It was invented in 1974 by a sexy guy named Ivan Perez
Jacob Free
It was invented by Hewlett Packard with the laser printer and page maker in 1980
Freya (jenny-carol) Cuthbertson
The first such desktop-size system specifically designed for personal use appeared in 1974;The first desktop was the MITS ALTAIR 8800, I believe made in 1974 and shown on the cover of Popular Electronics in January 1975, which became the inspiration for another company called Microsoft.
slide rules (linear, circular, cylindrical, etc.)nomographsmechanical desk calculatorsprinted lookup tablesnapier's bonessectorabacus and counting boardsfingersetc.
Desktop
right click on desktop and properties desktop customize desktop and select icon to view it on your desktop and click OK
The first desktop personal computer was the Programma 101. It was invented by Pier Giorgio Perotto and was produced by Olivetti company.
The first desktop computer was produced by an Italian company Olivetti. It launched at the New York World's Fair in 1964 and sold for $3,200.
Tower Systems in Boulder Colorado. It was sold by Dana Martin at a trade show in las Vegas.
The oldest calculator, the abacus, was invented in ancient Egypt(unknown date). The first Mechanical calculator, known as the Calculating clock, was invented by Willhelm Schickard in 1623. The first electronic desktop calculator were announced by the Bell Punch Co, in Uxbridge England in 1961. Finally, the first handheld computer was invented in 1980.
The Desktop image can be changed in from Desktop tab in the Desktop & ScreenSaver section of System Preferences. You can jump directly to this by right clicking on the Desktop and selecting Change Desktop Background.... from the menu that appears.