core. I especially like "don't look at the screen while the game is loading"

D.

I am just now finding the same thing, although the emulator appears to flag the errors
Have also just seen the Escape From Mars sheet but not yet found or tried to load it.

[EeDee]

The only game that does work on the emulator, and should, as far as I know, work on the core, but doesn't, is Caterpillar. Not sure what's going on there...

At the end of data input it just stops. If you press the space bar you can make out HIT P TO START but that's about it

[danielb]

The only game that does work on the emulator, and should, as far as I know, work on the core, but doesn't, is Caterpillar. Not sure what's going on there...

At the end of data input it just stops. If you press the space bar you can make out HIT P TO START but that's about it

Add a carriage return to the end of the file. It will then clear the screen, say "Hit p to start" and freeze.

D.

[EeDee]

Add a carriage return to the end of the file. It will then clear the screen, say "Hit p to start" and freeze.

D.

Yes it does
Any idea what is involved in getting it to load archived files?

[danielb]

Add a carriage return to the end of the file. It will then clear the screen, say "Hit p to start" and freeze.

D.

Yes it does
Any idea what is involved in getting it to load archived files?

What kind of archive?

D

[EeDee]

In the LOD version of Asteroids the text at the bottom of the screen is obscured by the Asteroids which doesn't occur in WinOSI

[EeDee]

Should add this for comparison

Screenshot_20211021-194119.png (2.92 MiB) Viewed 10225 times

[danielb]

That's weird...

I have also been comparing compatibility with the emulator, and on the whole I think the core holds up pretty well. There are a couple of games that don't work, like Caterpillar and Ridge Cruiser, and I'd really like to understand why.

I did find an Invaders game that will only load under Synmon, which the core doesn't have, and it got me wondering whether the older monitor might be more compatible with some games, like MonUK on the UK101.

D.

EDIT: Ridge Cruiser behaves in exactly the same way on the emulator as it does on the core, when the emulator is set to C2P. It seems to be a C1P exclusive and therefore won't run on the core.