Hardware and Software Computer System

The Computer Continuum3-2 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) Input Units Output Units 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 LCDCRT

The Computer Continuum3-5 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.

The Computer Continuum3-8 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

The Computer Continuum3-10 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

The Computer Continuum3-12 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.

The Computer Continuum3-13 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:

The Computer Continuum3-14 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 M emory 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.

The Computer Continuum3-18 Storage Devices  The four most important characteristics of storage devices: Speed and access time Cost / Removable versus non-removable Capacity Type of access

The Computer Continuum3-19 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.

The Computer Continuum3-20 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.

The Computer Continuum3-21 Capacity  Capacity - The amount of information that can be stored on the medium. UnitDescriptionApproximate Size 1 bit1 binary digit 1 nibble4 bits 1 byte8 bits1 character 1 kilobyte1,024 bytes1/2 page, double spaced 1 megabyte1,048,576 bytes 500,000 pages 1 million bytes 1 gigabyte1,073,741,824 bytes 5 million pages 1 billion bytes 1 terabyte1 trillion bytes 5 billion pages

The Computer Continuum3-22 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 Peripherals  Ports 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 Parallel hot-wire USB

Ports and Peripherals  Peripherals are devices that plug into a computer and are not housed internally. Examples: Printers Scanners Cameras

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 Display 640 x 480 Low Resolution 800 x 600 Medium Resolution 1600 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 End Of Sessions