Apple co-founder Steve Wozniak is the special guest at the 2012 Edinburgh technology festival that takes its name from Alan Turing, the father of modern computing.
Wozniak gets things under way with an hour long keynote speech at the Playhouse at 4pm on Thursday, followed by a VIP dinner at Archers Hall on the High Street.
Events, many free, range from public facing events to extremely technical computing sessions. Trends in gaming, tech start-ups, crowdsourcing for social good, big Pharma's plans for biotech, and working with "big data" come to the fore during sessions in Appleton Tower (Fringe Central during August).
CERN, the BBC, National Geographic, and Interactive Scotland are some of the organisations who are participating in the various sessions.
The Techcube at Summerhall hosts musicans and experimentalists in a Music Hack Day, and the Turing festival ends with a Start-up Party at the same venue.
As well as a main curated festival there is an open fringe called "A Bit on the Side" where anyone who wants to come to Edinburgh and talk about tech can do so.