Flynn’s Classification


Flyns classification depends on Data stream and Instruction stream.

Data stream- A data stream is the operations performed by the processor on data. A data stream is sequence of data having input, partial or temporary result.

Instruction stream- A instruction stream is the fetch and execution of data stream by the machine.

Based on the multiple data and instruction streams Flynns classify the digital computers in four categories-

1. Single instruction stream-single data stream (SISD)
2. Single instruction stream-multiple data stream (SIMD)
3. Multiple instruction stream-single data stream (MISD)
4. Multiple instruction stream-multiple data stream (MIMD)

1. SISD: A classical Von Neumann  computers comes under this categories.  
  • It has one instruction stream one data stream.
  • It does one thing at a time.
  • It has capability of manipulating one data stream at a time by executing a single instruction stream.
  • Most serial computers are based on SISD.
  • Instructions may get overlapped during their execution
  • Most SISD computers are pipelined.
  • SISD may have more than one functional units, which are supervised by control unit.
For example- IBM 370 computers.
2. SIMD: SIMD computers have single instruction stream to execute on multiple data stream.
  • It has a single control unit to generate one instruction stream at a time.
  • A single control unit have multiple ALUs (Arithmetic and logic units) to work on multiple data streams simultaneously.
  • It has capability to execute a single instruction stream on multiple data streams.
  • Its also known as vector or array processors machine.
  • In SIMD multiple processing units are supervised by a single control unit.
For example- ILLIAC-IV
3. MISD: MISD computers have multiple instruction stream to execute on single data stream.
  • This type of system is not to build practically, it’s a theoretical approach.
  • It has multiple instruction stream, which operate on sama data stream.
  • The output of one processor become the input of next processor.
4. MIMD- MISD computers have multiple instruction stream to execute on multiple data stream.
  • It has capability of performing several programs simultaneously.
  • It is similar to multiprocessor, in which multiple CPUs are operating independently to be a part of large system.
  • Both multiprocessor and multi computer comes under MIMD.
  • When multiple SISD works together than its called MSISD, which comes under category of MIMD.
  • If number of instructions are high than it’s known as tightly coupled else known as loosely coupled.
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.