Introduction to Computers and Programming
Introduction to Computers and Programming
- Computers are programmable devices designed to follow instructions.
- A program is a set of instructions that the computer follows to complete a task, also known as software.
- A programmer is someone who designs, creates, and tests programs, commonly referred to as a software developer.
Hardware and Software
- Hardware: Physical components of a computer system.
- Major components include:
- Central Processing Unit (CPU): Executes programs and is crucial for running software.
- Main Memory (RAM): Temporary storage that holds programs and data while the computer is on (volatile).
- Secondary Storage: Long-term data storage, including disk drives and solid-state drives (SSD).
- Input Devices: Components that collect data (e.g., keyboard, mouse).
- Output Devices: Components that present data (e.g., monitor, printer).
The CPU
- The CPU is the core of the computer that executes programs.
- Historically large but now found on microprocessors, which are compact and efficient.
Main Memory
- RAM allows the CPU to quickly access data while programs are running.
- Data in RAM is lost when the computer is powered off.
Secondary Storage Devices
- Secondary storage retains data for extended periods.
- Disk Drive: Uses magnetic encoding on spinning disks.
- Solid State Drive (SSD): Faster, with no moving parts, using solid state memory.
- Flash Memory: Portable and also uses solid state technology.
- Input: Data collected by the computer, which can be from humans or other devices.
- Output: The data processed by the computer for display or distribution, which can be text, images, or sounds.
Software Overview
- Software controls all computer operations:
- Application Software: Programs for everyday tasks (e.g., word processing, web browsing).
- System Software: Manages hardware operations, including operating systems and utilities.
- Data is represented as sequences of 0s and 1s (binary system).
- A byte can store one character and consists of 8 bits.
- Each bit can be a 0 or a 1; thus, a byte can represent values from 0 to 255.
Storing Different Types of Data
- Numbers: Binary representation allows encoding numbers, with larger values requiring more bytes.
- Characters: Stored as binary using encoding schemes like ASCII (limited to 128 characters) and Unicode (which supports many languages).
- Negative and Real Numbers: Negative numbers are stored using two’s complement; real numbers use floating-point notation.
- Digital Data: Images and music are stored as binary values representing pixels and audio samples, respectively.
How a Program Works
- The CPU performs operations using machine language.
- A program must be loaded into RAM, and the CPU processes it through the fetch-decode-execute cycle:
- Fetch: Reads the next instruction into the CPU.
- Decode: Interprets the instruction to determine the operation.
- Execute: Carries out the operation.
Programming Languages
- Assembly Language: Easier alternative to machine language that uses mnemonic codes.
- High-Level Languages: Simplifies programming without needing detailed CPU knowledge.
Compilers and Interpreters
- Programs in high-level languages require translation to machine code:
- Compiler: Translates the entire program at once, creating an executable file.
- Interpreter: Translates and executes one instruction at a time, used by languages like Python.
Using Python
- Python requires installation, including its interpreter.
- Modes of execution in Python:
- Interactive Mode: Direct input and immediate output.
- Script Mode: Save commands in a file with a .py extension and run them from the command line.
IDLE Programming Environment
- IDLE: Provides tools to write and execute Python programs, featuring a text editor for coding.
Summary of Chapter
- This chapter discussed:
- Main hardware components of a computer.
- Types of software and how data is stored.
- Basic CPU operations and the fetch-decode-execute cycle.
- The necessity of compiling or interpreting code and using Python effectively.