File Systems

A file system is the method an operating system uses to organize, store, manage, and keep track of files and folders on a storage device. It helps the computer identify where information is stored and makes it possible for users and programmes to save, find, open, and manage data.

This note focuses on the basic organization of files, file names and extensions, common file types, and the properties that describe a file.

1. What Is a File System?

A file system is a structure and set of rules used by an operating system to organize and manage data on a storage device such as a hard disk drive (HDD), solid-state drive (SSD), or USB flash drive.

When a file is saved, the file system keeps track of information such as:

• The file name and file type.
• The file's location within the storage structure.
• The amount of storage space used.
• Information about the file, such as its dates and attributes.

Files are commonly arranged inside folders (also called directories). Folders can contain files and other folders, creating a hierarchical structure.

<ExampleLabel>{=html}Example: Organizing school documents</ExampleLabel>{=html}

A student may create a folder named School and save files such as Science.docx, ICT Notes.pdf, and English.docx inside it. The folder structure makes it easier to locate related documents instead of keeping every file in one large collection.

2. File Name and File Extension

A file name is the name given to a file so that users can identify it. A file extension is the suffix at the end of a file name, usually written after the final dot (.). It commonly indicates the file format or type.

For example, consider:

Report.docx

• Report is the file name.
• .docx is the file extension.

The extension helps the operating system identify the file type and select a suitable application to open it. The application used can depend on the file association settings configured on the computer.

Common file extensions

Extension File type Common use

.exe Executable file Runs a programme in Windows .docx Word document Stores text documents .xlsx Excel workbook Stores spreadsheets and calculations .pptx PowerPoint presentation Stores presentation slides .accdb Access database Stores a Microsoft Access database

An extension is a useful indicator of a file type, but simply renaming a file extension does not convert the file's actual format. For example, renaming Report.docx to Report.pdf does not turn a Word document into a PDF.

3. How to View File Extensions in Windows

Windows may hide known file extensions by default, depending on the system settings. Showing extensions makes it easier to identify file types and distinguish files with similar names.

Steps

1. Open File Explorer.
2. Open the View menu or tab.
3. Find the option for File name extensions.
4. Select or tick the option to display extensions.

The exact menu arrangement differs between Windows versions. In newer Windows versions, the option may be under View → Show → File name extensions.

<ExampleLabel>{=html}Example: Identifying a document</ExampleLabel>{=html}

If extensions are visible, a file appears as Report.docx rather than only Report. This helps the user recognize that it is a Word document.

4. File Properties

File properties are details that describe a file. They provide information about its type, size, location, dates, and other characteristics.

In Windows, a user can usually view a file's properties by right-clicking the file and selecting Properties.

Main file properties

1. File type

The file type identifies the kind of file and is commonly associated with its extension.

For example: - .docx -- Word document. - .xlsx -- Excel workbook. - .jpg -- Image file. - .pdf -- PDF document.

The file type helps the operating system and applications determine how the file should be handled.

2. Size

The file size is the amount of data stored in the file. It is commonly displayed in units such as bytes (B), kilobytes (KB), or megabytes (MB).

For example, a text document may be only a few kilobytes, while a high-quality photograph or video may use several megabytes or more.

3. Location

The location shows where the file is stored. It may include the drive and the folder path.

<ExampleLabel>{=html}Example: File location</ExampleLabel>{=html}

C:\Users\User\Documents\Report.docx

This path indicates that Report.docx is stored in the Documents folder under the User account on drive C:.

4. Date and time

File properties can show dates and times related to the file, such as:

• Created: When the file was created in that location.
• Modified: When its contents were last changed.
• Accessed: When the file was last accessed, depending on system settings and file-system behaviour.

These details can help users identify recent changes and manage files.

5. Storage allocation (Size on disk)

Size on disk indicates how much storage space the file occupies on the storage device. It may be slightly larger than the file's actual size because file systems allocate storage in units called allocation units or clusters.

For example, a small file may use one complete allocation unit even if the file's contents do not fill that unit.

File size vs. size on disk

File size Size on disk

Amount of data contained in the Storage space allocated to the file file

Based on the file's data Depends partly on the file system's allocation method

May be smaller than size on disk May be slightly larger than file size

5. Why File Systems Are Important

A file system provides the organization needed for everyday computer use.

• Organization: Arranges files and folders in a structured way.
• Identification: Keeps track of file names and related information.
• Storage management: Records where file data is stored and which storage areas are in use.
• Access: Helps the operating system locate files when users or programmes request them.
• File management: Supports operations such as creating, opening, copying, moving, renaming, and deleting files.

Without a file system, the operating system would not have the usual structured method of organizing and locating files on a storage volume.

6. Important Terms

• File: A named collection of data stored on a storage device.
• Folder / Directory: A container used to organize files and other folders.
• File system: The method used by an operating system to organize and manage files on a storage device.
• File name: The name used to identify a file.
• File extension: The suffix after the final dot in a file name, commonly indicating its format.
• File path: The address that identifies the location of a file or folder.
• File properties: Information describing a file, such as its type, size, location, and dates.
• Allocation unit / Cluster: A unit of storage space that a file system allocates to store file data.

7. Exam-Focused Points

Students should be able to identify file extensions from examples, explain why extensions are useful, describe how to view extensions in Windows, and distinguish file size from size on disk.

8. Summary

A file system provides the structure an operating system uses to organize and manage files and folders. File names identify files, while extensions commonly indicate their types and associated applications. File properties provide further details, including type, size, location, dates, and storage allocation. Understanding these concepts helps users identify, organize, and manage stored information effectively.