Watching VSP&IK+ (C64)

We’ve got another piece of C64 scene history today, the Mean Team’s VSP&IK+ from 1987. This is another of those demos from the “Wild West” period when programmers were as much concerned if not more so with getting their latest creations out there and the name is pretty much self-explanatory; the IK+ part comes from the music by Rob Hubbard and Paul “Dokk” Docherty picture which were both being taken from the game of the same name, whilst the VSP refers to it being the first instance of Variable Screen Positioning, a hardware “feature” similar to but much harder to implement than the more common Flexible Line Distancing – FLD to its friends – which was in common use around that time.

This technique is sometimes referred to as DMA delay because that’s essentially how it works, waiting for a badline where the C64 fetches screen data and fooling the VIC-II into waiting for a fixed amount of cycles before that fetch actually takes place by setting the vertical scroll register to a value that won’t see it happen, then changing back to one where it will later in the line. One cycle equates to the width of a character so waiting five cycles will push the screen right by that many characters and it’s possible to travel an entire screen width, with the data wrapping around onto the start of the next line, something this demo masks by changing the attribute data. VSP-based scrolling is how games like Mayhem In Monsterland can move their backgrounds so quickly.

I remember seeing VSP&IK+ for the first time on a friend’s C64, casually thinking “oh that’s nice and smooth” in passing as it started up and the picture slid smoothly in from right to left and then staring in disbelief as it snapped back in the other direction at far too great a speed to merely be a double buffered bitmap scroller – we already knew about FLD and understood how it worked but this was nothing short of witchcraft at the time! It still makes me smile now despite knowing how the routine works and having my own examples.

Watching 10 Minute Trap (C64)

I was saddened to hear that Ben Daglish passed away last Monday; I’d only seen him play on a couple of occasions at Back In Time events and we’d met very much in passing at the same time – my own shyness prevented me from taking full advantage of those opportunities – but he, along with people like Rob Hubbard and Martin Galway was behind a significant chunk of the soundtrack from my formative years, composing for games I enjoyed including Krakout, Hades Nebula, Return Of The Mutant Camels and many more on the C64.

Ben also produced a number of demos with his friend and regular collaborator Tony Crowther under the We MUSIC banner – they put out a great cover of Stairway To Heaven amongst others – but there’s one that always stands out for me personally; it’s been known by a couple of names over the years including Space Gladiator but the filename on the version I received as a teenager was 10 Minute Trap. There are two flavours available with the sparser version hidden within the game Trap itself – the cassette inlay features a screenshot with the caption “hi scorers should enter re-arranged MODE” as a hint – as well as being available separately, but a retooled version also exists which added a couple of logos and an upscroller, this was released to promote UK online service Compunet and is the one I’m most familiar with personally.

The demo itself is very much built around the music, which is nearly ten minutes long and truly epic in scale – the burly, sometimes titular Space Gladiator at the bottom left of the screen accompanies parts of the music with his drum and will sometimes practise or just watch the action when not required – and there’s a window looking out on a couple of barren planets where the story unfolds. As the music gets going a flying saucer arrives to beam down a spaceman, leaving him behind to witness what appears to be a pitched interstellar battle with multiple craft flying past, missiles smashing into one of the planets and occasional stroboscopic flashes which are all tied into the soundtrack. I’ve always felt sorry for that spaceman actually, he looks rather lonely stranded there and observing from his solitary platform and waving at the UFOs as they whiz past!

The Compunet version’s scrolling text talks about the various online services available, sometimes punctuating events in the main window as it does so – the phrase “you’re never alone with Compunet” rather ironically appears as the spaceman is dropped off for example – and I’ve always rather liked that integration, the advertising could just have been wedged in with absolutely no regard to the original demo but time and thought obviously went into this. It helps that 10 Minute Trap is already an engaging, unusual demo of course, which is also why I’ll sit down and watch the Compunet version a couple of times a year just because I can… although subsequent viewings will be a little sadder knowing that one of its creators is no longer with us.

Digging around

Okay, so I’ve been relatively busy lately (so “forgot” to blog) and one of the things I did was tootle down to Kent to see family and friends and a garage of my old stuff. So, along with taking some bits and pieces back with me, I also took a few pictures and this post might be just a tad photo heavy…

This is an ATonce board, which is a PC AT emulator for the Amiga 500 and 500 Plus. It boasts a startling 7.2MHz of raw 80286 power with CGA, EGA and mono VGA graphics goodness. Yeah, it’s basically a 286 PC on a board that uses the Amiga as I/O, I think it cost me about a tenner because the stock was being cleared, but I never actually got around to installing the thing into an A500.

The way the prices on eBay are going, anyone’d think the C64GS was rare… or is it just me with three knocking about? Well, there’s more than three but I only found the board for a fourth machine and suspect that the fifth might be in our loft here somewhere and there could be more (six VIC 20s turned up, twice as many as I remember owning). One of these machines is not like the others though, because…

…although we didn’t finish the work, a friend and I started converting one C64GS into a C64. The two points of interest, a six pin serial connection and a keyboard connector added to the motherboard that wouldn’t normally be there, are marked in red and this is the unit that came back with me and starred in this video loading from one of the TIB DD-001 drives that made their way to Leeds in February.

Ah, my (t)rusty old Compunet modem. I never got to use the service itself, but Sean Connolly and I used to trade work files back and forth – we’d do it on Sundays because the phone calls were cheaper! Ah, those were the days when you got 1200 baud one way and 75 the other, so user-to-user transfers had to go at the lower speed.

A Camputers Lynx… there isn’t much I can actually say about this beastie, I got it untested from a charity shop without any leads or PSU and have never got around to actually firing it up. I previously found a dead spider inside when I opened it, though.

This is a wafer drive for the C64 (similar to the Sinclair Microdrive) that connects to the cassette port. This particular unit kept eating the boot wafer so it never actually worked, but that’s not really surprising for something that cost a fiver at a computer show I suppose…

This graffiti is on a wall by Sainsburys in Canterbury… yes Pac, we do indeed miss you – come back! [Sob!]

And finally, here’s the Amiga 1200 with 4Mb of RAM in it’s trapdoor and a battery-backed clock that stunned me by still working after all these years! Since getting it up to Leeds, I’ve replaced the 500Mb 2.5″ hard disk with a 2Gb CF card, ordered the cheap and cheerful PCMCIA to CF converter which can be seen poking out of the side (with a 32Mb FAT16 formatted card so I can quickly swap data back and forth between Amiga and PC), registered the excellent WHDLoad and possibly installed the odd game or two… I’ll even put the top half of the case back on eventually!