Altair 8800 Again Project

January 4, 2020 by 6 Comments

[Dirk] posted a video (you can see below) titled, “Mystery Retro Project Start.” That turned out to be the first of a multipart series on his Altair 8800 Again simulator. The front panel appears to be laser cut and in some future video episodes, we expect to see him simulate the CPU with a Teensy.

There have been plenty of 8800 clones ranging from projects that recreate the original PCBs, to those that just run a Raspberry Pi inside. The middle ground will use an Arduino or some other small CPU to simulate the 8080 CPU.

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Better Simulators With Homemade Potentiometers

May 24, 2019 by 22 Comments

Perhaps you’ve played a flight simulator before, using something like a mouse and keyboard. That’s a fine experience, but like any other activity you can get a lot more out of it if you put a little more effort into the experience. Some will upgrade to a joystick for a modest improvement, and others will build incredible accurate cockpit replicas down to the smallest detail. The builders of these “pits” are always looking for ways of improving their setups, and it’s from this world that we find a method of building specialized, inexpensive hall-effect sensors.

A hall-effect sensor is a circuit that outputs a voltage based on the presence of an external magnetic field. These can be used to make compasses, but with a permanent magnet in close proximity can also be used to create a potentiometer-like device at lower cost and with higher precision than a similarly-priced pot. There was a method of building these in the simulator world using the housing of a Bic pen and some strong glue, but [LocNar] has improved on this method as well. He repurposed some bearings and some stock metal tubing in order to fabricate a professional-level sensor at a fraction of the cost.

This build is essentially a solution for anyone needing a potentiometer that’s easier to build, less expensive, has higher precision, and interacts with a digital input in a much more predictable (and programmable) way. Certainly this has applications in the simulator world, but will work for many other applications. If you’ve never thought about the intricacies (and shortcomings) of potentiometers, some other folks have taken a deep dive into that as well.

Thanks to [Keith O] for the tip!

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Hackaday Links: May 19, 2019

May 19, 2019 by 16 Comments

Cheap nostalgia, that’s the name of the game. If you can somehow build and ship ‘cheap nostalgia’, you’re going to be raking in the bucks. For the ‘musicians’ in the crowd, the king of cheap nostalgia has something great. Behringer is cloning the Yamaha CS-80. and it was announced at this month’s Superbooth.

The Yamaha CS-80 is the synth in Blade Runner, and since Toto’s Africa is making a comeback on top-40 radio, it’s the instrument of our time. A Wonderful Christmas Time, it seems. Aaaannnyway, yes, there might be a huge and inexpensive version of one of the greatest synthesizers ever made real soon. The cheap 808s and 909s are making their way to stores soon, and the 101 needs a firmware update but you can buy it now. Cheap nostalgia. That’s how you do it.

The PiDP-11/70 is a project we’ve been neglecting for some time, which is an absolute shame. This is a miniature simulation of what is objectively the best-looking minicomputer of all time, the PDP-11/70. This version is smaller, though, and it runs on a Pi with the help of SimH. There are injection molded switches, everything is perfect, and now there are a whole bunch of instructional videos on how to get a PiDP-11/70 up and running. Check it out, you want this kit.

Considering you can put a phone screen in anything, and anyone can make a keyboard, it’s a wonder no one is making real, well-designed palmtop computers anymore. The Vaio P series of PCs would be great with WiFi, Bluetooth, and a slight upgrade in memory and storage. This was [NFM[‘s recent project. This palmtop gets an SSD. The object of modification is a decade-old Sony Vaio CPCP11 palmtop modified with a 256 GB SSD. The Vaio only supports PATA, and the SSD is mSATA, so this is really a project of many weird adapters that also have to be built on flex connectors.

Here’s something for the brain trust in the Hackaday comments. First, take a look at this picture. It’s the inside of a rotary encoder. On the top, you have a Gray code (or what have you) that tracks the absolute position of a shaft. On the bottom, you have some sort of optical detection device with 13 photodiodes (or something) that keeps track of each track in the Gray code. This is then translated to some output, hopefully an I2C bus. What is this device, circled in red? I know what it is — it’s an optical decoder, but that phrase is utterly ungooglable, unmouserable, and undigikeyable. If you were me, what would you use to build your own custom absolute rotary encoder and you only needed the sensor? I technically only need 10 tracks/sensors/resolution of 1024, but really I only need a name.

Lol, someone should apply to Y Combinator and pitch yourself as a B Corp.

VCF West: Homebrew Lisp Machines And Injection Molded PDPs

August 7, 2018 by 19 Comments

Someone walks into the Vintage Computer Festival and asks, ‘what’s new?’. It’s a hilarious joke, but there is some truth to it. At this year’s Vintage Computer Festival West, the exhibit hall wasn’t just filled to the brim with ancient computers from the Before Time. There was new hardware. There was hardware that would give your Apple IIgs even more memory. There was new hardware that perfectly emulated 40-year-old functionality. There’s always something new at the Vintage Computer Festival.

Some of the more interesting projects are just coming off the assembly line. If you want a modern-day Lisp machine, that one won’t be assembled until next week, although there was a working prototype at VCF. If you want the greatest recreation of the most beautiful hardware, VCF has your back. Check out these amazing builds below.

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Emulating A Forgotten UNIX Box

December 20, 2017 by 24 Comments

The AT&T 3B2 series of computers are historically significant, being the main porting platform for System V Release 3 UNIX. Unfortunately, the documentation for these computers has been nearly lost to the sands of time. They are, however, architecturally interesting machines, and [Seth Morabito] has been working for some time on reverse engineering them. Now, [Seth] is calling it: his AT&T 3B2/400 emulator is almost complete, resurrecting an ancient machine from the dead by studying UNIX source code.

The architecture of this computer is unlike anything you’ve seen before, but well-suited to a UNIX machine. The chipset is built around the WE32100 manufactured by Western Electric, and includes a WE32101 MMU for all the fancy memory-mapped I/O. The implementation of this computer is fairly complex, with oodles of glue logic, over a dozen PALs, and various support chips for a PLL and DRAM controllers. This is computer architecture the way it was intended: inscrutable, baroque, and with a lot of fancy custom chips.

The emulator for this system is a bit simpler: you can just download and run it with simh. This emulator simulates 1, 2, or 4MB of system memory, one 720KB floppy diskette, and either one or two 30MB, 72MB, or 161MB MFM hard disk drives. Not everything is implemented so far — [Seth] is still working on an 8-port serial card and a network card — but this is a minimum viable system for developing and analyzing the history of UNIX.

Getting Started With Blinking Lights On Old Iron

August 10, 2017 by 29 Comments

If you ever go to a computer history museum, you’ll be struck by how bland most modern computers look. Prior to 1980 computers had lights and switches, and sometimes dials and meters. Some had switchboard-like wiring panels and some even had oscilloscope-like displays. There’s something about a machine with all those switches and lights and displays that gets your hacker juices flowing. Have you ever wanted to get started in retrocomputing? Is it difficult? Do you need a lot of money? That depends on what your goals are.

There are at least three ways you can go about participating in retrocomputing: You can pony up the money to buy actual antique computers, you can build or buy old computers recreated with anywhere from zero to one hundred percent of period-authentic components, or you can experiment with emulators that run on a modern computer. As a hybrid of the second and third option there are also emulations in FPGAs.

You can see that the first option can be very expensive and you will probably have to develop a lot of repair and restoration skills. Watching [Mattis Lind] twiddle the bits on an actual PDP-8 in the clip above is great, but you’ll need to work up to it. The two techniques which get you going without the original hardware don’t have to break the bank or even cost anything presuming you already have a PC.

Although some sneer at emulation, for some machines it is almost the only way to go. You couldn’t buy the original EDSAC, for example. It is also a good way to get started without a lot of expense or risk. But regardless of how you do it, there’s one thing in common: you have to know how to operate the thing.

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Game Like It Is 1983

July 12, 2017 by 33 Comments

The first computer I ever physically saw — I think — was an IBM System/3. You might not remember them. They were business computers for businesses that couldn’t justify a big mainframe. They were “midrange.” Nevermind that the thing probably had the memory and processing speed of the CPU inside my mouse. Time progressed and IBM moved on to the System/3x (for example, the System/32). Next up was the AS/400 and finally the IBM i, which is still in production. Here’s a secret, though, most of the code I’ve seen running on an IBM i dates back to at least the System/3 days and maybe even before that.

If you are interested in history, or midrange computers (which are mainframe-like in their operation), you might want to actually play with a real machine. A quick glance at eBay tells me that you might be able to get something workable for about $1000. Maybe. That’s a bit much. What if you could get time on one for free? Turns out, you can.

The Cloud Option

Head over to PUB400.com and register for an account. This won’t be instant — mine took a day or two. The system is for educational purposes, so be nice and don’t use it for commercial purposes. You get 150MB of storage (actually, some of the documentation says 250MB, and I have not tested it). While you are waiting for your account, you’ll need to grab a 5250 terminal emulator and adjust your thinking, unless you are a dyed-in-the-wool IBM guy.

Even though the IBM i looks like an old 1970’s midrange, the hardware is quite modern with a 64-bit CPU (and the architecture can handle 128 bits) and well-known stability. However, the interface is, well, nostalgic.

Ready…

Depending on your host computer, there are several IBM 5250 terminal programs available. They recommend tn5250 or tn5250j which use Java. However, I installed Mochasoft’s emulator into my Chrome browser. It is a 30-day free trial, but I figure in 30 days I’ll be over it, anyway.

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