[femto]

It could also be an exercise in open computing, hailing back to an era before legal attacks and ubiquitous surveillance.

Being released in 1976, the Z80 architecture is well known and unencumbered by patents. It's also simple with fixed instruction timing, meaning it can be well tested, leaving few places for a back door to hide. The original hardware probably predates any surveillance programs (edit: and the silicon is being publicly reverse engineered by enthusiasts). There's a satisfying feeling of control, when in charge of a computer that is simple enough to understand in its entirety.

A Z80 won't be the fastest computer, but it might be useful for some tasks. Updates to the Z80, starting with FPGA cores, will be faster than the original, and might form a basis for enthusiasts to develop further. Let's face it, ARM's roots are in Z80 era processors.

[vidarh]

If that was the goal, basing it on something like the Motorola 680x0 family would've been a better choice:

* The architecture is already 32 bit.

* There are FPGA reimplementations, including a range of boards from different people, and open source designs (the Minimig) that people have produced working machines from.

* There's been a variety of work on producing more advanced versions of the cores, employing more modern design features.

* The M68k family has MMU support.

* There are Linux ports for M68k, as well as a number of other OS's.

Looking at his Google Plus ports, which includes various ancient hardware as well as a variety of old emulators, I think the retro appeal is more relevant.

[boyaka]

Not claiming to have much understanding about any of this stuff, but here's his comment from the link:

"+retrotails prower I'm sure +Dirk Hohndel would like an Atari ST port but once you get past 286 there are better OS to run. For m68k you have to deal with the lack of segmentation or banking in most cases (so vfork not fork), but if you can do that then given you've usually got real DMA I would have thought 2.11BSD/RetroBSD a far far better place to start, or even ucLinux. Many of the 68K platforms are also blessed with other open but non-Unix OS's especially the Atari where basically all the underlying OS code you need is nowdays available in a free form (eg FreeMiNT/XaAes - which is even uses rpm)

Some of the key assumptions in UZI and thus in Fuzix really stop making sense if you have a 32bit system or you have good offloaded I/O. I'm not entirely sure those assumptions don't break down by 286 to be honest. However 286 protected mode is so wonderfully demented and feature filled it has to be done."

[vidarh]

Everything he writes there makes sense. Nobody would bother with a UZI derivative on an M68k system, because you can run far more advanced OS's on them. But that's exactly why M68k would make far more sense if his OS was an "exercise in open computing".

But as a fun retro project, on the other hand, UZI / Fuzix seems like an awesome thing to play with (though I'd prefer to see a C64/C128 version...)

[gaius]

The original ARM was inspired by and designed on the 6502 (in the sense of they visited Western Digital and realized the designing a CPU was actually feasible for a small team, them emulated the design on a BBC Micro with 2nd processor) but IIRC Sophie Wilson stated they have no actual technology in common.

[vidarh]

I was very confused here. Western Design Centre, not Western Digital. WDC is still around [1] (or at least the website is up - it was last updated two years ago according to the front page).

For those unaware, the 6502 design was largely the product of two people: Chuck Peddle and Bill Mensch.

Chuck Peddle was an ex-Motorola guy that was on the 6800 team but was dissatisfied that Motorola was unwilling to bet on a much cheaper chip aimed at the mass market (the 6800 was around the $250 level before Peddle left; the 6502 debuted at $25 I believe).

Bill Mench was/is by pretty much all accounts a near super-human layout guy. At this time chips were still laid out without much, if any, computer assistance, and prototype turnaround was slow and expensive, so he was a major asset by cutting the number of prototypes needed (the legend - no idea if it is true - is that he had an amazing run of 9 or so designs that came back working on the first try; far simpler designs than these days of course, but to have any come back working on first try was uncommon).

Jack Tramiel at Commodore (who bought MOS) was always penny pinching, and so Mensch was able to retain rights to produce his own 6502 derivatives, and founded Western Design Centre, and have continued designing and selling related cores ever since.

[1] http://www.westerndesigncenter.com/wdc/

[gaius]

Yes, you are correct. The team from Acorn as they were then visited and realized that they too could do this, it didn't need the resources of a giant firm. Of course they already had an excellent track record.

[to3m]

There's an interesting interview about this (amongst other things - it's basically Wilson talking about her career - interesting throughout) here: http://www.computerhistory.org/collections/catalog/102746190

[72deluxe]

Very informative thanks. My dad still has a hefty collection of Micros (A, B, B+ and Master) and even has a second processor tucked away in his loft.

[boyaka]

The creators of Intel's 4004 (arguably the beginning of the microprocessor era) and the 8080 are the same men who left and founded Zilog. I would argue that the heart (brain?) of the work making these microprocessors so great is Masatoshi Shima. Of course there were other important people involved like Federico Faggin who worked closely with Shima and brought him to start Zilog, Yoshio Kojima who recruited Shima to Busicom to start working on the calculators, and Tadashi Sasaki (Sharp) with collaboration with Robert Noyce (Intel) who invested in Kojima's company (Busicom).

http://www.ieeeghn.org/wiki/index.php/Oral-History:Tadashi_S...

[codezero]

Unfortunately, widespread surveillance has been around for a lot longer than the 70s though it started to become more broad in scope around then.

https://en.wikipedia.org/wiki/Mass_surveillance_in_the_Unite...