I just read an interview with Steve Furber, the original ARM designer, in the May 2011 issue of the Communications of the ACM. It is a good read about the early days of the home computing revolution in the UK. He not only designed the ARM processor, but also the BBC Micro and some other early machines.
The title of this blog post is based on one fun little tidbit in the article. Steve actually keeps a functioning BBC Micro system around in the shape of an emulator. But the emulator is not running on his current PC directly, but on top an emulated Acorn Archimedes machine. A machine from 1981 emulated on top of a machine from 1987 that is in turn emulated on top of a machine from this year. A real-life example of how nested emulation can help save our digital heritage (an interesting topic I blogged about before).
He also has a physical BBC Micro around, and it is impressive just how high-quality construction could be back then. I still believe the old IBM keyboards are the best ever made, while the cheap laptop I am writing this on probably costs less to manufacture than that keyboard did… obviously at the expense of keyboard feeling. Grumble grumble kurmudgeon me, right? Steve loves the way the BBC Micro keyboard was designed, and claims that it could hold up to 10 years of abuse by children. In contrast, my old ZX Spectrum had some 4 keyboard membranes worn out in the six years or so I used it. But that is what cheap gives you.
He also touches on the topic of just how inaccessible computing is getting in terms of getting to grips with the machine and the hardware level. Back in the 1980s, you could pretty easily build things and attach them to your home computer. Slow buses and low-level access and no stupid operating system getting in your way facilitated that. He proposes people using a PIC development kit, but maybe an Arduino is a better choice. I like LEGO Mindstorms, but that is indeed a very high-level view of hardware and robotics. Not at all like the direct programming experience I had with my first ZX Spectrum back in 1984.
It is also funny to read how 1983-era 16-bit processors were not keeping up with memory – too complex instructions made the machine use memory too rarely. How the world had changed!