As part of the eternal quest within the realm of retrocomputing, storage devices can be one of the most challenging, especially when it comes to firmly obsolete hard drives, such as the CDC Finch drive. This compact 8″ HDD replaced the previous 14″ models with a form factor that was decidedly more portable. These Finch drives being 1980s technology that got run pretty hard before their retirement, it’s little wonder that they’d end up on the repair bench over at [Usagi Electric]
Introduced in the early 1980s, the CDC Model 9410 Finch drive was unlike its 14″ predecessors in that it is a sealed unit, with maintenance-free air filtration. With the 14″ models you’d have both fixed and swappable platters, with far less consideration for dust exposure. This makes these Finch drives more touchy to work on, not unlike HDDs today, and adds to the excitement when repairing one of these old drives.
In this video, two differently broken Finch drives are discussed. Both appear to have an issue on the controller board, with one not responding to communications on the interface, while the other featuring a dead short on the interface pins. The first drive was brought back to life by replacing a dead SN75110 line driver IC, as well as a dead 7818 voltage regulator that was only outputting a sad 0.3 V.
Unfortunately, after half an hour of uptime and in the process of dumping data the drive errored out with a Not Ready, indicating that there are further issues on the controller board to fix. The good news here is that the platters appear to be pretty robust, but the controller boards on these old drives tend to develop issues over the years, something which will be further explored in upcoming videos.
Spinning hard drives are being phased out of most consumer-grade computers in favor of faster technology like solid-state drives and their various interfaces. But there’s still millions of them in circulation that will eventually get pulled from service — so what do we do with them? If you’ve got one that would otherwise be going in the garbage, they can be turned into some other interesting devices like this laser text projector.
Even the slowest drives spin at around 5000 RPM, which is perfect for this type of application. The device works by mounting twelve mirrors, each at a slightly different angle, on a drum which is spun by the drive’s motor. Bouncing a laser off of the spinning drum results in a projection of twelve horizontal lines. By rapidly switching the laser on and off depending on which mirror it’s pointing at, the length of each line can be controlled.
Thanks to persistence of vision, that allows you to show text on the surface that the laser is projected on. At speeds this high, it took [Ben] of Ben Makes Everything quite a few iterations to get it to a usable space. From sensors that were too slow to lasers not bright enough to 3D prints that were not accurate enough, he goes through the design of his build and the process in excellent detail.
After solving all of the problems including building his own constant-current laser power supply, and burning up a few laser diodes in the process, [Ben] has a laser projector capable of displaying readable text at a great distance which is also portable, running on a 12 V power supply. There are some possible areas of improvement that he notes as well, such as an unbalanced 3D printed part causing a bit of a wobble and the Arduino controller not being fast enough for more text. But it’s an impressive project nonetheless, similar to a two-mirror version we saw some time ago but with the ability to display text as well.
Anyone who’s owned a game console from the last couple of generations will tell you that the machines are becoming increasingly like set-top computers — equipped with USB ports, Bluetooth, removable hard drives, and their own online software repositories. But while this overlap theoretically offers considerable benefits, such as the ability to use your own USB controller rather than being stuck with the system’s default, the manufacturers haven’t always been so accommodating.
Back in the “beige box” days of computing, it was pretty easy to tell what your machine was doing just by listening to it, because the hard drive was constantly thrashing the heads back and forth. It was sometimes annoying, but never as annoying as hearing the stream of Geiger counter-like clicks stop when you knew it wasn’t done loading a program yet.
That “happy sound” is getting harder to come by, even on retro machines, which increasingly have had their original thrash-o-matic drives replaced with compact flash and other solid-state drives. This HDD sound simulator aims to fill that diagnostic and nostalgic gap on any machine that isn’t quite clicky enough for you. Sadly, [Matthias Werner] provides no build details for his creation, but between the longish demo video below (by a satisfied customer) and the details of the first version, it’s easy enough to figure out what’s going on here. An ATtiny and a few support components ride on a small PCB along with a piezoelectric speaker. The dongle connects to the hard drive activity light, which triggers a series of clicks from the speaker that sound remarkably like a hard drive heading seeking tracks. A demo starts at 7:09 in the video below; the very brave — or very nostalgic — might want to check out the full defragmentation that starts at 13:11.
Storage technologies are a bit of an alphabet soup, with NAS, SAN, and DAS systems being offered. That’s Network Attached Storage, Storage Area Network, and Direct Attached Storage. The DAS is the simplest, just physical drives attached to a machine, usually in a separate box custom made for the purpose. That physical box can be expensive, particularly if you live on an island like [Nicholas Sherlock], where shipping costs can be prohibitively high. So what does a resourceful hacker do, particularly one who has a 3d printer? Naturally, he designs a conversion kit and turns an available computer case into a DAS.
There’s some clever work here, starting with the baseplate that re-uses the ATX screw pattern. Bolted to that plate are up to four drive racks, each holding up to four drives. So all told, you can squeeze 16 drives into a handy case. The next clever bit is the Voronoi pattern, an organic structure that maximizes airflow and structural strength with minimal filament. A pair of 140mm fans hold the drives at a steady 32C in testing, but that’s warm enough that ABS is the way to go for the build. Keep in mind that the use of a computer case also provides a handy place to put the power supply, which uses the pin-short trick to provide power.
Data is handled with 4 to 1 SATA to SAS breakout cables, internal to external SAS converters, and an external SAS cable to the host PC. Of course, you’ll need a SAS card in your host PC to handle the connections. Thankfully you can pick those up on ebay for $20 USD and up.
Universal Serial Bus has been the defacto standard for sending information to and from computer peripherals for almost two decades, but despite the word “universal” in the name this wasn’t always the case. Plenty of competing standards, including USB, existed in the computing world in the decades before it came to dominance, and if you’re trying to recover data from a computer without USB you might have to get creative with how it’s done.
[Ben] recently came across a 80486 with this problem, so he had to get creative to recover the contents of the drive. He calls it the “lunchbox” computer due to its form factor, and while it doesn’t have USB it does have a tried-and-trusted serial port to communicate with other computers. [Ben] wrote up a piece of software for both the receiving computer and the sending computer in order to copy the drive sectors one by one across a serial link to a standalone computer running Windows XP, and was able to recover the contents of the drive that way instead.
All of the code [Ben] wrote is available on his GitHub page for anyone looking to boot up a 30-year-old computer again. While it might sound uncommon, computers of this vintage are still around running things like CNC machines or old mainframes.
Throughout this two-year global COVID-19 nightmare, one thing that has been sorely lacking is access to testing. “Flu-like symptoms” covers a lot of ground, and knowing if a sore throat is just a sore throat or something more is important enough that we’ve collectively plowed billions into testing. Unfortunately, the testing infrastructure remains unevenly distributed, which is a problem this backpack SARS-CoV-2 testing lab aims to address.
The portable lab, developed by [E. Emily Lin] and colleagues at the Queen Mary University of London, uses a technique called LAMP, for loop-mediated isothermal amplification. LAMP probably deserves an article of its own to explain the process, but suffice it to say that like PCR, LAMP amplifies nucleic acid sequences, but does so without the need for expensive thermal cycling equipment. The kit contains a microcentrifuge that’s fashioned from an e-waste hard drive, a 3D printed rotor, and an Arduino to drive the motor and control the speed. The centrifuge is designed to run on any 12 VDC source, meaning the lab can be powered by a car battery or solar panel if necessary. Readout relies on the trusty Mark I eyeball and a pH-indicating buffer that changes color depending on how much SARS-CoV-2 virus was in the sample.