Difference Between Spooling and Buffering in OS

Spooling and buffering are the two ways by which I/O subsystems improve the performance and efficiency of the computer by using a storage space in main memory or on the disk. The basic difference between Spooling and Buffering is that Spooling overlaps the I/O of one job with the execution of another job while the buffering overlaps I/O of one job with the execution of the same job.

Let us find some more differences between spooling and buffering with the help of comparison chart shown below.

Content: Spooling Vs Buffering

1. Comparison Chart
2. Definition
3. Key Differences
4. Conclusion

Comparison Chart

Basis for Comparison	Spooling	Buffering
Basic	Spooling overlap the I/O of one job with the computation of another job.	Buffer overlaps the I/O of one job with the computation of the same job.
Full form	Simultaneous peripheral operation online	No full form.
Efficient	Spooling is more efficient tha buffering.	Buffering is less efficeint than spooling.
Size	Spooling considers disk as a huge spool or buffer.	Buffer is a limited area in main memory.

Definition of Spooling

Simultaneous peripheral operation online, acronym for this is Spooling. A spool is a kind of buffer that holds the jobs for a device till the device is ready to accept the job. Spooling considers disk as a huge buffer that can store as many jobs for the device till the output devices are ready to accept them.

In spooling, I/O of one job is overlapped with the computation of another job. For example, a spooler at a time may read input of one job, and at the same time, it may also print the output of another job.

Spooling can also process data at the remote sites. The spooler only has to notify when a process gets completed at the remote site so that spooler can spool next process to the remote side device.

Spooling increases the performance of the system by increasing the working rate of the devices. It naturally leads to multiprogramming.

Definition of Buffering

Before discussing buffering, let us discuss, what is the buffer? The buffer is an area in the main memory that is used to store or hold the data temporarily that is being transmitted either between two devices or between a device or an application. In simple words, buffer temporarily stores data that is being transmitted from one place to another. The act of storing data temporarily in the buffer is called buffering.

There are three reasons behind buffering of data, first is it helps in matching speed between two devices, between which the data is transmitted. For example, a hard disk has to store the file received from the modem.

Now, as we know the transmission speed of a modem is slow, as compared to the hard disk. So bytes coming from the modem is accumulated in the buffer space, and when all the bytes of a file has arrived at the buffer, the entire data is written to the hard disk in a single operation.

Secondly, it helps the devices with different data transfer size to get adapted to each other. It helps devices to manipulate data before sending or receiving. In computer networking, the large message is fragmented into the small fragments and sent over the network. At the receiving end, the fragments are accumulated in the buffer and reassembled to form the complete large message.

The third use of buffering is that it also supports copy semantics. With copy semantics, the version of data in the buffer is guaranteed to be the version of data at the time of system call irrespective of any subsequent change to data in the buffer. Buffering increases the performance of the device. It overlaps the i/o of one job with the computation of the same job.

Conclusion

Spooling and buffering both increases the efficiency of the computer but Spooling is better than buffering as it handles the processing of two jobs at a time.