Hardware Archive

On the eve of LG's launch, I sat down with webOS's head of product management and design, Itai Vonshak, as well as Colin Zhao, director of product management for LG's Silicon Valley Lab. As they demoed LG's new interface to me, I was by turns intrigued, bemused, and doubtful that it was up to the task of convincing people that it would be worth buying a new TV for. Most of all, I was impressed by the clarity of vision behind the new interface. For better or worse, webOS has an opinion about how smart TVs should treat their users, and by all appearances that opinion is executed very, very well. LG is better known for pretty schizophrenic Android skins on its smartphones, so to see the company produce something this coherent was a shock.

The CDC6600 and its family members are part of the computer industry history. A decade before the Cray 1, the members of the CDC6000 family were not only expensive and the most powerful systems at the time of introduction. They were also lean and wonderful architectures ! The elegance was also conveyed in several publications (many by CDC), where all the necessary knowledge was explained from the ground up. All you needed to know was supplied, clearly laid out, not just hints for efficient programming. Basically, you could rebuild your own computer by reading these books. 50 years later, they are invaluable reminders and tools, we can see where the computer industry comes from and realise that it is not that hard to do it ourselves, too.

In 1984 the government allowed developers to create services for the Minitel. The government took a 30% cut and passed the rest on to developers (sound familiar?) creating the world's first app store. From a user's perspective using apps on the Minitel was frictionless - you were just billed for what you used through your phone bill.

How big was this app store? In the nineties it was pulling in over a billion USD a year! This is an astronomical sum when you consider France's population size. Though the crossover point is near, the Minitel in its lifetime paid out more to developers than Apple has to iOS developers to date. Companies would advertise their apps in the subway, on highway billboards, and on television.

Michael Dell has the won the battle for control of the computer company that he created, after shareholders backed his $24.8bn offer to take Dell private and revive the struggling business away from the incessant pressure of Wall Street.

The vote clears the way for the huge buyout, in which Dell is working with private equity partners Silver Lake after seeing off a challenge from activist investor Carl Icahn.

The 8-bit Z-80 processor is famed for use in many early personal computers such the Osborne 1, TRS-80, and Sinclair ZX Spectrum, and it is still used in embedded systems and TI graphing calculators. I had always assumed that the ALU (arithmetic-logic unit) in the Z-80 was 8 bits wide, like just about every other 8-bit processor. But while reverse-engineering the Z-80, I was shocked to discover the ALU is only 4 bits wide! The founders of Zilog mentioned the 4-bit ALU in a very interesting discussion at the Computer History Museum, so it's not exactly a secret, but it's not well-known either.

I have been reverse-engineering the Z-80 processor using images from the Visual 6502 team. The image below shows the overall structure of the Z-80 chip and the location of the ALU. The remainder of this article dives into the details of the ALU: its architecture, how it works, and exactly how it is implemented.