Input, Process, Output

Supplemental Lecture Notes

Typical System

Computer case

Monitor

Printer

Speakers

Modem

Keyboard

Mouse

Computer ComponentsPower supplyHard driveExpansion cardExpansion slotSystem boardCD-ROM or DVD-ROMFloppy diskDrive bayCentral 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 StormParallel port – 25 holes; female connector; LPT1; printer or storage devicesMonitor portKeyboard portSerial port – 9 or 25 pins; male connector; COM1; mouse or modemGame portNetwork portUSB port

127 devicesPrinter, modem, joy stick

Firewire

Input and Output

Chapter 2

Input Devices

Keyboards

MiceTrackballs

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 imagesA 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 PrintersInk-jet: has a print head that sprays ink through tiny nozzles onto a page

2 to 10 pages (ppm)360 to 2400 dots per inchColor printers spray cyan, magenta, yellow and black to create different colors

Laser-printerWorks like a photo copierSpeed of 4 to 16 pagesHave a CPU600 to 2400Memory – 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

MonitorsVideo 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

CommunicationsModems 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 ConnectionsISDN – Integrated Services Digital Network

Digital phone line56 Kbps to 128 Kbps

Cable ModemSame cable as TV4000 Kbps

DSL – Digital subscriber lineHigh speed digital phone line1000 – 6000 Kbps

ScannersA 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

USBSupports up to 127 device

– USB 1.0: 12 megabits per second

– USB 2.0: 480 Mbps

FIREWIRE63 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 ProcessorIntel Celeron

Needs of home machines

AMD Athlon ProcessorBusiness and home use

AMD Duron ProcessorHome use

VIA Cyrix ProcessorInexpensive CPU

ProcessingRandom 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 cacheExternal Cache: On the system board and consists of Static RAM (SRAM chips)

Sometimes built into chip

RAM – slower main memoryEach 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 CoprocessorsA 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 mediaCan be write-protected

Can be damaged magnetically

CD-ROM

ROM (Read-only memory) - can’t be changed

650 Mb of dataEqual to entire set of encyclopedias

400 Floppy disks

Speed determines how fast a disk spinsLook for 24X

Speed of CD-ROM drive is the transfer rateIn 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 diskReferred to as burning a CD

DVD-ROM Drive

DVD – Digital Versatile DiskGenerally cannot change the information stored on a disk

Similar to CD but stores more information

Speed determines transfer rate (6 X)

Capacity1 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 DevicesJazz 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-DOSCommand driven

WindowsWindows 3.1Windows 9X (95, 98)Windows MEWindows XPWindows NTWindows 2000

UNIXMAC 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

UsesStore information

Find information

Analyze and print information

Databases

Organized in: Tables

Collection of information about a specific topic

FieldCategory of information

RecordSingle 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

0100001101 100000 001101 11000100101 10001 1000001110111001. . .

Assembly Languagesdifferent for each computer processor

main proc paymov ax, dsegmov ax, 0b00hadd ax, dxmov a1, b1mul b1, axmov b1, 04h

High-Level Languages

Higher Level LanguagesUse traditional programming logic where the programming instructions tell the computer what to do and how to perform the required operations.

4GLsUse 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 InputSequenceCalculateStore dataCompare and branchIterate or LoopWrite 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)