Skip to main content

2nd Chapter

Definition of SISD:

SISD (Single Instruction stream Single Data stream) is a type of computer architecture where one processor carries out one instruction at a time on a single piece of data. It follows a step-by-step processing method and is part of the Von Neumann model.

Key Points about SISD:

  • Single Processor: Only one processor is used to perform tasks.

  • Single Instruction Stream: Instructions are handled one after another, not in parallel.

  • Single Data Stream: Only one set of data is processed at any given time.

  • Sequential Execution: All operations happen one by one, in a straight line.

  • No Parallel Processing: It cannot handle multiple tasks at the same time.

  • Used in Basic Systems: This model is used in older or simpler computers.

Example of SISD:

An example of an SISD system is the Intel 8085 microprocessor. It processes one instruction and one data set at a time, making it suitable for small, simple computing tasks.





 Simple Definition:

SIMD means doing the same operation on many pieces of data at the same time.

🔹 Real-Life Example:

Let’s say you’re editing a photo and want to increase the brightness of every pixel.

  • Without SIMD: It changes one pixel at a time (slow).

  • With SIMD: It changes many pixels at once (fast).

🔹 Why is SIMD useful?

  • 🔄 It handles repeated, similar tasks very efficiently.

  • 🚀 It’s much faster than doing things one by one.

  • 🎮 It’s used in video games, image editing, audio processing, and even scientific tasks.







MISD (Multiple Instruction Stream, Single Data Stream)

  • What it means: Multiple processors (Processing Units or PUs) are working on the same data, and process is done by giving them multiple instructions.

Why it's used:

  • It's mainly used in systems where real-time fault detection is needed.

  • Example:In Aerospace or nuclear systems, it check for errors by comparing results of different operations on the same data.









MIMD (Multiple Instruction stream, Multiple Data stream)

What it means:

  • MIMD is a computer system where many processors work at the same time.

  • Each processor can run its own program (instructions) on its own data.

Key Points:

  • 💡 Multitasking: It's great when you need to do many things at once.

  • 🔧 Flexible: Each processor can do different work, not just repeat the same task.

  • 🧠 Complicated Design: It’s harder to build and manage because everything runs differently.

Example:

Imagine using your phone while on a video call, downloading a file, syncing emails, and playing music—all at once. In a MIMD system, each task is handled by a different processor running its own instructions on different data. This allows the phone to multitask smoothly and efficiently.








Comments

Post a Comment

Popular posts from this blog

Chap#10

Network topologies Definition: Network topologies define how nodes (processors/computers) are interconnected in parallel and distributed systems. The choice of topology affects performance, scalability, and cost. Key Metrics: Degree: Number of links per node. (Formula: deg = connections per node) Example: In a linear array, each node (except ends) has 2 links. Diameter: Longest shortest path between any two nodes. (Formula: diam = max distance) Example: Linear array with 8 nodes has diameter 7 (P₀ to P₇). Bisection Width: Minimum links to cut to split the network into two halves. (Formula: bw = min cuts) Example: Binary tree has bw=1 (cutting the root disconnects it).4 1. Linear Array Define : Nodes are connected one after another in a straight line. Each node (except the ends) connects to two neighbors one on the left and one on the right. Explanation : Simple to build and easy to understand, but not efficient for large networks. Long distance between farthest nodes makes comm...
Post a Comment
Read more
Asymmetric-key algorithms are algorithms used in cryptography that use two different keys  a public key for encryption and a private key for decryption. These keys are mathematically related, but the private key cannot be easily derived from the public key. Types: RSA (Rivest–Shamir–Adleman): It uses large prime numbers to generate the key pair and supports both encryption and digital signatures DSA (Digital Signature Algorithm): DSA is primarily used for creating digital signatures, ensuring the authenticity. Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext  Types: Stream Cipher:  Stream Cipher Converts the plain text into cipher text by taking 1 byte of plain text at a time. Block cipher: Converts the plain text into cipher text by taking plain text's block at a time DES? DES stands for Data Encryption Standard . It is a symmetric-key algorithm used to enc...
Post a Comment
Read more

Ai Mental Health & Cyber Safety Presentation

Module A - The Normalization Engine Linguistic Challenge: Roman Urdu lacks standardized orthography (e.g., "kesa" vs "kaisa"), creating orthographic "noise" that significantly degrades the accuracy of downstream AI models. Technical Role: Acts as a Sequence-to-Sequence (Seq2Seq) transliteration and lexical normalization layer to standardize inputs before analysis. Model: A specialized transformer architecture, specifically m2m100 fine-tuned on parallel corpora or UrduParaphraseBERT. Primary Dataset: Roman-Urdu-Parl (RUP). A large-scale parallel corpus of 6.37 million sentence pairs designed to support machine transliteration and word embedding training. Link: https://arxiv.org/abs/2503.21530 Outcome: Reduces orthographic noise by achieving up to 97.44% Char-BLEU accuracy for Roman-Urdu to Urdu conversion, ensuring Module B receives high-quality "clean" data for risk analysis. Module B - Risk Stratification (BERT) Heading: The "Safety ...
Post a Comment
Read more