Tech stories

How the computer was born

From Babbage's brass engines to the cloud: the ideas, machines and chips behind every CPU, RAM module and drive the exams ask you about.

8 lessons · 51 min

  1. 1Babbage's engines and Note GFreeA Victorian mathematician designed a programmable machine with a memory and a processor. Ada Lovelace wrote the first published algorithm for it.1821–1843 · 6 min
  2. 2Turing's machine and Bletchley ParkIn 1936 Alan Turing defined computation with an imaginary tape machine. During the war, machines built on his ideas helped break German ciphers.1936–1945 · 6 min
  3. 3ENIAC and the stored programENIAC was fast but had to be rewired for every job. Keeping the program in memory, next to the data, gave us the architecture every CPU still uses.1945–1948 · 7 min
  4. 4The transistor and the chipA sliver of germanium at Bell Labs replaced the vacuum tube. Ten years later Kilby and Noyce put whole circuits on one piece of semiconductor.1947–1960 · 6 min
  5. 5The microprocessor and Moore's lawA calculator order turned into the Intel 4004, a whole CPU on one chip. Moore's prediction of doubling transistors set the pace for fifty years.1965–1974 · 6 min
  6. 6The personal computer and its operating systemA hobby kit, a ready-made Apple and an IBM built from outside parts put a computer on every desk. The operating system made them usable.1975–1981 · 7 min
  7. 7Storage: from punched cards to SSDsEach storage generation answered one question better: how much, how fast, how cheap, and whether data survives without power. The exams ask the same.1890–today · 6 min
  8. 8From the iPhone to the cloudThe computer moved into your pocket and its work moved into data centres. Virtual machines, an idea from the 1960s, made both possible.1964–today · 7 min