Making Magnetic Tape From Scratch

The use of magnetic tape and other removable magnetic media is now on the wane, leading to scarcity in some cases where manufacture has ceased. Is it possible to produce new magnetic tape if you don’t happen to own a tape factory? [Nina Kallnina] took the effort to find out.

It’s probably one of those pieces of common knowledge, that magnetic media use iron oxides on their surface, which is the same as rust. But the reality is somewhat more complex, as there is more than one iron oxide. We follow [Nina] through this voyage of discovery in a Mastodon thread, as she tries first iron filings, the rust, and finally pure samples of the two iron oxides Fe3O4 and Fe2O3. She eventually achieves a working tape with a mixture of Fe2O3 and iron powder, though its performance doesn’t match manufactured tape. It turns out that there are two allotropes of Fe2O3, and she leaves us as she’s trying to make the one with better magnetic properties.

These results look promising, and while there is evidently a very long way to go before a home-made magnetic coating could replicate the exacting demands of for example a hard drive platter it’s evident that there is something in pursuing this path.

This may be the first time we’ve seen tape manufacture, but we’ve certainly seen extreme measures taken to rejuvenate old tapes.

an EIKI machine playing back a card

Finding Lo-fi In All The Strange Places

If you haven’t heard any lo-fi music yet, it stands for low-fidelity music. Lofi music today is characterized by audio imperfections such as cable noise or tape hiss. To get a pleasantly warm imperfect sound, many artists turn to vintage equipment. [HAINBACH] found an excellent instrument, the obsolete classroom tool known as magnetic card audio recorders.

The basic mechanism of the device is that it reads and writes to the two tracks on the quarter-inch tape fed through it. One track is meant for the teacher and one track is meant for the student. Originally designed to assist language learners, we can see why it would be an ideal source of good lo-fi samples. The microphone and speaker need to be high quality to hear the nuances of the example sentence. [HAINBACH] also admires the general tone and timbre of the device as opposed to just using a cassette recorder.

The tape in question is glued to little plastic cards. With some modification, you can run the card backward, create a loop, or stitch sections together. With multiple machines, you can run the card from one machine directly into another. They were made by several companies and can be found relatively cheap on online auction houses. While we can’t credit [HAINBACH] for coming up with the idea as it was featured in the movie Baby Driver, it’s still an example of an awesome hack.

Magnetic tape has long been a fascination of musical instruments. This Crudman, which is a modern-day interpretation of the much older Mellotron from 1963, is a great example of that.

Video after the break.

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DEC microVAX with tape drive

Bake It To ReMake It: Cooking Old Magnetic Tape To Recover Data

Those of us old enough may remember the heyday of the text adventure game genre from the first time around. London-based Magnetic Scrolls was an early pioneering company producing titles for the first Amiga and Atari ST platforms. Fast-forward to 2017 and [Hugh Steers], the original co-founder and core developer for Magnetic Scrolls has formed an initiative to revive and re-release the original games on modern platforms. Since the 1980s-era DEC MicroVAX used originally for development is not particularly rare in retro computing circles, and media containing source code was found in someone’s loft space, reviving the games was not a tall order.

First, he needed to recover a copy of the original source code from the backup tapes. But there was a problem, it turns out that the decaying tapes used a unstable polyurethane-based binder to stick the oxide material (which is what stores the data) to the backing tape, and this binder can absorb water over the years.

Not much happens until you try to read the tape, then you trip over the so-called sticky-shed syndrome. Secondly you may find that a small amount of the oxide layer sheds from the tape, coating the read head, rollers and guides inside the complicated tape mechanism. This quickly results in it gumming up, and jamming, potentially chewing up the tape and destroying it permanently.

This was further exacerbated by the behaviour of the DEC TK50Z tape drive, which needed to shuttle the whole length of the tape as part of its normal operation.

A temporary solution was to bake the tape in an oven to drive out the moisture and reduce the stickiness enough to run it through the drive safely. Then only the oxide-shedding problem remained. The TK50Z drive was swapped for a TZ30 which shuttles the tape less, but also critically with a simple hack, would allow the heads to be cleaned with IPA between read passes. This was enough to keep the gumming up at bay and allow enough data to be read from the tapes to recover several games worth of code, ready for the re-releasing process.

The video after the break shows [Rob Jarratt] working through the process of the data recovery.

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The Hidden Sounds Of The Past

If you stop to think, the number of pre-recorded voices and sounds you might hear on an average day might number in the hundreds. Everything from subway announcements, alerts on your phone, to sound effects at Disneyland is a sound that triggers in response to an event. [Techmoan] came across a device that many of us have interacted with, but likely never seen: a humble Sontranic 9A Announcer.

In their heyday, these sorts of devices formed the backbone of audio feedback. Messages from Father Christmas were recorded and could be reached when calling a number. Sound effects in theme parks that were activated when a ride activated some hidden switch. Anything where the sound effect needed to play on some sort of trigger.

An interesting thing to note is that this is not a reel-to-reel system. The tape is of the standard 1/4″ magnetic variety, perhaps a little thicker for extra durability. It instead sits in the top of the machine; coiling and uncoiling like a two-dimensional lava lamp. Additionally, there’s nothing clever about detecting the beginning or end of the audio loop (as there were four copies of the same recording on this particular tape). In fact, everything about this machine speaks of reliability as the most important design consideration. A reel-to-reel system would just add more points of failure.

After a little bit of diagnosing, [Techmoan] managed to get the device running again and found the message on the tape to be from the phone system, informing the listener that the line is no longer in service. This banal message is perhaps the best testament to the ubiquity of devices like these.

Perhaps in the future, we’ll see an instrument like this magnetic tape-based one created from a similar machine to the one [Techmoan] found.

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Bespoke Storage Technologies: The Alphabet Soup Found In Modern Hard Drives And Beyond

It seems like just yesterday (maybe for some of you it was) we were installing Windows 3.1 off floppy drives onto a 256 MB hard drive, but hard drives have since gotten a lot bigger and a lot more complicated, and there are a lot more options than spinning platters.

The explosion of storage options is the result of addressing a variety of niches of use. The typical torrenter downloads a file, which is written once but read many times. For some people a drive is used as a backup that’s stored elsewhere and left unpowered. For others it is a server frequently reading and writing data like logs or swap files. In all cases it’s physics that sets the limits of what storage media can do; if you choose wisely for your use case you’ll get the bet performance.

The jargon in this realm is daunting: superparamagnetic limit, LMR, PMR, CMR, SMR, HAMR, MAMR, EAMR, XAMR, and QLC to name the most common. Let’s take a look at how we got here, and how the past and present of persistent storage have expanded what the word hard drive actually means and what is found under the hood.

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Recorded Programming — Thanks To Bing Crosby

If you look up Bing Crosby in Wikipedia, the first thing you’ll notice is his real name was Harry. The second thing you’ll read, though, is that he is considered the first “multimedia star.” In 1948, half of the recorded music played on the air was by Bing Crosby. He also was a major motion picture star and a top-selling recording artist. However, while you might remember Bing for his songs like White Christmas, or for his orange juice commercials, or for accusations of poor treatment from his children, you probably don’t associate him with the use of magnetic tape.

In a way, Bing might have been akin to the Steve Jobs of the day. He didn’t power the technology for tape recording. But he did see the value of it, invested in it, and brought it to the market. Turns out Bing was quite the businessman. Want to know why he did all those Minute Maid commercials? He was a large shareholder in the company and was the west coast distributor for their products. He also owned part of the Pittsburgh Pirate baseball team and other businesses.

So how did Bing become instrumental in introducing magnetic tape recording? Because he was tired of doing live shows. You see, in 1936, Crosby became the host of a radio variety show, The Kraft Music Hall. This very popular program was live. That means you have to show up on time. If you go off on a tangent, you’ll run out of time. And if you make a mistake, there is no editing. Oh and one other thing. You have to do a nationwide live show twice: once for the east coast and another for the west. This was cutting into Bing’s “family time” which, as far as we can ascertain was a code phrase for golf.

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Magnetic Tape Storage May Not Be Retro

Magnetic storage is quickly becoming an antiquated technology but IBM may have given it a few more years. Currently, magnetic storage is still manufactured as hard disk drives (HDDs) but you won’t find a tape drive in a modern consumer computer. That’s not likely to change but IBM is pushing the envelope to make a tape drive that will be smaller and more economical than other massive storage options. In many ways, they’re the antithesis of solid state drives (SSDs) because tape drives are slow to retrieve data but capable of holding a lot inexpensively.

Three advances are responsible for this surge in capacity. Firstly, the tape “grains,” where each bit is recorded, have been shrunk by sputtering metal to a film instead of painting it on. Secondly, better servo control allows the reading mechanisms to read those tiny grains with the necessary accuracy. Lastly, stronger computation is used to read the data by using error detection and correction because when your tape is traveling four meters per second, it takes a long time to go back and double-check something.

IBM’s tape drive won’t replace your hard drive but it could back it up daily, many times over.

Check this out if your wetware needs a memory boost or this if your breakfast needs a memory boost.