Importance of Data Storage: Part I

Information has long been considered a key input for effective

operation of the modern enterprise. Enterprises having the right information, at the right

place and at the right time tend to outdo others. This has led to enterprises

intelligently acquiring information about customer preferences, competitors, etc. Further,

as almost all modern enterprises, in one way or the other, have been making use of

computers for several of its activities, a bulk of the past operations have been

accumulated as computerised information. Several organisations, like railways, airlines,

banking, meteorology, etc., by their sheer nature, are data intensive and, have thus, also

accumulated huge amounts of data. All these activities have led to a need for very large

data storage systems — systems which are efficient, inexpensive and easy to use. With

this need in mind, several kinds of mass storage media have been researched upon and

evolved. In the field of information technology, data storage function has reached a

critical phase considering the Gartner Group’s estimate that about 70% of IT budget

is being taken up by this function!

Data storage technologies have come a long way and at a very healthy

speed. In fact, the speed of storage systems development has been so great that supporting

technological parameters like data transfer rate and bandwidth have fallen well short of

keeping pace. Only the rise in processing speed has been comparable to that of storage

capacity. For example, in the last decade, processor speeds have risen from 10 MHz to 1000

MHz (100 times), PC storage capacities from 200 MB to 20 GB (100 times) while data

transfer speed has come up to 12 MB/s from 3 MB/s (4 times).

Several data storage media have been developed catering to specific

needs of computing. Some operations need very fast random access storages while some need

bulk storage devices - forming a data storage hierarchy. The major parameters to look for

in a storage media to determine its suitability to specific requirement are practical

storage capacity, access time, and frequency of usage and cost per MB. Based on this

principle, the major types of storage media evolved can be short-listed to Magnetic Tape,

Optical Tape, Magnetic Disk and Optical Disk. There are, of course, several other kinds of

media, but we shall limit our study to the above mentioned four which are important for an

enterprise.

Magnetic Tape

This is the most preferred media for long term archiving of data. It

has a very high survivability and low cost per MB. Magnetic tapes, which have been in use

for nearly five decades now, have a major limitation in the fact that they offer only

serial access to data resulting in poor access times. Although tape-marking facility is

available one needs to spin through the reel to access information. Magnetic tapes are

packaged as spools or housed in cartridges (plastic rectangular containers) to render them

free of dust and to facilitate ease of handling.

These tapes find extensive use in backing up periodic data in such

applications as banking, airlines, etc. These are also useful in applications where random

access is not critical, like entertainment, audio/video presentations etc. Removable disk

storage medium now poses a threat to magnetic tapes as its price per MB is fast reducing

while its capacity per unit is increasing.

Optical Tape

Optical Tapes provide tremendous data storage density. A single optical tape cartridge

can hold data that would otherwise need hundreds of magnetic cartridges! Costs of these

tapes are not yet low enough to encourage its preference over its magnetic counterpart.

Hence optical tape is yet to prove itself to be a commercially viable medium.

...Continued Part-II