Hard Disk: the size is important

Here I'm going to talk again about the magnetic hard disk (HD) and not of the new solid state hard disk (SSD), because in these the size is not a matter.

In the post Partitions of the hard disk. Are good or bad? I explained how is structured a hard disk and what is the search time. If you haven't read it, the search time is the time that spends the hard disk in put the head over the track that have to read, and this is the task that more time spend when the disk have to localize a data. What happens when the hard disk is more tiny? By one hand, if it use the same technology that other more big (same size of the magnetics domains), will have less capacity due to the lower area of surface of the disk, but in the other hand will be a lot of more fast.

This is something that never it's wrote in the specifications of a hard disk, because always they give it in the optimal conditions of performance, that is to say, when the disk is practically void and the files are put one at side of the other without fragmentation. Instead, when the hard disk is full and the files are fragmented along of all the disk due to the racking of information, the fact of that the hard disk be more tiny, enhance more the performance of this than the quantity of cache memory o the revolutions that it can rotate. For that between a hard disk of 3'5 inches that spins at 10.000 rpm and other of 2'5 inches that rotates, in first place the first will be more fast, but with the use will be a lot of more slow than the second.

About the the SSD as I have said already, the size is not a matter, because any data can be accesed at the same speed regardless of how are stored. For that reason although there are some magnetic hard disk that can compete in speed with the SSD, this is only in optimal conditions. A magnetic hard disk totally full and fragmented never will can compete in performance with a SSD.

Then, Why we don't use laptop hard disk in desktop computers? This is that thought the engineers of Western Digital when they designed its hard disk Velociraptor, that have 2'4 inches and is enclosed in a sink of 3'5 to facilitate its installation. Although is not a crazy idea buy a laptop hard disk to dock it in your computer.

But if we want speed, without having into account the capacity and durability, without any doubt a SSD is the ideal solution. This are specially recommended if we want make video edition, task that require the maximun speed that we can get of the hard disk.