lance_ewing

For a couple of reasons: The first is that there are already a couple of projects using FPGA to create a VIC chip replacement, e.g. Victor by Jon Brawn, and FATVIC by Thomas Lövskog. The main trigger to try a Pico 2 version was when I saw sodiumlightbaby's OCULA project for the Oric. The ULA in the Oric is the equivalent of the VIC chip in the VIC 20, i.e. the main custom chip. When it dawned on me that he was using the Pico 2 for the OCULA, I thought, "Hey! Why not try the same thing for the VIC chip?". So we've been collabing on it over the past 12 months. I think you're right though, that devices like the Victor that use FPGA will be able to get closer to 100% compatibility. The PIVIC will be an alternative that might not be 100% compatible but is very close and would suffice for most.

Yeah, the PIVIC is pin compatible, and the same size as the original chip, so no overhanging bits. The PCB is as big as the original VIC chip.

My original VIC 20 machine that I had in the 80s still works as well, but a few things have been replaced along the way. I still have the same 24K expansion cart that my Dad built 40 years ago and it also still works.

I'm also using the knowledge gained from reverse engineering the VIC chip to contribute to a soon to be released VIC chip replacement device called the PIVIC, powered internally by a Pico 2 chip.

Yeah, it was very difficult, but a lot of fun. We used to book the school library's BBC Micro out after school and spend an hour or two each day trying to beat it. I still remember working out how to use the torches to guide the little men to walk into the room with the spider, and how to escape from the prison cell. - I'd love to try porting this game to the VIC 20 at some point. Same cpu, but the VIC's graphics are more limited. Still, with some of the tricks that people use in some of the games and demos for the VIC, maybe something similar could be achieved. Pitfall for the VIC 20 is really impressive, graphically, given its on the VIC 20:

https://vic20.games/#/pitfall

JVIC (the libGDX version of JVIC) actually started out as mainly an Android project 10 years ago, but I didn't release it at that time. It was only a few months ago that I decided to add the html platform as a target, tidied it up in general, and thought it was time to release it. Given that this html version can be installed as an app on android phones, I'm not sure I need the android target anymore :D. It avoids the whole play store / app store process.

Do you mean specifically the Frogger game? Or in general? - If you mean in general, it hopefully does sound very close to the original VIC 20. I actually reversed engineered the VIC chip schematic from photos of the silicon chip, so the sound emulation is based on what I worked out from the reversed engineered schematic. Some of my discussion on that is covered here:

https://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.p...

I probably started the same way. I remember spending forever typing in BASIC games from magazines and books from the local library. They never worked straight off, so a bit of "debugging" was usually required, i.e. spot the typos.

Maybe at 10 years old, I wasn't thinking much about working, but the VIC 20 started me on the programming path, with an IBM PC being our next home computer a few years later.

Yeah, libGDX is my go to now for web-based emulators and interpreters. JVIC is the third one I've written now. The other two are JOric and AGILE:

https://oric.games/

https://agi.sierra.games/

They all use the GWT html target. I realise that there is now also a TeaVM target. I might try converting JVIC to use TeaVM at some point.

Back in the 80s, I was lucky that my father was an electronics design engineer, so he built a 24K expansion cartridge for us. I agree that there were some great games for the unexpanded VIC 20 though, such as Rockman. I loved that game. So many levels for a small game.

Yeah, that one is a great online emulator. I've played around a bit with that one. I have fond memories of the BBC Micro from my school days, especially the game Castle Quest.

How does it handle being run on a mobile phone? My main focus with JVIC was to try making it as easy as possible to use on mobile devices, although I'll admit that my testing has only been on Android so far. I haven't tried it on iOS yet.

Exactly the same story with me. I got my VIC 20 when I was about 10, in the mid 80s, and that is how I learnt how to program and how I knew what I wanted to do as a career.

In what way did it crash? What browser and device did you try running it on? - There might be an issue where its possible to start typing before the program load sequence has finished, e.g. where it has queued a "RUN" command for when the disk load has finished, but if you start typing before that, it might interfere with that RUN. I have an idea on how to fix that, if this is the issue. Just need to ignore key presses until all program load commands have been processed.

The code and instructions on how to use it are here: https://github.com/lanceewing/jvic

Only 9 hours remaining in the crowd funding campaign, but already over 400% funded, so this thing is really happening.

This video that Ken Williams put on Youtube a year or so back has got a short bit showing someone using the machine in the Sierra On-Line office:

https://www.youtube.com/watch?v=oY_JbTYXVjg

It is at about 1:47 into the video. It is the same machine shown in that LOGiN magazine article. This one appears to only support the 5 1/4 inch floppies, since I think the 3 1/2 inch disks weren't around at the time, so they must have got a newer machine later on.

Ken's title for the video claims it was from 1983, but from my research, I think that a September 1982 date is more likely. The whole thing is an amazing video actually. Well worth watching. Incredible that it actually survived and is now preserved on Youtube.

Yes, certainly, and any gaps could be filled in with what the NAGI project provides: https://github.com/sonneveld/nagi. NAGI is a fan-made AGI interpreter created by Nick Sonneveld. He disassembled the Sierra's original AGI interpreter and then used that to create equivalent C source code. It is interesting to compare what he came up with to the actual original AGI interpreter source code from the SQ2 disk. Nick had to make up appropriate names for things, as he obviously didn't have the memory map, but it is easy to see the equivalent functions etc when you compare equivalent modules.

Yeah, I do still enjoy them. I have been having to play through a few of them again recently in order to test my own AGI interpreter (https://agi.sierra.games). For example, I've recently been playing King's Quest IV on my phone using AGILE.

I bought Ken's book a while back. As Ken has mentioned in reference to that book, his memories of things aren't as clear as they used to be. It's a long time ago. Still a great read though. I enjoyed it.

I have also read "The Sierra Adventure" by Shawn Mills. That's another great book, in fact it has some quotes from various people that I hadn't seen anywhere else. I loved some of the inside story from Doug MacNeill in regards to the original King's Quest project.

I've actually been working on my own book in relation to Sierra, AGI, the AGI games, the tools, the fan-made games... all things AGI I guess. Its probably still a few years away from release though. I keep getting distracted by things like writing the web based AGI interpreter.

That scene at the end, where they land in the car park of the "Redwood" building in Oakhurst where the Sierra offices were, was one of my favourite parts. Like many of you I'm sure, I dreamed of one day working for Sierra in that building.

I think my PC still had EGA when I first played SQ4. I don't think there was a separate EGA version as such. I think it was the VGA version but I believe the interpreter supported a dithered mode that used the EGA palette but was dithered to try to match the VGA colours.

I can't remember what the specific puzzles in Space Quest II were that I got stuck on. I think the first one was probably still down on the planet. And I can't say for certain now why I was able to finish SQ3 so quickly. I guess things just seemed to flow. I certainly finished SQ3 quicker than any other Sierra game I played, by quite some margin. The others took at least a few weeks, if not months.

This was obviously back in the days before the Internet, and I hadn't yet discovered BBS boards either, so it was just me and my brother trying to work it out.

> MWC was a C compiler from the Mark Williams company that was very popular in those days.

Since publishing the article, I discovered some fragments of not yet linked compiled AGI interpreter obj files from the slack space on a KQ3 disk that mentions the MWC version number used, which was MWC86 V2.3.8.

I also discovered a directory entry in the slack space of another sector on the same disk that has the name of the executable, MWC.EXE, the size and the timestamp:

MWC.EXE 18420 23-Oct-1985 15:17:32

I was also wondering about these numbers when putting the article together. The photo of the 2.0D disk is of my own personal copy of the game. I assume the number is unique to that disk, but I haven't spent any time at all researching that. I wonder if someone has.

I found it very difficult to find references to it online. There is a reference in the "Hackers" book by Steven Levy to Sierra On-Line having one (he uses the name "Form Master"), and former Sierra employees have mentioned it as well but with the two words run together as FormMaster. As I couldn't find much more, I'm not sure which form of spelling is correct.

https://www.google.co.uk/books/edition/Hackers/JwKHDwAAQBAJ?...

There is a photograph in a September 1983 issue of a Japanese magazine called "LOGiN" of one of Sierra On-Line's disk copying machines but the article doesn't mention it by name. I wonder if it is the FormMaster/Form Master machine.

https://archive.org/details/login-september-1983/LOGiN%20-%2...

As an aside, that September 1983 magazine is the earliest clear reference to the development of King's Quest that I could find. It isn't mentioned by name but it is obvious that it is King's Quest that is being referred to.

I bought Space Quest II and III on the same day, back in 1989. I think it was on a Saturday morning, and by the end of the next day, I'd already finished Space Quest III. But Space Quest II took a lot longer, more like 2 months to finish. Having lived the game for longer, my memories of SQ2 are fonder.

I was wondering the same thing. I was the first post, then saw the second one. I was quite surprised to see this third one really take off like this. Yeah, perhaps it does depend on the time of day? - A big thank you to smcameron for reposting.

Yeah, sorry, that was a poor choice of words on my part. I have reworded the sentence slightly to hopefully avoid the legal implication.

Yeah, this could well be true. I was using a Hex Editor a lot back in the late 80s and early 90s, and that involved many of the Sierra games. Most of the time I was looking at the files installed on a hard disk though, as I generally installed the game from the floppy to the hard disk first and assumed I had everything. I think it would have been rare for me to be viewing the whole floppy disk of a Sierra game sector by sector in a Hex Viewer, although I did do that a lot for some disks. I'm surprised I didn't spot this back in those days. I bought this version of Space Quest II back in 1989.

It happened twice at Sierra, around the same time in fact. I have found part of the AGI interpreter source code on a King's Quest III disk (version 2.14, 720KB version, disk 1). There is nowhere near as much, but lucky for us, it happens to include a few complete files that were not on the SQ2 disk. So that increases the total amount of source a bit.

I have checked other Sierra disks, and so far the SQ2 and KQ3 occurrences are the only ones I know of.

Thanks for the link. I hadn't previously visited that site. Very interesting.

From a quick check, I can't see this particular Space Quest II disk's AGI interpreter uncompiled code mentioned in there yet. Do you agree?

I have noticed that the same thing happened with a King's Quest III disk, in fact it looks like it may have happened around the same time as the Space Quest II occurrence.