Choose an exam and explore concepts through visual explanations, topic maps and revision checks. Open the full chapter notes whenever you need more detail.
THE VISUAL LEARNING STUDIO
See the idea. Understand the connection.
35 visual explanations across 29 chapters, with topic maps throughout the library.
The chapter index will grow as additional notes are prepared. Chapters shown here are a learning collection, not a claim that the entire exam syllabus is complete.
SEE IT. CONNECT IT. EXPLAIN IT.
Understand the chapter visually
Start with the topic map, then open each explanation below. Detailed concept diagrams are being added to this chapter.
Use Recall mode to hide explanations; tap or focus a card to reveal one. Expand any diagram for a larger view.
Study the expanded notes and the credited detailed textbook lessons. The current chapter index covers core topics; it is not a claim of exhaustive coverage of every examination syllabus. Check the official syllabus and primary references.
Operating Systems — lesson overview
Core role
An operating system manages hardware resources and provides services through which application programs operate.
Processes, memory, storage and input/output need coordination so that programs can share a machine effectively.
The operating system is not identical to every installed application, and a graphical desktop is only one interface to system functions.
Files and processes
A file is an organised unit of stored data under a filesystem; a process is a running instance of program execution in the relevant model.
A directory organises filesystem entries. A filename extension can suggest a format but does not guarantee the actual contents are safe or correctly typed.
Permissions limit access to actions such as reading, writing or execution according to the system’s security model.
Memory and multitasking
Multitasking involves managing multiple execution activities; it does not necessarily mean every task is simultaneously running on a separate physical processor.
Virtual memory provides an abstraction of memory with implementation mechanisms that may involve secondary storage; it is not unlimited fast RAM.
Updating software can address defects and security weaknesses, but backups and compatibility considerations remain separate responsibilities.
