Operating Systems and File Management
What the exam tests
Questions cover the functions and types of an operating system, process and memory management in outline, and - most heavily - file naming, folder structure, path notation and everyday commands.
Core concepts
- OS functions: process management, memory management, file management, device management, security and the user interface.
- Types: single-user (MS-DOS), multi-user (a Linux server), real-time (an RTOS in embedded control), distributed and mobile.
- File names have a base name and an extension. The extension only suggests a type, and Windows hides known extensions by default, so report.txt.exe is an executable, not a text file.
- Paths: Windows uses a drive letter and backslashes, C:\Users\Anu\Docs\notes.txt. Linux uses a single root and forward slashes, /home/anu/docs/notes.txt.
- Wildcards: * matches any number of characters, ? matches exactly one. mv renames or moves; cp copies and leaves the original.
Worked example
In Linux you are in /home/anu/docs and run cd ../projects. The symbol .. means the parent directory, so the shell first moves up to /home/anu, then down into projects, ending at /home/anu/projects. Because ../projects is relative, the result depends on where you started; /home/anu/projects is absolute and lands in the same place from any directory. That difference is what the question is testing.
Traps
- Deleting a folder deletes everything inside it; there is no option to keep the files.
- Files deleted from a command prompt or a network drive may bypass the Recycle Bin entirely.
- A hidden extension can disguise an executable as a document.
- Formatting a drive erases the file table, not just the files, so recovery becomes far harder.