Transcript Management Information Systems Introduction

Hardware
Lecture 4
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Hardware Components
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Hardware Components
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Input Devices
Keyboard
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The most familiar input device
Used to enter letters, numbers and special characters
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Input Devices
Function Keys
Editing Keys
Numeric Keypad
Typewriter Keypad
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Function Keys
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F1 - If you are in an application and you press this key, you will
get its help file.
F2 - You select a program on your desktop and press this key. You
will be allowed to rename that program.
F3 - While you are working in windows explorer or on desktop, you
press this key you will get the 'Search' window.
F4 - While you are in Internet Explorer and you will press this key
the address bar will open.
F5 - To refresh the active window in any web browser, press F5.
F6 - This key is often used to move the cursor around the structure
of the program. Pressing it will often cycle you from window to
window.
F7 - Users have no use of this key in Windows. But in Microsoft Word
you will get spelling command.
F8 - The F8 key can be used to access Safe Mode if pressed during
the computer's boot up process. This is a trouble-shooting mode,
which will start the computer with minimal drivers.
F9 - The F9 key does not have any functionality in Windows.
F10 - The F10 key does not have any functionality in Windows.
F11 - If you press this key, you will enter the 'Full Screen' mode
most web browsers. This mode is also known as "KIOSK" mode.
F12 - The F12 key does not have any functionality in Windows.
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Input Devices
Cordless Keyboard
Portable Keyboard
Ergonomic Keyboard
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Input Devices
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Pointing Devices
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Mouse
Trackball
Touchpad
Pointing stick
Joystick
Light pen
Touch screen
Stylus
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Input Devices
Reading Tools
Read marks representing codes specifically
designed for computer input. Scanners
capture and digitize printed images. Eg.Flatbed
Scanners.
Optical Reader
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Input Devices
Optical Mark
Recognition
Bar Code
Bar Code Reader
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Input Devices
Magnetic Ink Character Recognition Reader
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Output Devices
Screen Output
 A monitor
or video display terminal (VDT) displays
Output devices characters, graphics, photographic images,
animation and video.
allow computer
Video adapter—connects the monitor to
to output data
the computer
in format
VRAM or video memory—a special
useful to user
portion of RAM to hold video images
or other
 The more video memory, the more picture detail is
displayed.
hardware.
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Output Devices
 Monitor
size: Measured as a diagonal line across the screen.
 Resolution: The number of pixels displayed on the screen
Pixels (or picture elements):
tiny dots that compose a picture
The higher the resolution, the closer together the dots.
 Image
quality is affected by resolution and color depth (or bit
depth).
Color
depth refers to the number of different colors a monitor
displays at one time.
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Output Devices
1-bit depth
4-bit depth
8-bit depth
16-bit depth
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Output Devices
Monitor
classes
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CRTs (cathode-ray tubes)
 LCDs (liquid crystal displays)
Overhead projection panels
• Video projectors
• Portable computers
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Liquid Crystal Display
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Output Devices
Dot Matrix printer
Paper Output
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Printers produce paper output or hard copy.
 Two basic groups of printers:
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Impact printers
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Line printers
Dot-matrix printers
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Output Devices
Non-impact
•Laser
printers
printers
−Laser
beam reflected off a rotating drum to create
patterns of electrical charges
−Faster and more expensive than dot matrix printer
−High-resolution output
•Inkjet
printers
−Sprays
ink onto paper to produce printed text and
graphic images
−Prints fewer pages/minute than laser printer
−High-quality color; costs less than laser printer
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Output Devices
Multifunction
printer or MFP combines a scanner,
printer and a fax modem.
A plotter can produce large, finely scaled engineering
blueprints and maps.
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Output Devices
Fax Machines and Fax Modems
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Facsimile (fax) machine
 Sending:
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Receiving:
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scans each page as an image
converts the image into a series of electronic pulses
sends those signals over phone lines to another fax
uses the signals to reconstruct the image
prints black-and-white facsimiles or copies of the originals
Fax modem
 Connect from PC to fax machine via modem and phone line
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Storage
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Magnetic Disks
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Random data access
Floppy disks
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Hard disks
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Provide inexpensive, portable storage
Non-removable, rigid disks that spin continuously
and rapidly
Provide much faster access than a floppy disk
Removable media (Zip & Jaz disks)
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Provides high-capacity portable storage
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Storage
1. The hard disk is a direct-access storage medium
with a rigid magnetic disk.
2. The data is stored as magnetised spots arranged
in concentric circles (tracks) on the disk.
3. Each track is divided into sectors.
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Storage
 Magnetic
Tape
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Can store large amounts of information
in a small space at a relatively low cost
 Limitation: sequential data access
 Used mainly for backup purposes
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Storage
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Optical Disks
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Use laser beams to read and write
bits of information on the disk
surface
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Not as fast as magnetic
hard disks
Massive storage capacity
Very reliable
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CD-ROM
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CD-R
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Optical drives that read CD-ROMs
WORM media (write-once, read many)
CD-RW
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Can read CD-ROMs and write, erase
and
rewrite data onto CD-R & CD-RW disks
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Storage
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DVD (Digital Versatile Disks)
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DVD-ROM drives
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Store and distribute all kinds of data
Hold between 3.8 and 17 gigabytes of information
Can play DVD movies, read DVD data disks
Read standard CD-ROMs, and play audio CDs
Read-only: can’t record data, music, or movies
DVD-RAM drives
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Can read, erase, and write data (but not DVD video) on multi-gigabyte
DVD-R (but not CD-R or CD-RW) media
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Storage
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Solid-State Storage Devices
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Flash memory is an erasable memory
chip:
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Sizes range from 16 MB to 1 GB
Compact alternative to disk storage
Contains no moving parts
Designed for specific applications
such as storing pictures in digital
cameras
Likely to replace disk and tape
storage
PC Card
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Processors
CPU or processor is the heart of the
computer, and it consists of 3 main
parts:
–Arithmetic Logic Unit (ALU)
–Control Unit
–I/O interface (consists of Registers)
The function of the CPU is to execute
programs stored in the main memory by
fetching instructions, examining them,
and executing them one after the other.
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Processors
CPU- CONTROL UNIT
Tasks carried out by a CPU are listed below:
1. Fetching the instruction or data item from memory
2. Decoding the instruction into commands the
computer understands.
3. Executing or carrying out the commands
4. Storing, writing the result to memory.
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Processors
CPU- ARITHMETIC LOGIC UNIT
1. The arithmetic logical unit (ALU) is responsible
for performing arithmetic and logical operations
and comparisons of data.
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Processors
CPU- REGISTERS
1. The CPU contains high-speed storage locations
called registers. Registers temporarily hold data and
instructions.
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Computer Memory
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RAM (random access memory)
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Used to store program instructions and data temporarily
 Unique addresses and data can be stored in any location
 Can quickly retrieve information
 Will not remain if power goes off (volatile)
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Computer Memory
Two types of SIMM's have been in general use. 30pin SIMM's and 72-pin SIMM's. 30-bit SIMM's
have 8-bit data buses; 72-pin SIMM's have 32-bit
data buses.
A DIMM has a 64-bit data
bus, which allows DIMM's
to be connected one at a
time to a CPU with a 64-bit
data bus.
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Computer Memory
ROM
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(read-only memory)
Information stored permanently on a chip
Contains startup instructions and other permanent data
CMOS
(complementary metal oxide
semiconductor)
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Special low-energy kind of RAM
Flash
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memory
Used for phones, pagers, portable computers, handheld
computers, and PDAs
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