ICT SYSTEMS

ICT SYSTEMS

1. Backing Storage-(Hard Drive,DVD,CD etc.)

   • Input- Entering data or instructions into a computer system
     • Process- Data is converted from one form to another by the CPU
       • Output- When the results of processing are produced e.g. displayed on a monitor
         • SOFTWARE- THE PROGRAMS,CODE OR INSTRUCTIONS THAT MAKE THE COMPUTER SYSTEM RUN
         • e.g. inkjet printer, laser printer,headphones,speakers
       • Main Internal Memory- RAM AND ROM
     • HARDWARE- THE PHYSICAL PARTS THAT MAKE UP A COMPUTER SYSTEM
     • e.g. mircophone, keyboard,scanner,tracker ball,mouse

2. The CPU (Central Processing Unit)- can be referred to as the brains of a computer. It contains a number of microprossessors and is responsible for executing a sequence of stored instructions.

3. Memory

   • RAM-Random Access Memory RAM is volatile ( looses data when power is lost. It stores data which can be changed and data the user is currently working on e.g. a letter in a word processor
   • ROM- Read Only Memory ROM is non volatile ( does not loose data when switched of). The data cannot be changed or written to the RAM it is fixed at manufacture. The ROM contains the BIOS ( start up instructions for the computer) so it needs to not be changed.
   • Backing/Secondary storage Stores more data than the main memory (RAM and ROM) that is not currently in use for the long term. It is non volatile but has a slower access time than the main memory.

4. Storage Devices

   • CD (optical storage)- 700mb
     • DVD (optical storage)- 4.7GB
       • Blu Ray ( optical storage)- 25GB
         • Floppy Disk ( magnetic disk drive)- 3.5mb
           • Hard Disk- ( Magnetic disk drive/solid state)- Up to 1TB
             • Flash memory stick (Flash memory- 4GB
               • Magnetic Tape (Magnetic disk drive)- up to 1TB
                 • Cloud storage- internet based storage system- offers large amount of space but is usually paid for by the number of gigabytes used.
                   • Pros: You can access your files online, easy to share your data worldwide
                     • Cons: Costs money, there can be technical issues, if your're a company the cloud company can see all your data stored.
                 • Pros: Cheapest storage device per mb, can storage large amounts of data, can be set up to do the backup overnight.
                   • Cons: Serial access used so quite slow, need a special place of equipment to record and read the data.
               • Pros: Small and stable, large storage capacity, not easily damaged.
                 • Cons: Easily lost or stolen, can only be reliably used 10000 times or so.
             • Pros: Large storage capacity, relatively cheap
               • Cons: Easily damaged by knocks, heat, magnetic fields. Not removable.
           • Pros: Easily transported, not easily damaged
             • Cons: Small storage capacity, easily lost or stolen, not many computers can use them.
         • Pros: Very large storage
           • Cons: Devices and media are expensive, cannot be used by DVD or CD drives, damaged by scratches.
       • Pros: Cheap to buy, large capacity
         • Cons: RW and double layer can be expensive, easily damaged by scratches
     • Pros; Cheap to buy, RWS can be written to more than once, all modern computers can use them
       • Cons: Can only write to them once, small capacity compared to DVD and Blu Ray, easily damaged by scratches.
   • Solid State Devices- There are no moving parts in a solid state drive which makes it faster than magnetic disk drives. They can be more reliable and often used in portable devices such as laptops as there are no moving parts so they won't get easily damaged. However, this means that they can be more expensive than magnetic hard disks. It is robust.
     • Magnetic disk drives- Use magnetic discs for storing files. Hard disks can store large amounts of data however it can be damaged if moved suddenly as they have moving partts. This is why they are used in desktop computers as they are not portable. As the disks use drive heads dirt and dust can damage the disks and make them unusable.

5. Systems Software

   • Operating Systems
     • Managing security
       • Managing the hardware
         • providing a user interface
           • Dealing with errors and using instructions
             • Managing computer memory
   • Drivers
     • A driver is a program that controls a device
       • Every device e.g. printer,disk drive, key board must have a driver program. It acts like a translator between a device and programs that use it. Each device has its own set of specialised commands that only the driver knows.
   • Utilities- designed to carry out small tasks to help the user with everyday tasks
     • managing the hard disk e.g. defragmenting files
     • Encrypting files
     • scanning for viruses
     • Compressing files

6. Application software

   • Word Processor
     • Desktop Publishing
       • Presentation Software
         • Photo editing software
           • Internet Browser
             • Graphics Software
               • Email Software
     • Spreadsheet
       • Database
         • Communication software
           • Web authoring software

7. File Types

   • .bmp (Bitemap)
     • .gif (graphical image file)
       • .png (portable network graphics)
         • .html (hypertexts mark up language)
           • .exe (executable file)
         • .mdb (Microsoft database)
           • .ppt (powerpoint file)
             • .mp3 (audio file)
               • .wav (audio file)
                 • .txt (text file)
                   • .xls (excel file)
                     • .swf (Adobe flash file/shockwave file)
                     • .wmv (windows media video/file
                       • .zip (compressed file)
                         • .jpg (image file)

8. Programming Software

   • Debugger- A debugger will find any errors in the code and highlight them so the programmer can correct them.
     • Editors- Programmers write source code using an editor. They will write the code in a programming langauge which is also knows as source code. This language resembles the human language.
       • Linkers- Used to join code together. A large computer program will usually be written by a large team which will need to combine all of their code to make a final program.
         • Interpreter- Can execute the instructions in source code by translating it one line at a time into machine code.
         • Machine Code- ( binery- 0's and 1's) the lowest type of code processed by computers CPU. Other program sare compiled into machine code in order to run them
       • Compilers- The compiler will turn source code into machine code. The source code is translated all at the same time.
   • Source code- written in a specific programming language which is then compiled into machine code e.g. Java, HTML,visual basic, C++

9. GUI: Graphical User Interface (made up of WIMP)- Windows,Icons,Menus,Pointer

   • Pros: User friendly, easy for beginners to use, user does not have to remeber commands of instructions
     • Cons: Uses a lot of memory and processing so it is a lot slower than command line interface, can require a number of commands to do a simple task.

10. CLI: Command Line Interface ( the user has to type in commands to tell the computer what to do.

    • Pros: Experienced users can type in commands and work very quickly without menus, good for motor impaired people due to minimize no. of commands, command driven programs do not need memory an processing power that GUI would nee, can often run on low spec machines.
      • Cons: Inexperienced users can find it difficult to use as a number of commands have to be learnt, no room for error.

11. DNI: Direct Neural Interface ( a direct connection between the brain and the computer to create commands.

    • Pros: allows paralyzed people to control a device with their brain, they can control a prosthetic limb, video games: they can have their thoughts displayed by a computer.
      • Cons: It is extremely expensive

12. 4 main types of computer: Supercomputer, mainframe computer,embedded computer and personal computer.