Transcript Computer System

Macquarie Fields College of TAFE
1
Version 2 – 13 March 2000
1 - HARDWARE
Macquarie Fields College of TAFE
Hardware Basics Modules
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3650A
3650B
3650C
3650F
Connect Hardware Peripherals
Install Software Applications
Maintain System Integrity
Apply Occupational Health and
safety
• 3650G Operate Computer Hardware
• 3650J Maintain equipment and
consumables
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Systems (some examples)
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Sound
Transport
Water
Communications
Political
Government
Computer System
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Computer System
• Input
• Processing
• Storage
INPUT
• Output
• Control
CONTROL
PROCESSING
STORAGE
OUTPUT
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Computer Systems
• Two Basic Areas:
• Hardware
• Software
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What is Hardware?
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Hardware
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Input Devices
CPU (Central processing unit)
Output Devices
Memory or Storage (internal and
external)
Collectively these describe the procedures
known as the Information Processing
Cycle
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Information Processing Cycle
CONTROL
INPUT
PROCESSING
STORAGE
OUTPUT
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Input Devices
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Keyboard
Mouse/Tracking ball/Pen etc
Touch Screen
Pressure Pad
Scanner
Macquarie Fields College of TAFE
Input Devices – What they are
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Keyboard
Mouse/Tracking ball/Pen etc
Touch Screen
Pressure Pad
Scanner
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Keyboard
The input device from which you type
information into the computer.
Keyboards generally have
alphanumeric keys, function keys,
special keys, and numeric keypad.
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Mouse
A mouse is a helpful tool when
designing columns, boxes, and
other parts of the document. It
is also helpful when
manipulating images
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Tracker Ball
Also known as trackballs. This is a
device where spinning a ball moves
the cursor on the screen.
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Touch Screen
A screen sensitive to the finger touch
so that the user’s finger can select
menu commands or move the cursor.
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Pressure Pad
A device with pre-determined coordinates on a pad that moves the
cursor in the direction that the
pressure is applied.
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Scanner
A scanner allows you to read images
like line art, photographs, and
signatures into the computer so that
they can be combined with text in a
document.
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Central Processing Unit (CPU)
Macquarie Fields College of TAFE
Central Processing Unit (CPU)
• What history do you know about the
CPU?
• What types of CPU’s have been
released?
• What are the functions of the CPU?
Macquarie Fields College of TAFE
Central Processing Unit (CPU)
The History
• Early personal computers where
known as XTs.
• XT computers used the 8086 & 8088
processor.
• These processors were 8 bit
processors and processed 8 bits on
an 8 bit bus.
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Central Processing Unit (CPU)
The History
• Next came the AT computer.
• The ATs were known as the 286 as
they used the 80286 processor
• Both XT and AT computers were
capable of only running one
application at a time
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Central Processing Unit (CPU)
The History
• The next generation the 386 was an
enhanced 286 but with distinct
advantages.
• This was the first processor to be
capable of running multiple
programs at once.
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Central Processing Unit (CPU)
The History
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The next Generations included:
80486 (486)
80586 (Pentium)
Pentium II
Today’s Pentium III
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Central Processing Unit (CPU)
The History
There are now three main competitors in
today’s microprocessor market:
•INTEL
•AMD (Advanced Micro Devices)
•IBM (International Business Machines )
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Microprocessor – How it works
Prefetch Unit
BUS Interface
Paging
Segment
RAM
Decode Unit
Execution Unit
Arithmetic
Math
Logic
Logic
Unit
Unit
Registers
Protect Test
Unit
Control Unit
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Central Processing Unit
Prefetch Unit
The Prefetch Unit decides when to order
data and instructions from the Instruction
Cache or the computer’s main memory
based on commands or the task at hand.
When the instructions come in the most
important task for the Prefetch Unit is to
be sure all the instructions are lined up
correctly to send off to the Decode Unit.
Macquarie Fields College of TAFE
Microprocessor – How it works
Prefetch Unit
BUS Interface
Paging
Segment
RAM
Decode Unit
Execution Unit
Arithmetic
Math
Logic
Logic
Unit
Unit
Registers
Protect Test
Unit
Control Unit
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Central Processing Unit
Bus I/O (input/output)
The Bus Unit is the place where
instructions flow in and out of the
microprocessor from the computer’s
main memory
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Microprocessor – How it works
Prefetch Unit
BUS Interface
Paging
Segment
RAM
Decode Unit
Execution Unit
Arithmetic
Math
Logic
Logic
Unit
Unit
Registers
Protect Test
Unit
Control Unit
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Central Processing Unit
Decode Unit
The Decode Unit does just that – it
decodes or translates complex
machine language instructions into a
simple format understood by the
Arithmetic Logic Unit (ALU) and the
Registers. This makes processing
more efficient.
Macquarie Fields College of TAFE
Microprocessor – How it works
Prefetch Unit
BUS Interface
Paging
Segment
RAM
Decode Unit
Execution Unit
Arithmetic
Math
Logic
Logic
Unit
Unit
Registers
Protect Test
Unit
Control Unit
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Central Processing Unit
Control Unit
The control unit is one of the most
important parts of the microprocessor
because it is in charge of the entire
process. Based on instructions from
the Decode Unit, it creates control
signals that tell the Arithmetic Logic
Unit (ALU) and the Registers how to
operate, what to operate on, and what
to do with the result.
Macquarie Fields College of TAFE
Microprocessor – How it works
Prefetch Unit
BUS Interface
Paging
Segment
RAM
Decode Unit
Execution Unit
Arithmetic
Math
Logic
Logic
Unit
Unit
Registers
Protect Test
Unit
Control Unit
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Central Processing Unit
Protection Unit
The Protection Unit verifies that the
Control Unit can access the address of
the first number stored in RAM. It then
forwards this number to the paging
and segment units where the virtual
address is translated into a ‘physical
address’ for the use of the Bus I/O.
Macquarie Fields College of TAFE
Microprocessor – How it works
Prefetch Unit
BUS Interface
Paging
Segment
RAM
Decode Unit
Execution Unit
Arithmetic
Math
Logic
Logic
Unit
Unit
Registers
Protect Test
Unit
Control Unit
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Central Processing Unit
Arithmetic Logic Unit (ALU)
The ALU is the last stage of processing
in the chip. The ALU is the smart part
of the chip that performs commands
like adding, subtracting, multiplying
and dividing.
Macquarie Fields College of TAFE
Microprocessor – How it works
Prefetch Unit
BUS Interface
Paging
Segment
RAM
Decode Unit
Execution Unit
Arithmetic
Logic
Unit
Registers
Protect Test
Unit
Control Unit
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Central Processing Unit
Data Cache
The Data Cache works very closely
with the “processing partners,” the
ALU & Registers, and the Decode Unit.
This is where specially labeled data
from the Decode Unit are stored for
later use by the ALU and where final
results are prepared for distribution to
different parts of the computer.
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CPUs - microprocessors
• One Million or more Transistors
• Two Main types of Architecture
– Complex Instruction Set Computer
(CISC)
• One instruction then executes it
– Reduced Instruction Set Computer
(RISC)
• Combines simple instructions and executes
• More speed and power
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CPUs - microprocessor
• Speed is measured by number of
times a second it moves data in and
out of the (CPU) processor
• Clock speed
• Consists of millions of transistors
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CPUs - microprocessor
• Transistors are .35 microns apart
• One Micron is 1/100th diameter of a
human hair
• Reducing distance = more speed
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Output Devices
• Monitor
– Screen/VDU/Display Screen
• Printer
• Modem (also an input device)
• Electronic Projector
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Output Devices – What they are
• Monitor
– Screen/VDU/Display Screen
• Printer
• Modem (also an input device)
• Electronic Projector
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Monitor
The computer’s
screen. The screen
gives you instant
feedback by
displaying whatever
input you have
entered.
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Printer
The device that
prints out a
document. Popular
printers include
laser printers, dotmatrix printers, and
ink-jet printers.
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Modem
• Modem stands for: Modulator/Demodulator
• Converts signals from one form to
another form compatible with another
kind of equipment
• Widely used in data communications
Microcomputer
Modem
Modem
Printer
Telephone Line
Sydney
Melbourne
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Modem
1
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1
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1
0
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Modem
Any of three techniques may be used
by a modem to modulate digital data
for transmission
• Amplitude Modulation
• Frequency Modulation
• Phase Modulation
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Modem
• Amplitude Modulation
The modulation of a wave by variation of
its amplitude. Uses the maximum
modulation of a wave
• Frequency Modulation
The modulation of a radio wave by
variation of it’s frequency
• Phase Modulation
The relative position of one complete
cycle of the wave is reversed to provide
the alternative wave
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Modem
There are three types of modems:
• The Acoustic Coupler
A box with two rubber cups into
which a telephone handset is placed.
• The Internal Direct Connect Modem
Transmits its signals directly through
the channel
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Modem
• External Direct Connect Modem
Is the same as the Internal version,
but all circuitry is housed in a
separate box equipped with a
telephone jack and a lead to connect
it to the computer
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Electronic Projector
Device that is used to project this
program and file onto the wall or
screen.
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Memory
Primary Memory (storage)
• Temporary Storage
known as RAM (Random
Access Memory).
• The computer uses RAM
to temporarily hold
programs and data.
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Memory
Primary Memory (storage)
• RAM is Volatile. This means
that it’s contents are lost
when power to the computer
is turned off.
• The more RAM you have, the
faster your computer will
run.
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Memory
Primary (RAM)
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The computer uses and manages RAM
for:
1. Operating System Software - Program
storage area which holds the step-bystep processing instructions
2. Data being processed by application Wording storage area in which
intermediate results are held during
processing
Continued
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Memory
Primary (RAM)
3. Working storage/temp for
processing – Input storage area in
which data is held temporarily until
processing takes place
4. Buffering of input/output – Where
finished results are kept before
being released to the screen,
printer or secondary storage device
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Memory
Secondary (storage)
• Permanent
– Non-volatile
– Slow
Types of Permanent storage are:
• Hard Disk Drive (HDD)
• Floppy Disks and Zip Drives
• RW–CD ROM
• DVD ROM
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Memory
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Tape Drives
Zip Drives
ROM (Read only memory)
Silicon Chips
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Hard Disk Drives
• Unlike a floppy disk, a hard disk is made
of aluminium or glass which has a thin
layer of magnetic material.
• The internal disk of a hard drive is called a
“platter”. This is spun from anywhere
between 1,200 rpm (revolutions per
minute) up to 36,000 rpm. Usually the
faster the disk spins, the faster data can
be retrieved.
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Hard Disk Drives
• Hard disk sizes – like
speeds – may vary,
however the physical
size of the drive and
platter will not change.
The storage capacity
may increase due to the
development of multiple
platters.
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Hard Disk Drives - Storage
• For information to be stored on a hard
disk, the drive must first be formatted.
This is the process of arranging the
magnetic surface of the disk into
tracks and sectors
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Hard Disk Drives - Diagram
Magnetic head
Sector
Swing arm
Spindle
Tracks
Platter
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Hard Disk Drives – Sectors and Tracks
Sectors and tracks are used because they
create a layout of co-ordinates similar to
that of a street directory.
To retrieve data the computer tells the hard
drives circuitry to move the swing arm thus
moving the magnetic head over the area of
the drive in which the required data is
stored.
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Floppy Disks
• Floppy disks are 3½” disks
incased in a hard cover.
• The term Floppy comes from
the earlier versions of 8” and
5¼” disks that were incased in
a flexible plastic cover.
• A floppy disk is commonly
used in both the home and
office as secondary media
5¼” Diskette
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Floppy Disks
• Floppy disks are portable allowing you to
save up to 1.4 Mb of data and
transferring this data to another
machine.
• Floppy disks are mainly used for:
• Transportation
• Archiving
• Installation of small programs
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Zip Disks
• Zip disks look like a 3½” floppy disk but
are much thicker
• They hold up to 100 Mb of data
• Zip drives are usually external drives,
allowing more freedom to transport from
one location to another
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Compact Disc
• CD-ROM is underlied on the optical
technology
• In the early 1980s, Philips and Sony
jointed their efforts to
develop the compact
disc, and the first disc
was released in 1983
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CD-ROM
The disc has three layers:
• The bottom layer is aluminium which
is used as a reflective layer.
• The middle layer is polycarbonate
substrate which is used to memorise
digital information
• The top is the
protective lacquer surface
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CD-ROM – Read and Write
• Under a CD writer the high power laser beam
can blast the polycarbonate substrate and
produce a long hole or short hole.
• Under a CD reader, when a low power laser
beam scans the hole and is reflected by the
aluminium layer, the reflection is detected by a
photodetector and then converted to the
signals as ‘1’ or ‘0’ in digital form.
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CD-ROM - Storage
Every hole on the CD represents a
bit. On a typical disc, 4,800 million
bits can be stamped to store 600
million bytes or characters of data
which is approximately equivalent
to 1,000 textbooks
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CD-ROM - Usage
CD-ROMs are widely used for:
• Extensive databases
• Resources
• Encyclopaedias
• Distribution of sounds, images
and multimedia systems
• High graphic games
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CD-ROM – Transfer Rates
TIME
1990
1993
1995
1999
1x
2x
4x
50x
INFORMATION
TRANSFER
RATE (KB/SEC)
150
300
600
6900
ACCESS TIME
(MILLISECOND)
1000
400
250
SPEED
The table shows the rapid development
of CD-ROM drives
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DVD ROM
• DVD (Digital Video/versatile Disc)
• Storage capacity varies; it can either be
4.7Gb, 9.0Gb, 13Gb and 17Gb. The discs
can be double layered and/or doublesided, hence the increase in memory
storage
• A 4.7Gb DVD can store roughly 7½ hours
of CD sound or 135 minutes of MPEG-2
compressed video
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DVD ROM - Compatability
DVD-ROM is backward compatible.
They can play:
• CD-ROM
• CD-I
• VCD
• And CD-R
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Hardware
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Input Devices
CPU (Central processing unit)
Output Devices
Memory or Storage (internal and
external)
Collectively these describe the procedures
known as the Information Processing
Cycle