2. In this presentation, we’ll discuss various input,
output, and CPU(central processing unit),memory
designed to meet the various needs and lifestyles
of people.
4. • Input device captures information and translates it into a form
that can be processed and used by other parts of your computer.
Keyboards
Pointing devices
Game controllers
Scanners
Styluses
Microphones
Digital cameras
Web cams
5. The keyboard is the most common input
device. Types of keyboards include:
• Wireless
• Multimedia and one-touch access
• Portable keyboards for PDAs
6.
7. Pointing devices are mainly used to choose and
enter commands
Pointing devices tend to have PS/2 connectors or
USB connectors
• PS/2 connector fits into a PS/2 port, which a small round
socket with small holes that fit the pins on the connector
• USB connectors fit into USB ports, and these are small
rectangular openings on the back or front of your computer,
or even on your keyboard or monitor
8. Various pointing devices are available
Types of pointing devices:
• Mouse
Mechanical mouse
Optical mouse
Wireless mouse
• Trackball
• Touchpad
• Pointing stick
9. Game controllers are used mainly to play games
Types of gaming devices
• Gamepads
• Joysticks
• Gaming wheels
• Force feed
10. Other types of input devices include:
• Scanners
• Styluses
• Microphones
• Digital cameras
• Web cams
11. •Scanner is a light sensitive device that helps you
copy or capture images, photos, and artwork
that exist on paper. Types of scanners include:
Flatbed
12. • Stylus is an input device consisting of a thin
stick that uses pressure to enter information
or to click and point
• Styluses are used with:
PDAs
Tablet PCs
Graphics tablets
13. • Microphones are used to
input audio
• Three main types of
microphones are:
Desktop microphones
Headsets
Directional microphones
• Speech recognition is
increasingly being included
in application software
14. Digital cameras are used to:
• Download images to a computer
• Post pictures to the Web
• Produce videos
Resolution is measured in
megapixels
Higher the resolution, better the
image quality, but the more
expensive the camera
15. • Web cam is a video camera
that can be used to take
images for uploading to the
Web
16. Output devices take
information within your
computer and present it to you
in a form that you can
understand
Main output devices:
Monitors
Printers
Speakers
18. CRTs
Flat-panel displays
Gas plasma
LCD (liquid crystal display)
Passive matrix
Active matrix
Called TFT (thin film transistor)
Separate transistor for every pixel
19. Inkjet – most popular
Makes images by forcing droplets
through nozzles
Top speed is 20 pages per minute
Laser
Forms images using an electrostatic
process
Prints between 3 and 30 pages per
minute
20. Resolution of a printer is the
number of dots per inch (dpi) it
produces.
Higher the resolution, better the
image, and usually the more costly
the printer
21. Multifunction printer:
• Scan, copy, fax, and print
• Can be either inkjet or laser
• Cost less than buying
individual units
• Take up less desk space
22. A speaker is a device that
produces computer output
as sound
Speakers are common
devices in computer systems
Examples include:
• Built-in speaker
• Two-device set speakers
• Surround sound speakers
23. ALU (arithmetic logic unit)
Performs calculations and comparisons (data changed)
CU (control unit): performs fetch/execute cycle
Functions:
Moves data to and from CPU registers and other hardware
components (no change in data)
Accesses program instructions and issues commands to the ALU
Subparts:
Memory management unit: supervises fetching instructions and data
I/O Interface: sometimes combined with memory management unit
as Bust Interface Unit
Registers
Example: Program counter (PC) or instruction pointer
determines next instruction for execution
24.
25. Small, permanent storage locations within the
CPU used for a particular purpose
Manipulated directly by the Control Unit
Wired for specific function
Size in bits or bytes (not MB like memory)
Can hold data, an address or an instruction
How many registers does the LMC have?
26. Use of Registers
Scratchpad for currently executing program
Holds data needed quickly or frequently
Stores information about status of CPU and
currently executing program
Address of next program instruction
Signals from external devices
General Purpose Registers
User-visible registers
Hold intermediate results or data values, e.g.,
loop counters
Equivalent to LMC’s calculator
Typically several dozen in current CPUs
27. Program Count Register (PC)
Also called instruction pointer
Instruction Register (IR)
Stores instruction fetched from memory
Memory Address Register (MAR)
Memory Data Register (MDR)
Status Registers
Status of CPU and currently executing
program
Flags (one bit Boolean variable) to track
condition like arithmetic carry and overflow,
power failure, internal computer error
28. Stores values from other locations (registers
and memory)
Addition and subtraction
Shift or rotate data
Test contents for conditions such as zero or
positive
29. Each memory location has a unique address
Address from an instruction is copied to the
MAR which finds the location in memory
CPU determines if it is a store or retrieval
Transfer takes place between the MDR and
memory
MDR is a two way register
34. Determined by two factors
1. Number of bits in the MAR
LMC = 100 (00 to 99)
2K where K = width of the register in bits
2. Size of the address portion of the instruction
4 bits allows 16 locations
8 bits allows 256 locations
32 bits allows 4,294,967,296 or 4 GB
Important for performance
Insufficient memory can cause a processor to
work at 50% below performance
35. DRAM (Dynamic RAM)
Most common, cheap
Volatile: must be refreshed (recharged with
power) 1000’s of times each second
SRAM (static RAM)
Faster than DRAM and more expensive than
DRAM
Volatile
Frequently small amount used in cache
memory for high-speed access used
36. Non-volatile memory to hold software that is
not expected to change over the life of the
system
Magnetic core memory
EEPROM
Electrically Erasable Programmable ROM
Slower and less flexible than Flash ROM
Flash ROM
Faster than disks but more expensive
Uses
BIOS: initial boot instructions and
diagnostics
Digital cameras