Lecture 1Comp 120 Spring 2002Joe Capowski336 Sitterson Hall962-1793capowski@cs.unc.edu

Class RollMy first chance to learn who you areEveryone will be accepted into the courseAnyone not on roll: print your name and PID on the last page

QuestionnairePlease turn them in

Teaching AssistantsJoshua Stough stough@cs.unc.eduOffice 349 Sitterson 962-1975Hours: Tues 1-2:30, Friday 3:30-5

Fang-Yi Tsai tsai@cs.unc.eduOffice 041 Sitterson 962-1916Office hours will be posted on website

Class ScheduleTues and Thurs 2 - 3:15 Sitterson 014Come to class! Some stuff is presented only here.Will not follow book exactlyClass will be interactive

TextbookPatterson and HennesseyComputer Organization and DesignMorgan Kaufmann PublishersExcellent book, but chapters out of the order we will usePay attention to green boxes The Big Picture

What is Comp 120?The stuff in the machine and how it worksDigital logicCircuit componentsData representationArchitecture and implementationAssembly language programming

Comp 120 has 3 partsBasics and Assembler language Chapters 1, 3, 4, appendices A, B-1Processor and performance Chapters 5, 2, appendices B-2, CEnhancements for speed and capacity, I/O Chapters 6, 7, 8

Comp 120 PrerequisitesFormal: Comp 114 or my permissionInformal: A year of programming in some high- level language, e.g., C, C++, Java Access to a computer with a compiler Lots of experience using PCs, Windows Intellectual curiosity; whats in the box?

Course webpageVisit it every day for current info, announcements, lecture notes, etc.

www.cs.unc.edu (dept home page) select academic affairs select course home pages select this course

Lecture notes on websiteAvailable a few days in advanceDownload and print before class to save a lot of verbatim note-takingInstructions on website under Frequently Asked Questions (FAQ)

Non-programming assignmentsTurn them in on their due date at the start of class on paper

Collaboration is strongly encouraged, buteach person must understand what he turns in

Programming AssignmentsStart early.never wait until night before Hard to predict how long it will take Usually takes more than one sitting Need time to think and discuss Unanticipated events will occur

Programming assignmentsDo them in any campus computer lab, or on your own computerSPIM simulator is installed on campus machinesDownload it onto your own machine as explained on page xvii of the textbook

Programming AssignmentsComp Sci dept has two computing labs, SN 019 and SN 030, not sure yet what their status is for Comp 120

Programming assignmentsDownload copy of grading sheet from webpageTurn in grading sheet, your listing, printout of results if applicable, all stapled together.Include an honor code pledge in the comments of the listing.remember to sign it.Turn the package in at the start of class.

Programming assignmentsI emphasize:Clarity -- must be understandable to humanSimplicity -- no payoff for being cute

Computer efficiency rarely importantProgram short length rarely important

Prog Assignments -- CollaborationCollaboration OK, even encouraged discuss and understand assignments discuss techniques and concepts

but...

Prog assignments -- collaborationEach student must independently Devise his problem solution Enter his own program Debug and run his own program Understand his own program

More description on course handout

Keep your returned materialsThe assignments build on each other.We record about many grades, so we do make mistakesIf you think we erred, your information is the proofKeep everything until you get your final grade

Comp 120 is the most important course you will ever take ..

Principles endure

Details change to increase speed and capacity

My personal story

Assignment for Tues, Jan 17Read course handoutRead P&H Chapter 1Do exercises 1.1 through 1.44 (dont panic, theyre just match the definition things)

Ready for first substance?

What is computer?Any ideas?

Computer: electronic machine thatStores numeric dataDoes logical and arithmetic operations on the dataReceives data from userPresents data to userObediently follows your program

A computer has..Four basic parts Computer Memory Magnetic Memory Devices (disks) Central Processing Unit (CPU) Input-Output (I/O) devices

H&P list 5 functional partsData pathControl Part of the Central Processing Unit (CPU)MemoryInput devicesOutput devices

5 Classic Computer Components

Central Processing Unit (CPU)Decodes and executes machine language instructionsFetches instructions and data from memoryCalculates results and returns them to memoryDatapath: the circuits where the data flowControl: hardware that decodes instructions and controls the data flow, like a traffic cop.

Principle of AbstractionHardware and software have hierarchical layersLower layers hide details from higher onesThe user or programmer doesnt have to know the lower level details to use the systemDriving a car is a good analogyBut analogy fails when you need performanceImplementation: how the details are constructed

Three levels of language High Level Language (e.g., Java) change = cash - cost - tax;Assembler Language mov cash, temp sub cost, temp sub tax, temp mov temp, change

Three levels of languageMachine Language 10100101 1011010, 1010010 10010101 1101101, 1110101 10010101 1101001, 1110101 11101101 1101100, 1101101All three levels do the same thingHigh level is best for a person

Instruction Set ArchitectureDesign the hardware to execute the machine language exactlyISA is the interface between the machine language and the hardware

Instruction Set ArchitectureGood News: different implementations of hardware are possible with no change in softwareBad News: Sacrifice speed enhancements that would be possible by changing the software.

Instruction Set ArchitectureBig Messages:Hardware and software are related -- you need to design them simultaneously if you want maximal performance.Sacrifice some performance or increase complexity (cost) to keep software constant (e.g., Family of 360 machines)

Three levels of language High Level Language (e.g., Java) change = cash - cost - tax;

This one statement has: three operands two operators

Three levels of language Assembler Language mov cash, temp sub cost, temp sub tax, temp mov temp, changeOne operator, two operands per statement

Close with some pretty pictures

Inside the caseb. Processorc. PCI slotse. Memory slots

Motherboard

ProcessorPentium III Xeon

MemoryRAMDRAMSRAMROMVolatile / Non-VolatileMagnetic

Hard Drive

Cathode Ray Tube CRTCathodeDeflection platesScreen covered with PhosphorElectron Beam

Mouse

End of Lecture 1