Category: hardware

Formatting a C64 Disk In 15 Seconds

Recently Commodore History investigated just how Commodore 1541 disk drives format disks, and why it took them over a minute. It was also an explanation of just what it means to format a floppy disk. We linked that last week.

Well, yesterday they posted a second video on matters involving formatting disks. (16½ minutes) This time they went over a routine written, for the same drives, that can format a disk in 15 seconds.

So, how can this new formatting method be more than four times faster? In a few ways. The drive’s normal format routine writes 1 bits throughout each entire track; the 15 second formatter doesn’t do anything like that. The stock routine attempts to size the between-sector zones differently depending on how far from the center the track is, and to make that work better it performs a measurement of how fast the drive motor runs. The quick format just uses a same-sized gap throughout the disk. It still reads okay because the drive uses the sync marks to find sectors, it doesn’t try to time the length of gaps when reading, it just looks for a sequence of 10 1 bits in a row. And Commodore’s format routine verifies each track as it’s recorded to the drive; the 15 second format simply moves on, assuming everything worked out.

The result is, the quick formatter does a worse job of setting up the disk, skipping some of the niceties of Commodore’s routine. I wonder if there are some cases where the quick format produces a non-working disk? The video notes that, because there could have been data on the disk before, it could result in cases where the drive gets confused when that leftover data resembles a sync mark or other essential drive structure. Commodore History mentioned at the end of the video that they tried to create such a disk, to see if it caused issues, but was unable to make it happen.

How the C64’s Disk Drives Formatted Disks

The 1541 disk drive was infamously slow, probably the slowest of the 8-bit floppy disk drives, the result of a VIC-20 Kernal bug that was inexplicably kept in the C64 for the sake of backwards compatibility. The problem could be fixed by writing your own disk routines, which is why so many games used fastloaders.

But the bug isn’t always at fault. The 1541 disk drive takes over a minute and a half to format a disk, but as it turns out it had good reason to, and the time consumed had nothing to do with the C64’s code because the drive does all the work itself; the Commodore 64 just waits throughout the process.

Commodore History goes into considerable detail on the process here (16½ minutes). During formatting the drive wipes out all the data that had been on the disk, lays down syncing structures, writes the disk ID to every sector, puts down the directory track and sets up the Block Allocation Map (BAM), and more. It’s an interesting, if not too useful these days, exploration of what disk drives at the time had to do to make the disk’s magnetic surface usable for data storage.

Creator of C64OS Talks VIC-II Video Timing

It’s a pretty good run-down of the various weird timing issues of the Commodore 64. Machines at that time had to do all kinds of weird things to keep up the overriding priority of microcomputers of the time: building a consistent video signal that could be displayed on a television. Nearly all machines needed special hardware to do the job of keeping up the display, to give the CPU time to run user programs, or anything at all.

Circuit diagram from the linked article

The C64’s VIC-II video chip is a product of many compromises. The C64 could contain so much memory affordably because it used dynamic RAM, which requires periodic refreshes, and one of the tasks of the VIC-II was to handle that. It also needed access to main memory in order to build the display image.

But both of these actions conflict with whatever the processor needs to do, so the computer is designed to actually put the 6510 to sleep when the VIC-II needs to access memory. This is why, when the screen is blanked, the machine runs a little faster and more consistently, and that’s why the screen is blanked when a connected Datasette is loading programs from cassette tape.

VIC-II and FLI timing (part 1 of 3, c64os.com)

The Ultimate Gameboy Talk

It’s a busy day for me coming up, so here’s one from my list of Youtube links: the Ultimate Gameboy Talk (1 hour 1 minute) by Michael Steil, but you don’t have to watch it on YT, as it’s also hosted on the website of Chaos Computer Club in various formats. The embed below is from Youtube though, since they usually have pretty good embedding:

This “ultimate” talk is ultimately about the hardware, its internals and quirks, and tricks that can be pulled off in it. Sure, it’s very technical and extremely geeks, but that’s pretty much the standard around these parts. Enjoy!

Luxocrates’ Project to Get C64 Commando Music Running On Arcade

I am back from DragonCon, but got hit by a staggering blow from life (which I will not mention the details of here) that’s going to take me a long time to recover from. So in the meantime, please enjoy this 19 minute video in which someone on Youtube describes his plan to get arcade Commando (a.k.a. “Wolf of the Battlefield”) to play Ron Hubbard’s excellent soundtrack from the C64 port.

Arcade Command didn’t have bad music at all, but Ron Hubbard’s score is generally regarded to outshine it. The two hardware platforms are really different: the C64 has a 6502-workalike and the legendary SID chip, while the arcade version used a custom platform. This is a first video in a projected series, so at this point we don’t even know if he’ll be successful. Let’s hope.

An ALU Implemented in K’nex

A lot of your less tech-savvy people look upon computer chips as some kind of magic, at least judging by how Hollywood movies depict hacking. And aliens can take control of computer systems just by inserting part of themselves into some console and sort of glowing while ominous music plays on the soundtrack.

But everything that happens in a processor is the result of simple logical operations: ANDs, ORs, NOTs, XORs and memory, all connected in different ways. And there’s some redundancy in that list: some of those logic gates can be constructed out of the others. The whole point of computers is you can perform billions of simple operations in a second, and complex operations are made out of lots of simple ones. When you’re working with binary numbers, all you need are simple operations.

Because of this, computers can actually be built out of physical parts, without even electricty, they’ll just be much bigger, and slower, and less durable, and may need some motor attached to them. Mechanical calculators have existed since the 1700s, and in the 50s-70s were common sights in offices. Arguably the first general-purpose computers, Charles Babbage’s Difference Engines (Wikipedia), were made from mechanical parts, but they had the disadvantage of not being made out of colorful pieces of plastic.

Shadowman39, an artiste who works in the medium of K’nex, has made a number of devices out of those construction toys, but an ALU, an Arithmetic Logic Unit that can increment, add, AND and XOR two binary numbers, is probably his most “practical” creation. He shows it off in this 15 minute Youtube video:

I want to see an alien that can nebulously control that monstrosity.

This ALU is one part of a larger processor project that’s still being built. I hesitate to call it a “microprocessor,” maybe we should call it a macroprocessor. We wish Shadowman39 the best, and hope he has enough time, energy and parts to realize his wondrous, ludicrous dream.

White Pointer Gaming on Pokemon Gold/Silver’s Real Time Clock & GB Mappers

White Pointer Gaming is another excellent source of retro game hardware information, and a few days ago they uploaded a dive into the specifics of the real time clock used in Pokemon Generation 2 (14 minutes), and as an encore discussed Gameboy mapper chips, a related topic. It seems the clock hardware is on quite a few other GB games as well, as it’s built in to a common mapper chip, but it needs extra power to run the clock, and an oscillator to keep the time accurate. Another game that uses the same mapper, but doesn’t have the oscillator? Pokemon Generation One. Hmmm!

The video mentions that powering the clock and oscillator causes Pokemon Gold, Silver and Crystal cartridges to run out of battery power, and lose their saved game data, much faster than other Gameboy carts with save game battery. Sorry to break it to you; your Pokemon are probably gone by now. Poor out a health potion for Pikachu.

Another interesting fact revealed is, the clock works by recording raw time since the game was last powered on, and the actual date and time are fully updated when the game is started up. If you wait a long time between plays, over 511 days, the timer can wrap around and lose track of how long it’s been.

Switch 2: Storage Issues and Backward Compatibility

A little bit more about the Switch 2? Sure why not?

First thing. I’ve mentioned this on social media, and I want to spread the word as much as I can about it, because this is going to catch people by surprise, and this way as many will find out about it going in as possible. In addition to costing $450 at launch, $500 with bundled Mario Kart World, and possibly more if Trump’s moronic tariffs stick, as stated in the direct, the Switch 2 uses a special incompatible variant of Micro SD cards, called Micro SD Express.

They’ve been out for a while, but uptake has been slow, mainly because their chief benefit is transfer speed, and Micro SD is fast enough for most purposes. But since its use in the Switch’s has been a performance bottleneck, Nintendo went with SD Express, which has the advantage of being faster, but the disadvantages of being both way less ubiquitous, easy to confuse with normal Micro SD cards, and of course, being more expensive. Ars Technica did a rundown, revealing that Micro SD Express cards are actually more expensive than SSDs at an equivalent price-per-gigabyte. It’s not a proprietary format, but consider that it’s possible that the only SD Express cards you’ll be able to find in a store that you buy your Switch from will be Nintendo-branded, and more expensive, it feels like it effectively is proprietary for now.

How to tell a standard Micro SD card from a Micro SD Express card? Express cards have an EX logo on their label, and they also have more contacts, as shown by this illustration from an SD Association whitepaper:

It’s true the Switch 2 has much more internal storage than the Switch. But many users will also be bringing their Switch digital libraries with them, meaning it’s possible for that storage to be full on day one. I have a 256 SD in my Switch, and I already have to make hard decisions about what I have installed and what I leave in “the cloud.” That will be my reality as soon as I transfer my eShop purchases to the Switch 2.

I mused a bit on Nintendo’s stating that the Switch 2 will be mostly backwards compatible with the Switch 1, meaning, not everything on the original Switch will work with it. What gives?

Nintendo has a page listing games that aren’t Switch 2 compatible. At first glance, it seems that all the issues are with games that are physically incompatible. Like, the Labo VR Kit isn’t compatible, because the Switch 2 is larger than the Switch 1, and it can’t actually fit into the cardboard goggles. Several other Labo kits are similarly “incompatible.” WarioWare Move It is mostly compatible, but the Switch 2 JoyCons don’t have the infrared camera the right JoyCon on the Switch 1 has. You can still pair Switch 1 JoyCons with a Switch 2 though, so if you have them laying around you can still play IR-requiring games. This also affects Game Builder Garage and some Labo titles.

Ring Fit Adventure and Nintendo Switch Sports use accessories that you insert a Switch 1 JoyCon into, and Switch 2 JoyCons won’t fit into them. And 1-2-Switch has a unique issue: the Switch 2 has more subtle rumble, and it seems a 1-2-Switch minigame uses that rumble to communicate information to players, which could end up being an issue.

But… that isn’t the whole story. It turns out there’s a good list of Switch games that have issues on the Switch 2, software issues, but you have to click through to a couple of PDFs to find out about those. Here’s a list of games with “start up issues,” meaning probably they won’t load. And here’s games with issues once they’re running. These lists may shrink over time as bugs are found and stamped out, but that might take a good while; it took years for the Wii-U to run the WiiWare game LostWinds.

Some notable games on the not-starting list: a selection of NeoGeo and Arcade Archives titles, Another Crab’s Treasure, Fornite (although I suspect there will be a Switch 2 native version), Nintendo’s own Fitness Boxing, Doom Eternal, Pizza Tower(!) and River City Girls Zero. Some of the games that play, but with issues: two Tetris The Grand Master games from Arcade Archives, Factorio, Fall Guys, Mega Man Legacy Collection and Stumble Guys.

The Atari 2600 Technical Wiki

There are quite a number of refreshing things about the Atari 2600 Technical Wiki. There’s its subtitle, “Woodgrain Wizardry,” which is excellent. Its dedication to a 47-year-old game console. There’s it being a wiki that isn’t being hosted on damnable ubiquitous Fandom. Its direct writing style, which gets right to the point of each page. It’s also not a Youtube video, which is sort of okay if you have a Premium account or a working adblocker, but a hellscape if you don’t. Its the kind of page Google Search de-prioritizes if you’re not doing a web-only search, and even if you do that, sometimes gets skipped over.

It is true, this one’s for hardcore geeks and programmers only. I love reading about stuff like how to do large 48-pixel graphic displays, useful for score readouts or title screens, even if I probably won’t ever use that information myself. Or on Bank Switching, which reveals that, since there’s nothing in the system’s tiny cartridges’ ROM space that indicates which bank switching scheme is being used, emulators scan through the executable image looking for signature bytes to determine when to map parts of it to the processor’s address space, and homebrew games try to give them appropriate hints so they’ll work smoothly.

There’s a page, Introduction to Processor Hardware, that gives us the surprising information that some EPROM chips, when used with the 2600, may act unpredictably when used in a dark room. That quality esoterica right there.

The Atari 2600 Technical Wiki

Doing Weird Things To A Sega 32X

The Youtuber: MattKC Bytes
What he did: Unexpected things to Sega’s aborted Genesis/Mega Drive add-on.
The address: here.
The length: about seven minutes.

The explanation: Did you ever play around with a 32X? Evidently not a lot of people did. It was straaaange. Unexpectedly powerful! A bit misjudged! Hosted a port of DOOM! Had a port of Virtua Racing that compares favorably with the Saturn version! Had that crazy hard-to-play Knuckles game that gave us Vector the Crocodile!

Have you ever hooked one up though? Its hardware is odd. It’s like a completely separate console to itself. The Mega Drive wasn’t made to support add-on processors and chips like that, so Sega used a clever solution: the 32X has its own video output, and also a video input. You plug the Genesis’ output into the 32X, and then the 32X into your TV. The 32X mixes the Genesis’ signal into its own, as if it were chromakeyed. Since the 32X cartridge supplies the program running on the Genesis as well as itself and they can talk to each other, the two processors and graphics chips should be able to sync perfectly, if awkwardly.

But: because the Genesis’ video signal emerges from that console through this external wire before reentering the 32X, it’s possible to do things to it while in transit. The Genesis supplies video timing information that the 32X relies on, so you can’t get a signal from the add-on without the Genesis’ AV plugged into it, but the Genesis does produce a viewable video signal that you can see on its own.

All the details are in the video, which has been embedded below for your convenience and amusement.