New Stuff For Old Stuff :: Blog

Sadly the Friday quiz that I subscribe to is having a break for three weeks. I have subscribed to other maths problems and this one that caught my eye this week: The Baseball Game Ivy has created a game for her school’s math fair. She put three baseballs, numbered 1, 2, and 3, into a bag. Without looking, a player will randomly draw a baseball from the bag, record its number, and then put the baseball back into the bag. They will do this two more times and then calculate the sum of the three numbers recorded. If the sum is less than 8, the player will win a prize. What is the probability that a player will win a prize when they play this game once? This isn't too difficult to work out. I did it with a spreadsheet but you can reason it out I think.  Look away now if you want to work it out for yourself first.  I haven't yet had the official answer, but the answer that I and my partner have both found is 85.185%, that being 23 winning combinations out of 27 possible combinations...

T his is an ARM2SID in my sixtyclone: Before now, I didn't appreciate that the ARM2SID is two ARMSIDs in one package. You might guess that from the name, but most of the pictures show two of them hooked together which gave me the incorrect impression that you needed two. Having two of these connected together actually gives you 3-SID sound and FM Sound Expander capability.  At first, I fitted a single ARMSID into my sixtyclone. It has a very good sound, is configurable for 6581 / 8580 and supports paddles.  For dual-SID work, I first tried the SID2SID board. It's cheap and easy to install, doesn't overhang any chips and works fine with two ARMSIDs. The drawback to this is that the second SID sits at either DE00 or DF00 and that's it. So for more configurability I tried a MIXSID. This gives you loads of configurability (ie option of having second SID at D420) and also allows you to mix the stereo.  A drawback to this solution is the size of it. I had to use an extra sock...

T his is the process that I've gone through quite a few times now with Vic and C64 keyboards, as well as Plus/4 and C16. The results are amazing; the keys feel as-new and make contact every time with a light tap. The computer being worked on here is another Vic from my deep stash. Most of my computers were collected for peanuts at car boot sales in the 90s, although one of these Vics (I don't know which one - possibly this one) is my original one.  This involves a complete disassembly, requiring a key-puller to remove the caps, and the correct screwdriver to separate the PCB from the mounting bracket. It's also necessary to desolder the two wires from the bottom of the mechanical shift-lock switch.  Cleaning the keycaps is a time-consuming job. I soak and scrub all faces of the caps. The legend on the top  is moulded in, so giving those a hard rub with a mild abrasive can only improve them. But this doesn't apply to the graphics printed on the front of the keys. Treat t...

 T his is another performance using my new "MIDI input" music driver.  This is another piece of original Dual-SID music. I've tended to like intros that start simply and build but I'm starting to doubt the wisdom of writing long ponderous intros. I may experiment with form and try something that dives straight in and uses the thin bits in the middle. My 16-channel MIDI to 6-channel SID voice music player is improving. The sound in the video is captured straight from my sixtyclone which you can see in the video. I realised later that I had failed to remove the sound from the separate video footage and so you can hear a faint strange echo and room ambience. The music is actually being generated by Logic Pro on a Mac (I can use anything that generates live midi events) and sent to the C64 via my Datel MIDI cart. This setup is working really well. Composing using the piano roll in Logic is great, it allows me to really fine-tune the length of the notes (or selectively ove...

T his year I decided to rewrite my music driver.  That's going well, and by combining that driver with my ' Knottifier ' which allows you to play the SID via a MIDI keyboard or instrument, I've come up with this. It receives MIDI data via a MIDI cartridge, with up to 16 channels. It allocates a free voice (if there is one), applies whatever sound patch you've chosen for that channel and plays the note. One channel typically carries all of the percussion with each drum being a different note. Some channels such as the piano and guitar here, may play chords, ie more than one note at a time. Canyon.mid is not my music, in case you don't know it. It's very complex, it has around 10 tracks, with multiple simultaneous notes on many of them. This is well beyond even dual SIDs, so I've taken out a number of the tracks and edited down the remaining ones a little. More work on this particular track and my sound patches could improve this rendition a bit. 

R ob Taylor has 'reverse engineered' the C64 board and is selling his modern re-creations. They are truly a thing of beauty. Of course you can use one to replace a bad board in a C64. But you can also use one to build a new C64. Bob still has plenty of boards left in three revisions and various colours .  Why did I start this?   I love using real hardware, just as I have done since '81. There's something about working directly with the actual hardware, a feeling that was lost for me in the 16-bit era, when we became more 'distanced' from the silicon.   I will always have and use all-original machines, they won't sit on a shelf to be looked at. But as a daily-driver, putting frequent stress on those old components bothered me.  We have to make up our own minds about emulation. It has its place for me but it's not the same. TheC64 is only a small step up from there (for me). I held off from the Ultimate and Reloaded for different reasons. After replacing ...

A t first the name filled me with fear because it made me think of flashing your own ROM cartridges, which is a voodoo I'm not at one with. It turns out that products like the Easyflash are less scary than they sound. I believe EF had 8 ROM slots that you could flash from the C64 itself and then it operated as a cartridge containing the ROM you selected.  If I have that wrong, forgive me, but it just demonstrates that KFF is easy enough for a numpty like me to use.  Creator Kim Jorgensen has taken that Easyflash idea and run with it.   Kung Fu Flash takes a micro SD card, on which you put as many program files, disk or cartridge images as you like. (If you buy one from Future Was 8-bit, it comes with a micro-SD which already has a lot of stuff copied to it.) The Menu button on the KFF menu gives you a file browser.  You simply select one of your .prg files to run it. In that respect it's a credible alternative to the SD2IEC.  If you select a .crt file, KFF will ...

Exhibit A. (6502 assembly code) Have you seen it yet?  This took me two sessions to find, God knows how many hours.  The frustrating problem with this bug is that it caused memory to be corrupted elsewhere, memory that happened to be a part of the program. So the symptoms made no sense.  The game would crash after losing the first life, during setup for the next life. Once I'd found the place where the crash was happening, it was a routine that had already worked properly once. What was going wrong when it ran the second time? After pausing the emulator just before the crash and opening the monitor to examine the memory, I could see that my code at that particular spot was now corrupt. But that corruption could have happened at any time after initialising the game. No clue as to the culprit.  I eventually started returning from the game at various points and using the monitor to check whether the corruption had happened yet. Eventually a pattern in the corruption its...

T his weekend I've tried a different approach to writing and recording a song and it's worked out so well I thought I'd make some notes here about the process. First of all, here's the finished music. I only spent an hour or two actually writing it. That was in itself an exercise in composing but I wanted to try this new method of recording and just got something down to work with. I like it a lot and will definitely expand it. All sounds here are produced by the C64, albeit one fitted with an ARMSID (set to 6581). Only because my working C64 with a real SID chip is playing up. Rather than try to write for 3 or 6 voices and then import that information to end up with a .prg that will run and play the music (aka a "sid") I've written any number of parts, with up to 3 voices in each, and used the C64 as a MIDI instrument, sending each part as MIDI to the computer and recording the audio that comes out of the computer. I think that Logic and other...

M y 'bionic' C64 has reached another milestone. I wrote about it after I'd installed a PLAnkton , ARMSID and TOLB , and in the process resurrected a 'black-screen' computer. Although I have an external SD2IEC which is good for plugging into any C64, Vic20 or C16 that I am using, I'd always intended to put an internal SD card drive inside this machine, I had envisaged simply leaving the drive inside the machine, opening it up whenever I wanted to copy anything to the card. But I found that Gaz Marshall has designed a replacement side panel for the C64 which has an SD card slot and houses the SD2IEC. It's available as a model for 3D printing , or ready-printed direct from his Shapeways shop . I hadn't found the shop for ordering the printed version, so I asked a friend to print one for me. Here's the result. Note that there's an all-in-one version, and a 'modular' version where you have to screw the tray to the side panel. ...

P rogress has been slow, I've been caught up in ironing out a few problems. Debugging those was tiresome, which meant that I found it easy to do other things instead. But now we have smooth scrolling background, music, enemies that scroll in from the left at an angle (hopefully soon multiple enemies / collectibles) multiplexing sprites (the sheep are each made of two sprites, a multicolour and a hi-res outline overlaid. The clouds are also sprites).

O nce I'd started writing a game for the C64 and started playing some of the great new games available , I decided that I needed a 64 that I can switch on and use as much as I like without worrying about stressing 35-year-old components (at least one of which is destined to fail in time ). Emulation is fine, in fact when I'm spending a lot of time playing one game I like to use all of the mod cons; big chair, big screen, Duoshock controller and VICE which makes loading up and saving the game at any point a breeze. That's not the same as switching on a 'real' 8-bit computer and playing a game from the time. I had a 'black screen' C64 and so there was an opportunity with a few options. Fit the original case / keyboard with a Pi, or with one of the modern boards - Ultimate 64 or C64 Reloaded These boards are new boards which emulate the original components. So we're still talking emulation, albeit hardware rather than software. In the case of the...