Software Application Software Interrupts Programming language, translators and IDEs

Software, Application Software, and Interrupts

• Unit 3 discussed hardware; this unit covers how hardware and software work together.
• Two types of software:
  • System software: fulfills computer needs (OS, utility programs).
  • Application software: provides user-specific features.
• Application software requires hardware, firmware, and an operating system.
  • Operating system supports applications.
  • Firmware enables operating system functionality.
  • Hardware hosts the boot loader (firmware or BIOS).

Interrupts

• Interrupts are signals sent to the processor for specific events, originating from software or hardware.
• Software Interrupts:
  • Division by 0.
  • Two processes accessing the same memory.
  • Program request for input.
• Hardware Interrupts:
  • Data input (keyboard press, mouse click).
  • Printer out of paper.
  • Hardware failure.
  • Output required.
  • Hard drive signal (data read).
  • Data required from memory.
  • New hardware connected.
• Interrupt Priority:
  • High-priority: Urgent matters (hardware failure).
  • Low-priority: Less urgent needs (data input).
• Interrupt Handling Process:
  1. Processor checks the interrupt queue before/after Fetch-Decode-Execute (FDE) cycle.
  2. If a higher priority interrupt is found:
     • Saves the current process state.
     • Retrieves the interrupt.
     • Identifies the source.
     • Executes the Interrupt Service Routine (ISR).

Programming Languages

• High-Level Language (HLL):
  • Uses English-like commands.
  • Advantages:
    • Easier to understand, write, and amend.
    • Easier and quicker to debug code.
    • Portable, machine independent.
    • One statement represents many low-level instructions.
    • Quicker to write programs.
    • Easier to maintain programs.
  • Disadvantages:
    • Programs take longer to execute.
    • Cannot directly manipulate hardware.
    • Programs can be larger.
• Low-Level Language:
  • Aligned with machine code (assembly or binary).
• Assembly Language:
  • Uses mnemonics; requires an assembler to convert to machine code.
  • Advantages:
    • Direct hardware manipulation.
    • Code written rapidly.
    • Code occupies minimal primary memory space.
  • Disadvantages:
    • Challenging to understand, read, write, and modify.
    • Debugging is more difficult.
    • Not portable; machine-dependent.
    • Multiple instructions per high-level statement.
    • Writing programs takes more time.

Translators: Compilers and Interpreters

• Translators convert High-Level Language (HLL) into machine code.
• Compiler:
  • Converts the entire code into an executable file in one go.
  • Generates an error report detailing all issues.
  • Advantages:
    • Compiled program can be stored for reuse.
    • Can be executed without the compiler.
    • Takes up less memory when executed.
    • Executed faster.
  • Disadvantages:
    • Takes longer to write, test, and debug.
    • Must be recompiled if the program is changed.
    • Designed for a specific processor.
    • Takes time to compile if there is not enough memory space.
• Interpreter:
  • Translates and runs the code one line at a time.
  • Halts execution upon encountering an error.
  • Advantages:
    • Easier and quicker debugging and testing.
    • Simplified program editing.
  • Disadvantages:
    • Cannot be executed without the interpreter.
    • Programs may take longer to execute.

Compiler vs. Interpreter

• Process:
  • Compiler: Translates entire code in a single operation.
  • Interpreter: Translates code sequentially, line by line.
• Error Handling:
  • Compiler: Generates an error report after translation.
  • Interpreter: Stops translation on error.
• Executable File:
  • Compiler: Produces an executable file.
  • Interpreter: No executable file; direct execution.
• Error Handling during Execution:
  • Compiler: Will not execute any code if errors are found.
  • Interpreter: Executes code until it encounters an error.
• Retranslation:
  • Compiler: Requires retranslation after error correction.
  • Interpreter: Allows real-time error correction.
• Dependency on Compiler/Interpreter:
  • Compiler: Compiled programs run independently.
  • Interpreter: Interpreted programs require the interpreter.
• Efficiency and Performance:
  • Compiler: No need for recompilation to perform the same task repeatedly.
  • Interpreter: Must be interpreted each time, impacting performance.
• Suitability:
  • Compiler: Suitable for sharing or selling finished work.
  • Interpreter: Primarily used during code development and testing.

Integrated Development Environment (IDE)

• Software application aiding programmers in writing and testing code.
• Simplifies error identification and fixing.
• Popular IDEs: Visual Studio, Eclipse, and PyCharm.
• Features:
  1. Editor for writing and modifying code.
  2. Translator to convert code into machine instructions.
  3. Run-time environment to execute code and observe behavior.
  4. Error diagnostics to identify and rectify programming errors.
  5. Auto-completion features for suggesting and completing code snippets.
  6. Auto-correction capabilities to fix syntax and logical errors.
  7. Pretty printing functionality to format code for improved readability.