Transcript Input, Process, Output - Washtenaw Community College

Input, Process, Output
Supplemental Lecture Notes
Typical System
Computer case
Monitor
Printer
Speakers
Modem
Keyboard
Mouse
Computer Components
Power supply
Hard drive
Expansion card
Expansion slot
System board
CD-ROM or DVD-ROM
Floppy disk
Drive bay
Central Processing Unit (CPU)
Random access memory (RAM)
Ports
Ports are connectors at the back of a
computer system that you use to plug in an
external device. This allow instructions and
data to flow between the computer and the
device
Any Port in a Storm
Parallel port – 25 holes; female connector; LPT1; printer or
storage devices
Monitor port
Keyboard port
Serial port – 9 or 25 pins; male connector; COM1; mouse
or modem
Game port
Network port
USB port
127 devices
Printer, modem, joy stick
Firewire
Input and Output
Chapter 2
Input Devices
Keyboards
Mice
Trackballs
Pointing Devices
Printers
Speed of a printer is measured in pages per minute
(PPM). A higher speed represents faster output
Resolution determines the quality of images
A higher resolution results in sharper images
Printer resolution is measured in dots per inch (dpi)
600 dpi is acceptable; 1200 is better for images
Resolution expressed with two numbers represents dots
per inch across and down
Types of Printers
Ink-jet: has a print head that sprays ink
through tiny nozzles onto a page
2 to 10 pages (ppm)
360 to 2400 dots per inch
Color printers spray cyan, magenta, yellow
and black to create different colors
Laser-printer
Works like a photo copier
Speed of 4 to 16 pages
Have a CPU
600 to 2400
Memory – 2mb to 8 Mb
Print Buffer and Spoolers
Printer buffer: section of memory printer
stores information waiting to print
Printer spooler: program on your computer
that stores information waiting to print
Stores more information than the buffer
One spooler for each connected printer
Monitors
Video cards translate instructions from
the computer into a form Most
computes the monitor can understand
require at least 2 mb of video card
memory
Monitor Metrics
The smaller the dot pitch, the crisper the
image
0.28mm is acceptable
Refresh rate is measured in hertz (Hz)
Times per second computer redraws the image
72 Hz or more is acceptable
Communications
Modems let a computer exchange
information through telephone lines
Speed of a modem determines how
fast it sends and receives messages
56,000 bps (56 Kbps)
V.90 standard: receive 56K and send 33.6K
Speed at which information flows
depend on the quality of the phone line
High-speed Connections
ISDN – Integrated Services Digital
Network
Digital phone line
56 Kbps to 128 Kbps
Cable Modem
Same cable as TV
4000 Kbps
DSL – Digital subscriber line
High speed digital phone line
1000 – 6000 Kbps
Scanners
A scanner is a device that reads
images and text into a computer
Optical Character Recognition (OCR)
software that places scanned text into a
document that can be edited in a word
processor
Color depth is measured in bits and
indicates the number of colors a scanner
can detect
Resolution
Resolution determines the amount of detail
a scanner can detect
Ranges from 600 dpi to 2400 dpi
You usually don’t need to scan at a higher resolution
than a printer can produce or a monitor can display
– Most monitors are 72 dpi
– Printers vary
USB and Firewire
High-speed ports that allow information to quickly
transfer between a computer and an external
device
USB
Supports up to 127 device
– USB 1.0: 12 megabits per second
– USB 2.0: 480 Mbps
FIREWIRE
63 devices at 400 Mbps
Can purchase Firewire expansion card
Processing
Chapter 3
CPU (Central Processing Unit)
Processes instructions, performs calculations,
and manages the flow of information
Performance:
CPU speed is a major factor in determining how fast a
computer operates (faster the speed, faster computer
operates)
Measured in megahertz (MHz) A clock cycle relates to the
clock that controls the timing in the microprocessor.
For example, a 900MHz (megahertz) clocked
microprocessor generates 900 million clock cycles per
second.
Each generation of CPU is more powerful than the
one before. It's clock cycles are faster at a given speed
Processing
The Central Processing Unit (CPU) is the
main chip in a computer
Processes instructions
Performs calculations
Manages the flow of information
Types of CPUs (Chips)
Intel Pentium Processor
Intel Celeron
Needs of home machines
AMD Athlon Processor
Business and home use
AMD Duron Processor
Home use
VIA Cyrix Processor
Inexpensive CPU
Processing
Random Access Memory – Temporarily stores
data inside a computer
Constantly overwritten
Measured in megabytes (MB)
If you have limited memory or you have many
programs open, your computer may need to
use part of the hard drive to simulate more
memory
Primary Storage
Speeds up computer by storing data the computer
has recently used
Internal Cache: On CPU chip (L1 or primary cache
External Cache: On the system board and consists of
Static RAM (SRAM chips)
Sometimes built into chip
RAM – slower main memory
Each time the computer requests data from RAM, the
computer places a copy of the data in memory cache
Constantly contains the most recently used data
Using Memory
1. Look through documents on your desk
(internal cache)
2. Look through documents in your desk
drawer (external cache)
3. Looking through documents in your filing
cabinet (RAM)
4. Go out and get it from the trunk of your
car (secondary storage)
Math Coprocessors
A special processing unit that assists the
CPU in performing certain operations.
A math coprocessor is a chip or part of a chip
that specializes in doing math. Hardware that
attaches to the motherboard or is part of the
CPU.
Also called numeric coprocessors or
floating point units (FPU).
Storage Devices
Chapter 4
Bus
Electronic pathway that carries information
between devices in a computer
Bus Width (think lanes of a highway)
8 bits is one character
Bus Speed (think speed limit)
Measured in MHz (millions of cycles per second)
Hard Drives
Magnetically stores data on rotating disks
called platters
Capacity is measured in bytes
Speed is measured in revolutions per minute
Floppy Drives and Drives
Removable media
Can be write-protected
Can be damaged magnetically
CD-ROM
ROM (Read-only memory) - can’t be changed
650 Mb of data
Equal to entire set of encyclopedias
400 Floppy disks
Speed determines how fast a disk spins
Look for 24X
Speed of CD-ROM drive is the transfer rate
In Kb (e.g. 3600Kbs)
CD-R & CD-RW Drives
CD-R (Compact Disc – Recordable)
Permanent store; not erasable
CD-RW
Can be erased and rewritten
Read / Write and Re-write speeds
Usually 74 minutes
Special software needed to record onto a disk
Referred to as burning a CD
DVD-ROM Drive
DVD – Digital Versatile Disk
Generally cannot change the information stored on a
disk
Similar to CD but stores more information
Speed determines transfer rate (6 X)
Capacity
1 side / 1 layer – 4.7 GB
1 side / 2 layer – 8.5 GB
2 sides / 1 layer – 9.4 GB
2 sides / 2 layers – 17 GB
Tape Drive
Backup helps you copy files to tape
cartridges
Try to find a drive that can store the entire
contents of your hard drive
Removable Storage Devices
Jazz Drive – 2 GB
Zip Drive – 250 MB
LS-120 Drive – 120 MB
Operating Systems
CPS120: Introduction to Computer
Science
Operating Systems
Software that controls the overall activity of the
computer
Ensure that all of the parts of the computer work
together smoothly
Functions:
Control hardware
Run software
Manage information
Programs that run on one operating system platform do
not generally run on others
Types of Operating Systems
MS-DOS
Command driven
Windows
Windows 3.1
Windows 9X (95, 98)
Windows ME
Windows XP
Windows NT
Windows 2000
UNIX
MAC OS
Unix
Can run single computer or entire network
Developed on mainframes in late ’60’s
True multi-tasking OS
Most widely used operating system on
Internet
LINUX
Unix-based system offered as freeware on
the Internet
Software
CPS120: Introduction to Computer
Science
Software
System software runs the machine
Application software helps you
accomplish specific tasks
Manufacturers also may create
minor software updates called
patches, to make corrections or
improvements to software
Utility Programs
Utility: A program that performs a specific task on
your computer
Norton utilities: recover files
Virusscan: anti-virus software
Acrobat Reader: View PDF (Portable Document
Format) files
Winfax pro
ViaVoice – Speech recognition
WinZip – Compress and decompress files
Application Software:
Word processor
Spreadsheets
Presentation Software
Database Software
Internet Software
Database Programs
Helps you manage large collections of
related information
Uses
Store information
Find information
Analyze and print information
Databases
Organized in:
Tables
Collection of information about a specific topic
Field
Category of information
Record
Single instance of information
Programming Languages
CPS120: Introduction to
Computer Science
Programming Languages
A programming
language is a set of
rules that provides a
way of telling a
computer what
operations to perform.
Levels of Programming
Languages
Machine language
Assembly Language
High Level Languages
Fourth Generation Languages (4GL)
Machine Languages
different for each computer processor
0100
001101 100000 001101 110001
00101 10001 10000
01110
111001
. . .
Assembly Languages
different for each computer processor
main
proc pay
mov ax, dseg
mov ax, 0b00h
add ax, dx
mov a1, b1
mul b1, ax
mov b1, 04h
High-Level Languages
Higher Level Languages
Use traditional programming logic where the
programming instructions tell the computer
what to do and how to perform the required
operations.
4GLs
Use high-level English-like instructions to
specify what to do, not how to do it .
Types of Programming
Languages
Machine language
Procedure-oriented languages
Object-oriented languages
Event-driven languages
What Can a Program Do?
A program can only instruct a computer to:
Read Input
Sequence
Calculate
Store data
Compare and branch
Iterate or Loop
Write Output
Fundamental Programming Concepts
Assignment of values to a variable
Iteration (Looping)
Over a set of set of statements
With respect to a logical expressions
(conditions)
Delegation of sub-tasks to functions /
procedures
The Structure Theorem
The Structure Theorem states that any algorithm
can be built from three basic control structures.
One-after-another (Sequence)
Decision-making (Selection)
Making choices between 2 or more alternatives
Repetition (Iteration)
Concerned with repetitive tasks (and the termination
conditions of loops)