Italy Secondaria di secondo grado – classe 2ª Computer science

1. Computer basics and programming

Computer architecture · Operating systems · Electronic documents · Internet · Algorithms and programming

• Computers and Computing: Evolution, Parts and I/O Devices – A computer is an electronic machine that takes input, processes it under the control of a program, stores data and gives output. Computing devices grew from the abacus to smartphones. Every computer has an input unit, a CPU, memory and an output unit, joined by buses and ports.
• Operating System – An operating system (OS) is the main system software that sits between the user and the hardware and manages all resources. Its functions: process management (sharing the CPU between programs), memory management (giving and taking back RAM), file management, device management (through drivers) and security (passwords, permissions). Users talk to the OS through a user interface: command line (CLI), graphical (GUI), touch, voice or gesture. Examples: Windows, Linux, macOS, Android, iOS.
• Office Software: Working with Electronic Documents – An office suite is a set of programs for electronic documents: a word processor for text documents, a spreadsheet for numbers and calculations, and a presentation program for slides. A document is built from elements (headings, paragraphs, lists, tables, images, headers and footers) and formatted with fonts, alignment, spacing and styles. A spreadsheet is a grid of cells named by column letter and row number (B3). Cells hold text, numbers, dates or formulas that start with =. Functions such as SUM, AVERAGE, MAX, MIN, COUNT and IF calculate over ranges (B1:B3), and results update automatically. Relative references change when copied; absolute ones ($B$1) stay fixed. Charts turn data into pictures. Presentations use one idea per slide. Save in editable formats (.docx, .odt, .xlsx, .ods, .pptx) or export to PDF.
• Internet Basics: How the Internet Works – The Internet is a huge network of networks. Devices join a router, routers join an ISP, and ISPs join the backbone cables. Data travels in small packets, each with an IP address. DNS turns names like example.org into IP numbers. Services such as the web, email, video calls and cloud storage run on top of it. To use it well: search with good keywords, check sources, protect your privacy, respect copyright, and save work in the right file format.
• Introduction to Problem Solving – Problem solving on a computer has stages: analyse the problem (inputs, outputs, rules), develop an algorithm (a finite, clear, ordered set of steps), code it in a programming language, test it with different inputs, and debug (find and remove errors). An algorithm can be shown as a flowchart (oval = start/stop, parallelogram = input/output, rectangle = process, diamond = decision, arrows = flow) or as pseudocode (structured plain English). Decomposition breaks a big problem into smaller sub-problems that are solved separately and then joined.