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+--- Forum: Random Image (https://forums.tymeg.net/forumdisplay.php?fid=4)
+--- Thread: Uncle DT's Random Image Thread (/showthread.php?tid=4)
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RE: Uncle DT's Random Image Thread - Blaze - 06-23-2026
After you left I had to look up the SIO technical specs, and you were right about the Happy speeds being faster than 19.2k. It's spec'd as running at 52k. The SIO has a theoretical speed of 120k, but you have to remove two capacitors and add a resistor in order to unlock that speed. It was originally capped at 19.2k because of two things: 1) the FCC putting a limit of how much interference was allowed and 2) Atari at the time didn't have any equipment that could handle speeds faster than 19.2k and therefore weren't able to measure interference above it. But the coolest thing was the 6532 MOS chip in the drive was called the RIOT (Ram In/Out Timer)...
RE: Uncle DT's Random Image Thread - Kruger - 06-24-2026
Damn the FCC, it's cause of them that Atari ended up blowing through 50% of the US stockpile of aluminum...
RE: Uncle DT's Random Image Thread - Blaze - 06-25-2026
I was confused as well. It seems that the limit is set in the OS in combination with POKEY and with a modified ROM and driver you can get 120k/bps. The 4.7k resistor and removing capacitors was to improve the reliability of high speed transfers. Stock components can reliably achieve 58k/bps, although the 1050 drive with the RIOT chip was limited to 19.2k. The Happy and other drive mods used a 6502 to replace the 6507 which was able to utilize the higher transfer rate. I gleamed a bit of this information from the Fujinet project and a Github repo HiassofT/highspeed-sio...
RE: Uncle DT's Random Image Thread - Kruger - 06-25-2026
So it looks like it's a combination of software in the computer along with the Happy that enables the 54k throughput. The onboard ram in the Happy enables it to cache sectors and send them more quickly, plus the Happy and SpartaDOS/Happy software/etc... essentially bypass the SIO routines completely and use their own in order to enable the high speed data transfers. Interesting....
RE: Uncle DT's Random Image Thread - Blaze - 06-25-2026
What was even more interesting was the US Doubler and it's smart algorithm copier. Utilizing the skewed format and optimizing the reading for it created some blazingly fast copy speeds. I remember now that I was using the Super Archiver on my drive and it had something very similar...
UltraSpeed
RE: Uncle DT's Random Image Thread - Kruger - 07-02-2026
Ok that was a cool video. And just reminded me how slow the 1541 drive was for C64 users. Pitting that 1541 against a US Doubler ultraspeed skew would be like putting a VW Bug on the track next to a top fuel dragster...
RE: Uncle DT's Random Image Thread - Blaze - 07-02-2026
I was looking up what the actual throughput was for the 1541 and got a little history lesson on the drive. What an absolute dumpster fire of a drive. That thing should never have seen the light of day until they ironed out all of its flaws...
RE: Uncle DT's Random Image Thread - Kruger - 07-06-2026
I seemed to remember the primary downfall to the 1541 was because they needed it to be CP/M backwards compatible and included some bugs to help ensure that was always the case. Then again, I can't remember what I had to eat for breakfast so I'm probably remembering totally wrong...
RE: Uncle DT's Random Image Thread - Blaze - 07-07-2026
Yeah, you had it right with the exception that it was the PET/CBM compatibility it needed. What I found amazing was that they used a 40 track mechanism, but the DOS only recognized 35 tracks. But it was the fact they didn't put in a zero track sensor and instead just let the heads beat against the rail stop a few times to ensure they were at the zero track. Of course that caused all sorts of alignment issues. Geniuses I tell ya. Oh, and I found the hack that allows you to remember what you had for breakfast; buy a 3.5lb bag of Fruity Dyno-Bites and you'll know what was for breakfast for the next two months...
RE: Uncle DT's Random Image Thread - Kruger - 07-07-2026
It's been a while since I've had any Malt-O-Meal products. But dammit, I do remember that a lot of them were much better than the originals that they were copying. I think the Dyno-Bytes were one of those...
RE: Uncle DT's Random Image Thread - Blaze - 07-08-2026
I remember getting an AFX race track set. I had the Can-Am style cars. I could spend hours running those cars around and around and around. And those guardrails were a requirement, but I was a bit annoyed at how fragile the little clips were that held them onto the track. We didn't know about super glue and the rubber cement glue I did have didn't work for crap on them. Tape and cardboard became a thing...
RE: Uncle DT's Random Image Thread - Kruger - 07-08-2026
Before I got my set, we would play on dad's set. His was an older style that connected using pins and these little U-shaped clips that would hold the track pieces together. And of course his cars were all classic late 50's and early 60's cars. They did make adapter tracks that I always wanted to allow me to use his tracks in addition to what I had in my kit...
Hmmm, I should probably see if he still has his...
RE: Uncle DT's Random Image Thread - Blaze - 07-08-2026
All I have left are just a couple slot cars. Although, I remember having some pieces that looked like that. Wasn't there a little tool you needed that would help cinch up the tracks? That'd be cool if your dad still had his tracks. I bet it would need a severe cleaning...
RE: Uncle DT's Random Image Thread - Kruger - 07-10-2026
I still have my slot cars and track. I talked to dad the other night and he thinks his are in the attic, maybe. I would like to find them now, if they are still there somewhere.
Oh, I am sure that steel wool is not a good option. I totally imagine the slivers getting into the magnets and hosing the motors completely. I always used a pink eraser to clean both my AFX track and train tracks...
RE: Uncle DT's Random Image Thread - Blaze - 07-10-2026
Yeah, those tiny steel threads all stuck up on the magnets and in the motors. What a pain. I watched a few videos and slot cars have come a long way especially being able to put multiple "ghost" cars on the track...