1. Winter 2016CISC101 - Prof. McLeod1 Today Take some of the “MAGIC” out of how computers work: An overview of computer architecture. How did the technology get to where it is today? –ENIAC –von Neumann Architecture –The Transistor –Integrated Circuits

2. Computer History Museum A very well laid out and informative site covering the history of computing: http://www.computerhistory.org/revolution/topics Winter 2016CISC101 - Prof. McLeod2

3. Winter 2016CISC101 - Prof. McLeod3 How Stuff Works Video See: http://computer.howstuffworks.com/23-computer- tour-video.htm

4. Winter 2016CISC101 - Prof. McLeod4 Computer Architecture (PC)

5. Winter 2016CISC101 - Prof. McLeod5 CPU “Central Processing Unit” –The heart of the computer. –Consists of millions of transistors on a single chip. –Next slide shows the physical layout of a pentium chip.

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7. Winter 2016CISC101 - Prof. McLeod7 CPU - Cont. The latest: Six Core – six processors on one chip! As hardware, they are characterized by their clock speed, which controls the number of operations per second that they can carry out. The first PC contained an 8080 chip, introduced in 1979 that had a clock speed of 2 MHz or (2,000,000 cycles per second). Now an Intel quad core i7 CPU chip can run 8 simultaneous threads on 4 cores at 3.4 GHz (3,400,000,000 cycles per second!)

8. Winter 2016CISC101 - Prof. McLeod8 Dual Core Processor

9. Winter 2016CISC101 - Prof. McLeod9 Quad core:

10. AMD six core: Winter 2016CISC101 - Prof. McLeod10

11. Intel six core: Winter 2016CISC101 - Prof. McLeod11

12. Winter 2016CISC101 - Prof. McLeod12 CPU - Cont. Responsible for: –Locating and carrying out program instructions from RAM. –Carrying out arithmetic operations on data stored temporarily in a few “registers”. –Moving data between RAM and other storage devices.

13. Winter 2016CISC101 - Prof. McLeod13 CPU - Cont. A CPU can only carry out machine language instructions. The pins attached to a CPU are either “on” or “off”. All high level program instructions must be reduced to binary machine code before the CPU can do anything with them.

14. Winter 2016CISC101 - Prof. McLeod14 RAM and ROM “Random Access Memory” –Volatile memory - when the power goes off, bye-bye go the bits! –Ultimately, numbers are stored in binary format (1 or 0) - more on this topic later! –RAM holds data and program instructions.

15. Winter 2016CISC101 - Prof. McLeod15 RAM and ROM “Read Only Memory” –Not volatile. –Contains code and (BIOS) data used to start (“boot”) the computer.

16. Winter 2016CISC101 - Prof. McLeod16 Other Components Disk storage: –Data stored on magnetic or optical media. –Not volatile! (Hopefully!) –Disk read/write operations are much slower than operations carried out in RAM by the CPU. –Program code is first loaded from the disk to RAM and then executed. –Modern (but still rather pricey!) solid state drives just have banks of non-volatile RAM:

17. Winter 2016CISC101 - Prof. McLeod17 Other Components Data ports –Serial (RS232), USB, video, etc. –Providing input/output for the user via the keyboard, mouse, monitor, sound card, microphone, printer, scanner, joystick, webcam (etc. - you get the idea!) Modem, Network card and/or Wireless Adapter –Provide a means of connecting to other computers.

18. Winter 2016CISC101 - Prof. McLeod18 First Electronic Computer: ENIAC (From Wikipedia:) “Electronic Numerical Integrator And Computer” First electronic computer, built in the late 1940’s to calculate artillery firing tables. ENIAC contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand- soldered joints. It weighed 30 tons, took up 680 square feet (63 m²), and consumed 150 kW of power.

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20. Winter 2016CISC101 - Prof. McLeod20 ENIAC, Cont. See the video at: http://www.youtube.com/watch?v=goi6NAHMKog

21. Winter 2016CISC101 - Prof. McLeod21 ENIAC, Cont. Six women (inducted into the Women in Technology International Hall of Fame) took several weeks to manually enter a single program into the machine: Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas and Ruth Lichterman

22. Winter 2016CISC101 - Prof. McLeod22 Operating the “Differential Analyzer” (an analog mechanical calculator) in the basement of the Moore School (1942-45):

23. Winter 2016CISC101 - Prof. McLeod23 ENIAC, Cont. In 1942, their annual salary was $1,620 The job title of all of the women was “Computer”!

24. Winter 2016CISC101 - Prof. McLeod24 von Neumann Architecture Conceived in 1944/5 The structure we have been referring is still used in modern computers: –Separate units for input and output. –Data is stored in a separate memory location. –The “ALU” carries out instructions on data items moved into the ALU. –The “Control Unit” acts as a stage manager.

25. Winter 2016CISC101 - Prof. McLeod25 “von Neumann Cycle” Fetch –The address of the next instruction is read from the instruction counter. The next instruction is read from this memory address to instruction register. Decode –The instruction is translated to a format that is usable for the execution unit by the decoder. Fetch operands –Depending to the actual instruction operands from a memory location have to be fetched to be accessible for the execution unit. Execute –The arithmetical logical unit performs the operations and writes the results to registers or memory according to the instruction. Update instruction counter –The instruction counter is incremented for the next cycle. Now the first step can start again.

26. Aside – The First Computer Bug In 1947 Grace Murray Hopper was a technologist on a Mark II Aiken Relay Calculator at Harvard University. She logged the following: Winter 2016CISC101 - Prof. McLeod26

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28. The First Computer Bug, Cont. The word went out that she had “debugged” the machine. Grace Murray Hopper became known as the “Mother of Cobol” and is one of the most important people in the history of computers. See: http://www.jamesshuggins.com/h/tek 1/grace_hopper.htm, for example. Lookup “Grace Hopper on Letterman” in YouTube. Winter 2016CISC101 - Prof. McLeod28

29. Winter 2016CISC101 - Prof. McLeod29 After the ENIAC Only this one ENIAC was ever built. It was followed by the “EDVAC” in 1950. The first commercial computer was the UNIVAC I, which was delivered to the Bureau of the Census in the U.S. in 1951. Walter Cronkite at right…

30. Winter 2016CISC101 - Prof. McLeod30 Before Transistors…

31. Winter 2016CISC101 - Prof. McLeod31 Vacuum Tubes, Cont. A bias voltage on the grid allows current to flow between the emitter (cathode) and the collector (anode). (Can also be used as amplifiers.) Large, lots of heat, lots of energy required…