1. Fluency with Information Technology 2012-04-25Katherine Deibel, Fluency in Information Technology 1 INFO100 and CSE100 Katherine Deibel

2.  Abacus: Fingers, strings, and stones  Antikythera mechanism: Greek mechanical astronomical tool  Babbage Difference Engine: Geared mechanical calculator  Vacuum tube computers: Colossus, Eniac, Univac  Transistor Computers: Manually-wired transistors  Integrated Circuits: Modern age computers 2012-04-25Katherine Deibel, Fluency in Information Technology2

3.  Integrated circuits (ICs) powered the information revolution  When computers were made of discrete parts, millions of hand connections  3 wires per transistor  2 per capacitor  2 per resistor  Labor intensive, expensive, error prone, unreliable, cumbersome, … even with robot manufacturing! 2012-04-25Katherine Deibel, Fluency in Information Technology3

4. Integrated circuits (ICs) solved that by two ideas  Integration: Circuits built as a unit from alike parts  Photolithography: Printing process to make chips 2012-04-25Katherine Deibel, Fluency in Information Technology4

5.  Inventor of the integrated circuit and the handheld calculator  2000 Nobel Prize for Physics  First integrated circuit: 2012-04-25Katherine Deibel, Fluency in Information Technology5

6. 758 million transistors (2008) 2012-04-25Katherine Deibel, Fluency in Information Technology6

7. 2012-04-25Katherine Deibel, Fluency in Information Technology7 substrate oxide 1. Prepare wafer substrate oxide 2. Add photoresist photoresist

8. 2012-04-25Katherine Deibel, Fluency in Information Technology8 substrate oxide 3. Align photomask 4. Expose to UV light photoresist glass chrome substrate oxide PR glass chrome

9. 2012-04-25Katherine Deibel, Fluency in Information Technology9 substrate oxide 5.Develop and remove photoresist exposed to UV light 6.Etch exposed oxide substrate PR oxide

10. We now have our circuit board 2012-04-25Katherine Deibel, Fluency in Information Technology10 substrate 7.Remove remaining photoresist oxide

11.  Think bookmaking  Used to be monks copying each page by hand  Printing press requires initial typesetting and then multiple copies are easy  Same idea with integrated circuits  Used to require wiring of individual transistors  Create the photomask and the circuit can be created again and again 2012-04-25Katherine Deibel, Fluency in Information Technology11

12.  Semiconductor:  Sometimes it conducts  Sometimes it doesn’t  One can control when semiconductors do and don’t conduct  That is the basis for PandA with silicon 2012-04-25Katherine Deibel, Fluency in Information Technology12

13. Example: an AND gate True only if both inputs are true Send “yes” signal on wire Make semiconductor conduct if input 1 is true Detect presence / absence of “yes” Make semiconductor conduct if input 2 is true 2012-04-25Katherine Deibel, Fluency in Information Technology13

14.  A charged field can control whether a semiconductor conducts or not  A transistor has three wires  Source (input)  Drain (output)  Gate (control)  The charge of the control wire (gate) is key  Neutral gate, channel doesn’t conduct  Charged gate, channel conducts In Out Gate 2012-04-25Katherine Deibel, Fluency in Information Technology14

15.  Deterministically execute instructions to process information  Chooses the next instruction as it is programmed  Executes specific instructions based only on the program and input it is given 2012-04-25Katherine Deibel, Fluency in Information Technology15

16.  A computer is an instruction execution engine  The fetch/execute cycle is the process that executes instructions Instruction Fetch (IF) Instruction Decode (ID) Data Fetch (DF) Instruction Execution (EX) Result Return (RR) 2012-04-25Katherine Deibel, Fluency in Information Technology16

17. Fetch/Execute cycle http://courses.washington.edu/fit100/sp1 2/videos/fetch-execute.swf 2012-04-25Katherine Deibel, Fluency in Information Technology17

18. Memory ALUControlInput Floppy Disk Hard Disk Scanner Keyboard Mouse Output Speakers Printer Monitor 2012-04-25Katherine Deibel, Fluency in Information Technology18

19.  Programs and their data must be in the memory while they are running 0 G 1 o 2 D 3 a 4 w 5 g 6 s 7 ! 8 ! 9 0 10... 11 byte = 8 bits 01000100 memory addresses memory contents 2012-04-25Katherine Deibel, Fluency in Information Technology19

20.  The Fetch/Execute cycle is hardwired into the computer’s control, i.e. it is the actual “engine” Instruction: ADDB 20, 10, 16 Put in memory location 20 the contents of memory location 10 + contents of memory location 16 6 10 11 12 13 14 15 12 16 171819 Zz 20... 21 6 10 11 12 13 14 15 12 16 171819 18 20... 21 2012-04-25Katherine Deibel, Fluency in Information Technology20

21.  Memory not usually broken up byte by byte  Many data types are longer than one byte  Integers are usually four bytes  Doubles (real numbers) are eight bytes  A word is a chunk of several bytes  32-bit machine → 4 bytes per word  Integers are one word  Doubles are two words 2012-04-25Katherine Deibel, Fluency in Information Technology21

22.  Instructions tell where the data is, not what the data is  An instruction might produce different values even if the command is the same 8 10 11 12 13 14 15 7 16 171819 15 20... 21 60 10 11 12 13 14 15 -55 16 171819 5 20... 21 Instruction: ADDB 20, 10, 16 2012-04-25Katherine Deibel, Fluency in Information Technology22

23.  The Arithmetic/Logic Unit does the actual computation  Most computers have only about a 100- 150 instructions hard wired Each type of data has its own separate instructions ADDB : add bytes ADDH: add half words ADD: add words ADDS: add short decimal numbers ADDD: add long decimal numbers ADDBU: add bytes unsigned … 2012-04-25Katherine Deibel, Fluency in Information Technology23

24.  Input units bring data to memory from outside world;  Output units send data to outside world from memory  Most peripheral devices are “dumb” in that the processor assists their operation  Disks are both memory devices and input/output devices 2012-04-25Katherine Deibel, Fluency in Information Technology24

25.  The program counter (PC) tells where the next instruction comes from  Instructions are a word long, so add 4 to the PC to find the next instruction (on a 32-bit machine) 110 111 112 113 114 115 116 117118119120... 121 ADD 210,216,220AND 414,418,720 Program Counter: 112 OR688,724 2012-04-25Katherine Deibel, Fluency in Information Technology25

26.  The rate a computer performs the Fetch / Execute cycle is controlled by its clock  Current clocks run 2-3 GHz (2-3 trillion cycles a second!)  In principle, one instruction per cycle  Not always achieved as instructions may take multiple cycles  Clever use of multiple ALUs allows for more than one instruction to be completed per cycle 2012-04-25Katherine Deibel, Fluency in Information Technology26

27.  Clock speed is not a good indicator of speed  Only good to compare CPUs in same brand  Other factors such as RAM and clock speed  Clock speed of the front-side bus ▪ Nervous system of computer ▪ Electrical pathway that connects CPU, RAM, hard drive  Memory ▪ Working memory of the computer ▪ Fast memory built into the CPU chip ▪ Having to save to disk is slooooooow 2012-04-25Katherine Deibel, Fluency in Information Technology27

28.  From the transistors to the CPU to the instructions, computers are well-structured  Explicit transistor layouts printed out en masse  Binary instructions connecting memory, input, output, and the logic units  Logic follows logic  Despite our experience, computers are not vindictive or cruel  Unless someone programs them that way 2012-04-25Katherine Deibel, Fluency in Information Technology28