Chapter 1 - Intro to Computers and Programming

computers

machines that can be programmed to perform specific tasks, from simple calculations to complex simulations

program

a detailed set of instructions (commands) that tell the computer ho to execute a particular task, such as calculating numbers or displaying images

programmer

• designs, creates and tests programs

• transforms ideas into functional software by writing code that the computer can execute

hardware

all the physical components of a computer system

• Central Processing Unit (CPU)

• main memory (RAM)

• secondary memory (storage)

• input devices

• output devices

Central Processing Unit (CPU)

a silicon chip that acts like the brain of the computer

• responsible for executing instructions and performing calculations

• controls and coordinates the activities of all other hardware

main memory (RAM)

temporary storage that holds data and instructions currently in use; provides fast access for the CPU to perform tasks efficiently

memory cell

an individual storage location in memory

address of a memory cell

the relative position of a memory cell in the computer’s main memory

contents of a memory cell

the information stored in a memory cell, either a program or an instruction

secondary memory (storage)

permanent storage for data and programs, such as hard drives, SSDs and external storage devices; retains information even when the computer is powered off

input devices

the components that collect data from people and from other devices, then send it to the computer (e.g., keyboard, mouse, scanner)

output devices

the components that format and present data that the computer produces for people or for other devices (e.g., video diplays, printers)

primary memory…

• is also called main memory

• is temporary

• is directly accessible by the CPU

• varies in nature (RAM is volatile, ROM is non-volatile)

secondary memory

• is also called auxiliary memory

• is permanent

• is not directly accessible by the CPU

• is always non-volatile in nature

bytes

tiny storage locations that a computer’s memory is divided into

How much information does one byte store?

a letter of the alphabet or a small number

What is each byte divided into?

8 smaller storage locations known as bits (binary digits)

How must any piece of data in a computer’s memory be stored?

as a binary numner

What is the computing power of a system largely determined by?

the CPU’s speed and the complexity of the program it runs

• the faster a computer is, the more power and energy it requires

How is a faster CPU able to handle more demanding tasks efficiently?

it can process more instructions per second

multicore processor

a computer chip that contains multiple processing units (cores) on a single chip, which work together to perform tasks simultaneously, improving performance and allowing for more efficient multitasking

How is a program run?

it is copied from secondary storage to main memory, and then the CPU executes the program in main memory

What process occurs when a CPU executes the instructions in a program?

the fetch-decode-execute cycle

fetch

the next instruction is fetched, or read, from memory into the CPU

decode

the CPU decodes the instruction that was just fetched from memory, to determine which operation it should perform

execute

execute the operation

Where does the CPU take the memory address of the next instruction from?

the register, a high-speed memory location inside the CPU

operating system (OS)

a supervisory program, that oversees the operation of the computer and serves as an interface between human and machine

• ex: Microsoft Windows, Apple’s MacOS, Linux

How does the OS interact with a program?

it retrieves and starts the program for you

What happens when you boot a computer?

the OS is loaded form the disk into memory

high-level language

a machine-independent programming language that combines algebraic expressions and English symbols

assembly language

uses mnemonic codes that correspond to machine language instructions

machine language

uses binary number codes understood by a specific CPU

input data

the data values that are scanned by a program

program output

the lines displayed in a program

Integrated Development Environment (IDLE)

a software package combining a word processor, compiler, linker and tools for finding errors

interpreter

a program that executes code line by line

compiler

a program that translates the entire code into machine language before execution

True or false: compilers are slower than interpreters

false

Python

a high-level, interpreted language used for the web, data analysis, AI, game development, and more

When did Python become popular?

after 2018 due to the AI revolution

Who was Python created by?

Guido van Rossum

When was Python first released?

February 20th, 1991

How does a compiler work?

it translates the high-level language program to a machine language program, which then can be executed at any time, without using the compiler

How does an interpreter work?

it translates each high-level instruction to its equivalent machine language instructions, then immediately executes them

What is the interpreter useful for?

scripting, quick prototyping, or languages like Python that prioritize ease of use

What is the compiler ideal for?

performance-critical applications, system programming, and languages like C that focus on efficiency

What 2 modes can the Python interpreter be used in?

script and interactive

interactive mode

enter statements directly in a shell; used by opening IDLE

script mode

save statements in a file/Python script; used by opening a text file (.py)

cell system

a program that allows you to run Python code in sets