AS Level5Paper 1 — Theory Fundamentals

System Software

The operating system's jobs, utilities, and how programs get translated.

YOU SHOULD BE ABLE TO

Describe the main tasks of an operating system.
Explain memory management, file management, process and hardware management.
Describe utility software: disk defragmenter, backup, formatting, virus checker.
Explain program libraries and DLLs.
Compare interpreters, compilers and assemblers.
Explain the stages of compilation.

SORT THEM

Match each job to the part of the operating system that does it.

PICK ONE, THEN PICK ITS GROUP

Memory management

empty

Process management

empty

File management

empty

Device management

empty

Security management

empty

PUT IT IN ORDER0/6

Click the stages below in the order they happen.

//Memory management

The OS decides which processes are in memory, keeps them from overwriting each other, and moves pages between RAM and disk when RAM is full. Paging splits memory into fixed-size pages; segmentation splits it into variable-size logical sections.

//The stages of compilation

Four stages, in order — a common exam question.

1. Lexical analysis   – strip comments/whitespace,
                        turn code into tokens
2. Syntax analysis    – check the grammar,
                        build a parse tree, report errors
3. Code generation    – produce object code
4. Optimisation       – make it smaller/faster

//Why a DLL

A dynamic link library is only loaded when needed and is shared by several programs. That keeps executables smaller and means a fix to the library benefits every program — but a missing or wrong version of the DLL breaks them all.

CHECK YOURSELF

1.Which stage of compilation removes comments and produces tokens?

2.What is the main benefit of a DLL over including the code in every program?

3.Which is a task of the operating system?