Operating Systems

Modern Computer Structure

An overview of the MOdern Computer Structure

Hardware → This is the part of the computer which provides basic computing resources. Like the CPU, memory, I/O devices/modules etc
Operating Systems → This exploits the hardware resources for use among applications and users. These contain of High Level and Low Level Procedures.

  • High Level → These procedures provide application programmers a clean and highly abstract set of resources

  • Low Level → These procedures manage hardware.

Applications in OS allocate system resources to solve the computing problems of the users, which are people, machines and/or other computers. examples of applications are compilers, text editors and games etc.


Basic Elements of Computer Hardware

CPU → Executes and controls program instructions
Memory → Stores data and/or programs. The heirerchy of memory is like this(Fastest to slowest):

  • Registers

  • Cache

  • Random Access Memory (RAM)

  • Persistent Memory (disk)

I/O module → Moves data between the computer and its external environment
System Bus → Enables communication among processors, main memory and I/O modules
Processors → Important CPU registers:

  • Program Counter(PC) has the address of the next instruction

  • Instruction Register (IR) holds the current executing instruction

  • Memory Address Register (MAR) points to the data addresses

  • Memory Buffer Register (MBR) stores data that is being transferred