a) Flynn’s Taxonomy
Flynn’s Taxonomy is a classification system for computer architectures proposed by Michael J. Flynn in 1966. The taxonomy is based on the number of instruction streams and data streams that can be processed by a computer architecture.
The four categories in Flynn’s taxonomy are:
- SISD (Single Instruction, Single Data): This is a traditional computer architecture that processes one instruction and one data item at a time. Examples of SISD systems include most personal computers.
- SIMD (Single Instruction, Multiple Data): This architecture processes multiple data items in parallel using a single instruction stream. Examples of SIMD systems include graphics processing units (GPUs) and digital signal processors (DSPs).
- MISD (Multiple Instruction, Single Data): This architecture processes a single data item with multiple instructions simultaneously. MISD architectures are rare and not widely used.
- MIMD (Multiple Instruction, Multiple Data): This architecture processes multiple data items and multiple instruction streams simultaneously. Examples of MIMD systems include multi-core processors and distributed computing systems.
b) Replacement algorithm
Replacement algorith is a technique used in computer memory management to determine which data to remove from memory when the memory is full and needs to make space for new data. The basic idea is to identify the data that is least likely to be used again in the near future and replace it with new data.
The most common replacement algorithms are:
- Least Recently Used (LRU): This algorithm removes the data that has not been accessed for the longest time.
- First-In-First-Out (FIFO): This algorithm removes the data that has been in memory for the longest time.
- Least-Frequently-Used (LFU): This algorithm removes the data that has been accessed the least number of times.
- Random: This algorithm randomly selects data to remove from memory.