Topic 2 – Environments, Functions of Components
and Health & Safety
Computer Systems
Computer Systems
Topic 2:
Environments, Functions of Components
and Health & Safety
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Environments, Functions of Components and Health & Safety Topic 2 - 2.2
Scope and Coverage - 1
This topic will cover:
• Computing Environments
– Home, business, computer gaming, networking,
real-time, communication
• Von Neumann architecture
– Example processors
– Fetch execute cycle
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Environments, Functions of Components and Health & Safety Topic 2 - 2.3
Scope and Coverage - 2
This topic will cover (cont.):
• Internet research – different types of processor
–
–
–
–
RISC v CISC
Single v multi-core
Multiprocessor
Distributed
• Health and safety practices – mains electricity, hot
components, lifting and carrying, electrostatic
precautions
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Topic 2 – Environments, Functions of Components
and Health & Safety
Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.4
Learning Outcomes
By the end of this topic, students will be able to:
•
•
•
Explain the role of computer systems in different
environments
Compare different types of computer systems
Build and configure a computer system to meet a
design specification
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Computer Systems
Topic 2 – Lecture 1:
Environments
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Environments, Functions of Components and Health & Safety Topic 2 - 2.6
Environments
• Computers are used in many different
environments and for many different tasks.
• This lecture provides an overview of the main
application areas where computers are found.
• It is not exhaustive or definitive.
• There are many areas of overlap:
–
–
–
–
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Gaming and home computing
Home and office/business computing
Networking applies in almost all environments
Etc. etc.
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Topic 2 – Environments, Functions of Components
and Health & Safety
Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.7
Home Computing – Early Years - 1
• Late 1970s – early 1980s
– Affordable micro computers became available
• Sinclair ZX80/81 and Spectrum
• Commodore 64 and Amiga
• Apple II
• Atari ST
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Environments, Functions of Components and Health & Safety Topic 2 - 2.8
Home Computing – Early Years - 2
• Late 1970s – early 1980s (cont.)
– Applications that were useful in the home became
available
• Mostly simple games
• Simple word processors and spreadsheets
• Music sequencing software – particularly for Atari
ST with its MIDI interface
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Environments, Functions of Components and Health & Safety Topic 2 - 2.9
Games Consoles - 1
• As well as general purpose micro computers,
specialist games consoles became available.
• Limited functionality
• Specific focus
• Originally
O i i ll d
developments
l
t off video
id arcade
d games
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Topic 2 – Environments, Functions of Components
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Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.10
Games Consoles - 2
• First generally available console was Atari Pong in
1975
– A simple tennis type game
– Very primitive monochrome block graphics
– More information and pictures at:
• http://www.pong-story.com/
• http://classicgaming.gamespy.com/View.php?vi
ew=ConsoleMuseum.Detail&id=3&game=12
• http://www.computernostalgia.net/articles/pong.
htm
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Environments, Functions of Components and Health & Safety Topic 2 - 2.11
Modern Home Systems – PC - 1
• General purpose PCs are common in homes.
• Same technology as office PCs
– x86 architecture (see more on this later)
– Microsoft Windows operating system
• Mainly used for Internet access, email and general
office applications, e.g. word processing and
spreadsheets
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Environments, Functions of Components and Health & Safety Topic 2 - 2.12
Modern Home Systems – PC - 2
• Lots of home and hobby applications available:
– Domestic finance and budgeting
– Picture editing and photograph management
– Family
y tree and genealogy
g
gy
• Also see Networking (later in this lecture)
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Topic 2 – Environments, Functions of Components
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Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.13
Modern Home Systems – Games
Consoles – In Class Discussion
Which games consoles have you used?
• Identify the games consoles that you have
experience of
• For each of the consoles identified,, list the keyy
features that make it different from other consoles
–
–
–
–
Main hardware
Controllers
Graphics resolution
Connectivity
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Environments, Functions of Components and Health & Safety Topic 2 - 2.14
Modern Home Systems –
Games Console Examples - 1
• A small number of systems rule the market
• Microsoft Xbox family
– Really a cut down PC with good graphics but a
restricted operating system
– Includes hard disk and DVD drive that can play
movies
• Which was a bonus when it launched
– Latest addition is the “Kinect” motion sensor
controller
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Environments, Functions of Components and Health & Safety Topic 2 - 2.15
Modern Home Systems –
Games Console Examples - 2
• Sony PlayStation
– Now at version 3
– Includes hard disk and Blu-Ray player
• Again,
A i ab
bonus when
h llaunched
h d
• “PlayStation Move” motion sensor added later
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Topic 2 – Environments, Functions of Components
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Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.16
Modern Home Systems –
Games Console Examples - 3
• Nintendo Wii
– Oldest of these example consoles (just)
– No hard drive – uses 512 MB flash memory and
supports
pp
SD cards
– First to have motion sensor technology built into
the Wii Remote
– Lower resolution graphics than the others
– As of April 2011 the best selling of these consoles
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Environments, Functions of Components and Health & Safety Topic 2 - 2.17
Modern Home Systems –
Games Console Examples - 4
• These are all major products that have sold
millions of units, so a quick web search will pull up
vast amounts of information.
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Environments, Functions of Components and Health & Safety Topic 2 - 2.18
Computer Games
• Now dominated by the home market
• Developed from arcade games
– E.g. Pong, Space Invaders, Asteroids, Pac Man
• Development largely dependant on processing
and graphics power
• Big business
• Drives the development of graphics power
– To support even more sophisticated virtual worlds
• See student workbook for some examples to
investigate
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Topic 2 – Environments, Functions of Components
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Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.19
Business Computing
• Computer Technology largely developed to supply
business needs
– From early data processing mainframes to modern
PC networks
• Applicable in every size and area of business
– Sole
S l ttrader
d using
i PC tto d
do accounts
t on
spreadsheet and word processor for business
correspondence
– Large multi-national financial corporation using
large mainframes to process millions of customer
records
– Everything in between
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Environments, Functions of Components and Health & Safety Topic 2 - 2.20
Networking - 1
• The vast majority of computers these days are
networked
– Figures difficult to obtain but probably over 95%
– Can you think of a computer system that is NOT
networked?
• Computers connected together to:
– Share resources
• Disk space, data, printers, Internet connections
– Provide communications
• Email, chat
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Environments, Functions of Components and Health & Safety Topic 2 - 2.21
Networking - 2
• The computer system does not really matter in this
discussion
– As long as it has a network interface and software
to connect it to the network
• Anything from a small PDA or Smartphone to a
supercomputer can be networked
• This is a brief overview – there are whole modules
on networking
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Topic 2 – Environments, Functions of Components
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Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.22
Network Classification - 1
Size & Scope: LAN and WAN:
• Networks can be classified in two main ways:
• Size & Scope
Local Area Network (LAN)
– Physically close, such as a company site or
college campus
– Usually using a single overall technology
(Ethernet)
– Usually owned and run by one organisation
– E.g. your college network or a home network
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Environments, Functions of Components and Health & Safety Topic 2 - 2.23
Network Classification - 2
Size & Scope: LAN and WAN
(cont.):
Wide Area Network (WAN)
– Physically large distances, between sites or even
countries
– May
M use a range off connection
ti technologies,
t h l i
such
h
as Asynchronous Transfer Mode (ATM)
– Links often operated by specialist suppliers
– Links often provided these days over the “public”
Internet
– E.g. the Internet
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Environments, Functions of Components and Health & Safety Topic 2 - 2.24
Network Classification - 3
Size & Scope: MAN and PAN:
Metropolitan Area Network (MAN)
– Spans a city, large campus or other geographical
area
• i.e. between a LAN and a WAN in size
– Single company or co-operatively managed
– E.g. Net North West provides Internet services to
academic institutions in North West England
• See http://www.netnw.net.uk/
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Environments, Functions of Components and Health & Safety Topic 2 - 2.25
Network Classification - 4
Size & Scope: MAN and PAN (cont.):
Personal Area Network
– Connects computer technology close to (within
physical reach of) one person
– Connecting PC, PDA, smartphone and peripherals
– Typically using Bluetooth wireless technology or
USB/Firewire
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Environments, Functions of Components and Health & Safety Topic 2 - 2.26
Network Classification - 5
Size & Scope: The Internet:
• Technically a WAN
• Global communications system with access to
virtually anywhere in the world
– and even off world
world, e
e.g.
g the international space
station
• Developed from ARPANET
• There is so much information online about the
development of the Internet – Look it up!
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Environments, Functions of Components and Health & Safety Topic 2 - 2.27
Network Classification - 6
Size & Scope: Intra- and Extra-:
Intranet
– A private computer network that uses Internet
technology (usually TCP/IP and HTTP) to deliver
g
documents and services within an organisation
– Often a website that is only accessible within a
company or via a company login
– “Intra” means “within” or “inside”
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Environments, Functions of Components and Health & Safety Topic 2 - 2.28
Network Classification - 7
Size & Scope: Intra- and Extra- (cont.):
Extranet
– An extension to an intranet allowing (restricted)
access to people outside the company
– Allows business-to-business
business to business (B2B) and possible
business-to-customer (B2C) transactions
– Does not grant whole company network access to
those outside the company
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Environments, Functions of Components and Health & Safety Topic 2 - 2.29
Network Technology
• There are a range of devices used in building a
network
– E.g. router, switch
• Not all networks use all these devices.
• Brief notes are given in your student workbook.
workbook
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Environments, Functions of Components and Health & Safety Topic 2 - 2.30
Communications –
Synchronous and Asynchronous - 1
• A large amount of communication is computer
based.
• Asynchronous Communication
– The receiver does not need to be available when
the message is sent
– Email, newsgroups, online forums and discussion
groups, text messaging
– Conversations are possible, but are spread out in
time, possibly over days or weeks
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Environments, Functions of Components and Health & Safety Topic 2 - 2.31
Communications –
Synchronous and Asynchronous - 2
• Synchronous Communication
– Both ends of the conversation have to be
available, online, at the same time
– Telephone (most of which is digital), conference
calls,, VoIP (Skype
( yp etc.),
), instant messaging/chat
g g
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Environments, Functions of Components and Health & Safety Topic 2 - 2.32
Communications – Other forms
• There are many other communication systems
available that use computer technology.
• Group schedules - allowing people to share their
calendars
• Collaborative authoring - enabling versioning or text
authoring tools
• Share whiteboard - allowing the collaborative drawing
of participants
• Chat room - resembling a multiple transmission of
short messages between all participants
• Lots of different social networking systems, such as
Facebook and Twitter
• Further examples are given in your student workbook.
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Environments, Functions of Components and Health & Safety Topic 2 - 2.33
Real Time Computing - 1
• A system where the output feeds back to the input
and the input is processed quickly enough to affect
the output
• In engineering terms, it is a feedback loop.
• E.g. modern car engine management systems are
real time computer systems
– Sensors around the car,
car including air temperature
and pressure, engine temperature, exhaust gas
sensors, gear position, speed and of course a
throttle position sensor provide the input
– The output is instructions to the fuel injectors on how
much fuel and air to allow into the engine ….
– Which directly affects exhaust gases, engine
temperature, speed etc…
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Topic 2 – Environments, Functions of Components
and Health & Safety
Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.34
Real Time Computing - 2
• In general, real time systems are embedded in the
devices they control and are not seen by the user
as computer systems at all
– In fact, they are not seen by the user at all
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Environments, Functions of Components and Health & Safety Topic 2 - 2.35
Environments
Any Questions?
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Computer Systems
Topic 2 – Lecture 2:
Functions of Components
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Topic 2 – Environments, Functions of Components
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Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.37
Basic Computer Architecture - 1
• The vast majority of computer systems are made
up of a standard set of functional devices,
connected together in a standard way.
• This is generally called the “Von Neumann”
architecture after the man who first documented it
– Paper available at:
http://qss.stanford.edu/~godfrey/vonNeumann/vne
dvac.pdf
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Environments, Functions of Components and Health & Safety Topic 2 - 2.38
Basic Computer Architecture - 2
•
•
But Von Neumann did not invent it – J. Presper
Eckert and John Mauchly, who were developing
the ENIAC at the Moore School of Electrical
Engineering, at the University of Pennsylvania, did
most of the work
And other researchers in other countries also
developed most of the concepts independently
• Including Alan Turing in the UK
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Environments, Functions of Components and Health & Safety Topic 2 - 2.39
Von Neumann Architecture
Memory
Control Unit
Arithmetic Logic Unit (ALU)
Accumulator
Input
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Backing
Storage
(not always
included at
this level)
Output
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Topic 2 – Environments, Functions of Components
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Environments, Functions of Components and Health & Safety Topic 2 - 2.40
Central Processing Unit (CPU) - 1
• There is some discussion over what is included in
the CPU
– ALU – definitely
– Control Unit – definitely
– Memory or primary storage – depends on who
you ask and your definition of memory
• The term CPU is often used synonymously with
“processor” and refers to the microprocessor at the
heart of the system, e.g. an Intel i7 processor
– Which has ALU, control unit, and some cache
memory on board
– But…does not include main memory (RAM)
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Environments, Functions of Components and Health & Safety Topic 2 - 2.41
Central Processing Unit (CPU) - 2
• Better to define what a CPU does:
–The CPU is the part of a computer that carries
out programmed instructions.
• The CPU controls the rest of the computer system,
system
including main memory (RAM), secondary or
backing storage (e.g. hard disk), input and output
devices.
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Environments, Functions of Components and Health & Safety Topic 2 - 2.42
Parts of the CPU –ALU - 1
• Arithmetic and Logic Unit
– Performs arithmetic and logical operations
– Always addition and negation of integers
– May include multiplication
• Otherwise does repeated addition
– Does not do subtraction
• Does negation and then addition instead
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Environments, Functions of Components and Health & Safety Topic 2 - 2.43
Parts of the CPU –ALU - 2
• Arithmetic and Logic Unit (cont.)
–May do division
• Or repeated subtraction instead
–May do floating point numbers as well
–Also does AND, OR, NOT and possible XOR
–Largely defines the rest of the CPU’s
architecture
• E.g. a 32 bit Accumulator implies a 32 bit
processor
• See “Fetch Execute Cycle” later for more on
internal details
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Environments, Functions of Components and Health & Safety Topic 2 - 2.44
Parts of the CPU – Control Unit
• Handles the instructions contained in the program
• In general, the input is the next instruction.
• The outputs are control signals to other parts of the
CPU or the rest of the computer.
• More detail is given in the student workbook for
you to read in private study.
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Environments, Functions of Components and Health & Safety Topic 2 - 2.45
Example Processor - 1 – Intel 4004
•
•
•
•
•
The first general purpose microprocessor
Originally designed for use in a calculator
Introduced November 15, 1971
Clock rate 740 kHz
B Width 4 bit
Bus
bits ((multiplexed
lti l
d address/data
dd
/d t d
due tto
limited pins)
• 2,300 transistors at 10 µm
• Addressable Memory 640 bytes
• Program Memory 4 KB
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Topic 2 – Environments, Functions of Components
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Environments, Functions of Components and Health & Safety Topic 2 - 2.46
Example Processor - 2 – Intel
Core i7 - 1
SF4
AJP1
• Released about 40 years after the original 4004
microprocessor
• Clearly shows the progress that has been made in
those 40 years
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Environments, Functions of Components and Health & Safety Topic 2 - 2.47
Example Processor - 2 – Intel
Core i7 - 2
SF7
AJP3
• Sandy Bridge version of i7
– Introduced January 2011
– Clock rate up to 3.46GHz
– Bus width 64 bit
– ~800 million transistors at 32 nm
– 256 kB L2 cache
– 12 MB L3 cache
– 6 physical cores, i.e. 6 real Pentium class processors
– Hyper-Threading is included
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Environments, Functions of Components and Health & Safety Topic 2 - 2.48
Von Neumann CPU Model
• Logical Structure of the computer system
– Routes of data transfer during processing
Memory
MAR
Input
MBR
Processor
ALU
Output
Temp
Control Unit
PC
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IR
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Visuals Handout – Page 16
Slide 46
SF4
This slide is likely to become dated quite quickly. See if notes in LG are sufficient for dealing with this
problem.
stephanie.falzon, 12/04/2011
AJP1
I have changed this slide so it emphasises the progress in 40 years of development rather than
focusing on the i7 being the most up to date.
Adrian J Pullin, 15/04/2011
Slide 47
SF7
This slide is likely to become dated quite quickly. See if notes in LG are sufficient for dealing with this
problem.
stephanie.falzon, 12/04/2011
AJP3
I have changed this slide so it emphasises the progress in 40 years of development rather than
focusing on the i7 being the most up to date.
Adrian J Pullin, 15/04/2011
Topic 2 – Environments, Functions of Components
and Health & Safety
Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.49
CPU Registers - 1
• Program Counter (PC)
– Holds memory address of next instruction
• Memory Buffer Register (MBR)
– Holds data and instructions traveling
g to/from
memory
• Memory Address Register (MAR)
– Holds memory address locations of data and/or
instructions to be read/written to memory
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Environments, Functions of Components and Health & Safety Topic 2 - 2.50
CPU Registers - 2
• Instruction Register (IR)
– Holds the instruction which is to be executed
• General Purpose Registers (TEMP)
– ‘Working
g areas’ for data p
processed by
y the ALU
– At least one – the Accumulator
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Environments, Functions of Components and Health & Safety Topic 2 - 2.51
Fetch Execute Cycle
• Defines how instructions
are retrieved and carried
out inside the processor
(CPU)
• Sometimes called the
Instruction Cycle or
Automatic Sequence
Control
START
Fetch next instruction
from memory to IR
Increment PC
Execute instruction in
IR
no
STOP?
yes
END
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Topic 2 – Environments, Functions of Components
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Environments, Functions of Components and Health & Safety Topic 2 - 2.52
Fetch Stage
START
• Copy contents of PC into
MAR
– Value of PC presented via
address bus
Fetch next instruction
from memory to IR
Increment PC
• Increment PC
– point
p
to next required
q
memory
y
access address
• Copy instruction from MBR
into IR via data bus
Execute instruction in
IR
no
– Instruction retrieved from
memory
– Placed in IR
STOP?
yes
END
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Environments, Functions of Components and Health & Safety Topic 2 - 2.53
Fetch
Memory
MAR
Input
MBR
Processor
ALU
Output
p
Temp
Control Unit
PC
IR
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Environments, Functions of Components and Health & Safety Topic 2 - 2.54
Execute Stage
• Decode instruction from IR
• Run instruction in IR
– May require getting data
from memory
– Location pointed to by PC
– PC++
• Unless current instruction is
STOP, repeat cycle
START
Fetch next instruction
from memory to IR
Increment PC
Execute instruction in
IR
no
STOP?
yes
END
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Environments, Functions of Components and Health & Safety Topic 2 - 2.55
Execute...
Memory
MAR
Input
MBR
Processor
ALU
Output
Temp
Control Unit
PC
IR
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Environments, Functions of Components and Health & Safety Topic 2 - 2.56
Fetch Execute Animations
• A number of animations are available on the
Internet to show the fetch execute cycle:
• http://www.eastaughs.fsnet.co.uk/cpu/executionfetch.htm,, and others on this page.
p g
• http://www.hartismere.com/Subjects/ICT/ALevel
Computing/CPUCycleAnimation
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Environments, Functions of Components and Health & Safety Topic 2 - 2.57
Assembly Language - 1
• Is at a level below high level programming
languages
–E.g. C++, Java, Pascal
• Assembly language is converted to machine
code
–Machine code is machine language – difficult
for a human to decipher.
–This is the data and instructions as used by the
processor and stored in memory.
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Assembly Language - 2
• Programs or sequences can be written in
assembly language
– Translated into machine code by an assembler
• Why write in assembly language?
– Faster (direct) access to CPU
– Some programs need to be written to operate at a
lower level
• E.g. Device Drivers
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Environments, Functions of Components and Health & Safety Topic 2 - 2.59
A Simple Assembly Program - x86
code
org 100h
mov dx,msg
mov ah,9
int 21h
mov ah,4Ch
int 21h
msg db 'Hello, World!',0Dh,0Ah,'$'
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Environments, Functions of Components and Health & Safety Topic 2 - 2.60
Functions of Components
Any Questions?
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Topic 2 – Environments, Functions of Components
and Health & Safety
Computer Systems
Computer Systems
Topic 2 – Lecture 3:
Health and Safety
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Environments, Functions of Components and Health & Safety Topic 2 - 2.62
Health and Safety Issues – For
people - 1
• Mains electricity
– Can cause anything from unpleasant to fatal shock!
– Usually only occurs inside power supplies
• Most computers operate at 12v or less
– Ensure mains is OFF and UNPLUGGED
– Wait for capacitors in power supplies to discharge.
• Hot components
– Some components inside a PC are hot enough to
cause burns.
– Turn off power and wait for components to cool
down before handling.
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Environments, Functions of Components and Health & Safety Topic 2 - 2.63
Health and Safety Issues – For
people - 2
• Lifting and carrying
– Some computer equipment is heavy.
– Get proper manual handling training and get
assistance if necessary.
• Trip
T i hazard
h
d
– The biggest cause of accidents
– It is very easy to put something on the floor and
then forget about it.
– Keep work area floors clear and tidy.
– Move anything that might be a hazard.
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Environments, Functions of Components and Health & Safety Topic 2 - 2.64
Health and Safety Issues –
For Equipment - 1
• Computer components are expensive and
delicate.
• Particularly susceptible to electric shocks
• Electrostatic discharge
– Discharge electrostatic by touching a suitable
earth point
• particularly if you are wearing manmade fibre
clothing
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Environments, Functions of Components and Health & Safety Topic 2 - 2.65
Health and Safety Issues –
For Equipment - 2
– Wear an electrostatic discharge wrist strap
• E.g. http://www.amazon.co.uk/Static-ElectroDischarge-Wrist-Strap/dp/B000Q8HA5E
– Or use a full anti-static kit, with wrist strap and mat
• E.g. http://www.amazon.co.uk/LINDY-43080-AntiStatic-ServiceKit/dp/B000I2JX3A/ref=sr_1_1?ie=UTF8&qid=1301
999033&sr=1-1
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Environments, Functions of Components and Health & Safety Topic 2 - 2.66
Health and Safety Issues –
For Equipment - 3
• Power surge
– Caused by plugging or unplugging components when
power is on
– Turn off power and unplug before working inside a PC
– Note: Powering down a PC from Windows does NOT
switch it of completely
• There is still power on the motherboard and inside the
PSU
• You may see a light on the back of the PSU or on the
motherboard, but if not, do not assume that there is no
power.
• Switch off at the wall and unplug
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Topic 2 – Environments, Functions of Components
and Health & Safety
Computer Systems
Environments, Functions of Components and Health & Safety Topic 2 - 2.67
Topic 2 - Health & Safety
Any Questions?
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Visuals Handout – Page 23