byu cs/ecen 124chapter 01 - abstraction1 cs/ecen 124 – computer systems winter 2010 section 001,...

BYU CS/ECEn 124 Chapter 01 - Abstraction 1

CS/ECEn 124 – Computer Systems

Winter 2010 Section 001, MWF 1:00 – 1:50 pm Section 002, MWF 2:00 – 2:50 pm Help Sessions, MWF 4:00 – 4:45 pm

Instructor: Paul RoperOffice: TMCB 3370, 422-8149Email: [email protected]

Office Hours: MWF 10:00 – 11:40 am

Let’s Get Started…

What’s inside this thing...


Concepts to Learn…

Computers Power of Abstraction Hardware vs. Software Turing Machine Universal Computing Devices The “Gap” Solving Problems w/Computer Levels of Transformation


Computers…

There is no magic to computing. Computers do not have minds of their own. You

have to tell them exactly what to do. Computers follow instructions exactly. Computers are made of very simple parts…

albeit, fast parts and a whole lot of them! We will study the MPS430 micro-controller, which

has all of the important characteristics of today’s commercial computers.

Computers


A Computer

A computer figures out what to do next – control. does the computations on the data – data path.

A computer uses a “program” for control and the data path.

A computer is called a a central processing unit, or a CPU, MPU, MSP, or simply, a processor.

Computers


Digital vs. Analog

Wristwatches (numbers vs. hands) LP’s vs. CD’s Rotary phone vs.

Cell phone NTSC vs. HDTV Slide rule vs.

calculator 737’s vs. 787’s

Computers


All Computers Are Created Equal…

In theory, any computer can compute anything that’s possible to compute given enough memory and given enough time.

In practice, solving a problem is constrained by time

weather forecast, next frame of animation, ...

cost cell phone, automotive engine controller, ...

power cell phone, handheld video game, ...

Computers


Computing Machines

Ubiquitous (meaning everywhere!) General purpose: servers, desktops, laptops, PDAs, … Special purpose: cash registers, ATMs, games,

telephone switches, … Embedded: cars, hotel doors, printers, VCRs, industrial

machinery, medical equipment, …

Distinguishing Characteristics Speed Cost Ease of use, software support & interface Scalability Reliability

Computers


Computing Machines

Use Abstraction

Hardware verses Software

to manage complexity. to enhance productivity. to hide unnecessary details when everything works. to focus on what is important.

are just different parts of a computing system. understanding together best solve computing

problems. mastery makes you more capable.

Computers


The Concept of Abstraction

We abstract naturally– focus on the essential aspects of an entity. hide the underlying complexity.

Avoid getting bogged down in unnecessary details (when everything is working fine).

More efficient to think about something at the highest possible level of abstraction.

Without abstraction, one would be overwhelmed by the complexity of a computer.

But, when something doesn’t work, then abstraction fails and you have to look at the details.

Abstraction


Hardware versus Software

Some people think that its OK for– Software engineers to be clueless about hardware, or Hardware engineers to be clueless about software.

Don’t believe it! Hardware and software are both essential parts of a

computing system. Computer systems work best when designed by someone

who understands both parts. Hardware designers that understand programming design

the best computers. Software designers that understand the capabilities and

limitations of hardware design more efficient programs.

Hardware/Software


Computing Devices

Alan Turing In 1936 he proposed a way to define the

term “computable” The Turing Machine

Basic abstract symbol-manipulating devices which can be adapted to simulate the logic of any computer algorithm.

Anything that can be computed,can be computed by a TM…

The TM is not a real machine,but an abstract machine

Turning Machine


Turing Machine

Mathematical model of a device that can performany computation – Alan Turing (1936) ability to read/write symbols on an infinite “tape” “state” transitions, based on current state and symbol

Every computation can be performed by some Turing machine. (Turing’s thesis)

Tadda,b a+b

Turing machine that adds

Tmula,b ab

Turing machine that multiplies

Turning Machine


Turing Machine DetailsTurning Machine


Turing Machine Example

Old Read Write NewState Sym Sym Move State

S1 1 0 R S2S2 1 1 R S2S2 0 0 R S3S3 0 1 L S4S3 1 1 R S3S4 1 1 L S4S4 0 0 L S5S5 1 1 L S5S5 0 1 R S1

Step State Tape 1 S1 11

“Action Table”

Start State(State Register)

Tape Read Head

2 S2 01 3 S2 010 4 S3 0100 5 S4 0101 6 S5 0101 7 S5 0101 8 S1 1101 9 S2 1001 10 S3 1001 11 S3 10010 12 S4 10011 13 S4 10011 14 S5 10011 15 S1 11011 --HALT--

Turning Machine


Universal Turing Machine

A Universal Turing Machine is a theoretical device that can simulate any other Turing machine. that accepts both input data and instructions as to how

to operate on the data. that is also a Turing Machine!

Ua,b,c c(a+b)

Universal Turing Machine

Tadd, Tmul

A computer is a universal computing device.

Universal Turning Machine


The “Gap”

Wordprocessing…Games…Surfing the web…

10101101011011…

Computational Problem

Implementation

The “Gap”


Overcoming the Gap

Problems

Algorithms

Language (Program)

Machine (ISA) Architecture

Micro-architecture

Circuits

Devices

Programmable

Computer Specific

Manufacturer Specific

As we move down, many choices must be

made.

This is how we make our living!

The “Gap”


Problem Solving w/Computers

ProblemProblem

ProgramProgram

Programming:use language to express design

AlgorithmAlgorithm

Software Design:choose algorithms and data structures

Instruction SetArchitecture


Compiling/Interpreting:convert language to machine instructions

Solving Problems


Deeper and Deeper…



DevicesDevices

Process Engineering & Fabrication:develop and manufacturelowest-level components

CircuitsCircuits

Logic/Circuit Design:gates and low-level circuits toimplement components

Micro-Architecture

Micro-Architecture

Processor Design:choose structures to implement ISA

Instruction Set Design:Design ISA that enables efficient problem solving

Solving Problems


Levels of Transformation

Problems

Algorithms

Language (Program)


Micro-architecture

Circuits

Devices

Problems

Algorithms

Language (Program) Programmable

Fixed

Which Levels are Programmable?Solving Problems


Problems

Why not use natural languages to program computers? Incomplete

Missing words and/or word structures for computer procedures.

ImpreciseWords that mean the same thing are difficult to translate into computer instructions.

Ambiguous – the most unacceptable attribute!To infer the meaning of a sentence, alistener is often helped by the tone of thespeaker, or at the very least, the contextof the sentence.

ProblemsAlgorithmsPrograms


Micro-architectureCircuitsDevices

Solving Problems


For example…

Consider the English sentence,

“Time flies like an arrow.”

One is noticing how fast time passes,

One is at a track meet for insects,

One is writing a letter to the Dear Abby of Insectville.Problems

AlgorithmsPrograms



Solving Problems


Algorithms

An algorithm is a step-by-step procedure that: guarantees to terminate (finiteness) each step is precisely stated (definiteness) each step can be carried out (effective computability)

Examples Starting a car Computing the average of n integers

For any given problem, there are usually multiple algorithms that will work.




Solving Problems


Programs

The next step is to transform the algorithm into a computer program using a computer language. computer languages communicate with the computer computer languages are defined by a grammar computer languages are mechanical rather than

natural computer languages are not ambiguous

More than 1,000 programming languages different languages for different purposes

financial processing/report generation manipulating lists of symbolic data natural language processing

often, just a personal preference




Solving Problems


The Program Level

Most computers run a management program called the operating system (OS).

Application programs interface to the machine architecture via the OS.

An example:

Application Program

Operating System

Program (Software)

This lecture

PowerPoint

Windows XP

Data

Application Program

Operating System




Solving Problems


High-Level Languages (HLL’s)

Machine independent not dependent on a particular machine’s organization can be compiled to run anywhere

Easier to write than low-level languages Usually result in higher programmer productivity Incorporate higher levels of abstraction

data structures (stacks, arrays) control structures (loops, switch statements, …)




Solving Problems


Low-Level Languages (LLL’s)

Machine-specific internal machine organization is exposed to the

programmer they can access the nitty gritty details

numbers and types of registers specific instructions memory addressing modes condition code flags, special purpose hardware features

Assembly programming lower productivity, but higher performing code




Solving Problems



Problems

Algorithms

Language (Program)


Micro-architecture

Circuits

Devices

Programmable

Computer Specific

Manufacturer Specific



Instruction Set Architecture (ISA)

Next is to translate the computer program (language) into the instruction set of a particular computer

Specific to a CPU data types

What are the different representations of operands operations on data

What functions can be done addressable memory

Where are operands stored addressing modes

How to find operands in memory

Machine code, or the 1’s and 0’s that instruct the machine.






Micro-Architecture

The micro-architecture transforms the ISA into an implementation. 8051 IA-32

386 486 Pentium Pentium-II, III, IV Xeon

MSP430 How the operations in the ISA are implemented

how do you add two binary numbers? or, how do you access memory?

faster and more com

plex






Circuits

The next step is to implement each element of the micro-architecture with simple logic circuits.

Gates, adders, multiplexers Flip flops, memory cells Adders, subtracters, multipliers

Circuits are used to make the computer do useful things like multiply or store a result.






Devices

Finally, each basic logic circuit is implemented by a particular device technology. Wires and traces Types of circuits (transistors)

CMOSNMOSGallium arsenide

Devices are the building blocks for more complex circuits.






High vs Low Level Programming

Swap v[i]and v[i+1]

Very high-level languageobjectivesor tasks

More concrete, machine-dependent; error-prone, harder to write, read, debug, maintain

More abstract, machine-independent;easier to write, read, debug, maintain

Inte

rpre

ter

temp=v[i];v[i]=v[i+1];v[i+1]=temp;

High-levellanguagestatements

One task =Many instructions

Com

pile

r

MOV.B 0x0001(SP),R14MOV.W SP,R15INCD.W R15ADD.W R15,R14MOV.B @R14,0x0000(SP)MOV.B 0x0001(SP),R14INC.W R14MOV.W SP,R15INCD.W R15ADD.W R15,R14MOV.B 0x0001(SP),R13MOV.W SP,R15INCD.W R15ADD.W R15,R13MOV.B @R14,0x0000(R13)MOV.B 0x0001(SP),R15INC.W R15MOV.W SP,R14INCD.W R14ADD.W R15,R14MOV.B @SP,0x0000(R14)

Assemblylanguageinstruction,mnemonic

One statement =Several instructions

Ass

em

ble

r

415E 0001410F532F5F0E4EE1 0000415E 0001531E410F532F5F0E415D 0001410F532F5F0D4EED 0000415F 0001531F410E532E5F0E41EE 0000

Machinelanguageinstructionsbinary (hex)

Mostly onefor one



Example: Levels of Translation

Algorithm

C-language program (HLL)c = a + b;

by hand

Machine language programs0010110010010001111

assembler

Assembly language program (LLL)ADD.W r4,r12

compiler

Algorithm

Language

ISA

program execution




Problems

Algorithms

Language (Program)


Micro-architecture

Circuits

Devices

Labs 4-5

Lab 3

Labs 6-8

Labs 9-10

Labs 11-12

Lab 2



Review: Descriptions of Each Level

Problem Statement stated using "natural language“ ambiguous, imprecise

Algorithm step-by-step procedure, guaranteed to finish definiteness, effective computability, finiteness

Program express the algorithm using a computer

language high-level language, low-level language



Review of Each Level (continued…)

Instruction Set Architecture (ISA) set of instructions the computer can execute data types, addressing mode

Micro-architecture detailed organization of a processor implementation different implementations of a single ISA

Logic Circuits combine basic operations to realize microarchitecture many different ways to implement a single function

Devices properties of materials, manufacturability


Auxilliary Slides…


From Components to Applications

Subfields or views in computer system engineering.

High-level view

Com

put

er d

esig

ner

Circ

uit

desi

gne

r

App

licat

ion

des

igne

r

Sys

tem

des

igne

r

Log

ic d

esig

ner

Software

Hardware

Computer organization

Low-level view

App

licat

ion

dom

ains

Ele

ctro

nic

com

pon

ents

Computer architecture


What Is Computer Architecture?

Like a building architect, whose place at the engineering/arts and goals/means interfaces is seen in this diagram, a computer architect

reconciles many conflicting or competing demands.

Architect Interface

Interface

Goals

Means

Arts Engineering

Client’s taste: mood, style, . . .

Client’s requirements: function, cost, . . .

The world of arts: aesthetics, trends, . . .

Construction technology: material, codes, . . .


Parts of a Computer System

The space of computer systems, with what we normally mean by the word “computer” highlighted.

Computer

Analog

Fixed-function Stored-program

Electronic Nonelectronic

General-purpose Special-purpose

Number cruncher Data manipulator

Digital


Price/Performance Pyramid

Classifying computers by computational power and price range.

Embedded Personal

Workstation

Server

Mainframe

Super $Millions $100s Ks

$10s Ks

$1000s

$100s

$10s

Differences in scale,

not in substance


Automotive Embedded Computers

Embedded computers are ubiquitous, yet invisible. They are found in

our automobiles, appliances, and many other places.

Engine

Impact sensors

Navigation & entertainment

Central controller

Brakes Airbags


PC’s and Workstations

Notebooks, a common class of portable computers, are much smaller than desktops but offer substantially the same capabilities. What are the main reasons for the size difference?

byu cs/ecen 124chapter 01 - abstraction1 cs/ecen 124 – computer systems winter 2010 section 001,...

Documents

computing problems

computer systemswinter

computing system

essential parts

abstractionall computers

data data path

fast parts

different parts