Homemade Computer from 1970s Chips

Sometimes it starts with a 555 timer and an op-amp. Other times with a small microcontroller. But the timing’s not so great and needs a dedicated timing crystal circuit. And maybe some more memory, and maybe the ATtiny should be swapped out for some 74LS-series chips. And now of course it needs video output too. Before you know it, you’re staring at a 40-chip computer that hearkens back to a simpler, yet somehow more complex, time of computing. At least that’s where [Marcel] is with his breadboard computer based on 1970s-era chips.

For what it does, this homebrew computer is …read more http://pje.fyi/PMxNxC

Paul Jacob Evans

The Oldest Known Surviving PC Operating System

You’ll all be familiar with the PC, the ubiquitous x86-powered workhorse of desktop and portable computing. All modern PCs are descendants of the original from IBM, the model 5150 which made its debut in August 1981. This 8088-CPU-driven machine was expensive and arguably not as accomplished as its competitors, yet became an instant commercial success.

The genesis of its principal operating system is famous in providing the foundation of Microsoft’s huge success. They had bought Seattle Computer Products’ 86-DOS, which they then fashioned into the first release version of IBM’s PC-DOS. And for those interested in these early PC operating …read more http://pje.fyi/PLd4xj

Paul Jacob Evans

Procedurally Generating Random Medieval Cities

With procedural content generation, you build data algorithmically rather than manually — think Minecraft worlds, replete with all the terrains and mobs you’d expect, but distributed differently for every seed. A lot of games use algorithms similarly to generate appropriate treasure and monsters based on the level of the character.

Game developer [Oleg Dolya] built a random city generator that creates excellently tangled maps. You select what size you want, and the application does the rest, filling in each ward with random buildings. The software also determines the purpose of each ward, so the slum doesn’t have a bunch of …read more http://pje.fyi/PGNvjV

Paul Jacob Evans

Building a Replica Final Cartridge III

The Commodore 64 was the computer of the 8-bit era, and remains the highest selling computer of all time. In addition to disk and tape drives, it also had a cartridge interface. A popular extension cartridge was the Final Cartridge III, which offered a variety of disk utilities and a GUI. [Greisi] was in possession of a no longer functional cartridge, and decided to reverse engineer the device.

[Greisi] started by desoldering all the ICs and mapping out a schematic for the board. The design centers around common parts for the era, such as a UV-erasable EPROM and some 74-series …read more http://pje.fyi/PCZfkc

Paul Jacob Evans

The Modern Retrocomputer: An Arduino Driven 6845 CRT Controller

[MmmmFloorPie] revived an old project to create the retro mashup of a 6845 CRT controller and a modern Arduino Uno. When it comes to chips, the Motorola 6845 is the great granddaddy of Cathode Ray Tube (CRT) interfaces. It was used in the IBM Monochrome display adapter, the Hercules graphics controller, CGA, Apple II terminal cards, and a host of other microcomputer and terminal systems.

Way back in 1989, [MmmmFloorPie] was a senior in college. His capstone project was a 68000 based computer which could record and playback audio, as well as display waveforms on a CRT. The CRT in …read more http://pje.fyi/P8lzmX

Paul Jacob Evans

Your Next Desktop… QNX?

QNX has a long checkered history as an embedded operating system. QNX was always famous for being a real time operating system with a microkernel architecture. That is, kernel functions run as a set of coordinated tasks instead of as a single piece of code. A recent release of QNX 7 (see video, below) allows it to run on 64-bit desktop computers and [elahav] decided to tackle turning this embedded RTOS into a desktop operating system.

That might sound far-fetched, but QNX is a POSIX-compliant system and has all the features you’d expect in a system like Linux or BSD. …read more http://pje.fyi/P3gNxV

Paul Jacob Evans

The Improved Luggable PC

There are exactly two types of personal computers available today. If you need a lot of horsepower, a powerful GPU, or a full-power CPU, you’re going to end up with a desktop. If you need something portable, you’re getting a laptop with a wimpy CPU and an underpowered GPU. Historically, there has been a third type of PC, the luggable. The luggable is a desktop PC crammed into a case that makes it slightly more portable than a desktop and a monitor.  You cannot buy a luggable PC case right now. They simply do not exist as a commercial product …read more http://pje.fyi/Nvhg3C

Paul Jacob Evans