Parallel computer models

Parallerl Computer Model - Multiprocessor and Multicoputer

Multiprocessor and multicomputer are distinguished by a shared common memory and unshared distributed memories.

Shared Memory multiprocessor- Three most common shared memory multiprocessors models are –
1. Uniform Memory Access (UMA)
2. Non-uniform Memory Access (NUMA)
3. Cache Only Memory Architecture (COMA)
1. Uniform Memory Access (UMA)
  • In this model, all the processors share the physical memory uniformly.
  • All the processors have equal access time to all the memory words.
  • Each processor may have a private cache memory.
  • Same rule is followed for peripheral devices.

When all the processors have equal access to all the peripheral devices, the system is called a symmetric multiprocessor.

When only one or a few processors can access the peripheral devices, the system is called an asymmetric multiprocessor.

2. Non-uniform Memory Access (NUMA)
In NUMA multiprocessor model, the access time varies with the location of the memory word.
Here, the shared memory is physically distributed among all the processors, called local memories.
The collection of all local memories forms a global address space which can be accessed by all the processors.

3. Cache Only Memory Architecture (COMA)
The COMA model is a special case of the NUMA model.
Here, all the distributed main memories are converted to cache memories.

Distributed - Memory Multicomputer:
A distributed memory multicomputer system consists of multiple computers, known as nodes, inter-connected by message passing network.

Each node acts as an autonomous computer having a processor, a local memory and sometimes I/O devices.

In this case, all local memories are private and are accessible only to the local processors.

This is why, the traditional machines are called no-remote-memory-access (NORMA) machines.

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