lec02-cs110 computational engineering
DESCRIPTION
A keynote on Problem Solving using ComputersTRANSCRIPT
CS110: Models of Computing
Lecture 2V. Kamakoti
3rd January 2008
• What IS a computer?• A computer is a machine• Something that operates mechanically• But it is a flexible machine• Its behaviour is controlled by a program• A program is like a spell cast on a machine• Programmers are like wizards• Programs reside in the memory of the
machine– Charles Babbage (1791-1871)– “The stored program concept”
Early Computing Hardware
The Slide rule The Chinese Abacus
The gear replaced the beads inearly mechanical calculators
“History of computing hardware”From Wikipedia, the free encyclopedia
Jaquard looms
Used punched cards to weave different patterns
The DifferenceEngine
The London Science Museum'sreplica Difference Engine, builtfrom Babbage's design.
Part of Babbage's differenceengine, assembled after hisdeath by Babbage's son, usingparts found in his laboratory.
The First ProgrammerAugusta Ada King, Countess ofLovelace (December 10, 1815 –November 27, 1852), born AugustaAda Byron, is mainly known forhaving written a description ofCharles Babbage's early mechanicalgeneral-purpose computer, theanalytical engine.
The programming language ADA is named after her.
ENIAC – the first electronic computerPhysically, ENIAC wasmassive compared to modernPC standards. It contained17,468 vacuum tubes, 7,200crystal diodes, 1,500 relays,70,000 resistors, 10,000capacitors and around 5million hand-soldered joints.It weighed 30 short tons (27 t),was roughly 8 feet (2.4 m) by3 feet (0.9 m) by 100 feet (30m), took up 1800 square feet(167 m²), and consumed 150kW of power.
2000: Intel Pentium 4 ProcessorClock speed: 1.5 GHz# Transistors: 42 millionTechnology: 0.18µm CMOS
High Level Prog.
Assembly Language
Operating Systems
Digital Hardware
Structured
Computer
Organization
A typical PC Specification fromtoday’s Newspaper
• Intel Core 2 Duo 6550 2.33GHz• 2x2MB L2 Cache/ 1333MHz FSB• Intel DG31PR Motherboard• 2GB DDR2 RAM 667MHz• 160GB SATA 3Gbps HDD• Onboard Intel Graphics Controller• Onboard 10/100Mbps Ethernet• Onboard Sound card• 19” Widescreen TFT Monitor (Viewsonic)• Logitech Keyboard and Optical Mouse• DVD Writer• Creative 2.0 Speakers• 500VA UPS
The computing machinePROCESSOR
The computer is made up of a processor and a memory. The memorycan be thought of as a series of locations to store information.
MEMORY
01234……. (say) 256 MEGABYTES
The computing machinePROCESSOR
The processor treats part of the information in memory as instructions,and a part of it as data. A program is a sequence of instructionsassembled for some given task. Most instructions operate on data. Someinstructions control the flow of the operations. It is even possible to treatprograms as data. By doing so a program could even modify itself.
MEMORY
01234……. 256 MEGABYTES
program data
Variables
• Each memory location is given a name.• The name is the variable that refers to the
data stored in that location.• Variables have types that define the
interpretation data.– e.g. integers (1, 14, 25649), or characters (a, f, G,
H)• All data is represented as binary strings. That
is, it is a sequence of 0’s and 1’s, of apredetermined size – “word”. A byte is madeof 8 bits.
Instructions
• Instructions take data stored in variables asarguments.
• Some instructions do some operation on thedata and store it back in some variable.
• The instruction “XX+1” on integer type saysthat “Take the integer stored in X, add 1 to it,and store it back in (location) X”..
• Other instructions tell the processor to dosomething. For example, “jump” to a particularinstruction next, or to exit
Programs• A program is a sequence of instructions.• Normally the processor works as follows,
– Step A: pick next instruction in the sequence -Program Counter
– Step B: Decode the instruction– Step C: get data for the instruction to operate upon– Step D: execute instruction on data (or “jump”)– Step E: store results in designated location
(variable)• Different parts of the processor are
responsible for the above steps.
Test Your Understanding -Please copy in your notebook
• Name at least 20 important electroniccircuitry/peripherals inside/connected toa PC.
• What are the four prominent levels in aStructured Computer Organization?
• What are the five steps taken by theprocessor to execute an instruction?
Test Your Understanding -Please copy in your notebook
• Suppose each stage takes onemillisecond, then each instruction takesfive milliseconds to complete execution.
• Then 10000 instructions shall take50000 milliseconds.
• Is there a way to improve this?
Answers
20 components
1) Motherboard2) Processor Chip3) Cache4) Bus5) Memory6) Printer7) USB pen drive8) External Disk
20 components
9) CD/DVD Drive10) Monitor11) Webcam12) Keyboard13) Mouse14) Graphics Card15) Speaker16) Mic
20 components
17) Network Card - Wired18) Wireless Network card19) Power Supply20) Floppy drive
Four levels: High level, Assembler lang. level,Operating Systems and Digital Hardware
Making it fast
Fetch + Inc. PC
Decode Instrn
Fetch Data
Execute Instrn
Store Data
10000 Instructions
No pipelining takes
50000 Units. Eachhardware isindependent.
With Pipelining
I1I2
I1
I3
I2
I1
I4
I3
I2
I1
I5
I4
I3
I2
I1
First Instructioncompletes at end of5th unit
Second instructionat end of 6th unit
10000th instructionat end of 10004units
The concept• Instruction Level Parallelism• You can use more than one CPU - Multicore
Creative Problem - 1• The Towers of Hanoi: Move from peg 1 to
peg 3, such that a larger disk is not on top ofa small one.
Src: wikipedia
One disk - one move
One disk - one move
Two disks - three moves
Two disks - Move 1
Two disks - Move 2
Two disks - Move 3
Three disks - 7 moves
Three disks - move 1
Three disks - move 2
Three disks - move 3
Three disks - move 4
Three disks - move 5
Three disks - move 6
Three disks - move 7
The problem
How many? Proveit.
n
73
32
11No. of MovesNo. of Disks
Thank You
• Monday– Lab starts on Monday
• RF-ID 1 to 60 - Monday batch• RF-ID 61 to 120 - Tuesday• RF-ID 121 to 180 - Wed• RF-ID 181 to 240 - Thurs• RF-ID 241 to 300 - Fri
– Lab details + solution to Towers of Hanoi