Computer Basics

8 - System Software: Types

There are two basic types of operating systems:

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 in 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 have 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. Next 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.

The next step up in complexity is multiple users. On a network several users can be using the same computer or even the same program on that computer. This is called time-sharing.

If a computer has multiple CPUs, it can do multiprocessing. Rather than a single CPU giving out turns to various programs, the different CPUs can work simultaneously. Speed increases immensely. Of course cost does, too!

It is possible for a computer to use more than one operating system through the use of virtual machines."Virtual" means it's not really there. But programs written for different operating systems are fooled into thinking their required operating system is present.

Common Operating Systems for Desktop Computers

Originally the operating system was created by each company that manufactured a processor and motherboard. So each operating system was proprietary, that is, unique to each manufacturer. Problem: changing to a new computer meant your software had to be replaced! Not good marketing. So there was pressure early on to standardize things so that software could be transferred to the new (and of course better!) computer. This required more standardization in operating systems.

The winner in the PC market was MS-DOS, Microsoft's Disk Operating System, and its twin at IBM, PC-DOS, also written by Microsoft. Now it's hard to recall those days when each computer had its own unique operating system. More on DOS Commands

Windows versions (95, 98, Me, NT, 2000, XP, Vista, and 7) are operating systems on their own. The earlier versions of Windows use DOS as the operating system and add a graphical user interface which will do multitasking. But with Windows 95 Microsoft released an operating system that can take advantage of the 32-bit processors.

Windows XP is an upgrade to Windows 2000. It comes in two versions - Home and Professional. The Professional version contains all the features of the Home version plus more business features, like networking and security features.

Microsoft: Which edition of WindowsXP to choose

Windows Vista was released in early 2007. It has higher requirements for memory and processor speed than previous versions of Windows. Vista comes in several different flavors for home and business purposes.

Microsoft: Which version of Windows Vista is right for you

Windows 7 was released in late 2009. There are several versions with differing prices.

Microsoft: Which version of Windows 7 is right for you?

The Apple Macintosh is a multitasking operating system that was the first graphical interface to achieve commercial success. The Mac was an immediate success in the areas of graphics production, and still commands the lion's share of that market. Apple made a major marketing error when they decided to keep their hardware and software under tight control rather than licensing others to produce compatible devices and programs. While the Apple products were of high quality, they were always more expensive than comparable products that were compatible with Microsoft's DOS operating system. Apple's share of the computer market has dropped to an estimated 2.4% worldwide and 3.48% of the US market (MacWorld July 3, 2002). This is an example of how a near lock on a market can be lost in a twinkling. 

The current version is Mac OS X, which is version 10. Since January 2002, all new Mac computers use Mac OS X. Subversions are named Jaguar, Panther, Tiger, Leopard.... Most statistics show that Mac are making a comeback (Feb. 2010 - see chart at bottom of page), but the total usage is still low compared to the total number of Windows systems.
 

UNIX is an operating system developed by Bell Labs to handle complex scientific applications. University networks are likely to use UNIX, as are Internet Service Providers. A lot of people have experience with UNIX from their college work. Many computer old-timers love UNIX and its command line interface. But all those commands are not easy to remember for newcomers. X-Windows is a graphical interface for UNIX that some think is even easier to work with than Windows 98.

Linux is an operating system similar to UNIX that is becoming more and more popular. (And it has the cutest logo!)
It is a open-source program created by Linus Torvalds at the University of Finland, starting in 1991. Open source means that the underlying computer code is freely available to everyone.  Programmers can work directly with the code and add features. They can sell their customized version of Linux, as long as the source code is still open to others. You can find more info at the Linux home site. 

By the way, the word Linux is generally pronounced with a short i and the accent on the first syllable, like LIH-nucks. On the Wikipedia page about Linux, at the lower right, there is a link to an audio file of Linus Torvalds pronouncing it in English.

Life Cycle

There are other operating systems besides the ones listed above, especially for mobile and tablet devices. New operating systems may still appear and take over the market position of the one that are popular now. Nothing in computers is so sure as change!

Microsoft, for example, has adopted a schedule for phasing out online support and updates for its operating systems. 
Windows Life Cycle
For example, under this schedule, the end of sales for Windows XP being pre-installed on a computer was Oct. 22, 2010. The end of mainstream support was April14, 2009. Limited support is available somewhat longer for commercial customers - that's not for individual users! There will be no more security updates and no technical support of any kind from Microsoft for products that have passed their End of Life date.

Which is most popular?

It depends on who you ask! There is no one who can accurately report the true usage of any operating system. Various companies can report what they sold in a particular period of time and combine that info to see their "market share". Internet sites can report the operating systems of those who come to visit them. Someone might be able to estimate the "installed base" for an operating system, meaning the number of computers currently using that operating system. But no one can really tally the whole world, or even a whole country.

The pie chart below shows statistics in a Wikipedia article on operating systems as of January 2010.
 
The chart shows the median of values from several sources, all of which used data from web browser visits to web sites. This, of course, omits completely any computer that did not visit those sites. But it's the best we can do.

	Usage share of web client operating systems. Source: Median values from Usage share of operating systems      Windows XP (58.64%)      Windows Vista (23.25%)      Windows 7 (7.70%)      Mac OS X (5.12%)      Linux (1.04%)      iPhone (0.72%)      Other (1.32%)
Check the current numbers at http://en.wikipedia.org/wiki/Usage_share_of_operating_systems

The next two pie charts are from a different source, HitsLink.com. Desktop computers and Mobile or Tablet devices use different operating systems. Check the current numbers by clicking the links below the charts. These charts show the various versions separately.

HitsLink.com:Desktop Operating Systems              HitsLink.com:Mobile/Tablet Operating Systems

~~  1 Cor. 10:31 ...whatever you do, do it all for the glory of God.  ~~

Last updated: 03 Oct 2011