Windows evolution is treated in this article. As is well known, the computers have an existence for over 20 years; the PCs have become more competitive with the introduction of graphic user interface. A type of interface: GUI (Graphic User Interface) is a software that shows the programs, procedures and files in the form of graphic symbols. Users interact with the computer by manipulating these symbols, so that is no longer necessary to introduce controls on the keyboard. The DOS operating system, which the user must remember, it is the place where it is often stored an application. Using DOS commands, the user can manipulate the files, disk, memory and many more.
The microcomputer from Apple – Macintosh (1984) was the first computer system that provided a natural interface with the software through the operating system. It was designed from the start operating with a graphic interface for users. The ease of working with graphic interfaces made possible the development of some platforms. One of them is Windows.
At the beginning Windows was seen merely as an extension or a “fronded” DOS operating system. Windows looked like an application of programs written for a small number of computers. Windows was initially released as something like an average system which allowed the user to switch between applications. Windows 1.0 version first published in 1985, leaves much to be desired considering the graphic appearance or the less encouraging mechanisms and poor memory management. It is a disappointment rather than success on the market. It started slowly and awkward in main part due to low memory capacity of these microcomputers at that time. The users had to limit their application to consume less than 640 KB of RAM.
The next version of Windows 2.0 was released in 1987 and was not a disaster, but still far from what is called today a graphic interface. Windows was almost just a menu system that provided a list of available applications. The disadvantages of the interface are explained by the poor performance of the 8086 microprocessor and the memory management of its computing capacity which is extremely reduced. A step forward in the evolution of Windows systems (starts with Windows 2.0) was represented by multitasking, which is the process of running multiple applications, “apparently” at the same time. Due to restrictions imposed by the capacity of RAM, Windows 2.0 cannot speak of a true multitasking, but more of switching between tasks.
In terms of extended memory management, the user may start multiple applications at the same time only when he has the available memory (in other words, when the memory is not affected by MS-DOS to Windows and other applications, which is rather difficult for those times). For the first two versions of Windows we cannot talk about operating a “real” system that uses 1 MB of RAM.
The microprocessor market was launched and an opening era was on its forefront; this led to a rewriting and upgrading of the Windows platforms. A new microprocessor was created, able to manage the extended memory, which has been taken over by the next version of Windows known as Windows 286. The multitasking remained “primitive”, only the switching between different applications was real (enabled applications could open any memory, but only one application was active.). Windows/286 operating mode has been called “standard” because it was based on the capacity to process and to manage an extended memory, even if it was limited to addressing the physical maximum memory of 16 MB.
In 1988, with the release Windows/386 finally the user could use applications in the “multitasking” mode. This mode of application cannot be held in its fullness because the concept of multitasking was cooperative (programs working together). But the programs run with a few moments delayed one from another.
In cooperative multitasking, the programs have complete control on how the time period is managed by the processor. In this case, only the user is the one who usually switches to another application during processing of another one. Because the active application that represent the main one has the control over the memory system, there is no way to remove it from memory and therefore, if inside the active application an error occurred, invariably it occurs in all the system, so the above version and all Windows systems will have to use improved operating modes, which will allow the existing and cooperative multitasking run and also create a virtual memory.
Based on personal computers with microprocessors, we can now talk about how the computer can use the memory by breaking the barrier beyond the 640 KB of conventional memory. To run the program (DOS or Windows) in extended memory, the processors create a virtual system memory address that can be simulated with 640 KB memory (up to the limits of the available extended memory). Thus, each virtual machine has 640 KB for each application to make the processor “believe” that the program works with its own memory, but each virtual system is part of the entire computer, which only has a limited amount of memory.
Windows version 3.0 was released in 1990 and was considered as the second successful operation of the graphic interface, after W/386. W 3.0 product was the version that started to offer users a good reason to prefer DOS applications. Windows’s appearance has improved and the program has provided a better functionality. This first version introduced the concept of program startup manager that is in fact a Windows interface in which is active at least one window. Version 3.0. widely used icons to represent applications. Windows 3.0. could run in a cooperative multitasking system with 16-bit applications. A major deficiency of version 3.0. consists of the system instability, meaning that some applications violate the system integrity.
In 1991, the market experiences the most popular version of the Windows operating platform before it turns into an operating system. Version 3.1. allowed the resumption of 16-bit applications, which could be tranformed into to 32-bit. Some of the strengths that brought Microsoft to this version: the elements tend to dominate the 3D graphics interface, a mechanism has been introduced to included items related to OLE, which enables a dynamic binding of objects in a complex document, the fonts problem was solved by introducing the possibility to update them, True Type fonts are scalable, that is they are reduced or enlarged to keep a readable form (the previous technology required a different set of fonts for each dimension separately), File Manager and Print Manager applications have been improved, multimedia features were integrated, introducing MCI interface (Media Control Interface), which can use virtual memory by using space on the hard disk to simulate RAM, an improved capacity of utilization and management of the drivers, an increasing overall system reliability and many more.
A detached version of Windows 3.1 was created afterwards; the system needed to respond to processing of the working groups and this was the version of peer to peer network known as Windows for Workgroups 3.11. WfW gave almost the same features as the W3.1. but increased the reliability comparing to other versions. The advantages of W version 3.11. included electronic mail (e-mail and many detailed enhancements to the interface).
Windows 95 was launched in June 1995 and replaced the old product with a real platform Windows 3.x providing an operating system performance. Windows 95 may be succinctly characterized by: multitasking enabled; the system always has control over the applications and the computing time, 32-bit applications are running smoothly on this new operating system – you do not need to run only applications written for DOS, Plug & Play included in this OS as a standard as part of the operating system, it has an application programming interface (API Aplications Programs Interface) and more.
Windows 98 is the operating system which brings stability and improves the reliability compared to Windows 95. Windows NT is a 32-bit version of Microsoft user interface that provides real mode multitasking on personal computers based on Intel microprocessors and workstations. Windows NT (New Technology) runs only protected, allowing application designers to use up to 4 GB of RAM. Windows NT has advanced file management features, powerful network functions, being a system which is a real client – server system.11