Computer science

• hardware


  The physical components that make up a computer system. It's physically connected to a computer or is something that can be physically touched.

  
• operating systems software


  Controls and manages the computer. Examples are Windows, Mac OS and Linux.

  
• input


  Data entered into a system. Examples would be bar-codes scanned in a supermarket, or key strokes entered by a typist.

  
• processing

  Turning the input into a useful form. For example, comparing bar-code data with a database to analyse which item it corresponds to.
• output


  The visible or audible result of data processing - information that can be used. For example, the name and price of an item is displayed on a monitor following a bar-code scan.
• component


  Basic building block of a system, e.g. the main component that makes a computer work is the microprocessor.

  
• storage


  Information is kept for later use, e.g., information on the stock levels after the item has been scanned.
• devices


  Pieces of hardware. For example, a monitor is an output device.

  
• microprocessor


  A silicon chip that contains a central processing unit, which acts as the "brain" of a computer.

  
• CPU

  Central processing unit; the part of the computer that does most of the data processing. It's responsible for interpreting and executing most of the commands from the computer's hardware and software.

  
• applications software

  Computer programs that are designed to carry out specific tasks.
• software

  It's a program or set of instructions that the processor runs in order to carry out tasks that the user requires. The part of a computer system that you cannot see or touch.
• data

  The raw values entered into, stored and processed by information systems. Can be input to the system through devices like the keyboard, or collected automatically by sensors. Data can also be output to devices such as a monitor or printer.

  
• information


  Produced as output and feedback, with a context that gives it meaning.
• RAM


  Random Access Memory is the "working memory" in a computer. Temporarily stores parts of the operating system and any applications you run, to allow faster access to data and to improve performance. Typically referred to simply as "memory" even though other types of memory may exist inside a computer.

  
• hard drive


  The hard disk drive (HDD) is the main, and usually largest, data storage hardware device in a computer.

  The operating system, software titles and most other files are stored in the hard disk drive.

  
• optical drive


  Retrieves and/or stores data on optical discs like CDs, DVDs, and BDs (Blu-ray discs).

  
• ROM


  Read-only memory
• bit


  the smallest addressable unit of data that a computer can process and store
• how many bits in a nibble?

  4 bits
• how many bits in a byte?

  8 bits
• how many bytes in a kilobyte (KB)?

  1000 bytes
• how many KB in a megabyte (MB)?

  1000KB
• how many MB in a gigabyte (GB)?

  1000MB
• how many GB in a terabyte (TB)?

  1000GB
• how many TB in a petabyte (PB)

  1000TB
• A program is a set of instructions that tells the computer what to do.
• embedded system is A computer system with a dedicated/specific purpose or function. It is built into a physical product/device.