Introduction

Operating Systems is essential software running in the background of a computer system. It manages the basic functions, such as Input and Output control, Security and Multi programming. Examples of Common Operating Systems can be Windows, Mac OS and Android for phones. When a computer is first tuned on, the initiated programs are loaded into memory from the ROM(READ ONLY MEMORY) which contain Bios (Basic Input Output System). These programs run a security check and if no errors are detected, the O.S will load up and run.

Interrupts and Buffers

Buffer: A buffer is a temporary storage area, which most of the time located in the RAM. A buffer acts as a holding area for data. The CPU can manipulate the data in the buffer before sending it to another device. Once the job is done the information in the RAM is deleted.  For example, printers and computers have a buffer. Buffer insure that the video never stops and waiting for the data from the internet.

Interrupts: A interrupt is a signal sent from a device or software to the processor. This will cause the processor to temporarily stop what it is doing and service the interrupt. An interrupt handler takes into account all of these signals and prioritizes them in a queue in order to figure out which one to deal with first

Jon Von Neumann diagram:

Keywords:

  • CU – Control Unit
  • ALU – Arithmetic Logic Unit
  • MU – Memory unit
  • PC – Program Counter
  • MAR – Memory Address Register
  • MDR – Memory Data Register
  • CIR – Current Instruction Register

 

von-neuyman-diagram

 

The Von Neumann model is basically the functions of a computer, before this model computer couldn’t store information or data, unless you would physically have to do it. Computers contains three main components: ALU, CU and MU. CU contains PC and CIR while MU contains MDR and MAR, the memory storage.

Steps of how this works:

  1. CU fetches/gets instructions
  2. Address is copied from the PC to the MAR
  3. Instructions copied from the MAR to the MDR
  4. Contents of the MDR is copied into the CIR,PC discretely increased by 1
  5. Next instruction is fetched (fetched execute cycle)
  6. Instructions are decoded and then executed using the control bus

My prezi link of this chapter:

https://prezi.com/ci7d4rerfgtg/copy-of-operating-system-and-computer-architecture/