Computers – a historical perspective

INFORMATION AND COMPUTERS

• What is information?
• Computing requirements to process information: representation, manipulation, storage
• Binary information: two states (on-off, true-false)

• Multiple bit representation of information:
• numbers (32 bits) -> double/float; int
• Characters (8 bits) -> ASCII chars
• Numerical equivalence of multiple bits:
• The computer doesn't know/care what the bits are supposed to be used for, it just sees bits
• numbers/chars can be manipulated by same instructions.

• The Byte:
• smallest addressable block of bits. Always 8 bits.
• The Word
• the register size used by the CPU – might be 8, 16, 32 or 64 bits
• Use hexadecimal notation as a shorthand
• 2 hex chars = 1 byte
• Eg 11111111 = 0xFF

HEX - BINARY (4 Bits To A Hex Digit)

THE HISTORY OF COMPUTERS – KEY PLAYERS

• Charles Babbage (1791-1871)
• Claude Shannon 1937
• Konrad Zuse 1938
• John Atanansoff 1940
• Howard Aiken and Grace Hopper 1944
• John Von Neumann 1945
• John Mauchly and J Presper Eckert, 1946
• Fred Williams and Tom Kilburn 1948

MAJOR HISTORICAL COMPUTING PARADIGMS

• Batch mode processing #24h turn-around!
• Time-sharing #Many terminals, 1 CPU
• Personal computing #Computer games!
• Networking #Older than it looks, and surprisingly robust
• Embedded systems Windows XP for embedded systems(TM) controlling
• Supercomputers/GPU ATMs, EWFTPOS, nuclear Still the thing when you use power plants. What could Supercomputers> Cloud and Edge Computing possibly go wrong?

THE HISTORY OF COMPUTERS

• Drivers for computers evolution:
• National security (military superiority) – SIGINT, spying.
• Commercial imperative – replace people, do things cheaper.
• Related technologies – need to interface with other systems.
• More recently:
• gaming, Big Data, AI (GPUs!)

MOORE’S LAW

• Computing power approximately doubles every year

https://www.nextbigfuture.com/2019/02/the-end-of-moores-law-in-detail-and-starting-a-new-golden-age.html

SUMMARY

• Computers are fundamentally about information:
• representation, manipulation, storage
• Computer systems have a rich history:
• Spanning centuries, accelerating after WW2
• Context evolving:
• from large scale machines in labs, to pocket-sized smart phones, and everywhere in between!
• Next Lecture:
• Bit representation and organisation