Input Output Programming

Duration: 6 min

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Inside: a video lesson and guided study material.

Module outline

  1. HPSC Interview Preparation: Interview Preparation
  2. Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis, DSA using Python
  3. Data Structure & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Sorting Algorithms, Minimum Spanning Trees, Time Complexity Analysis, Graph Theory, Shortest Path Algos
  4. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security
  5. Computer System & Organisation: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer
  6. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, SQL, File Organization & Indexing, Transaction Management, Concurrency Control
  7. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling
  8. Digital Logic & Circuits: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  9. Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Pushdown Automata & CFG, Turing Machines, Moore & Mealy Machines
  10. Compiler Design: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  11. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Data Warehousing & Mining
  12. Introduction to Emerging Trends: Emerging Tech Trends
  13. Digital Society & Cyber Law: Society, Law & Ethics
  14. HPSC PGT Previous Year Paper:
  15. HPSC Assistant Professor Previous Year Paper:
  16. Live Sessions: HPSC Live Sessions, EMRS TGT/PGT Live Class
  17. Full Mock Test:
  18. HPSC PGT - MOCK Test Series:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a detailed walkthrough of input-output programming for a basic computer, using assembly-like code examples. The lecture begins by defining the purpose of I/O programs: to write symbols to memory and print them from memory. It then presents two main code segments: (a) Input a character, which uses a loop to check an input flag (CIF) and, when set, reads a character via INP and stores it in a memory location (CHR); and (b) Output one character, which loads a character from memory (CHR) into the accumulator (AC) and prints it via OUT. The video also displays a table of the computer's instruction set, explaining key instructions like SKI (check input flag), BUN (branch unconditionally), INP (input character), OUT (output character), and STA (store accumulator). The instructor uses on-screen annotations to highlight key lines of code and explain the logic of the programs, such as the flag-based polling mechanism for I/O operations.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a slide titled 'Input Output Programming'. The instructor explains that I/O programs are needed for writing symbols to memory and printing them. The slide displays two code segments: (a) 'Input a character' and (b) 'Output one character'. The first segment shows a loop using SKI to check the input flag (CIF). If the flag is 0, it branches back to check again. If the flag is 1, it executes INP to input a character, OUT to print it, and STA CHR to store it. The second segment shows LDA CHR to load a character into the accumulator (AC), followed by a loop using COF to check the output flag. If the flag is 0, it branches to check again. If the flag is 1, it executes OUT to print the character and HLT to halt. The code concludes with a memory location CHR storing the character 'W' (HEX 0057).

  2. 2:00 – 5:00 02:00-05:00

    The instructor continues to explain the code, focusing on the input program. He points out that the SKI instruction checks the input flag (CIF). If the flag is 0, the BUN CIF instruction branches back to the beginning of the loop to check again. When the flag becomes 1, indicating input is ready, the program proceeds to INP to read the character, OUT to print it, and STA CHR to store it in memory. He then moves to the output program, explaining that LDA CHR loads the character 'W' from memory into the accumulator (AC). The COF instruction checks the output flag (COF). If the flag is 0, the BUN COF instruction branches back to check again. When the flag becomes 1, the OUT instruction prints the character, and HLT halts the program. The instructor emphasizes that the flag is used to poll the I/O device's status, ensuring the program only proceeds when the device is ready.

  3. 5:00 – 5:34 05:00-05:34

    The video transitions to a slide titled 'Instruction Set of the Basic Computer'. This slide presents a table with columns for Symbol, Hex code, and Description. The instructor explains that this table defines the basic instructions of the computer. He points to specific instructions like SKI (F100), which skips the next instruction if the input flag is on, and COF (F000), which skips the next instruction if the output flag is off. He also explains that INP (F400) inputs information and clears the flag, while OUT (F800) outputs information and clears the flag. The table also includes other instructions like LDA (2 or 8), STA (3 or 9), and BUN (4 or C).

The video provides a comprehensive overview of fundamental input-output programming concepts for a basic computer architecture. It demonstrates how to implement character input and output using a polling mechanism, where the program repeatedly checks a status flag (CIF or COF) to determine if an I/O device is ready. The core of the lesson is the use of conditional branch instructions (BUN) to create a loop that waits for the flag to change state. The instructor effectively uses the provided code examples and the instruction set table to explain the function of each instruction, such as SKI, COF, INP, and OUT, and how they interact to perform I/O operations. The key takeaway is the concept of status flags as a means of synchronization between the CPU and I/O devices, a foundational principle in computer architecture.

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