File Organisation (Cambridge (CIE) A Level Computer Science): Revision Note
Exam code: 9618
Modern computer systems handle vast amounts of data
Everything from bank transactions to music libraries is stored in files
To retrieve information quickly and efficiently, data must be organised properly
What is file organisation?
Files are used to store data permanently on secondary storage
Data in a file is stored as a collection of records, where each record represents a single item (e.g. a customer, a transaction, a product)
The way records are arranged within a file is called the file’s organisation method
Choosing the right method affects how quickly data can be searched, added, updated, or deleted
Why is file organisation important?
Reason | Explanation |
|---|---|
Efficient data access | Well-organised files allow fast searching and retrieval |
Supports large-scale systems | Enables millions of users to access data simultaneously (e.g. online banking) |
Improves program performance | Reduces load times and processing requirements |
Enables reliable updates | Helps manage changes to stored data safely and accurately |
File organisation methods
What are the different file organisation methods?
The way data is arranged within a file affects how efficiently it can be accessed and updated
Each file organisation method has its own strengths and is suited to different types of tasks
Serial file organisation
Description | Example use case |
|---|---|
Records are stored in the order they arrive (no sorting). To find data, the file must be searched from the beginning. | Logging sensor data, storing queued messages |
Simple to implement, but slow to search if there are many records
Sequential file organisation
Description | Example use case |
|---|---|
Records are stored in a sorted order based on a key field. Searching can stop once the target is passed. | Payroll systems, exam results |
More efficient for searches and ideal for files that are read often but rarely updated
Direct (random) file organisation
Description | Example use case |
|---|---|
Records are placed at specific locations using a hashing algorithm. This allows instant access to any record. | Bank account access, real-time stock updates |
Best for fast, real-time access to individual records
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