5.1.2 How the Operating System Manages a Computer
A computer may have many programs active while sharing a limited set of resources. The operating system coordinates these demands so that the processor, memory, storage and peripheral devices can be used in an organised and secure way.
By the end of this section, you should be able to:
- Explain why an operating system must manage shared resources.
- Describe the roles of process, memory, hardware, file and security management.
- Use the term process accurately when discussing a running program.
- Apply each management category to an unfamiliar computer-use scenario.
- Explain how several management tasks may cooperate during one user action.
Five Core Management Responsibilities
The operating system does not simply “run everything”. It carries out distinct management responsibilities. These categories help us explain its work, although one real event may involve several categories at once.
| Management area | Main question answered by the OS | Typical action |
|---|---|---|
| Process management | Which running program should use the processor or another shared resource? | Scheduling processor time and resolving competing requests. |
| Memory management | Which memory locations can each process use? | Allocating, protecting and releasing areas of main memory. |
| Hardware management | How can processes use input, output and peripheral devices? | Communicating through device drivers and coordinating device access. |
| File management | How should stored data be named, organised, found and accessed? | Maintaining folders, file information and permissions. |
| Security management | Who is allowed to use the system, data or particular resources? | Authenticating users and enforcing access rights. |
Process Management
A program stored on a drive is not yet a process. Once the program begins execution, the operating system treats that running instance as a process. Several processes may be ready to run at the same time, but they must share processor time and may also compete for files or devices.
| OS action | What it means | Original example |
|---|---|---|
| Scheduling | Selecting which ready process receives processor time next. | A video call, browser and virus scan all require CPU time. |
| Tracking process state | Recording whether a process is running, ready, waiting or finished. | A print process waits while the printer is busy. |
| Resolving resource conflicts | Coordinating access when multiple processes request the same resource. | Two applications send jobs to one printer. |
| Starting and ending processes | Creating a process when a program launches and reclaiming resources when it ends. | Memory is released after an image editor closes. |
Memory Management
Programs need main memory while they are running. The operating system keeps a record of which areas are in use, assigns suitable areas to processes and makes memory available again when it is no longer needed.
| Responsibility | Explanation | Why it matters |
|---|---|---|
| Allocation | Assigns an available area of memory to a process. | The process needs space for its instructions and data. |
| Protection | Prevents one process from reading or changing memory assigned to another without permission. | Reduces corruption, crashes and unauthorised access. |
| Tracking | Records which memory areas are free and which process owns each occupied area. | Prevents the same space being allocated incorrectly. |
| Release | Returns memory to the available pool when a process ends or no longer needs it. | The memory can then be reused by another process. |
Hardware Management
Applications should not need a different collection of low-level instructions for every model of keyboard, graphics adapter, printer or storage device. The operating system uses system software, including device drivers, to communicate with peripherals and coordinate their use.
| Hardware-management task | Example |
|---|---|
| Receive and pass on input | Keyboard input is made available to the active application. |
| Send output to a device | Audio data is passed to the sound hardware. |
| Coordinate shared use | Print jobs from several applications are placed in an orderly queue. |
| Detect device status | The OS reports that a removable drive is unavailable or a printer is offline. |
File Management
Stored data must be organised so that users and programs can create, locate, read, change and delete files. The operating system maintains the structures and information required to carry out these operations.
| Feature | OS responsibility | Example |
|---|---|---|
| File and folder organisation | Maintains directories and the relationships between folders and files. | A coursework folder contains separate source-code and evidence folders. |
| File naming and metadata | Stores names and information such as size, type, location and dates. | The OS shows when a report was last modified. |
| File operations | Provides controlled methods to create, open, save, rename, copy and delete files. | An application requests permission to replace an existing file. |
| Access permissions | Controls which users or processes may read, write or execute a file. | Students may read a shared template but cannot overwrite it. |
Security Management
The operating system helps protect the computer and its stored data by deciding who may enter the system and what each authenticated user or process is allowed to do.
| Security responsibility | How the OS contributes |
|---|---|
| User authentication | Checks credentials or another authentication method before granting access. |
| Access rights | Enforces permissions for files, folders, applications and devices. |
| Separation of users and processes | Restricts one account or process from accessing protected data belonging to another. |
| Security records | May record logins, failed access attempts and other important system events. |
How the Management Tasks Work Together
When a student opens a protected design file and prints it, the action crosses several management categories.
| Stage | Management task involved |
|---|---|
| The user signs in. | Security management authenticates the account. |
| The design application starts. | Process management creates and schedules a process. |
| Space is assigned for the application and file data. | Memory management allocates and protects memory. |
| The file is located and permission is checked. | File management and security management cooperate. |
| The finished design is sent to the shared printer. | Hardware management and process management coordinate the print job. |
Interactive: Operating System Activity Classifier
The existing classifier has been retained. It includes the five core management areas and three supporting OS responsibilities. Select the category that best matches each card, then consider whether another responsibility also contributes.
Common Mistakes and Misconceptions
- Listing without explaining: naming “memory management” earns less than explaining allocation, protection or release.
- Program = process: a process is a running instance of a program.
- Memory management = storage management: in this context, memory means main memory used by active processes, not simply files on a drive.
- Hardware management = repairing hardware: the OS coordinates communication with devices; it does not physically repair them.
- File management = writing the file contents: applications often produce the content, while the OS organises storage and controls file operations.
- Security = password only: security also includes authentication, permissions, separation and enforcement of access rights.
Practice
Try these original questions
- Define the term process.
- Explain why process scheduling is needed on a computer running several applications.
- Describe two responsibilities involved in memory management.
- Explain how a device driver supports hardware management.
- Describe three tasks carried out as part of file management.
- Distinguish between user authentication and access rights.
- A browser, backup program and music player all become active. Explain how the OS manages their use of processor time and memory.
- Two students use the same computer. Explain how file management and security management can work together to protect each student’s work.
- A print job is delayed because another application is already using the printer. Identify two relevant OS management areas and explain each one.
- Correct this statement: “The operating system stores every program in the same part of memory and lets each application control the printer directly.”
Review
| Management area | A strong explanation includes... |
|---|---|
| Process management | Running programs, scheduling processor time and coordinating shared resources. |
| Memory management | Allocating, tracking, protecting and releasing main memory. |
| Hardware management | Device drivers, input/output communication and coordinated peripheral access. |
| File management | File operations, folder organisation, metadata and permissions. |
| Security management | Authentication, access rights and protection between users and processes. |