30th anniversary of the Sinclair ZX Spectrum

Today I went to HORIZONS: A celebration of the 30th anniversary of the
Sinclair ZX Spectrum
which was part of Sci-Fi London 2012.

Chris Smith who runs the site zxdesign.info gave
a quite technical talk on reverse engineering the Spectrum’s
ULA. This information
is available in the book: The ZX Spectrum ULA: How to Design a
. Chris also
gave some technical details on determining exactly how many machine cycles
could be executed between line refreshes and how this knowledge could be used
to overcome the ZX Spectrum’s 2 colour per 8x8 pixel block limit.

There was time for some of the attendees to talk about their memories of the
Spectrum and things they’d done. One person had a Speccy
which is an FPGA
implementation of a Spectrum that can read data from SD card.

There were a couple of RaspberryPi‘s on show:
one playing a short film and the other running a Spectrum emulator running
Manic Miner which has to be one of
my all-time favourite Spectrum games - I spent hours playing it and the sequel
Jet Set Willy when they were
released. My son started playing the game and got hooked - I have a suspicion
that if I set up an emulator on the home PC he’d put as many hours in playing
it as i did 29 years ago. Eben Upton of RaspberryPi fame also gave a short
talk on how the Raspberry Pi came to be.

What I hadn’t expected is that people are still developing for the ZX
Spectrum. Using emulators and PC-based development environments experienced
programmers are making use of the detailed knowledge of the machine that was
not readily available (AFAIK) in the 1980s and still cranking out new games
such as Chris Smith’s isometric 3D
and Jason Railton’s