A closer look at the Computer hardware (that is used to execute a computer program)

In the previous webpage, we saw the internal components of a computer:

We will now explore the different components of a computer and study their functionality

Logical (functional) organization of computer hardware

A computer contains 4 types of components:

 
  • The Central Processing Unit (CPU) --- also known as a processor.
  • Memory (a.k.a. Random Access Memory (RAM)         
  • Input devices (e.g., mouse, key board, scanner, disks...)
  • Output devices (e.g., terminal, printer, disks, ...)

Categorizing components of computer further into core/non-core components

The components in a computer can be further classified into 2 (broader) categories:

  1. Computer system components (or core components) consisting of:

      1. The Central Processing Unit (CPU) --- also known as a processor.
      2. The Computer memory (a.k.a. Random Access Memory (RAM)

    The computer system performs the main (computational) function of the computer

  2. Peripheral devices (a.k.a.: I/O devices)           

      • Input devices (e.g., mouse, key board, scanner, CD-ROM...)
      • Output devices (e.g., terminal, printer, ...)
      • Input/Output devices (e.g., disk, network card,...)

    Peripheral devices are auxiliary devices that allow users to enter inputs into the computer and/or obtain outputs from the computer

The function of each type of component in a computer: (1) the CPU

The Central Processing Unit (CPU):

  • The CPU will fetch the next instructions in a computer program from the computer memory and execute the (fetched) instruction

The function of each type of component in a computer: (2) the memory

The memory (or RAM):

  • The memory is a storage component that stores:

      1. Instructions of computer programs
      2. Variables (= data) used in the computer programs

The function of each type of component in a computer: (3) the input device(s)

The input devices:

  • Input devices enables human users to enter data into the computer (= machine)

Note: all data are represented by binary numbers when it is inside the computer !!

The function of each type of component in a computer: (4) the output device(s)

The output devices:

  • Output devices enables the computer to show data stored inside the computer to a human user in a "humanly" readable manner

Remember: all data inside the computer are represented in (not-human-friendly) binary !!

The input/output devices
 

  • Input/output (I/O) devices are peripheral devices that can be used both as input and output devices

  • IO devices are not used to facilitate communication between humans and computers:

      • I/O devices are used as data storage (e.g.: hard disk) or data communication (e.g.: network card)

  • The most commonly used used IO device is a (hard) disk

      • Users can store data in files to a disk

        (The disk functions as an output device)

      • Users can read their data files from a disk

        (The disk functions as an input device)