Operating Systems and File Management
What the domain covers
Operating Systems and File Management tests how an OS manages hardware, processes, memory, and files, and how you navigate and protect stored data. Expect definitions of kernel, GUI, CLI, scheduling, virtual memory, file attributes, paths, and common file operations.
Core rules and concepts
- The kernel is the privileged core; it handles interrupts, scheduling, memory, and device drivers. User programs request services through system calls.
- A process is a program in execution. Typical states are new, ready, running, waiting, and terminated. The scheduler chooses among ready processes.
- Virtual memory lets programs use more address space than physical RAM. Pages are swapped to disk; excessive swapping causes thrashing.
- A file system organises files into directories/folders and stores metadata: name, size, type, timestamps, permissions, and location.
- An absolute path starts at the root (for example C:/Users/Asha/notes.txt); a relative path starts from the current directory.
- Permissions control read, write, and execute access. Backups protect against deletion, corruption, and ransomware.
Worked example
A 10 KB file is stored on a file system whose cluster (allocation unit) is 4 KB. The file needs ceil(10/4) = 3 clusters. Allocated space is 3 × 4 KB = 12 KB, so 2 KB is slack space. Reason: storage is allocated in whole clusters, not in exact byte counts. Many small files therefore waste more space than one large file of the same total size.
Traps that cost marks
Deleting a file usually removes its directory entry, not necessarily the data immediately. Formatting creates a new file system and can erase the index. Renaming does not change content. Moving within the same volume is usually fast; moving across volumes copies data. Virtual memory is not extra RAM, and the Recycle Bin is not a backup.