How Is Data Written To A Hard Drive

A key concept in information storage is that it is linear, logical, and systematic in nature. When someone 'saves' data to the hard disk drive, the disk will follow a logical system.

A difficult disk can be compared to a large, foursquare piece of graphing paper composed of squares, a thousand long and a thousand wide. Each square can accommodate one kilobyte of information and thus a 'strip' having a thousand squares tin can store i megabyte of data. In such a case, the disk head will 'fill up' in the upper leftmost foursquare first and so continue down the line – one square at a time until all the appropriate squares are filled.

A second key concept to remember is that information storage follows a uncomplicated rule – data is stored (or 'written') on the first available space, wherever this may be.

Data Storage Example

Imagine that someone is saving a 1-Mb Word certificate on the hard disk. Saving a one MB file means the disk will systematically 'fill in' a thousand squares.

After saving the Word document, assume that a 3 MB photograph is saved to a difficult deejay. Following the cardinal data storage concepts, the disk writer head will go through the disk and expect for the commencement bachelor space, which, in this example, happens to exist the foursquare post-obit the Discussion document'due south concluding kilobyte. Thus, the three MB photo will be saved in the space next to the Word certificate.

How Data is Stored in your Hard Disk

Afterward, go back to the Word document and trim it down, ending up with a file 700 KB in size, which is so saved to the hard disk. Given the smaller file size, the 1 MB space requirement was reduced to 700 KB, leaving 300 KB free or (using the analogy to a higher place) 300 blank squares immediately after the Word certificate. There is now available space between the Word Document and the three MB photograph.

When yet some other file is saved, say a 2 MB Excel file, the hard disk will follow its rule of saving information on the offset bachelor space. Thus, the Excel file will be split into 2 portions: 300 KB will be written on the 300 KB complimentary space and the remainder will exist placed in the next available space, afterward the image file.

The Problem

Information storage, while designed to be logical and systematic, leads to file fragmentation. Imagine adding, deleting, and editing files for days, weeks, and months. After a few months, the hard disk will become and then fragmented that the disk will accept quite a bit of time to find a single file's fragments.

Information technology is piece of cake to see from this that data retrieval would be easy if the file components were in a unmarried, face-to-face location on the hard disk. De-fragmentation is the process in which the different file fragments in a data storage system are located, 'gathered,' and consolidated into specific areas of the storage device, thus making information technology easier to retrieve data. This allows speedier processing too as reduced wearable and tear on information retrieval mechanisms.