Intro to Computer Organization

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Intro to Computer Organization

• CS227
• Western Washington University

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Hardware Software
Hardware the actual machine and its support
devices Examples Monitor, disk drive, CD ROM,
printer, CPU, keyboard, mouse Software programs
that make the machine do something Examples OS,
word processing, games Neither would be of much
value without the other!
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Computer Hardware

• A main unit connected to peripheral devices
• The main unit
• Central processing unit (CPU)
• Arithmetic Logic Unit (ALU) - responsible for
  evaluating arithmetic logical expressions
• Control Unit - responsible for the execution of
  the program
• Main memory (RAM)
• A sequence of locations where information
  representing instructions and data can be stored

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More Hardware

• Peripherals
• Input devices - keyboards, mouse
• Output devices - monitor, printers
• Secondary memory devices - floppy disks, hard
  drives, CD-ROM
• Communication
• Organized around a group of wires called a bus

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Conceptual View of A Computer
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Computer Software

• System software
• The operating system
• A large program that allows the user to
  communicate with the hardware
• control computer access/security, allocate
  peripheral resources, schedule resources
• Without this your system is worthless!
• Applications software
• Programs designed for a specific use
• word processing, games, CAE tools
• The reason why people actually buy/use computers!

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Abstract View of Hardware and Software Components
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Memory Terms

• Blocks
• a fixed number of pages
• how main memory is segmented
• Pages
• a fixed number of bytes
• how a block is segmented
• Word
• 2 bytes
• Bytes
• 8 bits
• Bits
• a binary digit

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Another Memory Categorization

• Volatile
• it goes away when the power goes away
• too small to hold everything
• Main memory (RAM)
• Non-volatile
• sticks around even when theres no power
• secondary storage
• floppy disks, cds, tapes, hard drives

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Computer Languages

• Machine language
• a sequence of binary digits
• architecture dependent
• Assembly language
• uses opcodes and registers
• also architecture dependent
• High level languages
• These are the ones that youll be programming in
• C, C, Pascal, PL/1, Fortran, Cobol, Basic, Ada,
  Smalltalk
• Not as much architecture dependent
• Some have become standardized
• Compilers
• Translate instructions in a particular language
  into machine language
• Interpreters
• Interpret code usually at runtime and execute
  machine specific instructions

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Compiled vs. Interpreted
Most high level programming languages are
compiledC, C. What are the advantages? What
are the disadvantages? Java is an example of a
high level programming language that is both
compiled and interpreted. What would be the
advantages and disadvantages of this approach?
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A Layered Approach to Architecture
There is a huge gap between what people want
computers do and what computers know how to
do. Why is there a gap? Language. One solution
is for people to learn how to speak the language
of a computer. Another solution is provide
some sort of translation or interpretation
between the language that people speak and the
language that computers understand. In actuality
there are a series of languages involved in
bridging this gap. These are called layers.
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The Virtual Machine
In this layered approach, we can view each layer
as a virtual machine that understands a specific
language. If a computer is designed with n
levels, it can be regarded as n different virtual
machines, each with a different machine language.
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Multilevel Machines
Most modern computers are designed with somewhere
between 2 - 6 layers.
Problem-oriented Language level
Level 5
Assembly Language level
Level 4
Operating system machine level
Level 3
Instruction set architecture level
Level 2
Microarchitecture level
Level 1
Digital logic level
Level 0
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Level 0 - Digital logic level This is a hardware
level. The physical objects are called gates.
The gates are organized to form memory,
registers, adders, etc. Level 1 -
Microarchitecture level This level contains a
collection of registers forming local memory and
an ALU. These items are connected via a data
path. Level 2 - Instruction set architecture
level The instruction set is designated by the
hardware manufacturer. Level 3 - Operating
system machine level In many cases this level
subsumes the contents of the underlying level.
That isinstructions from the ISA level may more
than likely also be present in this level. The
purpose of this level is to carry out
instructions from the next 2 levels.
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Level 4 - Assembly language level This level
provides a means for programmers to write
programs for levels 1,2, and 3 that is not as
unpleasant as machine code. Programming at this
level requires the use of a translator called an
assembler. Level 5 - Problem-oriented language
level At this level, the languages most closely
resemble human language. They are designed for
application development and require translation
via compilers or interpreters.
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Milestones in Architecture
Zeroth Generation Mechanical Computers (1642 -
1945) Pascal, Leibniz, Babbage, Zuse Atanasoff
used capacitors First Generation Vacuum Tubes
(1945 - 1955) Colossus British government Eniac
Mauchley-Eckert which became Unisys IAS
vonNeumann IBM Second Generation Transistors
(1955 - 1965) DEC PDP 1 minicomputer Control
Data Corp(CDC) 6600 Seymour Cray Burroughs B5000
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Third Generation Integrated Circuits (1965 -
1980) IBM 360 and 370 series PDP 11 Fourth
Generation Very Large Scale Integration(VLSI)
(1980 - ? ) IBM personal computer IBM
clones Apple Operating systems are born
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Computer Families
Each of the following architectures define a
family of processors. Pentium II
Intel UltraSPARC II Sun Microsystems picoJava
II Sun Microsystems
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Pentium II Family
This family has evolved from a calculator chip.
It started out as a 4-bit CPU on a chip for a
Japanese calculator manufacturer. Heres a
summarized history 4004 8008 8086 8088 80286 8038
6 80486 Pentium Pentium Pro Pentium II
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UltraSPARC II Family
This family grew out of one persons love of
running UNIX who had a distaste for doing so on
timeshared computers. A graduate student at
Stanford built the first SUN(Stanford University
Network) workstation. It was originally powered
by a Motorola 68020 processor, and came with
built-in Ethernet connection. SUN-1 SUN-2 SUN-3 T
hen switched to a RISC architecture to design
their own processor SPARC(Scalable Processor
ARChitecture). UltraSPARC I a 64 bit
architecture
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picoJava II Family
This family of processors was also developed by
Sun Microsystems. This architecture is the
hardware implementation of the Java Virtual
Machine. This family of chips is marketed
towards embedded systems development.