How does it Disk Cache.

How does it Disk Cache.

The slowest of any computer your drive. The units and the keyboard are the main items
personal computer that contain moving parts. The rest of the PC is simply to move the electrons from side to
other. But the mechanical parts moving in the real world, which takes into account the mass and inertia. No matter how
fast a hard drive can be mechanical parts seem sluggish compared to the other components that move
data at the speed of electricity.

There are ways to minimize this inherent slowness units. Some are faster than others. One is
make sure that the files are defragmented disk - ie, clusters that make up such files are
close to each other, and the read and write heads need not go all the physical space of the disk to unite
different parts of the file. Another way is to circumvent the problem by choosing a unit into RAM, which is part of
PC memory and is configured to cheat the PC, making it work as if it was a real unity.

However, despite these tricks, it is impossible to totally eliminate disk access. Reading programs and data files
the disc is essential for any self-respecting computer. The easiest and most efficient way to compensate for the slowness of
disk drives is to use a disk cache. Basically, a disk cache becomes faster computer operations,
maintaining data in RAM of your application that are most likely to be requested from the unit.

The concept behind the disk cache is similar to the cache RAM. But as the speed difference between
disk drive and any chip RAM is much greater than between a RAM chip fast and slow, causes the disk cache
results much more evident that cache RAM. There are several programs disk cache for sale, one of them came
MS-DOS. Some are better than others, but even the one offering the lowest efficiency will provide noticeable difference.

The most modern disk controllers come with a circuit for units with RAM cache so that the cache itself does not use the
memory that would be required by the programs. However, one can obtain similar results by loading programs flights
cache memory resident using the main system memory to cache units.

Source: Evolution of Computers