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A
powerful back-up
During the past few weeks we have been engaged in a conversation
about system maintenance (I call it a conversation in acknowledgement
of the various queries I have received through email and my responses
to them). The hardware in your system will work better and more
reliably, and last longer, if it is maintained regularly according
to the directions that have been outlined. But ultimately, you can
still get away with poor preventive maintenance practices in most
cases; at worst your hardware will fail and you will have to replace
it. This may prove expensive, but not the end of the world, usually.
However, there is one thing that if lost, cannot be so easily replaced
and that is your data.
Data can never
be replaced; it can only be protected against loss. This is why
it is so critical that you take proactive steps to reduce your chances
of data loss which, if you are on the receiving end, may prove catastrophic.
This week we will examine the risks to data, and how to prevent,
detect and correct problems that may threaten it. This includes
a look at viruses, what they are, and how to deal with them and
also problems you encounter with storage media in general and how
to correct them.
The best way
to avoid data loss is of course to prevent it by using your computer
wisely. There are many specific activities you can undertake, which
will help protect your data and prevent it from being lost, backing-up
your data being the most effective way.
Back-ups
Data has a great disadvantage compared to hardware in that it can
be lost, and once lost, it is never easily replaced. You can get
your hard disk replaced under warranty, but the new one will come
to you empty. However, data has a great advantage that compensates
for this weakness: because unlike your hard disk drive, it can be
readily and easily duplicated.
By creating
backups of important data on a timely basis, you can ensure that
your data, or most of it anyway, will never be truly lost; at worst,
some will be lost and you will experience the inconvenience of restoring
it in the event of a hard disk failure, for example. It is absolutely
critical that you create backup copies of all important data, documents
and programs on your hard disk, so that you have some protection
in the event that catastrophe strikes which may include virus attacks
(more on that as we go on), natural disasters, theft, hardware/software
failure and sabotage to name a few. Here, on your part, it is essential
that common sense prevails.
For example,
you should take care not to store your back-up media at the same
location as your PC or server (even poultry farmers never put all
their eggs in the same basket), because in case of fire or flood
you have no better chance of saving your backups than saving your
machine itself. By keeping them in different locations and at a
sufficient distance from each other, you have a better chance of
saving one or the other.
Virus
detection and protection
Viruses are unwanted programs that spread from computer to computer,
much the way real viruses do in humans and animals. They are sometimes
very dangerous and can in fact wipe out your entire hard disk if
you are unlucky—and if you don’t protect yourself. Taking
steps to protect yourself from viruses is an essential part of any
data problem prevention routine.
There would
have been a time when you only had to worry about you (and your
family) screwing up your own PC. Now you even have to worry about
complete strangers doing it for you. Due to the nature of how software
works, it is possible to write programs that can modify or create
other programs; a compiler being a straight-forward example. It
is also easy to duplicate a piece of code and write it to various
locations on a hard disk.
Advances such
as the Internet have made it possible for computer viruses to spread
much more quickly than ever before, and more computer users in general,
especially those that don’t understand what viruses are, have
given virus writers a much richer set of targets.
Viruses are
a fascinating topic. Here we will take a brief look at viruses,
what they are, where they come from, how they spread and how to
protect yourself from them. Generally all viruses:
* Run without
the user wanting it to and/or create effects that the programmer
wants but that the user did not want or request.
* Have the
ability to “infect” or “modify” other
files or disk structures.
* Replicate
itself so it can spread to other files or systems.
There are three
major types of viruses, each very different from the other. Of course,
there are many subcategories within each group as well (and to make
matters worse, there are virus hoaxes to confuse the issue):
* Boot Sector
Infectors: Also sometimes called boot record infectors, system
viruses, or boot viruses, these programs attack the vulnerable
boot program that is stored on every bootable floppy disk or hard
disk. This code is executed by the system when the PC is started
up, making it a juicy target for virus writers. By installing
themselves here they guarantee that their code will be executed
whenever the system is started up, giving them full control over
the system to do what they wish. They are spread most commonly
through infected bootable floppy disks.
* File Infectors:
These viruses directly attack and modify program files, which
are usually .EXE or .COM files. When the program is run, the virus
executes and does whatever it wants to do. Usually it loads itself
into memory and waits for a trigger to find and infect other program
files. These viruses are commonly spread through infected floppy
disks, over networks, and over the Internet.
* Macro Viruses:
The newest type of virus, these clever programs make use of the
built-in programming languages in popular programs such as Microsoft
Word and Microsoft Excel. These programs allow users to create
programs that automate tasks, called macros. The most common type
of macro virus right now infects Microsoft Word documents.
As you can
see, it is a dangerous world out there. Keep hooked on to Techno
Page to keep abreast of the dangers and tips on how to combat them.
And don’t hesitate to write in to technopage_lk@yahoo.com
Virus
hoaxes
Along with the thousands of real viruses that circulate
the world, there are dozens of virus hoaxes that computer users
have to contend with. Loosely speaking, a virus hoax is a rumour
or warning about a virus that is spread from well-meaning person
to well-meaning person, telling them not to download a programme
or take other action, or they will get a virus. But the virus does
not exist, and in fact it is the virus warning that is really the
only thing that is, in essence, a virus! If you think about it,
the warning is what is spreading from system to system (even though
it doesn’t generally cause any damage aside from wasting people’s
time).
Improve
your computer literacy
MathML
Short for Mathematical Mark-up Language, an XML application is for
describing mathematical notations and capturing both its structure
(including its complex two-dimensional symbolic notations) and its
content and enabling that structure and content to be communicated
over the Web. To communicate mathematics over the Web, it is essential
to have a system that facilitates the processing, searching and
indexing of data, and the reuse of that data in other mathematical
applications and contexts. |
