Structure of a Computer

Introduction of Structure of a Computer

• Structure of a Computer is also considered as Hardware of Computers.
• Hardware is considered as the first part of a computer. 
• Hardware does all the physical work of a computer with the help of software.
• Hardware is an essential component of any computer system.

Definition

• Hardware is all the visible/touchable/physical components of the computer system.
• Hardware is just a collection of circuits and pieces of plastic, wood, fibers, metal, etc.

Features

• The computer hardware is essentially pieces of complex electronics that understand only 1’s and 0’s i.e. electrical ON or OFF conditions. Hence, the instructions to perform a task on a computer are written in a series of binary 1’s and 0’s.
• Hardware components are the building blocks of a computer system.

Examples

• Examples of hardware are –
  • Input Units: Mouse, Keyboard, Scanner, etc.
  • Central Processing Units: ALU, CU, etc.
  • Memory Units: Hard disk, Flash drive, etc.
  • Output Units: Monitor, Printer, etc.

Structure/Hardware Components of a Digital Computer 

• Each computer consists of a series of hardware components/devices that together operate as an integrated unit or computer system.
• The major key elements of a digital computer are the central Processing Unit(CPU)/Operational Unit, Input Unit, Output Unit, and Memory/Storage Unit.
• These all are located directly or indirectly on the motherboard of the CPU Cabinet.
• The typical hardware components of a computer system are-
  • CPU

  • Input Unit

  • Output Unit

  • Memory/Storage Unit 

  • CPU Cabinet/System Unit/Computer Case :
    • A box-like structure that contains almost all the components of a computer inside it.
    • A computer case covers the computer circuitry.
    • It is also known as a cabinet, box, computer chassis, etc.
    • It is a box that contains different components of a computer like CPU, Motherboard, RAM, Power supply unit, etc. It contains a motherboard as a major structure but also includes several ports & connectors, SMPS, etc.
    • Computer cases are available in many different forms and sizes like desktop cases, full-size tower cases, mini tower cases, etc.
    • ATX is the most popular form factor used for desktop computers these days.
    • The computer case includes input/output ports and power buttons.
    • The motherboard is the main component placed inside the computer case.
    • The power supply unit is also attached to the case. A power supply unit is responsible for providing power to other components of a computer.
  • Mother Board/Main Board/System Board : 
    • It is a printed circuit board on which several devices are plugged in.
    • This printed circuit board is often called the motherboard.
    • The motherboard contains the circuitry and connections that allow the various components to communicate with each other.
    • Motherboard holds some of the most important components of the computer system.
    • In a typical computer microprocessor, main memory and other components are connected to the motherboard.
    • It acts as a base for other components.
    • The motherboard also provides connectors for several other devices.
    • A motherboard allows many different parts of our computer to receive power and communicate with one another.
    • The shape, size, and layout of a motherboard is called a form factor.
    • The Motherboards usually provide the interface between the CPU memory and input/output peripheral circuits, main memory, and facilities for the initial setup of the computer immediately after power-on.
    • All other major components of the computer are either plugged in directly to this motherboard or connected through a bunch of wires.
    • CPU, RAM, and Device Cards are plugged into various slots of the motherboard. Devices like Hard Disk, Floppy Drives, and CDROM Drives, which are attached to the CPU cabinet, are connected through wire ribbons.
    • The motherboard has printed circuitry which allows all these components to communicate with each other.
    • The motherboard is the main circuit board of a microcomputer.
    • It is also known as the main board or system board.
    • It is the circuit board in which all the components are connected through cable within a personal computer.
    • Many devices are connected to the motherboard directly or indirectly.
    • Motherboards usually provide the interface between the CPU memory and input/output peripheral circuits, main memory, and facilities for the initial setup of the computer immediately after power-on.
    • Some major parts of a motherboard are: –
      (a) ATX Power Connector: –
      • ATX stands for Advanced Technology Extended (ATX) power connector is used to connect a computer’s power supply to a motherboard.

  (b) AGP Slot : –

• • • • Accelerated Graphics Ports (AGP) is a point-to-point channel that is used to attach a video card to a motherboard.

(c) CD-in Header : –

• • • • At this, the CD drive is plugged in connected, or attached.

(d) FDD Header : –

• • • • The floppy Disk Drive (FDD) header is used for the Floppy drive. Now this slot is obsolete because floppy disks are outdated.

(e) HDD Headers : –

• • • • Hard Disk Drive header is used for connecting to the hard disk.

(f) PCI Slots : –

• • • • It is used for connecting the PCI (Peripheral component interconnect) card.

(g) USB Headers : –

• • • • It is a group of pins to which an internal USB cable can be attached to provide extra USB ports.
      • These ports are used for attaching external/auxiliary devices such as pen drives, printers, etc.

• • SMPS (Switch Mode Power Supply) :
    • A power supply or power supply unit (PSU) is an internal component used to supply power to the components of a computer.
    • A power supply is rated by the number of watts it generates.
    • CPU cabinet also houses a power supply unit which provides power to all the components of the computer system.
  • Ports and Connectors.
    • On the back end of the CPU cabinet, we have seen several connection slots, technically called Ports and Connectors.
    • These slots are used to connect various input/output devices such as a keyboard, mouse, printer, or scanner, to the computer.
    • They act as an interface between the peripheral devices and CPU directly or indirectly to communicate with each other.
  • Operational Unit : 
    • It is the functional unit of a computer.
    • To complete operations successfully, the computer allocates the task among its various functional/operational units. These are 1) arithmetic logical unit 2) control unit    

Von Neumann Architecture :

• Mathematician John Von Neumann conceived a computer architecture that forms the core of nearly every computer system in use today. This architecture is known as Von Neumann architecture.
• It is a design model for modern computers that has a central processing unit (CPU) and the concept of memory used for storing both data and instructions.
• This model implements the stored program concept in which the data and the instructions both are stored in the memory. All computers share the same basic architecture which has memory, an I/O system, an arithmetic logic unit (ALU), and a control unit (CU).