1 comp201 computer systems dr richard nelson [email protected] room g.1.29
TRANSCRIPT
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Computer Systems
Course Outline Course Web Page:
http://wand.cs.waikato.ac.nz/~201/2004/index.html
Class Representatives Introducing Computer Systems
Hardware Software
WRAMP and REX Board
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Topics
Introduction to course Data representation Assembly language programming Processor structures
(end of first term…)
I/O Memory management Operating systems Data communications
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Course Structure
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Administration
Website
Class Reps
Linux
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Introduction
Chapter One – Englander
Computer Systems: Course is about the function and design of the
various units of that make up digital computers Also about the interaction between software and
hardware
Question: What do the insides of a Computer look like and why do we care?
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Introduction
A single question, but many answers. You should care, for many reasons…
As a User You will be aware of strengths and limitations of your
computer system As a Programmer
You will be able to write better programs As a Systems Analyst
You will need to specify computer systems for purchase As a Systems Administrator or Manager
You will be able to more effectively manage computer systems
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Computer Ad
Suppose you need a new computer, can you understand these specifications enough to make an intelligent choice?
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Computer Ad (2)
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Components of a Computer System The Computer Hardware
Processor, Memory, Input/output devices, interconnects
The Software Programs, structures
The Data to be Manipulated Data format, max and min values, precision
The Communications Component Networking, human interface
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Computer Systems Introduction Components of a Computer System
The Computer Hardware The Software The Data to be Manipulated The Communications Component
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The Hardware Component
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The Hardware Component
CPU (central processing unit) Where operations and calculations carried out Composed of three main units
Arithmetic Logic Unit – where arithmetic and logic operations are performed
The control unit – controls processing of instructions and movement of internal data
The interface unit – moves data and instruction between the CPU an other components
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Memory Often known as primary storage or RAM (random
access memory) Made up of a large number of cells
Each location can hold a binary number (8/16/32/64 bits on most computers, 32 bits on REX board)
Each has a unique address Amount of primary storage has raised dramatically
over time: 64K bytes was considered a large amount of memory in 1980 Current PC’s come with 128Mbytes or 256Mbytes as standard That’s about 2000 times as much!! More memory allows more sophisticated programs to be run
E.g. Windows
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Sound Card
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Network Card
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Processor
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Memory
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Mother Board
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Expansion Slots
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Software, a key component
Without the software, the hardware is useless.
The software, often termed the Program, exists at different levels of abstraction. Processor itself operates on binary (bits) Humans understand and like higher-level
programs
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Below your Program
Instructions (which tell the computer what to do) are collections of symbols (bits)
For example, the bits 1000110010100000 may tell one computer to add two numbers together
This is in fact the way that the first programmers communicated to computers very tedious and error-prone
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Front panel… early computer
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Below your Program
Assembly languages and assemblers were developed to help programmers eg. ADD C, A, B
Programmer’s productivity later further improved by the introduction of high-level languages and compilers
FORTRAN, COBOL, BASIC were early languages C, C++, Java are more recent
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At the different levels, a program may take on different structures:
int greater(int a, int b)
{ int c; if (a > b) c = a; else c = b; return c;}
greater:...lw $2,16($fp)lw $3,20($fp)slt $2,$3,$2beq $2,$0,$L2lw $2,16($fp)...
compile
8FC20010 8FC3001400000000 0062102A10400005 000000008FC20010 ...
asmC code
Machine code
Assembler code
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Below your Program
Other improvements that have helped programmers develop software include: Use of subroutine libraries which include widely
used routines Use of operating systems to better manage a
computer’s resources Newer languages are less rigid in structure,
allowing programs to be created which are readable.
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Technology => dramatic change
Processor logic capacity: about 30% per year clock rate: about 50% per year
Memory DRAM capacity: about 60% per year (4x every 3 years) Memory speed: about 10% per year Cost per bit: improves about 25% per year
Disk (Hard drive) capacity: about 60% per year
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Moore’s Law
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Characteristics over Time
Year Name Size (cu. Ft.)
Power (watts)
Performance (adds/sec)
Memory (KB)
Adjusted price (1996$)
Adjusted price / perfomance
1951 UNIVAC1 1000 124,500 1,900 48 4,996,749 1
1964 IBM S/360 model 50
60 10,000 500,000 64 4,140,257 318
1965 PDP-8 8 500 330,00 4 66,071 13,135
1976 Cray-1 58 60,000 166,000,000 32,768 8,459,712 51,604
1981 IBM PC 1 150 240,000 256 4,081 154,673
1991 HP9000 /model 750
2 500 50,000,000 16,384 8,156 16,122,356
1996 Intel Pro PC
2 500 400,000,000 16,384 4,400 239,078908