Transcript Information Systems Hardware - Jui

IMIS Lecture 4
Information Systems Hardware
J.-S. Rayson Chou, P.E., Ph.D.
Assistant Professor
Computer Hardware Equipment Categories
Input
The act of entering information into a computer using a
device that is best suited for the format of the data (i.e. a
keyboard for character information)
Processing
Transforming inputs into outputs by use of highly
specialized computer components that are integrated
to communicate with input and output devices
Output
The act of receiving information from a computer
using the device that best suits the application (i.e.
a printer for a memo)
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Computer Hardware
Output Device
Monitor
Input Device
Keyboard
Processing Device
The System Unit
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Input Needs and Devices
Entering Text and Numbers
The keyboard is the primary entry device for this
requirement. Ergonomic versions have been created to
minimize repetitive stress injuries
Pointing and Selecting
These devices come in many shapes, sizes and styles
including: mice, light pens, touch pads, touch screens,
joysticks, etc., and are used for many applications from
drafting documents to online gaming
Entering Batch Data
The most common device for this is the scanner used in
conjunction with optical character recognition (OCR)
software that can convert text into digital data quickly.
Other techniques are optical mark recognition, barcode
readers, magnetic ink character readers, etc.
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Input Devices – Text and Pointing
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Input Needs and Devices
Smart Cards
A special kind of credit card with a magnetic strip,
microprocessor, or memory circuits that can be used for
many applications and is resistant to tampering
Entering Audio
Sound is digitized when stored and processed on a
computer and generally comes in two categories
• Voice Input – this is done by speaking into a microphone
and can be made very powerful when coupled with voice
recognition software enabling a voice conversion to text or
other forms
• Other Audio – this is done through connecting a computer
to other audio transfer devices (e.g. musical instrument digital
transfer (MIDI))
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Input Needs and Devices
Entering Video
Images are digitized and stored in both still and moving
formats or “streaming video”. A number of devices can be
used for this purpose
Still Images
These images are generally entered from digital cameras,
devices that can read digital camera cards or chips, or CDs
generated at the time of film camera processing
Streaming Video and Streaming Media
Steaming video images contain only video, while streaming
media combine both audio and video. Images can be
entered into a computer using VCR’s, video cameras, DVD,
Web cams, etc.. These are extremely large files due to the
dense nature of the video content
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Input Needs and Devices
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Processing
Processing
The role of processing in a computer system is to
translate inputs into outputs. This is done through a
combination of language and system components
Language
Computers speak a
language called binary or
“machine language”
which consists of 0s & 1s
System Unit
The physical box that
houses all of the working
electronic components of
the computer
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Processing – Language
Binary or Machine Language
• The language that all computers use
• IT is expressed in 0s or 1s only (see below)
• Binary utilizes Base-2 math to convert from normal
characters to binary code (e.g. A = 0100 0001 in binary)
Binary Example
How a Computer Uses it
A = 0100 0001
Bit
A single
0 or 1
Byte
(8 bits)
Makes up
one
character
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Processing – Language Binary Example
Example – ASCII Binary
Types of Binary
Micro Computers
• ASCII - 8 bit
• Extended – 8 bit
Mainframe Computers
• EBCIDIC – 8 bit
Other Types
• Unicode – 16 bit
(used for international
languages)
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Processing – The System Unit
The System Unit
The physical box that houses all of the working electronic
components of the computer
Components
• Support – electronic equipment to run the machine
• Central Processing Unit (CPU) – the primary
processor in a computer
• Primary Storage – temporary and permanent storage
used by the computer to operate
• Secondary Storage – longer-term storage for data
• Ports and Slots – mechanisms to connect devices
and specialty processors
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Processing – Motherboard, Power Supply, Fan
Motherboard
Contains all the of the components that do the actual
processing work including
• Central Processing Unit
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RAM and ROM
Secondary Storage Devices (e.g hard drive)
Slots - connecting specialty processors
Ports - connecting input/output devices
Power Supply
Converts standard 110/240 volt AC to lower voltages
such as 5/10 volt DC for use in the computer
Fan
Low voltage device designed to protect the computer
from the high heat generated by the CPU
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Processing – Mother Board Example
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Processing – Central Processing Unit
Central Processing Unit (CPU)
Called the “brains of the computer”, its role is to perform
the operations of the computer using two components:
• Control Unit – this device interprets instructions and
transmits direction to the computer’s components
• Arithmetic Logic Unit – this device performs math as well as
logical operations by interpreting and executing instructions
CPU Operations
• Fetching - loading the next program instruction from memory
• Decoding - determines the next operation by using registers
(temporary storage) to store the instructions and memory
location used
• Retrieving – loading the necessary data from memory and
telling the ALU to execute the required instructions
• Storing – placing the results of the computations in a register
or in memory
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Processing – Central Processing Unit
Moore’s Law (1970s)
Dr. Gordon Moore from Intel
hypothesized that processing
performance would double
every 18 months
CPU Processing
Intel Pentium IV
CPU packs 55
million transistors
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Processing – Central Processing Unit
Clock Speed
The system clock generate pulses at a rapid rate regulating
the speed of the processor. A clock tick is one pulse and
the clock speed is measured in hertz (see below)
Registers
Provide temporary storage where data must reside while it is
being processed or manipulated
Cache Memory
A small block of memory used by the processors to store
those instructions most recently or most often. This
significantly increases the speed of the processor. Cache
memory comes in two types:
• Internal – incorporated in the microprocessor’s design
• External – is not built into the CPU but is located on the
motherboard for easy access
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Processing – Central Processing Unit
Computer-Related Speeds
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Processing – Primary Storage
Primary Storage
This storage is used for temporary storage to support
computer processing and come in RAM and ROM types
Random Access Memory (RAM)
This is the computer’s main processing storage and
consists of several chips containing thousands of
electronic circuits etched in silicon mounted on a small
circuit board call a single inline memory module
(SIMM). RAM has the following characteristics:
• Provides temporary storage for computer operation
• Stores data programs and data currently in use
• CPU can randomly access the data stored in RAM
• Instructions are considered volatile and will be lost
when the computer is turned off
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Processing – Primary Storage
Read-Only Memory (ROM)
This memory exists on a chip on the motherboard and
contains information that can be read by the computer
but not written to. ROM stores the instructions required to
run the computer before the system software takes over
Electrically Erasable Programmable Read-Only
Memory (EEPROM or also called Flash Memory)
This is a variation of ROM that can be read and
repeatedly written to and erased like RAM, but is different
in that the information is retained after the power is turned
off
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Processing – Secondary Storage
Secondary Storage
This nonvolatile storage is used to permanently store
information and is not part of the CPU but is connected
through the system bus. It comes in many types
Hard Drives
These devices use a thin layer of magnetic media on a
plastic or steel disk and have a very high storage
capacity. Redundant array of independent disks
(RAID) is a storage technique using multiple hard disks to
secure data against a single device failure or “crash”
Diskettes
These are portable magnetic media, similar to hard
drives, written to by inserting the diskette into a diskette
drive. A high-capacity diskette drive system that stores
over 100 times a normal diskette is called a ZIP drive
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Processing – Secondary Storage
Optical Disk
This technology uses a laser to: write by burning spots
into a disk coated with a metallic substance representing a
data package; read by interpreting the reflection of the
light off the burned in data spots. These disks come in
several types:
• Magneto-Optical (MO) – this disk contains tiny magnetic
crystals allowing the disk to be written to multiple times and is
extremely high capacity
• Compact Disk (CD) – this technology is standard equipment
on PCs and comes in two types: (CD-R) write once; (CD-RW)
allows to write multiple times
• Digital Video Disk (DVD) – a common storage format used
for movies and other video media but can also be used for
data storage and holds over 7 times a CD’s capacity
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Processing – Secondary Storage
Magnetic Tape
Used for storage of computer information consisting of a
narrow tape coated with a magnetic substance, Unlike all
other secondary storage mediums, this technology reads
and writes data sequentially. Tape is commonly used for
backing up data from other secondary storage technologies
Secondary Storage – A Comparison
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Processing – Ports and Slots
These are devices used to provide hardware
interfaces – plugs and sockets - to connect devices to
computers and components to provide a fully functional
computer
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Output Devices
Video
A visual display of data that supports motion using a
monitor (black and white or color) coming in two types:
• Cathode Ray Tube (CRT) – a boxy device…like a television
• Liquid Crystal Display (LCD) – a flat screen used in
notebooks or as a stand-alone device
• Projection – A device that projects a picture onto a screen
CRT
LCD
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Output Devices
Printers and Plotters
A visual display that is presented on hard copy (e.g. paper)
• Dot Matrix – older technology using a series of dots to create
characters, typically in black and white
• Ink-jet – newer technology that sprays ink onto paper in
character or image format in color or black-and-white
• Laser – a very high-quality technology that uses an
electrostatic process that burns ink into characters or images
and also comes in black-and-white or color (very expensive)
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Output Devices
Audio
Audio is transmitted using a sound card connected to
speakers that is inserted into one of the motherboard’s
slots. The computer translates digits into sound by
sending the data to the sound card that interprets these
data into tones
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Types of Computers
Supercomputers
Mainframe
Computers
Workstations
Microcomputers
Midrange
Computers
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Types of Computers - Generations of Computing
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Types of Computers – Supercomputer & Workstations
Supercomputer
These are the most powerful and
expensive computers on earth and are:
• built and used for one specific purpose
(e.g. weather forecasting)
• thousands of time more powerful than
a high-powered PC
Workstations
A special class of computers designed
for individuals, with high power to
perform specialized tasks, and fits on the
desktop and used for:
• extremely data-intensive processing
(i.e. design or financial analysis)
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Types of Computers – Mainframe & Midrange
Mainframe
Computer
Midrange
Computer
These are the backbone of large
corporate and government computing and:
• can process very large amounts of
information
• support hundreds or thousands of users
simultaneously
These are smaller versions of mainframe
computers used in smaller organizations
and for multiple functions and:
• supports tens, or hundreds, of users
• used as servers including Web,
database, and application servers
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Types of Computers – Microcomputers
Personal
Computers
PCs come in desktop and portable
models and are commonly used for
personal and business uses, they are
generally low cost and have many
powerful applications written for them
Network
Computers
A network computer is a microcomputer
with minimal memory and storage,
designed to connect to a network,
especially the Internet, using resources
provided by servers at low cost
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Types of Computers - Microcomputers
Portable Computers
These smaller, lighter weight computers are designed to
enable mobile processing
Notebook
A lightweight PC designed to be portable with
sufficient battery power to be useful
Tablet PC
A small PC with a removable screen that can be
used as a writing tablet with a stylus
Handheld Computer
Small computers that can be carried on the body
including PDAs, cell phones, etc.
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