System softwarex

feastcanadianSoftware and s/w Development

Dec 14, 2013 (3 years and 8 months ago)

79 views

System software

is a catch
-
all term for the programs that handle the running of your
computer's hardware. The two main categories are:

operating systems


utility programs



Operating Systems

B
etween the hardware and the application software lies

the
operating
system
. The operating system is a program that conducts the
communication between the various pieces of hardware like the video
card, sound card, printer, the motherboard and the applications.




Functions

A
ll operating systems must handle the same basic tasks. These functions can be divided
into three groups:


T
here are two basic types of operating systems:

single program

and
multitasking
.


A

single program

operating system allows only
one program

to run at a
time. This means that if you are working in a spreadsheet and want to write a
memo, you must shut down the spreadsheet application and open up a word
processor. This is annoying, especially if you need to quote some data from the
spreadsheet i
n your memo! So new operating systems were designed that allowed
multiple programs

to run at the same time.

The simplest form is
multi
-
tasking
. What this really means is that the
programs are taking turns with the processor. It allows a single user to ha
ve the
spreadsheet and the word processor open at the same time, and even more. Now
the user can see to copy data from one to the other. Much better!!

The computer must decide on how many time slices each program gets. The active
program gets the most. Nex
t is programs that are doing things but which aren't the
foreground program. Last is programs that are open but aren't doing anything. They
need a little bit of time every now and then to see if they are supposed to do something
yet.



Utility Programs

A

utility program performs tasks related to the maintaining of your computer's health
-

hardware or data. Some are included with the operating system. But someone
always thinks they have a better version for you to buy. And they are frequently right!




File Management

programs make it easier to manage your files. In the high days of
DOS it didn't take much to improve on the text
-
only type
-
it
-
all
-
yourself methods that
DOS provided. Many programs were written to help the user find files, create and organiz
e
directories, copy, move, and rename files. Some even used the mouse to point and click to
accomplish these tasks. You don't appreciate the vastness of the improvement until you've
tried to do these things from the command line. The newer graphical interf
aces that come
with current operating systems have reduced the need for alternate file management
programs.


Disk Management

programs involve formatting and defragmenting disks.
Defragmenting

means putting files on the disk so that the whole file is in sequence.
This reduces the time to access the file. Some disk management programs even let you
specify that certain files that are accessed often, like the operating system itself and
frequently

used programs, are at the front of the disk. Anything that speeds things up will
have customers.


Memory Management

software handles where programs put their current data in
RAM. They move certain memory
-
resident items out of the way. This can effectiv
ely
increase the memory available by getting all the unused pieces together in one spot, making a
useable amount.


A
backup

program, which also restores the backed up data, is a must if
you have any data at all that you want to keep around for a while.
The
software will compress the data to take up the least space (Recall the problem with slack
space we found in the discussion of
Storage: Disk Format
).

































Data Recovery

programs are for those who just said "Whoops!" They attempt to
recover deleted or damaged (corrupted) files.



Data Compression

programs squeeze out the slack space generated by the formatting
schemes, as discussed under
Storage: Disk Format
.





Security Software


This category includes

a number of different kinds of programs, all of which are
trying to protect your computer and your data from attacks and damage and being
controlled without permission. No one program can protect against all of the bad guys
out there. Using a set of overla
pping programs is the best way to keep your