Computer Growth Revolution or Explosion? How many computers in the home? Computers around us – a typical day. The Internet:
Internet Growth Number of Host Computers: Jan. 2000 – 72, 398, 092 (ISC Survey) July 2000 – 93, 047, 785 (ISC Survey) Jan. 2001 – 109.6 million (ISC Survey) Number of users: 407.1 million (2000) (CIA) Growth in traffic: June 1991,1.3 trillion bytes. June 2000, 768 trillion bytes (per month)
What Is a Computer? “ An electronic device, or assemblage of devices, that accepts inputs, processes them according to a set of instructions, stores the instructions, the inputs and the results of processing them and produces the results as output.” (Modified from Blissmer). Concepts: data, inputs, stored programs (software) outputs and hardware.
Components of Computers What are the components that come to mind? How do they fit together functionally? The “ architecture.” A look back into history: Are the concepts of numbers, number systems, writing, records and record processing a modern invention?
History (per Denise Schmidt-Bessarat) Which came first? Writing or number system? Chronology of rise of numbers & writing: 8000 BC: in Sumeria – Tokens with simple shapes 4400 BC: in Uruk (Erech in the Bible) More complex tokens – manufactured items (Show transparency )
(Cont’d.) 3700 BC Tokens enclosed in hollow clay balls 3500 BC Transition from tokens to writing 3100 BC Pictographic writing on clay tablets 3000 BC Conversion to cuneiform Circulate clay tablet)
Pioneers of Computing John Napier(1550-1617) Logarithms Wm. Oughtred (1575-1660) - slide rule Blaise Pascal (1623-60) Mechanical calculator Joseph-Marie Jacquard (1752-1834) – punched card loom Chas. Babbage (1792-1871) – difference engine & analytical engine Augusta Ada, Countess of Lovelace – first programmer Herman Hollerith (1860- 1929) – punched card machines Wm. Eckert & John Mauchly ENIAC (1944-45) John von Neumann Stored program computer (1945-1951)
Babbage Analytical Engine ( begun in 1833) Four components: Input – punched cards Store – hold data and instructions Mill – processes data Output – printed out Follows instructions programmed into it by its operators Processed data from store kept in store
Von Neumann Architecture Five: components: Input Memory Control Arithmetic-logical unit (ALU) Output
Von Neumann Architecture (Cont’d.) CONTROL MEMORY ALU INPUTOUTPUT Data/Instruction Flow Control Flow
What is Architectural Design? (Computer Architecture, Blaauw&Brooks) Architecture: “Minimal set of properties that determine what programs will run and what results they will produce.” Functional specifications. Components, infrastructure, principles of operation. Implementation. Realization.