Category Archives: 6502

Edilbert Kirk’s Z-Machine for CBM computers

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I never heard of this one before, but it’s legit!… As long as you have expanded your RAM, Edilbert’s Z-Machine opens up the world of Infocom to a whole host of machines:

  • C64
  • C128
  • CBM 4032
  • CBM 8032
  • CBM 8096 / CBM 8296
  • VC-20 (32K / 40K)
  • +4
Sweet looking 8296 from xAD / nIGHTFALL‘s post on nightfallcrew.org

I’ve never seen the more advanced ‘European Business’ PET’s before, I’ve only dealt with the incredibly limited PET 2001-8C Chiclet keyboard models that were so insanely limited. It wasn’t until much later I saw the dual disk drives (4040’s??) that could have helped those machines so much more, but that was that. I’d been asked as a kid to make an electronic card file on an 8kb machine with a single tape drive. Sadly 8 year old me didn’t know about loading and saving sequential records on tape. Or maybe luckily as I can only imagine how insanely slow this would have been, and or tedious to not only save and update, but find things.

Anyways I thought I’d fire up some mythical 8296 beast with 128Kb of RAM. Attaching the disk image, and firing up “LOADER”, you can watch it load up as much as possible into memory:

And once it’s loaded up, the Z-Machine is active!

Now granted I don’t have a PET to test with, but using VICE, I can happily say that for an 8bit machine, this is incredibly fast. Maybe it’s the disk subsystem interface, as the VIC-20/C64 have an absolutely dreadful interface, but yeah wow playing HHGTTG on a non C64!

You can find downloads over at “PET FOOD“.

Anyways this is pretty neat, and all new to me. Just like the Tandy CoCo 6809 interpreter source being found was as well.

The price of Commodore 64’s is getting out of control.

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I’ve been looking on and off the last year, and they all seem to be $100 USD minimum for one that is either ‘as-is’ or broken. Good working ones are selling for double or more.

I’ve been disappointed, as I haven’t played with one in years.

Commodore 64 C

And then as a fluke I found an auction for a kind of beat up Commodore 64c for a mere £40! Naturally shipping it to Hong Kong was going to cost more than that, and with all the Wuhan Flu thing going on, I really didn’t expect it to show up any time soon. Yet, one week after I bought it, the Commodore arrived!

It’s a little dirty, but overall it feels okay. I was a bit nervous if it would even turn on. However as it was in the UK, the power supply is already 220v, and the TV I have in the office is PAL (it should have had SCART too, but they sent me the UK one, not the continental one ….)

Now for those who have never setup a PAL Commodore before, they output to CHANNEL 4. The cable to the TV (LEAD, lol!) has 2 different ends to it, so only one side goes to the TV, and the other to the equipment. Unlike NTSC, there is no channel 3/4 select, nor is there an external RF modulator, it’s all contained in the 64c’s chassis.

Nice.

I had to wave my phone around for a bit to get the TV to scan the analog band with the Commodore powered up, but after 5 minutes, it finally had done it’s scan and I could behold the hew of the blue screen.

It looks much better in person, but yeah there it is. I haven’t’ had time to do much else, but I wanted to share this quick bit.

I also got a datasette with it, but I’m oddly enough out of audio cassettes. It feels so weird to have no software for a machine.

Asking some suppliers I was able to get some 10 packs of 60 minute tapes for å…ƒ 27.5, or approximately $3.75 for a pack of 10. If this were 1982 I could be a media mogel! But in 2020 I suspect that I can measure the demand for new tapes on one finger.

I have big plans for this little thing. Although amateur surgery may be part of it.

Running CP/M on the Commodore 64!

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CP/M cartridge retail box

Back in 1983 there was this great idea of expanding the Commodore 64 with the then popular (but declining) base of serious business software from the CP/M side of the world by creating a cartridge with a z80 processor inside, and a special port of the CP/M operating system that would take over the C64 letting you run real programs like Fortran, Cobol and the far better (and updated) Microsoft Basic v5!

However as always the major failing of CP/M was the massively different and incompatible diskettes of every platform.  The Commodore 64, lacking in RS-232 ports, and it’s incredibly incompatible 1541 drive rendered it nearly impossible for the average home user to transfer any programs in the specially formatted CP/M diskettes for the cartridge.  Not being able to read a standard 1541 diskette would prove to be it’s undoing.

While messing around in Vice, I saw that this cartridge is emulated now!  A quick search led me to zimmers.net where I was able to then locate the needed cpm.d64.gz, and I was booted up into CP/M and of course that hit the first snag which is of course, where is the software?

Well another search brought me to the package ‘ctools‘ which I quickly built on the Linux subsystem for Windows (I had to add -fpermissive to get it compile..), and now I could take that CP/M diskette delete the contents, and for the heck of it insert in Zork.. Of course where to find Zork along with other CP/M software?  The zip zork123_80.zip can be located on retroarchive.org, even fun things like Microsoft BASIC v5.21 (Interpreter), along with the manual.

CP/M only recognized a single drive, so you have to swap diskettes (Such a typical Commodore 64 experience), and here we go!

via Vice

Naturally the Commodore 64’s 40 column mode is… terrible.

However even back in 1984, a fine program aptly called soft80.com sets up the Commodore 64 in high resolution graphics mode, and emulates an 80 column mode.  Even better, the magic for the most part happens on the 6502 side, meaning it doesn’t take away from the precious memory on the CP/M side.

Zork 1 under CP/M / Soft80

Its worth noting that although Infocom games are dreadfully slow on the Commodore 64, playing under CP/M is also dreadfully slow, taking some 10-15 seconds to complete a command.

At least under emulation there is the warp mode.  And what took an hour to put together would have been months no doubt in the 1980’s ending in the CP/M cartridge going into a drawer to never be seen again.

A Z80 on a cart is pretty interesting.  It would have been interesting if other CPUs had made their way, a 68000 would have been interesting to have bridge the 8 bit world out, or even if Commodore had tried to put an 8088 onto that card, as early PC’s were nowhere near the 640kb hard disk wielding monsters they would become much later.  Naturally one could only dream of the power of an 80386 or the once vaunted NS32016

BBC releases its computer history archive

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I thought it was somewhat worth mentioning that the BBC was releasing their old Computer Literacy Project Archive.  Although they for some reason never released any of their materials to the colonies and or territories, so although I’ve never seen any of this stuff, I’m sure others know far more about it.

I’m kind of surprised they didn’t keep this kind of thing up, although I guess after David Braben made it a priority again, and the Raspberry Pi was born, completing the cycle of the birth of Elite!

DooM for the VIC 20

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I just found out about this one, it’s DooM! … on an 8bit.  No really!

I was watching this video of the 8bit guy, and (jump to 19:20) he quickly mentions DooM on the VIC 20.

Over on Denial, The Commodore Vic 20 Forum  Kweepa did the seemingly impossible by using cc65 and some assembly for a somewhat cut down (haha!) DooM on the 8bit.  The source is even available on github.

It has cut down the video rendering obviously, but still has some of the C enemy AI logic, it’s a bit more like Wolf in that there is no height in the cut down levels, but wow it’s still amazing to see.  The sound effects were re-cut from the PC speaker stuff, and yes, even reduced versions of the MIDI music make the cut!

Naturally this won’t run on a stock 20, rather you need to get the maximum 37kb of RAM, and it requires a floppy disk drive.

It’s really cool to check out, and yes it runs on VICE.

I’m more so surprised that this didn’t ignite more 6502, or other non 32bit machine versions of DooM.  You can find download information for the d64 image here, and a direct link here.

NES emulator written in JAVASCRIPT.

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Well I guess we have officially crossed the bridge, where multiple Ghz machines can run scripts that can emulate a 1.8Mhz 6502 in realtime.

behold JNES.

And frankly the bigger thing to behold is just how FAST Google chrome is at java script. On my Intel Centrino laptop the google benchmark (http://v8.googlecode.com/svn/data/benchmarks/v5/run.html) scores 105 in Internet Explorer 8, while Google Chrome scores 3330.

That’s not a typo, Google Chrome is more then 31x faster than IE at executing Java Script.

I’ve got to find out where that whole NaCL thing went to, and where it is.

But seriously, go check it out! Mario in a browser without flash!