Hardware software concepts distributed system


Hardware concepts :-

Hardware in Distributed Systems can be organized in several different ways:

  • Shared Memory (Multiprocessors , which have a single address space).
  • Private Memory (Multicomputers, each CPU has a direct connection to its local memory).

Multiprocessors – Bus Based

  • Have limited scalability
  • Cache Memory help avoid bus overloading.

Multiprocessors – Switch Based

  • Different CPUs can access different memories simultaneously
  • The number of switches limits the number of CPUs that can access memory simultaneously

          a) A crossbar switch
          b) An omega switching network

Multicomputers :-


  • All CPUs and memory are identical;
  • Connected through a broadcast shared multi access network (like Ethernet) in bus based systems;
  • Messages routed through an interconnectionn network in switch-based multicomputers (e.g., grids, hipercubes…).


  • The most usual topology;
  • Computers may vary widely with respect to processor type, memory size, I/O bandwidth;
  • Connections are also diverse (a single multicomputer can simultaneously use LANs, Wide Area ATM, and frame relay networks);
  • Sophisticated software is needed to build applications due to the inherent heterogeneity;
  • Examples: SETI@home, WWW…

Software Concepts :-

Uniprocessor Operating Systems

  • An OS acts as a resource manager or an arbitrator : Manages CPU, I/O devices, memory
  • OS provides a virtual interface that is easier to use than hardware
  • Structure of uniprocessor operating systems: Monolithic (e.g., MS-DOS, early UNIX)
  • One large kernel that handles everything: Layered design
  • Functionality is decomposed into N layers
  • Each layer uses services of layer N-1 and implements new service(s) for layer N+1
More topics from Distributed System to read:


EasyExamNotes.com covered following topics in these notes.
Python Programming ↓ 👆
Java Programming ↓ 👆
JAVA EasyExamNotes.com covered following topics in these notes.
JAVA Programs
Principles of Programming Languages ↓ 👆
Principles of Programming Languages
EasyExamNotes.com covered following topics in these notes.

Previous years solved papers:
A list of Video lectures References:
  1. Sebesta,”Concept of programming Language”, Pearson Edu 
  2. Louden, “Programming Languages: Principles & Practices” , Cengage Learning 
  3. Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill. 
  4. E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley

    Computer Organization and Architecture ↓ 👆

    Computer Organization and Architecture 

    EasyExamNotes.com covered following topics in these notes.

    1. Structure of desktop computers
    2. Logic gates
    3. Register organization
    4. Bus structure
    5. Addressing modes
    6. Register transfer language
    7. Direct mapping numericals
    8. Register in Assembly Language Programming
    9. Arrays in Assembly Language Programming


    1. William stalling ,“Computer Architecture and Organization” PHI
    2. Morris Mano , “Computer System Organization ”PHI

    Computer Network ↓ 👆
    Computer Network

    EasyExamNotes.com covered following topics in these notes.
    1. Data Link Layer
    2. Framing
    3. Byte count framing method
    4. Flag bytes with byte stuffing framing method
    5. Flag bits with bit stuffing framing method
    6. Physical layer coding violations framing method
    7. Error control in data link layer
    8. Stop and Wait scheme
    9. Sliding Window Protocol
    10. One bit sliding window protocol
    11. A protocol Using Go-Back-N
    12. Selective repeat protocol
    13. Application layer
    1. Andrew S. Tanenbaum, David J. Wetherall, “Computer Networks” Pearson Education.
    2. Douglas E Comer, “Internetworking with TCP/IP Principles, Protocols, And Architecture",Pearson Education
    3. KavehPahlavan, Prashant Krishnamurthy, “Networking Fundamentals”, Wiley Publication.
    4. Ying-Dar Lin, Ren-Hung Hwang, Fred Baker, “Computer Networks: An Open Source Approach”, McGraw Hill.