This morning’s Observer column.

The communications theorist Marshall McLuhan observed that “we look at the present through a rear-view mirror”. And that “we march backwards into the future”. Amen. Remember the horseless carriage? Not to mention the fact that we still measure the oomph of a Porsche 911 in, er, brake horsepower.

But the car industry is a ferment of modernism compared with the computer business. When the bitmapped screen and the Wimp (windows, icons, menus, pointer) interface first surfaced in the early 1970s at Xerox Parc, its geeks searched for a metaphor that would make this new way of relating to computers intelligible to human beings. So they came up with the “desktop” on which were displayed little images (icons) of documents and document folders, just like you’d find on an actual desktop. Well, on the desktop of an efficient bureaucrat anyway…

I inadvertently added 100 years to John Locke’s life in the last line of the piece. The essay dates from 1696, not 1796. I should have spotted that: Locked died in 1704. What a difference a key makes.

LATER: Some commenters on the piece asserted that it was Apple who put the trash can on the desktop. Not true: Here’s the desktop of the Xerox 8010 with the trash clearly visible on the bottom.