Hardware and Software Computer System

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Basic Concepts of Computer Hardware

This model of the typical digital computer is often called the von Neumann computer. Programs and data are stored in the same memory:

primary memory. The computer can only perform one instruction at a time.

CPU(Central Processing Unit)

InputUnits

OutputUnits

Primary Memory

Input Devices Input Devices:

devices that input information into the computer such as a keyboard, mouse, scanner, and digital camera.

Output Devices Output: devices that

output information from the computer such as a printer and monitor.

Display monitors: Hi-resolution monitors come in two types:Cathode ray tube (CRT) - Streams of electrons make phosphors glow on a large vacuum tube.Liquid crystal display (LCD) - A flat panel display that uses crystals to let varying amounts of different colored light to pass through it.

Developed primarily for portable computers.

Printer

LCD CRT

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Output Devices Audio Output Devices

Windows machines need special audio card for audio output.

Macintosh has audio playback built in. Audio output is useful for:

Music CD player is a computer. Most personal computers have CD players that can

access both music CDs and CD-ROMs. Voice synthesis (becoming more human sounding.) Multimedia Specialized tasks (i.e.: elevator’s floor announcements)

Central Processing Unit CPU (Central Processing Unit) also called the

Microprocessor or “The Brain” of the Computer. Processor speed: The speed at which a

microprocessor executes instructions. This is usually measured in megahertz (MHz).

Brands of Processors include: Pentium Celeron MAC AMD Cyrix

Central Processing Unit Computer chip: also called the

microprocessor may contain an entire processing unit.

Computer chips contain millions of transistors. They are small pieces of semi-conducting material (silicon).

An integrated circuit is embedded in the silicon. Computers are made of many chips on a circuit board.

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Storage Devices Common Basic Technologies for Storing

Binary Information: Electronic Magnetic Optical

Data Storage Devices (magnetic and electronic technologies) The hard-drive is a

mechanical storage device typically located internally.

Fast recording and recovery of data

Large storage capacity Magnetic Primary storage device for

data and programs Speed is measured in

R.P.M.’s

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Optical Technology

Uses lasers to “read” the binary information from the medium, usually a disc.

Millions of tiny holes are “burned” into the surface of the disc.

The holes are interpreted as 1s. The absence of holes are interpreted as 0s.

Data Storage Devices (cont’d) CD-ROM (compact disk

read only memory) Approximately 600

to 700 megabyte of storage

An optical device read by a diode laser

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Optical Disks Optical Disks: CD-ROM and DVD

CD-ROM (Compact Disk - Read Only Memory) By its definition, CD-ROM is Read Only. Special CD drives “burn” information into blank CDs.

Burn: A laser is used to “burn” craters into the surface to represent a binary 1.

Two main types of CDs: CD-R (Compact Disk - Recordable) CD-WR (Compact Disk - ReWritable)

It takes longer to write to a CD-R than a hard drive. Special software is needed to record.

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Output Devices DVD (Digital Versatile Disk)

Allows up to 17 gigabytes of storage (from 4.7 GB to 17 GB).

Compatible with older CD-ROM technology. The four versions of the DVD:

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Magnetic Technology Magnetic Technology

Two parts to most of the magnetic forms of information storage:

The medium that stores the magnetic information. Example: Floppy disk. Tiny spots on the disk are

magnetized to represent 0s and 1s. The device that can “read” that information from the

medium. The drive spins the disk. It has a magnetic sensing that moves over the disk. Performs nondestructive reading.

Data Storage Devices (Magnetic technology) Floppy diskette is

magnetic storage device for small amounts of data (1.44MB).

FLASH drive is a compact and portable electronic storage device. USB (plug and play)

supported

Computer Memory Computer memory is binary (0 or 1) (on or off). The byte is the standard unit of measurement. A byte is composed of 8 bits (binary digits). Typical units of measurement:

1 KB (kilobyte) = 1000 bytes 1 MB (megabyte) =1000 kilobytes or 1 million

bytes 1 GB (gigabyte) =1000 megabytes or 1 billion

bytes

Computer Memory (electronic technology) RAM (random access

memory) stores data that is processing. This type of memory is erased when the computer is turned off.

ROM (read only memory) contains special instructions for the computer to operate.

Cache memory increases the speed of the processor by recording and anticipating instructions.

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Storage Devices The four most important characteristics of

storage devices: Speed and access time Cost / Removable versus non-removable Capacity Type of access

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Speed (Access time) Speed (Access time) - How fast

information can be taken from or stored onto the computer memory device’s medium. Electronic circuits: Fastest to access.

40 billionths of a second. Floppy disks: Very slow in comparison.

Takes up to 1/2 second to reach full speed before access is even possible.

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Cost Cost

Megabyte: A Million bytes. Gigabyte: A billion bytes.

Two parts to a removable secondary storage device:

The cost of the medium. (Cheaper if bought in quantity) The cost of the drive.

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Capacity Capacity - The amount of information that

can be stored on the medium.

Unit Description Approximate Size1 bit 1 binary digit1 nibble 4 bits1 byte 8 bits 1 character1 kilobyte 1,024 bytes 1/2 page, double spaced1 megabyte 1,048,576 bytes 500,000 pages

1 million bytes1 gigabyte 1,073,741,824 bytes 5 million pages

1 billion bytes1 terabyte 1 trillion bytes 5 billion pages

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Type Access Type of Access

Sequential - Obtained by proceeding through the storage medium from the beginning until the designated area is reached (as in magnetic tape).

Random Access - Direct access (as in floppy and hard disks).

Maindboard

Graphic User Interface (GUI) GUI (Graphic User Interface) is a set of

images and icons seen on the desktop used to operate a program.

The GUI makes the programs loaded on the computer easier to access and use. Basic Windows GUI

Icons are small pictures that represent files, commands, or windows.

Windows is a GUI operating system unlike UNIX, which uses text commands.

Video Cards Video cards plug into the

motherboard and are used to display video.

VRAM is video memory that enhances the refreshment rate of the image.

Video cards have chipsets that can increase the speed of video display.

Ports and PeripheralsPorts are an interface between the computer and

another peripheral device such as a disk drive, mouse, printer, modem, monitor, camera, FLASH drive or keyboard.

Examples: Serial Parallelhot-wire USB

Ports and PeripheralsPeripherals are devices

that plug into a computer and are not housed internally.

Examples: PrintersScannersCameras

Resolution Resolution refers to the

number of pixels (picture elements) in the monitor image.

Increased resolution uses more computer resources but increases the visual clarity of the display.

Resolution Screen resolution is measured in pixel per inch

(ppi), and printer resolution is measured in dots per inch (dpi).

Computer screen resolution is approximately 72 ppi.

Width x Height (Pixels) Video Display640 x 480 Low Resolution800 x 600 Medium Resolution1600 x 1200 High Resolution

LAN and WAN LAN: are networks usually

in the same company or building. The Local Area Network is connected via telephone lines or radio waves. Most LANs connect workstations.

WAN: are systems of LANs that are connected. (Wide-area network)

Bandwidth and Baud Rate Bandwidth is how much

information can be carried in a given time period (usually a second) over a wired or wireless communications link.

Baud rate is the rate at which information is transferred in a communication channel.

Multitasking and Multiprocessing Multitasking is the ability

to execute more than one task (program) at the same time. Only one CPU is used but switches from one program to another.

In multiprocessing, more than one CPU is used to complete a task. Example: network rendering.

Multimedia Multimedia software

programs include sound, pictures, video, text, and hypertext to create presentations. Software includes:

PowerPoint Macromedia Director FLASH

File Management Different programs have different file extensions. Naming files - avoid the following characters in naming files:

Examples: @ * .

Understand the parts of a path name.

Example: C:\MyDocs\trial.php

Drive designator Directory or folder File name File extension

File Management Saving files - know the difference

between “save” and “save as”. “Save” will save the open document over the saved document while “save as” creates a new document if you rename the document. Save often so work will not be lost.

Exporting – converts a native format to a non-native file format used in various software programs. In vector programs, file types may be exported.

Software Operating System Ex :MS. Windows, Linux, Macintosh Aplication Software Ex :Ms.Office, Macromedia, WinRar

Any Questions

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