Computer Architecture: Components and Types

Posted on Mar 19, 2025 in Computers

The Architecture of a Computer

Computer architecture encompasses all component parts, their function, and the communication between those parts that allow them to work together in a coordinated manner.

Solution Background: Von Neumann Architecture

In the Von Neumann architecture, the program is stored in memory along with the data. The computer reads data from memory and interprets it as either a program instruction or data. Having a single bus makes the response speed slower, as the system cannot search for a new instruction until the completion of data transfers from the previous instruction.

Main Constraints of Von Neumann Architecture:

  • Limiting the length of instructions by the data bus, which forces the microprocessor to perform multiple memory accesses to find complex instructions.
  • The speed of operation is limited due to the single bus for both data and instructions. This prevents simultaneous access to both, and prevents overlapping access times.

Harvard Architecture

This model, used by PIC microcontrollers, features a Central Processing Unit (CPU) connected to two memories (one with instructions and another with data) through two different buses. Both buses are fully independent, allowing the CPU to access data memory and instruction memory independently and simultaneously. Because they are independent, they may have different contents in the same direction and different lengths.

Advantages of Harvard Architecture:

  1. The size of the instructions is not related to the data. Therefore, it can be optimized so that any instruction occupies a single program memory location, thus achieving higher speed and shorter program length.
  2. The access time to the instructions may overlap with the data, achieving greater speed in any operation.

Multiprocessor Architecture

The goal: To increase the processing capacity of computers.

The solution: Use multiple processors for tasks and processes. A computer in which more than one processor is used is called a multiprocessor architecture. Two modes of operation exist in multiprocessor systems:

  • Standalone Mode: Each microprocessor executes a different program. There is a simple interconnection between systems.
  • Parallel Mode: Several microprocessors help implement a program. The system shares its components.

Basic Computer Components

  • Motherboard: The main circuit board on which the computer is built. It houses the CPU and other systems directly connected to it.
  • CPU (Central Processing Unit): The main microprocessor that controls the operation of the system. The computer can have one or more CPUs.
  • RAM (Random Access Memory): Stores instructions and data used in a program. It is a volatile memory.
  • Hard Drive: All integrated devices on the computer that allow information to be saved.
  • Expansion Slots: Connections on the motherboard that allow for the connection and expansion of the system. They may also serve to connect different processors.
  • Inputs/Outputs: Connections accessible from the outside that allow many different devices to be connected.
  • Power Supplies: The device, or group of devices, dedicated to transforming the electrical grid current into the power needed for the various devices that make up the system.
  • Cooling System.
  • Removable Storage Drives.
  • Keyboard, Mouse, Monitor.
  • Communications and Peripherals: Modems, network cards, printers, etc.