©G. Millbery 2005Components of an Information SystemSlide 1 Module Software and Hardware Components of an Information System

©G. Millbery 2005Components of an Information SystemSlide 2 Difference Between Hardware and Software  Hardware: Physical equipment that makes up a computer system If you can kick it or take an axe to it it is hardware.  Software: Programs, routines and procedures (together with their associated documentation) which can be run on a computer system. It is important not to confuse the media used to transport software with software itself A CD is a piece of hardware which you can touch and kick and it may contain software which you cannot touch. The CD is not software it is hardware

©G. Millbery 2005Components of an Information SystemSlide 3 Examples of Hardware  Hardware: Central Processor Peripherals – these are hardware devices which are attached to the central processor: »They can be classified into four types:  Input: –Keyboard, Mouse, Scanner  Output: –Monitor, Speakers  Backing Storage: –Hard Disk, Floppy Disk Drive  Communications: –Modem

©G. Millbery 2005Components of an Information SystemSlide 4 Examples of Software Acceptable terms  Word processor  Spreadsheet  Database  Presentation   Operating System Unacceptable terms  Word  Excel  Access  PowerPoint  Outlook  Windows XP

©G. Millbery 2005Components of an Information SystemSlide 5 Standardisation  In general, hardware produced by one company will not be compatible with that produced by another  Hardware: A POS terminal by IBM could not plug into an ICL system  Software: A program written for the Mac would not run on a PC

©G. Millbery 2005Components of an Information SystemSlide 6 Standardisation  Software standardisation Output may appear different: »E.g. web pages viewed on different systems  Different layout, resolution of images, etc. Standardisation of file formats »Importing and exporting of data between applications  Advantages of Standardisation Hardware and software will be known to be compatible Choices from where to purchase equipment Agreed standards for equipment – comeback if not up to standard  Disadvantages of standardisation Less choice Less competition amongst suppliers

©G. Millbery 2005Components of an Information SystemSlide 7 Input Devices KeyboardNumeric Keypad JoystickMouse TrackerballMicrophone Touch ScreenScanners OCRDigital Camera Graphics TabletDigitiser Push SwitchSensor ADCFoot Mouse Puff Suck SwitchEye-Typer Examples include:

©G. Millbery 2005Components of an Information SystemSlide 8 Output Devices Loud Speaker Printer Monitor Plotter Buzzer LED Examples include:

©G. Millbery 2005Components of an Information SystemSlide 9 Loud Speaker  Used to give confirmation of actions  Can be used to read lines of text  Increased use with CDs and Music (MP3s)  Music technology requires specialist sound output devices.

©G. Millbery 2005Components of an Information SystemSlide 10 LED and Buzzer  LED Can display the status of a device »FDD light displayed when in use »Lights on a Printer indicates status - on-line or off line for example. Can be used to signal to hearing impaired people  Buzzers Gives confirmatory actions »Set sounds to events in Windows »Bar Codes beep to indicate successful entry

©G. Millbery 2005Components of an Information SystemSlide 11 Printers  Three main types of printers: Impact Printers InkJet Printers Laser Printers  Choice of: Colour Black and White  Selection of different resolutions

©G. Millbery 2005Components of an Information SystemSlide 12 Impact Printers  Physical Connection between print head and paper  Noisy  Slow (chain printers can be very fast)  Cheap to run  Colour or Black and White  Low Resolution  Can do Carbon Copies  Print on multi part paper

©G. Millbery 2005Components of an Information SystemSlide 13 InkJet Printers  Ink is fired at the page and the number of DPI can be very high High resolution  Colour or black and white  High running costs  Faster than a dot matrix but not as fast as laser  Can not print carbon copies

©G. Millbery 2005Components of an Information SystemSlide 14 Laser Printers  High Quality Images  Fast Printing  Colour or Black and White (Colour is expensive)  Medium to low running costs  Excellent Quality  Need special transparencies to produce OHPs  Cannot do Carbon Copies

©G. Millbery 2005Components of an Information SystemSlide 15 Monitor (VDU)  Most common Output device  Range of Sizes – standard is 17”, but 21” or greater is available for specialists: For example, designers Newspapers and magazines  High quality output  Bulky, but LCD screens can reduce footprint size More expensive than standard monitors Less affected by glare Fewer health issues compared to standard monitors  Possible health issues with standard VDU’s

©G. Millbery 2005Components of an Information SystemSlide 16 Storage Devices Tape Hard Disk Floppy Disk CD ROM / R / RW Other Storage Devices Examples include:

©G. Millbery 2005Components of an Information SystemSlide 17 Role of Storage Devices  To store data that is not currently being processed  Non volatile storage of programs and data  Sometimes referred to as secondary store or mass storage.

©G. Millbery 2005Components of an Information SystemSlide 18 Tape  Serial Access to data  Used almost exclusively to hold backup data  Can hold in excess of 100Gb of data  Specialist devices required to read the tape  Slow access to data.

©G. Millbery 2005Components of an Information SystemSlide 19 Hard Disk  Sealed unit holding many GB of data  Fast direct access to the data.  Two types (standards): SCSI (Small Computer Systems Interface) »High speed of transfer (historically – catching up) »Specialist card required – controller separate from device »Can daisy chain devices »MTBF (mean time between failures) greater on SCSI – reliability IDE (Integrated Device Electronics) »Standard interface in PC’s (More common than SCSI) »Cheaper and slower than SCSI (catching up in speed)

©G. Millbery 2005Components of an Information SystemSlide 20 Floppy Disk  Floppy Disk Drive is standard on PCs  Portable between machines  Limited storage capacity (1.44 MB)  Slow access to data  Can be set to read only by use of a tag  Inexpensive  Constant use increases unreliability

©G. Millbery 2005Components of an Information SystemSlide 21 CD ROM  WORM (Write Once Read Many) Holds 650 MB Data Used for static data (data which does not change) »Encyclopaedias »Software Programs  RW CDs allow you to rewrite onto the CD. This is only possible a limited number of times and requires specialist equipment. (approximately 1000)  DVD now available – Holds 12GB of data Also RW DVDs  CDs/DVDs used to hold Music, Video, Pictures, etc.

©G. Millbery 2005Components of an Information SystemSlide 22 Other Devices  Zip disks (100 MB, 250 MB, 750MB etc)  Super Floppy Disk (120 MB)  Jazz Disks (1GB +)  Flash Memory (1 GB+)  All storage devices are pushing amount of storage they can hold Figures constantly changing

©G. Millbery 2005Components of an Information SystemSlide 23 Magnetic v Optical Devices  Magnetic Disk or Tape »Can be reused many times »Very large storage capacity  Optical CD Rom, DVD »RW CD ROMs/RW DVDs exist – limited life cycle »Limited storage capacity

©G. Millbery 2005Components of an Information SystemSlide 24 Backup and Archive  Backup Making copies of data or programs in case the originals are lost or corrupted.  Archive The storage of information for long periods of time. Removing the data from the original medium and transferring it to off line/secondary storage  Considerations of Media:  Speed of Backup (Direct or Serial) and speed of recovery  Amount of data (MB or GB)  Portability (Tapes, Removable disk)  Compatibility with other systems (CD, tape, etc)

©G. Millbery 2005Components of an Information SystemSlide 25 Storage Capacity  0 / 1 = bit (binary – on or off)  = 8 bits  8 bits = 1 byte  1024 bytes = 1 kilobyte (kB)  1024 kB = 1 megabyte (MB)  1024 MB = 1 gigabyte (GB)  1024 GB = 1 terabyte (TB)

©G. Millbery 2005Components of an Information SystemSlide 26 Types of Software  Operating Systems  User Interfaces  Utilities  Translation  Application

©G. Millbery 2005Components of an Information SystemSlide 27 Operating Systems  A program or suite of programs that control the entire operation of the computer.  Deals with the basic functions of the computer.  At a technical level, it handles the basic and central functions such as input and output operations and interrupts.  Examples include: MS-DOS, OS/2, UNIX, RISC-OS, Windows XP, LINUX, BeOS, etc.

©G. Millbery 2005Components of an Information SystemSlide 28 User Interfaces  Methods by which the user can interface with the operating system/application Command line Dialog boxes Menus Windows

©G. Millbery 2005Components of an Information SystemSlide 29 Utilities  Designed to perform a commonplace task, for example the transfer of data from one storage device to another, sorting a set of data, disk editor.  They are designed to make the operation of the computer easier.  Other examples: formatting programs, backup programs, anti-virus, etc.

©G. Millbery 2005Components of an Information SystemSlide 30 Translation  Programs which convert a program from one language to another, for example from low level language to machine code.  This is the general name for three types of translators: Assemblers Compilers Interpreters

©G. Millbery 2005Components of an Information SystemSlide 31 Application  Generic  Tailor-Made  Off-the-shelf  Programming Languages  Cross over between categories: Generic is off-the-shelf Programming languages can be off-the-shelf and used to create tailor-made software

©G. Millbery 2005Components of an Information SystemSlide 32 Generic  These are off-the-shelf packages which do not meet a specific purpose but serve a general purpose  For example: Microsoft Office and components Corel Suite Lotus Suite »Word Processors, Spreadsheets, Databases  The software can then be customised to produce the result you want.

©G. Millbery 2005Components of an Information SystemSlide 33 Tailor-Made  Either: Bespoke »The application is written for the purpose by a software house  Disads: Time consuming, expensive, limited support/books.  Ads: Fulfils purpose, individual support  Or: Customisation »A generic application is customised using a programming language  Disads: Need to purchase the application and you get more than required.  Ads: Cheaper, lots of support.

©G. Millbery 2005Components of an Information SystemSlide 34 Off-the-Shelf  Purchasing solutions from a shop without alteration  For example: SAGE payroll package Heritage Library Database  The idea is to be able to open the package and run the software which delivers a specific solution  Can be generic (word processors)

©G. Millbery 2005Components of an Information SystemSlide 35 Programming Languages  There are a variety of programming languages available.  Each language has a specific purpose FORTRAN – Formula Translation »Mathematical and Scientific COBOL – Common Business Orientated Language »Business, Data Processing  Languages can also be used to enhance the application: Use of VBA to write macros, or write dll’s