Operating Systems

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1. Introduction

2. Development

3. Category Operating Systems.

4. The most popular operating systems for the PC.

5. Conclusion

1. Introduction

Without software, a computer is nothing more than a useless metal mass. With the software, a computer can store, process and retrieve information, find spelling errors in manuscripts, have adventures and participating in many other valuable activities to earn a living. The computer software can be broadly classified into two classes: system programs, which control the operation of the computer itself and the application programs, which solve problems for its users. The fundamental program all system programs is the operating system (OS), which controls all the computer resources and provides the basis on which they can write application programs.

2. Development

What is an Operating System

Since its creation, digital computers have used a coding system manual in binary number system, ie with 0S. This is because integrated circuits operate on this principle, that is, no current or no current.

At the origin of the history of computers (forty years ago), there were no operating systems and the introduction of a program to be executed became an incredible effort that could only be done by very few experts. This made computers were cumbersome to use and that have high technical expertise required to operate them. It was so complex handling, which in some cases be reached disastrous outcome.

In addition, the time required to enter a program in those big machines slow process exceeded by far the execution was unprofitable and the use of computers for solving practical problems.

More elaborate means were sought to manipulate the computer, but that in turn simplify the work of the operator or user. That’s when the idea to create a way for the user to operate the computer with an environment, language and well defined operation to a real use and exploitation of this. Operating systems emerge.

An operating system is responsible for providing the user with a friendly and simple to operate, interpret, encode and issue orders to the central processor to perform the specific tasks required and to complete an order.

The operating system is the essential tool to make the computer a useful object. Under this name are grouped all those programs that allow users to use this jumble of wires and circuits that would otherwise be difficult to control. An operating system is defined as a set of manual and automated procedures, which allow a group of users sharing a computer system efficiently.

Command Line Interface.

The shape of the interface between the operating system and the user in which this type commands using a special command language. Systems with command line interfaces are considered more difficult to learn and use the graphical interface. However, command-based systems are generally programmable, which gives them a flexibility no graphics based systems lack a programming interface.

Graphical User Interface.

It’s the kind of display that allows the user to choose commands, initiate programs and see lists of files and other items using visual representations (icons) and lists of menu items. Selections can be activated either via the keyboard or the mouse.

For authors of applications, graphical user interfaces offer an environment that handles the communication with the computer or computer. This makes the programmer can concentrate on the functionality, since it is not subject to the details of the display or input via mouse or keyboard. It also allows developers to create programs that perform just as common tasks, such as saving a file, because the interface provides standard control mechanisms like windows and dialog boxes. Another advantage is that applications written for a GUI are independent of devices: as the interface changes to allow the use of new input and output devices, such as a large screen monitor or an optical storage device, applications can be used without changes.

Functions of Operating Systems.

* Interprets the commands that allow the user to communicate with the computer.

* Coordinate and manipulates the computer hardware, such as memory, printers, disk drives, keyboard or mouse.

* Organize files on various storage devices such as floppy disks, hard disks, CDs or tapes.

* Manages hardware failures and data loss.

* Provide a basis for the creation of making software that makes computers work similarly different, bridging the differences between the two.

* Set the environment for the use of software and peripherals, depending on the type of machine being used, should be set in a logical layout and equipment characteristics. As for example, a microcomputer having two drives physically can simulate the use of other drives, they can be virtual using part of the main memory for that purpose. Should be connected to a network, the operating system becomes the working platform and the users who controls or elements that share resources. Similarly, provides protection to the information it stores.

3. Category Operating Systems.

Multitasking Operating System.

Operating mode is available in the operating system, by which a computer processes multiple tasks simultaneously. Several types of multitasking. Switching contexts (context switching) is a very simple type of multitasking in which two or more applications are loaded at the same time, but only where the application is processing that is in the foreground (the user sees ). To activate another task that is in the background, you must bring to the foreground the window or screen containing that application. In cooperative multitasking, which is used in the Macintosh operating system, the background tasks receive processing time during timeouts of the task that is in the foreground (for example, when this application is waiting for user information) and provided that this application allows. In multitasking systems timeshare, like OS / 2, each task receives the attention of the microprocessor for a split second. To keep the system in order, each task receives a priority level or processed in sequential order. Since the user’s sense of time is much slower than the computer’s processing speed, multitasking operations appear to be simultaneous timeshare.

Monotareas OS.

Monotareas operating systems are more primitive and the opposite is seen, ie can only handle one process at a time or can only perform tasks at a time. For example when the computer is printing a document, you can not start another process or respond to new instructions until you finish printing.

Single-user operating system.

Monousuarios systems are those that can only serve a single user, due to the constraints imposed by the hardware, software, or the type of application you are running.

These types of systems are very simple, because all input devices, output and control depend on the task that is being used, this means that the instructions given are processed immediately, as there is a single user. And are oriented mainly by microcomputers.

Multiuser operating system.

It is the opposite of single-user and in this category are all systems that simultaneously meet the needs of two or more users, who share the same resources. Such systems are used especially in networks.

In other words is the fragmentation of the time (timesharing).

Batch sequence.

The batch sequence or batch processing on microcomputers, is the execution of a list of operating system commands one after another without user intervention. In larger computers collection process programs and data sets of users, the execution of one or a few at a time and resource delivery to users. Batch processing can also refer to the process of storing transactions for a certain period before they are sent to a master file, usually a separate operation that takes place overnight.

Operating systems batch (batch), in which the programs were treated groups (batch) in instead of individually. The function of these operating systems was a program loaded into memory and run the tape. At the end of this, was made the jump to a memory address from where was resuming control of the operating system that the following program loaded and executed. Thus the time between work and the other decreased considerably.

Real Time.

A real-time operating system processes instructions received instantly, and once they have been processed shows the result. This type is related monousuarios operating systems, as there is a single operator and no need to share the processor among multiple requests.

Its main feature is to respond quickly, for example in case of danger would require immediate responses to prevent a catastrophe.


The timesharing computer or computers is the use of a system for more than one person at the same time. The timeshare separate programs running concurrently, sharing lots of time assigned to each program (user). In this respect, is similar to multi-tasking capability is most common in microcomputers or microcomputers. However timeshare is generally associated with multi-user access to larger computers and service organizations, while multitasking microcomputers related involves performing multiple tasks for a single user.

4. The most popular operating systems for the PC.

Operating systems are normally used UNIX, Macintosh OS, MS-DOS, OS / 2, Windows 95 and Windows NT.


The meaning of these letters is the Microsoft Disk Operating System. Microsoft is the name of the company that designed this operating system, and IBM was the company that standard to adopt in their microcomputers.

This operating system uses floppy disks with a particular organization. Discs can be recorded on one or both sides and the information is organized into 40 tracks of 8 or 9 sectors size of 512 characters, reserving for itself the system disk information, which may be removable or hard disk drive, bearing capacity in the second but similar structure.

The names of the files in MS-DOS, which are used for both letters and numbers, are composed of two parts: the file name and extension, both of data separated by a period. Different drives are identified by the MS-DOS through a letter followed by a colon. The most common extension types are like memory appear loaded with them, ie they can be loaded directly into memory without the help of the operating system.

The extension. EXE require the DOS boot the place in memory, which means that the operating system must be in memory. The type. BAT are compounds of commands that are executed sequentially.

The operating system has several components:

* Control Routines, which operate IBM.DOS program, and handle the operations of input / output.

* Command Processor, also called COMMAND.COM, which processes two types of commands available to the DOS, ie the internal memory or residents and non-residents or foreign, residing in the operating system disk.

* Routines services accessible from the program control.

It is also possible to subdivide the disk into subdirectories which allow a more flexible use of the information.

MS-DOS is far from the ideal operating system, since, for the moment, it is a single-tasking system, but although this was resolved, would continue to design problems that cause the behavior of the machine is unreliable. Despite these disadvantages, and that there are other operating systems in the world of microcomputers, we must bear in mind the huge amount of software that has been developed for DOS and you should take advantage as much as possible.

OS / 2.

Initially developed by Microsoft Corporation and International Business Machines (IBM), after Intel introduced

launches its 80286 processor. But society does not last long as Windows IBM saw as a threat to the OS / 2.

But IBM continued to develop this operating system. The OS / 2 was initially very similar to MS-DOS, has a command line, but the difference is with the DOS command interpreter, which is a separate program from the operating system kernel and appears only when Clicking one of the icons “OS / 2 prompt” within the Workplace Shell. Another difference is that the other in a multitasking operating system.

In the OS / 2 many commands are identical to those of its counterpart but has more commands because it is larger, modern and complete.

The graphical environment is the Workplace Shell (WS), is equivalent to a workspace administrator for WS.

Macintosh OS.

The operating system is the interface between applications and the hardware of the Macintosh. The memory manager scans and automatically frees memory for applications and the operating system. This memory is typically located in an area called cluster. The procedural code of an application also takes up space in the cluster. Now is a list of the major components of the operating system.

* The load segments charger to run programs. A complete application can be loaded or individual can be broken in seconds that can be loaded dynamically as needed.

* The event manager operating system reports the occurrence of various low-level events, such as pressing a button or mouse click. In normal conditions, the event manager of the toolbox transfer these events to applications.

* The file manager is responsible for input / output of files, the device manager handles the input / output devices.

* Device drivers are programs with which the various types of devices can present uniform interfaces input / output applications. Three device handlers are integrated into the operating system in ROM: disk handler handles the access to information in records, the sound driver controls the sound generator, and the handler sends and receives serial data over ports serial (thus establishing communication with serial peripheral devices such as printers and modems).

* With the printer driver applications can print data in various printers.

* With AppleTalk Manager applications can transmit and receive information in a communications network AppleTalk.

* The vertical retrace Manager program activities to be undertaken during vertical retrace interrupts that occur 60 times each second when the video screen refreshes.

* The system error handler takes control when a fatal system error and displays an error box appropriate.

* The general utilities operating system offer various useful functions such as getting the date and time, comparison of strings and many more.

* The starter pack is called by the standard file package to start and name albums, most often applied when the user inserts a disk that is not assigned initial values.

* The package provides floating point arithmetic double precision arithmetic. The package offers a transcendental functions random number generator and trigonometric, logarithmic, exponential and financial. Macintosh compilers automatically generate calls to these packages for numerical manipulations.


It is a multiuser operating system that incorporates multitasking. It was originally developed by Ken Thompson and Dennis Ritchie at AT & T Labs Bell in 1969 for use in mini computers. The UNIX operating system has several variants and is considered powerful, more portable and independent of specific equipment other operating systems because it is written in C. The UNIX is available in several forms, among which account AIX, a version of UNIX adapted by IBM (for use on workstations based on RISC), A / UX (graphical version for Apple Macintosh computers) and Mach (a rewritten operating system, but essentially UNIX support for NeXT computers).

UNIX and its clones support multitasking and multiple users. Your file system provides a simple method of organizing files and allows file protection. However, UNIX instructions are not intuitive.

This system offers a number of very interesting tools, such as:

* Include language compilers and interpreters.

* Existence of the user interface, such as windows, menus, etc.

* Many facilities at the time of organization of files.

* Inclusion of query languages.

* Graphical facilities.

* Text editing programs.


SCO is the leading global provider of Unix server operating systems, and one of the leading providers of customer integration software that integrates Windows PCs and other clients with UNIX servers from leading manufacturers. Application servers SCO critical business operations run daily reviews of a wide range of commercial, financial, telecommunications, and government, as well as corporate departments and small to medium businesses of all types. SCO sells and supports its products through a worldwide network of distributors, resellers, system integrators, and OEMs.


* Provides access to shared files and printers from PCs running Windows (R) 95, Windows NT (TM), Windows 3.1, Windows for Workgroups, OS / 2 (R), and MS-DOS (R)

* SCO TermLite, terminal emulator, includes support for SCO ANSI and VT320 on TCP / IP or NetBEUI

* Network Management Tools and monitoring powerful and easy to use with other utilities can be accessed remotely

* Includes the NetBEUI protocol layer for small networks, systems running on SCO OpenServer Release 5 Host and also SCO OpenServer systems Enterprise Version 5

* NT server tools allow management of shared resources on a server using UNIX system from a PC running Windows

* Automatic configuration connectivity layers, including NetBIOS over TCP / IP, and NetBEUI

Fully adhered to the emerging standard called CIFS.


Features: Among the features of Solaris are: Portability: the ABI software application that consists of a binary interface (Application Binary Interface) runs with a Shrink-wrapped (Shrink wrapped) software on all systems sold with the same microprocessor architecture. This forces application developers to reduce software development cost and bring products to market quickly, and forces users to upgrade hardware while retaining their software applications and minimize their costs conversin.ESCALABILIDAD: Applications are used more frequently in overtime, and requires more powerful systems to support them. To operate in a growing environment, software must be able to run on a wide range of powerful and should be able to take advantage of the additional power being procesando.INTEROPERATIBIDAD: heterogeneous computing environment is a reality today. Users buy from many vendors to implement the solution they need. The standardization and interface are clear criteria for a heterogeneous environment, allowing users to develop strategies to communicate through your network. The Solaris operating system can interoperate with some popular systems on the market today, and applications running on UNIX can communicate fcilmente.COMPATIBILIDAD: The computer technology continues to advance rapidly, but needs to stay competitive in the field to minimize their costs and maximize revenue.

Microsoft Windows NT.

Microsoft has not only been writing software for desktop PCs but also for powerful workstations and network servers and databases.

The Windows NT operating system from Microsoft, released on May 24, 1993, is a network OS that provides power, speed and new features in addition to the traditional features. It is a 32-bit OS, and you can work on processors 386, 486 and Pentium.

Besides being multi-tasking, multi-threaded and multiprocessor offers a graphical interface. And bring all the necessary software for networking, allowing customer to be a network or server.

Microsoft Windows 95.

It’s a multitasking environment endowed with a graphical user interface, which unlike previous versions, Windows 95 does not need the MS-DOS to be executed, as it is an operating system.

This OS is based on menus, on-screen displays and a pointing device called a mouse. One of the main features of Windows 95 is that the file names are not restricted to eight characters and three extension can be up to 256 characters for a complete description of the file contents. It also has Plug and Play, a technology jointly developed by PC manufacturers, with which a user can easily install or connect devices automatically enabling the host system hardware resources without user intervention.

Microsoft Windows 98

This Windows supports all types of hardware, including the latest standards such as DVD-ROM and the ability to watch TV on PC.

It also offers features plug and play, which means that if you install a HARDWARE device plug and play, as internal modem, computer operating if it lacks the power, speed and memory to take advantage of its features.

Windows 98, the next step in the Windows family of operating systems for desktop. In a way it is a continuation to expect from Windows 95.

As was obvious to predict, this new version continues to support 32 bits in its totality but still must wait for incorporation any security functionality present in the 32-bit and is now a feature of the NT family.

From the user standpoint common Windows 98 brings nothing new.

Microsoft has made relatively large changes in the interface, so that if a user knows how to use Windows 95, you know how to use Windows 98.

Windows 98: New version of the Windows operating system. Arguably a compilation of features. Many of them were already in Internet Explorer 4.0 (to be installed with the update d desktop) in Windows 95 OSR-2.

Enables support for FAST32 (like Windows 95 ORS-2) and the Active Desktop (IE 4).

Windows 2000

Windows 2000 Professional is fast. Faster than Windows 98.

With 64 MB of memory, Windows 2000 runs on average 25% faster than Windows 98. And it slows down with heavy loads.

Users can run more programs and do more tasks simultaneously because Windows 2000 is based entirely on a 32-bit architecture. Adding more memory, Windows 2000 is faster still.

Supports up to 4 GB of RAM and up to two symmetrical. Unfortunately, achieving this level of performance with Windows 98, even with more memory, impossible.

Improved interface

Windows 2000 Professional enhances the familiar Windows interface to reduce clutter in the desktop (eliminates unnecessary items), simplifying the menu (new functionality introduces smart start menu adapts to the way you work, showing only applications most frequently used).

Keep your network and PC’s current

Windows 2000 Professional works perfectly with their current teams. The infrastructure of operating systems your company is very good, and works with Windows 2000 Server, Windows NT Server, Novell NetWare or UNIX.

Additionally, support for resource sharing built from computer to computer (peer-to-peer) with Windows 9x and Windows NT Workstation Windows 2000 Professional allows interoperate with earlier versions of Windows.

A Windows system safer.

Windows 2000 Professional is very safe at all levels. Based on the integrated security system in all Windows NT operating systems, allows users and administrators to select the appropriate level of protection for your information and applications to exchange or store information on separate computers in the network, an intranet or Internet.

With its Encrypting File System (EFS), Windows 2000 protects perfectly the data from your hard drive.

With support for Kerberos, Windows 2000 protects your corporate network or intranet. Kerberos protects data to track and monitor the activity of each user in a network.

Windows 2000 Professional protects even the most secret communications across a public network with support for Public Key, the L2TP (Layer 2 Tunneling Protocol) and smart cards.

Smart cards are new devices that provide more secure, because instead of relying on only one factor to authenticate a user, require a combination of credentials (such as a user name and password).

Simplified desktop management

Windows 2000 Professional makes life easier for administrators. Several attendees and problem detectors help end users to perform routine or difficult tasks, reducing the time that administrators must spend helping and reducing the number of support calls.

Windows 2000 Professional gives administrators more control over individual desktops.

Windows 2000 offers an unprecedented multilingual support, allowing users to create and view documents in the language used in about 120 international areas.

Windows Millenium

Windows Me supports and shares the same code as Win98, which was an improvement of Win95.

This option will be sold as an OEM (Original equipament manufacturer), ie presented in PC’s.


MY PC: The icon has changed and also how to see the hard drives, as they are now “under My Computer” in the tree showing the Windows Explorer.

Network environment is now> My Network Places.

SEARCH MENU: You have changed the interface, to keep doing the same job, albeit more friendly than before.

Taskbar: apart to find it in the start menu is also found in within the control panel.

Now we can set all those old tricks with a single mouse click, for example:

* Show context menu.

* Move and size of the bar.

* Move programs.

With Windows Millenium can say to God at (MS-DOS), and will not be available boot options “Command Prompt Only” and “Restart in MS-DOS mode”.

Configuration files “CONFIG.SYS” and “AUTOEXEC.BAT” not executed, whether or not, only make sense when you install Windows, then it will not matter content.

(NOTE: Do not run any MS-DOS program, you need to insert parameter in the CONFIG.SYS file. Should bear in mind that Windows Me Millennium Edition and is not 100% compatible with applications designed for MS-DOS.)

System Restore

The system creates at our request “Checkpoints” as we act:

* At the start of each day or occasionally

* Every time we install applications using setup, install and install (if you have another name System Restore does not work, so we could try to rename the installation file). The system creates a checkpoint before installing any new device offers:

* Install new driver.

* Touching Windows settings.

And with a single click “PC Restore”, retrieve the state of our PC to a specific day and time, thus avoiding wasted time and reinstatements, back to the day when the PC was running at 100%, with the push of a button.

We will display a calendar and within it, each day, the points at which we can recover the situation.

Should be noted that the system restore to a date before today, everything is restored as it was that day except the. Doc,. Bmp,. Pdf, email, browser history, favorites and the entire contents of the My Documents folder, for those who use this option will force us to be attentive to other content not currently keep in My Documents, so that there traslades.

This option consuming disk space (though we can set all your options), but will give us much more stability.

Windows XP

This offers an enhanced output menu. The Output menu can now group their apps and more frequent arrivals

This plan focused task allows you see your options of Windows as associated with this task.

Fellow scientific quest: retrieve information search task we are currently using.

This is new

Now you can:

* Order prints directly from the Internet.

* Link directly to camera scanner wizard.

* Images in Slideshow view.

* Post pictures to the Internet.

* Tables of distribution companies by e-mail easier.

* Improves printing, paint and do the best job of photographs.

You can also examine a single image Flastbed browser.

Downloaded updates for Windows, can also be applied to all users on a computer.

Windows is updated now integrates with the help and support center in Windows XP Home Edition. The device manager also investigate Windows.

Internet Connection: instructional protects your computer, when connected to the Internet. Now you can rest assured because the Windows XP does not allow unwanted Internet attacks.

Thanks to the enhanced engine Windows 2000, Windows XP takes on a new and improved look and expands the overall computing experience.

Windows XP has a new look to largely falicitar use by any PC user to improve their skills.

The new graphic design will make it simple computing tasks, and provide a new view of the known deskop, it is the most significant upgrade of the Windows interface since Windows 95.

What is a Windows XP PC Ready

A Windows XP PC now, must find the following hardware requirements:

1. – Preinstalled with Microsoft Windows 2000 Professional or Microsoft operating system Windows Millennium Edition.

2. – Deployments “Design 2000 for Windows” and the logo on the PC or notebook.

3. – Have a minimum of 128 MB of RAM

Windows XP, computer lists are the minimum hardware requirements to run the Windows XP Professional and Windows XP operating systems Home Edition.

Hardware drivers, if needed, is available from the original equipment manufacturer (OEM) in the release of Windows XP.

Welcome Screen / access: Windows makes creating individual accounts for users of your computer, which means that each time you access the system will have its own customized environment.

And if your family shares a computer, Windows XP allows you to go from one user to another quickly without shutting down or restarting any programs.

Start Menu: The familiar Windows interface has been enhanced to further facilitate its use.

5. Conclusion

Having researched and analyzed can see that they have developed various types of operating systems with different interfaces and categories. But we have seen that all operating systems have changed by programmers, and continue to evolve.

The dialogue between the user and the machine is usually done through a command line interface or a graphical user interface (GUI acronym). The command-line interfaces require entering via a keyboard short instructions. The GUI windows used to organize files and applications with icons and menus that list of instructions. The user directly manipulates these visual objects on the screen by pointing, selecting and dragging or by moving them with a mouse.

Using the GUI is easier than the command line interfaces. However, the introduction of instructions with a GUI is slower, so the GUI usually have the option of using a system equivalent to the command line as quick alternative for experienced users.

Operating systems are normally used UNIX, Macintosh OS, MS-DOS, OS / 2, Windows 95 and Windows NT. UNIX and its clones support multitasking and multiple users. Other OS multiuser and multitasking OS / 2, initially developed by Microsoft and IBM, Windows NT and Win95 developed by Microsoft. The multitasking OS Apple Macintosh OS is called. The MS-DOS is a popular OS PC users but only allows a user and task.