Filing Systems

Definition: Filing Management

The FILING SYSTEM is the part of the Operating System that deals with how files are held on backing storage. It controls the processes involved in saving, loading or deleting files.

 

 

 

 

 

Hierarchical Filing Systems

Most modern computers today use a hierarchical filing system.

An area where files are stored is called a directory or folder.

Each directory can contain other directories or sub-directories.

 

 

 

 

 

 

 

 

Advantages of Hierarchical Filing systems

• Allows you to create sub directories to keeps group of related files. This makes it much easier to find files.
• Sub groups of files contain fewer files, so its easy to see all the files in a single directory.
• Files can share the same name provided they are in different folders.

 

 

 

 

Sequential & Random Direct Access to Data

There are two main methods of accessing the data sequential or random/direct access.

a. Sequential Access

When a system uses sequential access to data it goes to each record in a file one after another in sequence. Sequential access is commonly used when recovering data from taped backup systems. Magnetic tape is often used because of its cheapness.

Sequential access is similar to the users access songs on a cassette or video tape. With a song or program towards the end of the tape, you have to wind through the tape to get to it. Accessing information can be quite slow.

 

 

 

b. Random or Direct Access

A system using random/direct access goes directly to the data it requires. This method is used in interactive processing because the data can be accessedand processed immediately. Direct access is also called random access because the data can be read from the disk in any order, not just the order in which it was written. Accessing the information is much faster.

 

 

 

What you should be able to do!

1. Explain the role of the Filing System.

2. Describe two ways of organising files in a computer system.

3. Provide some advantages of organising files in a hierarchy or in sub folders.

4. Explain the difference between Sequental and Random File Access.

5. Explain the role or purpose of Device Drivers .