Mysterious Files PH

Although digital computers are – much like their human computer counterparts – about performing calculations, another crucial element is that of memory. After all, you need to fetch values from somewhere and store them afterwards. Sometimes values need to be stored for long periods of time, making memory one of the most important elements, yet also one of the most difficult ones. Back in the 1950s the storage options were especially limited, with a 1959 Bell Labs film reel that [Connections Museum] digitized running through the bleeding edge of 1950s storage technology.

After running through the basics of binary representation and the difference between sequential and random access methods, we’re first taking a look at punch cards, which can be read at a blistering 200 cards/minute, before moving onto punched tape, which comes in a variety of shapes to fit different applications.

Electromechanical storage in the form of relays are popular in e.g. telephone exchanges, as they’re very fast. These use two-out-of-five code to represent the phone numbers and corresponding five relay packs, allowing the crossbar switch to be properly configured.

After these types of memory, we move on to magnetic memory, in the form of well-known magnetic tape that provide mass storage in relatively little space. There is also the magnetic drum, which is much like a very short and very fast tape and provides e.g. working memory. This is what e.g. the Bendix G-15 uses for its clock signal and working memory, while magnetic tape and punched tape are used for application and data storage.

Next we cover magnetic-core memory, which stores a magnetic orientation in its ferrite rings or on a ferrite plate. This is non-volatile memory, but has low bit density and performs destructive reads, preventing its use beyond the 1970s. Today’s NAND Flash memory has significant overlap with core memory in its operating principles, both in its advantages and disadvantages.

An interesting variation on core memory is Twistor memory, which saw brief use during the late 1960s and early 1970s. Invented by Bell Labs, it was supposed to make for cheaper core-like memory, but semiconductor memory wiped out its business case, along with the similar bubble memory. An interesting feature of Twistor memory was the ability to add write-inhibit cards containing permanent magnets.

Fascinatingly, a kind of crude mask ROM is also demonstrated, before we move on to the old chestnut of vacuum tubes. Demonstrated is a barrier-grid tube, which uses electrons to create an electrostatic charge on a mica surface. This electron beam is also used to read the value, which is naturally destructive, making it somewhat similar to core memory in its speed and functionality.

Finally, we get the flying-spot store system, which is a type of optical digital memory. This is reminiscent of optical disc systems like the Compact Disc, and a reminder of all the amazing breakthroughs that we’d be seeing over the next decades.

Perhaps the best part about this video is that it shows the world as it sidled still mostly unaware towards these big changes. Memory storage was still the realm of largely hand-assembled, macro-sized devices, vacuum tubes and chunky electromechanical relays. Only a few years after this video was released, we’d see semiconductor technology turn the macro into micro, by the 1970s nerds would be fighting over who had the most RAM in their home computers, and CD-ROMs would set the world of computer storage and home game consoles ablaze by the 1990s with literally hundreds of MBs of storage per very cheap disc.

Considering that the Nintendo DS already has its own remake of Super Mario 64, one might be tempted to think that porting the original Nintendo 64 version would be a snap. Why you’d want to do this is left as an exercise to the reader, but whether due to nostalgia or out of sheer spite, the question of how easy this would be remains. Correspondingly, [Tobi] figured that he’d give it a shake, with interesting results.

Of note that is someone else already ported SM64 to the DSi, which is a later version of the DS with more processing power, more RAM and other changes. The reason why the 16 MB of RAM of the DSi is required, is because it needs to load the entire game into RAM, rather than do on-demand reads from the cartridge. This is why the N64 made do with just 4 MB of RAM, which is as much RAM as the ND has. Ergo it can be made to work.

The key here is NitroFS, which allows you to implement a similar kind of segmented loading as the N64 uses. Using this the [Hydr8gon] DSi port could be taken as the basis and crammed into NitroFS, enabling the game to mostly run smoothly on the original DS.

There are still some ongoing issues before the project will be released, mostly related to sound support and general stability. If you have a flash cartridge for the DS this means that soon you too should be able to play the original SM64 on real hardware as though it’s a quaint portable N64.

Magnet placement tools are great because they remove finger fumbling while ensuring correct polarity every time. [EmGi] has made a further improvement by making a version that auto-feeds from an internal stack of magnets.

That is a trickier task than one might imagine, because magnets can have a pesky habit of being attracted in inconvenient ways, or flipping around and sticking where they should not. [EmGi] solves this with a clever rack and pinion mechanism to turn a single plunger press into a motion that shears one magnet from a stack and keeps it constrained while the same magnet responsible for holding it to the tip takes care of dragging it down a feed path. It’s easier to see it work in action, so check out the video (embedded below) in which [EmGi] explains exactly what is going on.

This design is actually an evolution of an earlier, non-reloading version. This new one is mechanically more complex, but if it looks useful you can get the design files from Printables or Makerworld and make your own.

The only catch is that this reloading design is limited in what sizes of magnet it can handle, because magnet behavior during feeding is highly dependent on the physical layout and movements. For a different non-reloading placement tool that works with any magnet size and is about as simple as one can get, you can make your own with little more than a bolt and a spring.

Thanks [Keith] for the tip!

There was a period from the 1970s to the mid-2000s or so when a fixture underneath the family TV set was a VHS videocassette recorder. These were a masterpiece of cramming a color video signal into the restricted bandwidth of an affordable 1970s helical-scan tape deck, which was achieved by clever use of frequency shifting and FM carrier modulation. Very few of us will have had the ultimate iteration of the VHS format though, W-VHS, which managed the same trick but with HD video. But how? [Superchromat] is here with the answer.

W-VHS used a frequency modulated carrier, but instead of splitting luminance and chrominance in the frequency domain like its VHS ancestor, it did so in the time domain in the same way as some 1980s satellite TV standards did. Each line first contained the color information, then the brightness. Thus it sacrificed some color resolution and a little horizontal image resolution, but kept a much higher vertical image resolution. In the video below the break we go into significant detail about the compromises required to pull this off, and if you watch it through you’ll learn something about magnetic tape recording as well as FM.

The W-VHS standard is largely forgotten now as a last hurrah for the format, but it’s still in the sights of the VHS Decode project. The work in this video is helping them retrieve the highest quality images from these tapes, by capturing the raw RF from the heads and using DSP techniques to decode them.

When you’re livestreaming, it can be tempting to fire off all kinds of wacky sound effects like you’re a morning radio DJ back in the heady days of 1995. If that’s who you want to be, you might like this soundboard project from [Biker Glen].

The build is based around an RP2040 microcontroller. It’s paired with an I2S digital-to-analog converter for sound output, which in turn feeds a small amplifier hooked up to a speaker or a line output.  The RP2040 is programmed to respond to MIDI commands by playing various sounds in response, which are loaded off a microSD card. It’s able to act as a USB MIDI host, which allows it to work seamlessly with all sorts of off-the-shelf MIDI controllers like the MIDI Fighter or the Novation Launchpad.

It’s an interesting hardware solution to a problem that you could probably also solve with software on your streaming machine, especially if you’ve already got a USB MIDI controller. However, there’s something to be said for lightening the load when your streaming computer is already doing lots of hard work to truck video up to the cloud already. Files are on Github if you’re eager to replicate the build.

Soundboards are just fun, which is why we’ve featured them before. Meanwhile, if you’re whipping up your own streaming accessories at home, be sure to let us know on the tipsline!

As common as the Xbox 360 was, the development kits (XDKs) for these consoles are significantly less so. This makes it even more tragic when someone performs a botched surgery on one of these rare machines, leaving it in dire straits. Fortunately [Josh Davidson] was able to repair the XDK in question for a customer, although it entailed replacing the GPU, CPU and fixing many traces.

The Xbox 360 Development Kit is effectively a special version of the consumer console — with extra RAM and features that make debugging software on the unit much easier, such as through direct access to RAM contents. They come in a variety of hardware specifications that developed along with the game console during its lifecycle, with this particular XDK getting an upgrade to being a Super Devkit with fewer hardware restrictions.

Replacing the dead GPU was a new old stock Kronos 1 chip. Fortunately the pads were fine underneath the old GPU, making it easy to replace. After that various ripped-off pads and traces were discovered underneath the PCB, all of which had to be painstakingly repaired. Following this the CPU had apparently suffered heat damage and was replaced with a better CPU, putting this XDK back into service.

We are going to bet that as a kid, you had a View-Master. This toy has been around for decades and is, more or less, a handheld stereoscope. We never thought much about the device’s invention until we saw a recent video from [View Master Travels and Peter Dibble]. It turns out that the principle of the whole thing was created by the well-known [Charles Wheatstone]. However, it was piano repairman [William Gruber] who invented what we think of as the View-Master.

[Gruber] didn’t just work on normal pianos, but complex player pianos and, in particular, the pianos used to record player piano rolls. He was also, as you might expect, a stereo photography enthusiast. Many of the ideas used in automating pianos would show up in the View-Master and the machines that made the reels, too. In the 1930s, stereoscopes were not particularly popular and were cumbersome to use. Color film was also a new technology.

[Gruber] realized that a disk-like format would be easy to use and, more importantly, easy to mass produce. The reels had a few features to simplify their use. For example, if you show each image in sequence, you’d eventually see pictures upside down. [Gruber’s] solution? Use an odd number of pairs and advance the reel two positions for each jump forward. That way, you never show an image to the wrong eye.

The model “A” didn’t look much like the View-Master you probably remember. By 1940, the toy was a hit. But initially, it wasn’t really a toy so much as a way for adults to view distant sites. Of course, World War II could have stopped the enterprise dead, but instead, they shifted to producing training aids for the military. The War Department would buy 100,000 viewers and about 6 million reels to help train soldiers to identify aircraft and ships, as well as to estimate range.

Training was always a key use of the View-Master technology, but the company eventually bought a competitor with rights to Disney films and exploded into a must-have toy. When the company was bought by GAF, the focus on the toy market grew. Despite some efforts to keep the company relevant in an era with virtual reality and other 3D technologies, View-Master is, sadly, a bit of nostalgia now, even though you can still buy them. But it is impressive that despite many changes to the viewer and the production methods, the View-Master reel remained virtually unchanged despite the production of about 1.5 billion of them. Sure, there were fancy viewers that had audio tracks, too, but the basic idea of an odd number of film frames mounted in a circle in a notched disk remained the same.

These days, a phone can be your View-Master, at least, if you can cross your eyes. Want to preserve your View-Master reels for posterity? So did [W. Jason Altice].