The clock was started on the 1st of January 1970 and is used to measure 'Co-ordinated Universal Time' on UNIX systems. Parties are planned in San Francisco, London and Dubai to mark the event, called by some the digital equivalent of the birth of Christ.
While celebrations go on however the anniversary also raises the issue of what happens when UNIX times runs out.
The original system for measuring time was recorded in 32 bit and as such can only store 4,294,967,296 seconds or 136 years.
This covers a period between 1901 and 2038 and on Tuesday, 19 January 2038 UNIX systems will effectively restart their clocks.
The so-called "UNIX Millennium Bug" may not be of serious concern to consumers or some business processes but embedded systems developers are already looking at the issue.
Moves are already afoot to change the clock to 64 bit time, which would last for about 293bn years into the future, giving our ancestors more than enough time to sort out future problems.
