Hackaday Retro Edition: TRS Wiki

April 28, 2015 by Brian Benchoff 14 Comments

1977 was a special year for computing history; this year saw the release of the 8085 following the release of the Z80 a year before. Three companies would launch their first true production computers in 1977: Apple released the Apple II, Commodore the PET 2001, and Tandy / Radio Shack the TRS-80 Model I. These were all incredibly limited machines, but at least one of them can still be used to browse Wikipedia.

[Pete]’s TRSWiki is a Wikipedia client for the TRS-80 Model I that is able to look up millions of articles in only uppercase characters, and low resolution (128×48) graphics. It’s doing this over Ethernet with a very cool Model I System Expander (MISE) that brings the lowly Trash-80 into the modern era.

The MISE is capable of booting from CF cards, driving an SVGA display and connecting to 10/100 Ethernet. Connecting to the Internet over Ethernet is one thing, but requesting and loading a web page is another thing entirely. There’s not much chance of large images or gigantic walls of text fitting in the TRS-80’s RAM, so [Pete] is using a proxy server on an Amazon Web Services box. This proxy is written in Java, but the code running on the TRS-80 is written entirely in Z80 assembly; not bad for [Pete]’s first project in Z80 assembly.

The Hackaday Retro Edition is our celebration of old computers doing something modern, in most cases loading the old, no CSS or Javascript version of our site.

If you have an old computer you’d like featured, just load up the retro site, snap some pictures, have them developed, and send them in.

Extreme Vectrex Multicart Plays Bad Apple

April 24, 2015 by Theodora Fabio 17 Comments

[Sprite_TM] had a Vectrex console that he wanted to play with. Alas, his makeshift multicart had fallen into disrepair. Rolling up his hacking sleeves, he set about making a new one, a better one. His PCB design included his microcontroller of choice: the ST STM32F411, a 32-bit 100Mhz ARM Cortex M4, along with a 16MB SPI flash chip. [Sprite_TM] wanted to make programming games onto the multicart simple. Using the libopencm3 firmware library for the STM in conjunction with Elm-Chans FatFS, the multicart could be plugged into a computer’s USB port and have any game data dragged and dropped onto it like a USB stick. The PCB then connects directly into the Vectrex’s cartridge port. The first cartridge file is a basic menu that lists all of the game ROMs stored in the flash memory. When the user selects the game the STM loads that ROM file which the menu software then boots.

After loading his entire Vectrex ROM library onto the multicart, [Sprite_TM] realized he had far too much space left over – so he decided to add some extras. His first choice was Bad Apple (YouTube link), a music video made by fans of the Touhou Project game series. The video features black and white silhouettes of the many game characters in a shadow art style. Since its debut, Bad Apple has been ported from everything from the Sega Genesis (YouTube link) to laser scanners (YouTube link). It was time for the Vectrex to join the list.

After ripping the video from YouTube, [Sprite_TM] used MPlayer to save each frame as a PNG along with a wave file of the music. Next, he ran Potrace on the PNG files to get vector versions. Using a custom PHP script, the resulting JSON file was post-processed into relative vectors the Vectrex uses. Digital audio was possible by having the Vectrex’s 8-bit DA-converter perform double duty both for the video circuit and the audio. However, the volume must be turned to the max in order to hear the music. Incidentally, the DAC can only output audio in this scenario when vectors are not being drawn, so the event timing needed to be adjusted. The video and audio data was re-parsed after a modified version of VecX was used to get the timing events synchronized before transferring Bad Apple onto the multicart.

You can see the Vectrex version of Bad Apple after the break, along with a 3D-engine based on Doom levels. The engine is written in C and makes use of the Z-buffer, creating the effect of solid 3D-objects in front of each other. There are no weapons or enemies to dispatch here, but the effect is impressive nonetheless.

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VCF East X: The Mega Mix

April 23, 2015 by Brian Benchoff 21 Comments

The Vintage Computer Festival East was last weekend, and now it’s time to wrap everything up. We’re going to start this off with a video of the biggest, most intolerable jerk on the planet walking around the boardwalk at Ashbury Park. Thanks to [Fran] for filming it.

That video, despite the wretched casting director, included the reveal of the PDP Straight-8, the 50-year-old minicomputer that was repaired and refurbished by [David Gesswein] just this year. You can see some pictures of that and more below, and a little more on [David]’s website.

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VCF East X: Amigas And Non-Apple Macs

April 22, 2015 by Brian Benchoff 13 Comments

The Amiga 1000, the original Amiga, was introduced in 1985, making this the 30th anniversary of the Commodore Amiga. Of course this needed to be represented at the Vintage Computer Festival, and [Bill Winters] and [Anthony Becker] were more than up to the task:

The guys brought with them a representation of nearly every Amiga, and also have a few neat gadgets to plug into these cool little boxes. The Amiga 1200 has been heavily upgraded with a compact flash drive. With the proper adapters and cards, this neat machine can be upgraded with Ethernet, WiFi, or just about every conceivable networking solution.

Attached to the A500 is a Gotek floppy drive emulator, a relatively standard if weird device that turns a PC floppy drive connector into a USB mass storage solution. This floppy emulator did not originally support Amiga disk formats, but with a firmware modification, everything just works. That’s a great story in itself, and something we should probably cover another time.

If you’re wondering what it was like for [Bill] and [Anthony] to dig through their garage for their exhibit, here you go.

Portable Macintoshen

The first Macintosh was released in 1984. Macintosh users wanted a slightly more portable machine, but the first ‘luggable’ Mac wouldn’t be released until late 1989. The market was there to fill the gap, with some bizarre machines exhibited by [Matt Bergeron]:

The Outbound laptop and notebook were unlicensed clones of the Macintosh. Instead of pirating the Apple ROMs, the Outbound computers required buyers to pull the ROM chips from their Macs and install them in the slightly more portable version. This was, of course, inconvenient, and we can imagine there were more than a few ROM chips cloned.

The Dynamac was a different beast, using the entire PCB from a mac SE or SE/30. To this, the creators of the Dynamac added a custom video card and electroluminescent display that was also capable of driving an external monitor. Very cool stuff.

VCF East X: The World’s Largest USB Thumb Drive

April 20, 2015 by Brian Benchoff 27 Comments

The Vintage Computer Festival last weekend featured racks and racks of old minicomputers, enough terminals for an entire lab, and enough ancient storage devices to save a YouTube video. These storage devices – hard disks, tape readers, and 8″ disk drives – were only connected to vintage hardware, with one exception: a DEC RL02 drive connected to a modern laptop via USB.

The DEC RL02 drive is the closest you’re going to get to a modern mechanical hard drive with these old machines. It’s a huge rack unit with removable platters that can hold 10 Megabytes of storage. [Chris] found one of these old drives and because he wanted to get into FPGA development, decided to create a USB adapter for this huge, old drive.

The hardware isn’t too terribly complex, with a microcontroller and an FPGA that exposes the contents of the drive over USB mass storage. For anyone trying to bootstrap a PDP-11 or -8 system, [Chris] could download disk images from the Internet, write them to the disk, and load up the contents of the drive from the minicomputer. Now, he’s using it with SimH to have a physical drive for an emulated system, but the controller really doesn’t care about what format the disk pack is in. If [Chris] formatted a disk pack with a FAT file system, he would have the world’s largest and heaviest USB thumb drive in the world.

Video below.

Update: As promised, [Chris] put all the code in a git

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VCF East: [Bil Herd] And System Architecture

April 20, 2015 by Brian Benchoff 13 Comments

Last Friday the Vintage Computer Festival was filled up with more than a dozen talks, too many for any one person to attend. We did, however, check out [Bil Herd]’s talk on system architecture, or as he likes to call it, the art and science of performance through balance. That’s an hour and fifteen minute talk there; coffee and popcorn protocols apply.

The main focus of this talk is how to design a system from the ground up, without any assumed hardware, or any specific peripherals. It all starts out with a CPU, some memory (it doesn’t matter which type), and some I/O. That’s all you need, whether you’re designing a microwave oven or a supercomputer.

The CPU for a system can be anything from a 6502 for something simple, a vector processor for doing loads of math, or have a RISC, streaming, pipelined, SIMD architecture. This choice will influence the decision of what kind of memory to use, whether it’s static or dynamic, and whether it’s big or little endian. Yes, even [Bil] is still trying to wrap his head around endianness.

MMUs, I/O chips, teletypes, character displays like the 6845, and the ANTIC, VIC, and GTIA make the cut before [Bil] mentions putting the entire system together. It’s not just a matter of connecting address and data pins and seeing the entire system run. There’s interrupts, RTCs, bus arbitration, DTACK, RAS, and CAS to take care of that. That will take several more talks to cover, but you can see the one last Friday below.

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VCF East X: Minicomputing With The Raspberry Pi

April 19, 2015 by Brian Benchoff 9 Comments

The Vintage Computer Festival in Wall, New Jersey doesn’t just attract locals; [Oscar] came all the way from Switzerland to show off his PiDP-8/I. It’s a miniature minicomputer, emulated in SimH, with blinkenlights and toggle switches mounted to a Raspberry Pi Hat.

Although the PiDP-8 is emulating a machine with thousands of discrete transistors, the design is exceptionally simple. On the board is 92 LEDs, a bunch of diodes, 26 toggle switches, a driver chip, and that’s about it. All the multiplexing for the switches and LEDs is taken care of in software. On the Raspberry Pi side, [Oscar] is able to run FOCAL, OS/8, and, like a normal-sized PDP-8, can toggle in programs manually.

Instead of having connecting to the ribbon cables coming out of RK01 disk drives and DECtapes, [Oscar] is emulating those too. All the files that would reside on old Digital storage mediums are now stuffed into USB thumb drives. A USB hub is plugged into the Pi, and when one of these USB disk packs is plugged into the hub, loading an operating system or a program is just a matter of flicking a few toggle switches.

[Oscar] has been working hard to turn the PiDP-8 into a kit, and the word around the booths is that this will happen sometime this summer. The expected price for this kit is very interesting: somewhere between $100 and $150 USD. For that price, we’d expect someone to rig up an Arduino-based paper tape reader very quickly, perhaps this afternoon.

More pics and a video of the PiDP-8/I below.
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