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Introduction
1.1 DOS restrictions
1.2 Benefits of the system
6.1 Options
6.2 Innovations since Windows 2000
7.1 Innovations
7.2 Multimedia
7.3 Mobility
7.4 Security
8.1 BSD license
8.2 Birth of FreeBSD
8.3 Other BSD systems
Conclusion
Bibliography
Introduction
Today, there are a large number of different types of operating systems that differ in areas of application, hardware platforms, and methods of implementation. Naturally, this also causes significant functional differences between these operating systems. Even for a specific operating system, the set of functions performed is often not so simple to determine, a function that is performed today by a component external to the OS, tomorrow may become an integral part of it, and vice versa. Therefore, when studying operating systems, it is very important to single out from the whole variety those functions that are inherent in all operating systems as a class of products. A computer operating system is a set of interrelated programs that acts as an interface between applications and users on the one hand, and computer hardware on the other. In accordance with this definition, the OS performs two groups of functions:
1 providing the user or programmer with an extended virtual machine instead of real computer hardware, which is more convenient to work with and easier to program;
2 increasing the efficiency of using a computer by rationally managing its resources in accordance with some criterion.
In order to successfully solve their problems, a modern user or even an application programmer can do without a thorough knowledge of computer hardware. He does not need to be aware of how the various electronic components and electromechanical components of the computer function. Moreover, very often the user may not even know the processor instruction set. The programmer user is accustomed to dealing with the powerful high-level features that the operating system provides.
So, for example, when working with a disk, it is enough for a programmer who writes an application to work under the OS, or for the end user of the OS, to represent it in the form of a certain set of files, each of which has a name. The sequence of actions when working with a file is to open it, perform one or more read or write operations, and then close the file. Particulars such as the frequency modulation used during writing or the current state of the motor of the mechanism for moving magnetic read / write heads should not worry the programmer. It is the operating system that hides most of the features of the hardware from the programmer and provides the opportunity for simple and convenient work with the required files.
If the programmer worked directly with the computer hardware, without the participation of the OS, then to organize the reading of a data block from the disk, the programmer would have to use more than a dozen commands indicating many parameters: the block number on the disk, the sector number on the track, etc. And after completion exchange operations with the disk, he would have to provide in his program for the analysis of the result of the operation performed. Given that the disk controller is capable of recognizing more than twenty different options for completing an operation, programming an exchange with a disk at the hardware level can be considered not the most trivial task. The user's work looks no less burdensome if, in order to read a file from the terminal, he needed to set the numerical addresses of tracks and sectors.
The operating system saves programmers not only from the need to work directly with the disk drive hardware by providing them with a simple file interface, but also takes care of all other routine operations related to managing other computer hardware devices: physical memory, timers, printers, etc.
The operating system not only provides users and programmers with a convenient interface to the computer's hardware, but is also a mechanism for allocating computer resources.
MS DOS is the most widely used operating system for personal computers. The number of applications for MS-DOS is in the tens of thousands. There has never been such a large number of programs in the rapidly developing computer field. This variety of programs keeps the MS DOS operating system at the forefront of more advanced and more powerful operating systems. Naturally, this OS has its advantages and disadvantages.
1.1 DOS restrictions
Without a doubt, the main distinguishing feature of the computing systems of the 90s is the graphical user interface (GUI). Supporters of the GUI claim that this interface, focused on the direct visual perception of the objects being processed, greatly speeds up the work with the PC and, due to the ease of development, makes it more accessible to the mass consumer.
A more serious drawback is the 640K memory limit available to DOS programs. Actually, DOS can use up to 1 Mb of RAM, but the IBM PC architecture reduces available memory to 640K. There are many workarounds - mapped memory, expanded memory, DOS extenders , blocks of high memory created by memory managers for the 80386 processor, but the fact remains that there is no natural way for application programs to use the megabytes of RAM installed on modern machines.
The only reliable way to overcome these barriers once and for all is to force the processor to run in protected mode. But neither DOS nor its application programs are capable of running in this mode, so vast expanses of memory remain inaccessible to most programs.
The skeletal nature of DOS attracts software developers. Most major application programs communicate with the screen, keyboard, and printer bypassing DOS, since the services it provides for organizing an interface with these and other devices are completely insufficient. DOS, for example, does not support serial I/O over interrupts. Programmers spend quite a lot of time writing drivers for hundreds of different printers and video adapters. Hardware configurations are so varied that it is difficult to write a program that runs on any IBM-compatible computer. Other than a generic DOS file system, there isn't much that can help here.
An application written for Windows, on the other hand, will run on any PC that meets the stringent requirements of Windows. Importantly, the responsibility for preparing drivers is shifted from the software developer to the hardware manufacturer, so that the developer can devote more time to working on the core of the program.
It is not so easy to learn how to use various DOS programs. DOS does not have a standard interface for application programs, so what works in one program will most likely not work in another. In order to save a file in a Windows program, it is enough to select the Save item from the File menu. In WordPerfect for DOS, you must press F10 to start this process. In the Lotus 1-2-3 package - /FS. This list can be continued indefinitely. Studies show that the average user of an IBM-compatible PC regularly uses two or three applications, while users of Macintosh computers use almost twice as much. One possible explanation for this difference is that the similarity of Macintosh software products makes it easier for a user familiar with one application to learn others.
Another "black ball" against DOS is the complete lack of multitasking. DOS is designed to run only one program at a time, and trying to make it work differently (except in some very specific cases) is fraught with the risk of crashing the system. Even TSRs, which are a limited but still very useful exception to the rule, complicate things when they conflict with each other or with other elements of the system. There are a large number of products from various companies that provide multitasking or task switching on DOS-based systems, but none of them can compare in efficiency with an operating system such as OS / 2, which from the very beginning was designed to run several programs simultaneously .
1.2 Benefits of the system
One of the most obvious strengths of DOS is its moderate hardware requirements. In order to run Windows at a more or less acceptable speed, you need at least a PC based on the 80386 processor with at least 4MB of RAM. If need be, DOS can run just fine with 640 KB on an 8088 processor. DOS programs run fast, in large part because most of them use the text display mode. Even graphical DOS programs are usually several times faster than their Windows counterparts, since they are not dominated by GDI (Graphics Device Interface, graphics device interface, a Windows component that programs use to display on the screen). What one interprets as a disadvantage, another considers a virtue.
The simplicity of DOS allows you to do things that are not possible in more complex operating environments. For example, you can create very powerful utilities using the DEBUG command. The DOS API (application programming interface) is simple enough that even novice programmers can learn to write useful programs. At the same time, the Windows API is very complex and takes several months to master. In addition, writing programs for Windows requires sophisticated tools such as resource editors, compilers, and debuggers that run on that operating system. It is no coincidence that there is much less shareware and freeware for Windows.
The key idea behind Windows is to make programs completely independent of hardware. Windows 3.1 was originally designed to take over communication with a particular type of display or printer. Both the user and the programmer creating an application under Windows are provided with universal tools that remove the problem of ensuring compatibility with specific hardware (hardware compatibility) and software (software compatibility). A unified single graphical user interface makes it easy to learn new software products.
One of the means of ensuring software compatibility is the mechanism for exchanging data between different applications. A special "mailbox" (clipboard) Windows 3.1 allows the user to transfer information from one application to another, without worrying about its format and presentation. Unlike professional operating systems, where the mechanism for exchanging data between programs is available only to the programmer, in Windows 3.1 this is done very simply and clearly for the user.
The mechanism for exchanging data between applications is a vital feature of a multitasking environment. And at present, software manufacturers have already come to the conclusion that one "mailbox" is clearly not enough to transfer data from one application to another. A new, more universal mechanism has appeared - OLE (Object Linking Embedded - Built-in Object Link), which allows you to transfer heterogeneous data from one application to another.
Windows not only allows you to work with a familiar software product, but also offers additional features (launching several programs at the same time, quickly switching from one program to another, exchanging data between them, etc.). The ability to work with all MS-DOS application programs (word processors, DBMS, spreadsheets, etc.) is provided.
Windows 3.1 can run in one of three modes: Real (real), Standard (standard), 386 Enhanced (extended). During the installation process, Windows analyzes the available hardware resources and automatically sets the mode that makes the best use of the available hardware.
In real mode, Windows 3.1 does not use hardware features that are not supported by MS-DOS (this mode is the only one possible for machines with an 8086/8088 processor): as in MS-DOS, the user is limited to 640 KB of RAM.
In Standard Mode (available on computers with 80286 or 80386 processors), Windows 3.1 fully utilizes the extended memory available on the computer, loading all applications written specifically for Windows into it. DOS programs are loaded into regular memory.
In advanced mode (available on computers with an 80386 processor and higher), when running applications (both Windows and regular MS-DOS programs), Windows 3.1 supports the so-called. virtual machine mode (the program being launched, as it were, is allocated its own computer with all the resources), realizing a multitasking environment.
Windows 3.1 allows you to run several programs at the same time (including the same program several times), with the ability to instantly switch from one program to another. This allows you to initiate a long process (printing, sorting, and copying large amounts of data) and move on to other work, rather than waiting for it to finish.
Windows 95 is an evolutionary product of Windows 3.1x and does not mean a complete break with the past. While it introduces many important changes from the 16-bit Windows architecture, it retains some of the key features of its predecessor. The result is a hybrid OS that can run 16-bit Windows applications, DOS-derived programs, and legacy real-mode device drivers, while still being compatible with true 32-bit applications and 32-bit virtual device drivers. Among the most important improvements introduced in Windows 95 are its native ability to run 32-bit multi-threaded applications, protected address spaces, preemptive multitasking, much wider and more efficient use of virtual device drivers, and increased use of 32-bit storage hips. system resource data structures. Its most significant drawback is that it is relatively weakly protected against poorly performing programs containing errors.
Each native Windows 95 application sees an unstructured 4 Gb address space that houses itself plus Windows 95 system code and drivers. Each 32-bit application runs as if it were taking exclusive control of the entire PC. The application code is loaded into this address space between the 2 and 4 Gb marks. Although 32-bit application programs do not "see" each other, they can communicate through the clipboard (Clipboard), DDE and OLE mechanisms. All 32-bit application programs run according to a preemptive multitasking model based on the management of individual threads. The thread scheduler, which is part of the virtual memory management (VMM) system, distributes system time among a group of concurrently executing threads based on an estimate of each thread's current priority and whether it is ready to run. Preemptive scheduling allows for a much smoother and more reliable multitasking mechanism than the cooperative method used in Windows 3.1x.
Windows 95 system code is located above the 2 Gb limit. The space between the 2 and 3 Gb marks contains ring 3 system DLLs and any DLLs shared by multiple programs. (Intel 32-bit processors provide four levels of hardware protection, named from ring 0 to ring 3. Ring 0 is the most privileged.) Ring 0 components in Windows 95 map to a space between 3 and 4 Gb. These important, highly privileged sections of code contain the virtual machine management (VMM) subsystem, the file system, and the VxD drivers.
The memory area between 2 and 4 Gb is mapped to the address space of each 32-bit application program, i.e. it is shared by all 32-bit application programs in your PC. This organization allows API calls to be served directly in the application program's address space and limits the size of the working set. However, this comes at the cost of reduced reliability. Nothing can prevent a program containing a bug from writing to addresses belonging to system DLLs and causing the entire system to crash.
The area between 2 and 3 Gb also contains all the 16-bit Windows applications you run. For compatibility purposes, these programs run in a shared address space, where they can mess with each other just as they did in Windows 3.1x.
Memory addresses below 4 Mb are also mapped to the address space of each application program and shared by all processes. This allows compatibility with existing real-mode drivers that need to access these addresses. This makes another area of memory unprotected from accidental writes. The lowest 64 of this address space cannot be accessed by 32-bit applications, which makes it possible to catch bad pointers, but 16-bit programs that may contain errors can write data there.
Windows NT is essentially a server operating system tailored for use on a workstation. This is the reason for the architecture, in which the absolute protection of applications and data takes precedence over considerations of speed and compatibility. The extreme reliability of Windows NT comes at a high system cost, so you need a fast processor and at least 16 Mb of RAM to get reasonable performance. Like OS/2 Warp, Windows NT achieves low-memory security by forgoing compatibility with real-mode device drivers. Windows NT runs its own 32-bit NT applications, as well as most Windows 95 applications. Like OS/2 Warp and Windows 95, Windows NT allows you to run 16-bit Windows and DOS programs in your environment. programs.
The memory allocation scheme of Windows NT is very different from the memory allocation of Windows 95 and OS/2 Warp systems. Native application programs are allocated 2 Gb of special address space, from the 64K boundary to 2 Gb (the first 64K are completely inaccessible). Application programs are isolated from each other, although they can communicate through the Clipboard, DDE and OLE mechanisms.
At the top of each 2 Gb application block is code that the application program perceives as ring 3 system DLLs. These are actually just call forwarding stubs called client-side DLLs. When calling most API functions from a client-side DLL application, local procedures (Local Process Communication (LPC)) are invoked, which pass the call and its associated parameters to a completely isolated address space where the actual system code is contained. This server process checks the parameter values, executes the requested function, and sends the results back to the application's address space. Although the server process itself remains an application-level process, it is completely protected from and isolated from the application that calls it. Between the 2 and 4 Gb marks are the low-level system components of Windows NT ring 0, including the kernel, the thread scheduler, and the virtual memory manager. The system pages in this area have supervisor privileges, which are set by the processor's physical ring protection circuits. This makes the low-level system code invisible and unwritable to application-level programs, but results in performance degradation during ring transitions. For 16-bit Windows applications, Windows NT implements Windows on Windows (WOW) sessions. Like OS/2 Warp, Windows NT allows 16-bit Windows programs to run individually in their own memory spaces or shared in a shared address space. In almost all cases, 16-bit and 32-bit Windows applications can communicate freely using OLE (through special thunk routines if necessary) whether they run in separate or shared memory. Native applications and WOW sessions run in preemptive multitasking based on the control of individual threads. Multiple 16-bit Windows applications in the same WOW session run according to the cooperative multitasking model. Windows NT can also multitask multiple DOS sessions. Since Windows NT is a fully 32-bit architecture, there are no theoretical limits on GDI and USER resources.
The system was announced in 1994. Alpha testing was conducted from early 1995 to September 1997. The first public beta version of the system was released on September 27, 1997. The system was originally called Windows NT 5.0 because it was the next major version of Windows NT after Windows NT 4.0. However, on October 27, 1998, it received its own name, Windows 2000. The final version of the system was released to the general public on February 17, 2000.
Windows 2000 was released in four editions: Professional (workstation and power user edition), Server, Advanced Server, and Datacenter Server (for use on servers). In addition, there is a "limited edition" of Windows 2000 Advanced Server Limited Edition and Windows 2000 Datacenter Server Limited Edition designed to run on 64-bit Intel Itanium processors.
Subsequently, Windows 2000 was replaced by Windows XP (client side) and Windows Server 2003 (server side) operating systems. As of 2005, Windows 2000 has continued to be popular, especially in large companies where updating operating systems on a large number of computers is associated with serious technical and financial difficulties. According to a study by Assetmetrix, in early 2005, Windows 2000 accounted for more than 50% of Windows workstation operating systems in companies with more than 250 computers. At the same time, in companies with less than 250 computers, Windows XP is more popular.
5.1 New since Windows NT 4.0
Some of the most significant improvements in Windows 2000 over Windows NT 4.0 are:
· Support for the Active Directory directory service. The Active Directory back end comes with the Server, Advanced Server, and Datacenter Server editions, while the Professional edition provides full support for the client-side service.
· IIS version 5.0. Compared to IIS 4.0, this version includes, among other things, version 3.0 of the ASP web programming system.
· NTFS version 3.0 file system (also called NTFS 5.0 internally in Windows 2000 -- NT 5.0). This version of NTFS for the first time introduced support for quotas, that is, restrictions on the maximum amount of stored files for each user.
· Updated user interface, including Active Desktop based on Internet Explorer version 5 and thus similar to the Windows 98 interface.
· Language Integration: Previous versions of Windows were released in three flavors - for European languages (single-byte characters, writing only from left to right), for Far Eastern languages (multi-byte characters), and for Middle Eastern languages (writing from right to left with contextual variants of letters). Windows 2000 combines these features; all its localized versions are made on a single basis.
Windows XP (development codename Whistler; internal version Windows NT 5.1) is an operating system in the Windows NT family of Microsoft Corporation. It was released on October 25, 2001 and is an evolution of Windows 2000 Professional. The name XP comes from the English. experience (experience).
Unlike previous Windows 2000, which came in both server and client versions, Windows XP is a client-only system. Its server counterpart is Windows Server 2003. Although Windows Server 2003 is based on the same code as Windows XP, almost entirely inheriting its user interface, Windows Server 2003 still uses a newer and redesigned version of the NT 5.2 kernel; Windows XP Professional x64 Edition, which appeared later, had the same kernel as Windows Server 2003 and received the same security updates, as a result of which one could say that their development went “in parallel”.
Since April 14, 2009, Microsoft has stopped free support for the operating system (OS) Windows XP, now Windows XP users will not be able to contact Microsoft for free technical support in case of incidents, for design changes and in other situations. Now they will have to use the services of "extended support" for this - this means that all calls will become paid. Extended support will continue until April 8, 2014.
At the end of December 2010, Windows XP is the most widely used operating system in the world with a market share of 47.2%. The maximum of this value was 76.1% and was reached in January 2007.
6.1 Options
Windows XP came in many flavors:
· Windows XP Professional Edition was designed for businesses and entrepreneurs and includes features such as remote desktop access, file encryption (using the Encrypting File System), central permissions management, and support for multiprocessor systems.
· Windows XP Home Edition - a system for home use. It is released as an inexpensive "stripped down" version of the Professional Edition, but is based on the same kernel.
· Windows XP Tablet PC Edition is based on the Professional Edition and contains special applications optimized for stylus input on tablet personal computers. The most important feature is the understanding of texts written by hand and the adaptation of the graphical interface to the rotation of the display. This version is only sold together with the corresponding computer.
· Windows XP Media Center Edition is based on the Professional Edition and contains dedicated multimedia applications. The computer is usually equipped with a TV card and a remote control (RC). The most important feature is the ability to connect to a TV and control a computer via the remote control thanks to a simplified Windows control system. This system also contains functions for receiving VHF radio.
Windows XP Embedded is an embedded component operating system based on Windows XP Professional Edition and is designed for use in various embedded systems: industrial automation systems, ATMs, medical devices, point of sale terminals, gaming machines, VoIP components, etc. Windows XP Embedded includes additional embedding features such as write protection filter (EWF and FBWF), booting from flash, CD-ROM, networking, using the native system shell, etc.
· Windows Embedded for Point of Service is a specialized operating system based on Windows XP Embedded configured for point of service and optimized for retail and service industries. Based on this platform, you can create an ATM, payment terminal, gas station, cash register, etc. Additionally, Windows Embedded for Point of Service includes POS for .NET technology for rapid development of retail applications and support for retail peripheral equipment.
· Windows XP Professional x64 Edition is a special 64-bit version designed for AMD64 Opteron and Athlon 64 technology processors from AMD and EM64T technology processors from Intel. This system does not support processors from other manufacturers, nor does it work with the Intel Itanium processor. Although the first 64-bit processors appeared in 2003, Windows XP Professional x64 Edition was not released until April 2005. The main advantage of the system is fast work with large numbers (Long Integer and Double Float). Thus, this system is very efficient, for example, in performing floating-point calculations required in areas such as special effects for motion pictures and 3D animation, as well as in the development of technical and scientific applications. This system supports mixed mode, that is, the simultaneous operation of 32-bit and 64-bit applications, however, for this, all drivers must be 64-bit. This means that most 32-bit applications can run on this system as well. The only exceptions are those applications that are highly dependent on the computer hardware, such as antiviruses and defragmenters.
· Windows XP 64-bit Edition - This edition was designed specifically for workstations with IA-64 architecture and Itanium microprocessors. This edition of Windows XP has been out of development since 2005, after HP stopped developing Itanium microprocessor workstations. Support for this architecture has remained in server versions of the Windows operating system.
· Windows XP Edition N -- system without Windows Media Player and other multimedia applications. These versions were created under pressure from the European Antimonopoly Commission, which required "lightweight" Windows XP. Currently, this distribution is designed for developing countries. If desired, the user can download all the missing applications for free from the Microsoft website. Exists in both Home and Professional versions.
· Windows XP Starter Edition -- a heavily functionally limited version for developing countries and financially weak regions. In this version, only 3 applications can run at the same time, and each application can create a maximum of 3 windows. The system completely lacks network functions, does not support high resolution, and is also not allowed to use more than 512 megabytes of RAM or a hard disk larger than 120 gigabytes. The system can run on Intel Celeron or AMD Duron level processors.
· Windows Fundamentals for Legacy PCs -- a stripped-down version of Microsoft Windows XP Embedded Service Pack 2 designed for legacy PCs.
6.2 New compared to Windows 2000.
Some of the most notable improvements in Windows XP over Windows 2000 are:
· New GUI design, including more rounded shapes and smoother colors; as well as additional functional improvements (such as the ability to present a folder as a slideshow in Windows Explorer).
· Support for the ClearType text smoothing method, which improves the display of text on LCDs (disabled by default).
· The ability to quickly switch users, allowing you to temporarily interrupt the work of one user and log in as another user, while leaving the applications launched by the first user included.
· A "remote assistance" feature that allows advanced users and technicians to connect to a Windows XP computer over a network to resolve problems. At the same time, the assisting user can see the contents of the screen, conduct a conversation, and (with the permission of the remote user) take control.
· A system recovery program designed to return the system to a certain previous state (this function is an extension of a similar program included in Windows ME), as well as improving other methods of system recovery. So, when loading the last known good configuration, the previous set of drivers is also loaded, which in some cases makes it easy to restore the system in case of problems that arose as a result of installing drivers; the ability to roll back drivers, etc.
· Improved compatibility with older programs and games. A special compatibility wizard allows you to emulate for a separate program the behavior of one of the previous versions of the OS (starting with Windows 95). However, the compatibility feature is present in Windows 2000 Service Pack 2.
· Possibility of remote access to the workstation due to the inclusion of a miniature terminal server in the system (Professional edition only).
· More advanced system management functions from the command line.
· Windows Explorer support for digital photo formats and audio files (automatic display of metadata for audio files, such as ID3 tags for MP3 files).
· Windows XP includes technologies developed by Roxio that allow you to directly burn a CD from Explorer without installing additional software, and work with rewritable CDs becomes similar to working with floppy disks or hard drives. Media Player also includes the ability to record audio CDs. The ability to work with disk images is not provided.
· Windows XP can work with ZIP and CAB archives without installing additional software. Working with archives of this type is possible in Explorer as with ordinary folders, which can be created and deleted, go into the archive, add / delete files, just like working with ordinary folders. It is also possible to set a password for the archive. If necessary, you can assign any third-party software to work with these archives.
· Improvements in the EFS subsystem, consisting in the optional recovery agent, more secure key storage. Encrypted files are now not just deleted, but overwritten with zeros, which is much more reliable. Starting with SP1, it becomes possible to use (and is used by default) the AES algorithm, along with DESX and 3-DES.
· Customizable toolbars to optimize access to files, folders, and Internet resources. It is enough to place them on the edge of the Desktop (like a sidebar) or on the Taskbar (in the form of a link).
Windows 7 is the operating system of the Windows NT family, following Windows Vista. In the Windows NT line, the system is version number 6.1 (Windows 2000 - 5.0, Windows XP - 5.1, Windows Server 2003 - 5.2, Windows Vista and Windows Server 2008 - 6.0). The server version is Windows Server 2008 R2, the version for integrated systems is Windows Embedded Standard 2011 (Quebec), the mobile version is Windows Embedded Compact 2011 (Chelan, Windows CE 7.0).
The operating system went on sale on October 22, 2009, less than three years after the release of the previous operating system, Windows Vista. Although initially the operating system was supposed to go on sale as early as August 31, 2009. Volume Licensing partners and customers were granted access to RTM on July 24, 2009. The final unlicensed version (a copy of the discs that went on sale) was available to everyone from the first days of August 2009.
Windows 7 included both some of the developments that were excluded from Windows Vista, as well as innovations in the interface and built-in programs. Inkball, Ultimate Extras were excluded from Windows 7; applications that have analogues in Windows Live (Windows Mail, Windows Calendar, etc.), Microsoft Agent technology, Windows Meeting Space; the ability to return to the classic menu and the automatic docking of the browser and email client have disappeared from the Start menu.
7.1 Innovations
The operating system has support for multi-touch control. This feature was first demonstrated by Microsoft at the annual TechEd "08 conference in Orlando. The demonstration used system build 6.1.6856, as well as a prototype laptop with a multi-touch screen.
Branch Cache network technology allows you to cache the contents of Internet traffic. If a user on the local network needs a file that has already been downloaded by one of the users on his network, he will be able to get it from the local cache storage, and not use a channel with limited bandwidth. The network cache can work in two modes - Hosted Cache and Distributed Cache. In the first case, the file is stored on a dedicated local server running Windows Server 2008 R2, in the second case, the server is not required, and the cache is distributed for storage on users' computers. The technology is designed for large networks and is offered for implementation in enterprises as part of the Corporate and Ultimate versions of the OS.
Rice. 1 The Start menu in Windows 7 has become shorter and has lost icons
The OS also has about 120 wallpapers, unique for each country and language version. For example, the Russian version includes a Russia theme with six unique high-definition wallpapers. All versions include 50 new fonts. Existing fonts have been improved to correctly display all characters. Windows 7 is the first version of Windows to include more fonts for displaying non-Latin characters than for displaying Latin characters. The font control panel has also been improved - by default, it will only display fonts for which the layout is installed on the system. Implemented support for Unicode 5.1. The Instant Search search bar now recognizes more languages. An additional advantage of Windows 7 is closer integration with driver manufacturers. Most of them are auto-detected, and are 90% backwards compatible with Windows Vista drivers.
Windows 7 supports folder aliases internally. For example, the Program Files folder in some localized versions of Windows was translated and displayed with a translated name, but remained in English at the file system level.
Windows 7 is more compatible with Windows XP than Windows Vista (SP1, SP2), for example, it was not possible to run some old XP programs on Windows Vista.
7.2 Multimedia
The new, 11th, version of DirectX, released for the first time as part of this operating system, has the following improvements: support for new compute shaders, multi-threaded rendering, improved tessellation, new texture compression algorithms, etc.
Windows Media Player 12 received a new interface and became truly "omnivorous", unlike its predecessor, which required a large number of codecs to play. However, it cannot play licensed Blu-Ray video discs, but it can read and write data to them.
7.3 Mobility
While Windows Mobility Center hasn't changed much since Windows Vista, Windows 7 runs longer than its predecessor on laptops and consumes less power, especially when playing DVDs. On a system introduced in late August 2009 with two identical laptops preloaded with Windows 7 and Windows Vista, the gain was up to 20%. It also showed a record speed of loading the system - 11 seconds. The system included an SSD and other high performance components. A similar test inspired enthusiasts to test the impact of the browser on battery life. Included in Windows 7, Internet Explorer 8 showed the best results on the Intel platform.
However, according to the results of independent tests, it was found that Windows 7 is noticeably faster than Windows XP in draining the laptop battery. Starting in August, Laptop magazine (laptopmag.com) experts have been testing the final version of Windows 7, including measuring the battery life of portable PCs running it. The overall result was disappointing: the average netbook running the "seven" as a whole runs on battery 47 minutes less compared to XP. In the case of the ASUS 1008HA model, the "shortage" was 57 minutes or 16.7%. Other publications also conducted similar studies and also came to these conclusions. The loss is from 10 to 30 percent of the time of work.
A possible reason is the optimization of Windows 7 for graphics accelerators, while many netbooks run on integrated Intel and VIA graphics cards, which sometimes do not support Aero functions. Also, many netbooks run Windows 7 Starter Edition, which does not fully support Aero. Another possible reason is the lack of OS support from netbook manufacturers. So, with new drivers and BIOS dated November 2009, Asus Eee 1000HA works under Windows 7 for as long as under Windows XP.
Remote Desktop.
The Remote Desktop feature has also been changed. Support for the Aero Peek interface, Direct 2D and Direct3D 10.1 was introduced, support for multiple monitors, media extensions, DirectShow, and the ability to play audio with low latency.
7.4 Security
Windows 7 has a more flexible User Account Control (UAC) setting, which, unlike Windows Vista, has two more intermediate states between the "Always notify" and "Never notify" modes - "Notify only when programs try to make changes to the computer ” (default position), “Notify me only when programs try to make changes to the computer (do not darken the desktop)”. It's worth noting that, unlike Vista, dimming only happens when the program is active and in the foreground. If you clicked while opening UAC and deactivated the program, the dimming may not occur.
Changes have been made to BitLocker encryption technology, and the BitLocker to go removable media encryption feature has been added, which allows you to encrypt removable media, even without a TPM module.
Added the ability to protect data on USB drives using Enhanced Storage.
Improvements have also been made to the Windows firewall - the function of notifying the user about blocking a program that tries to access the network has returned.
With Group Policy and the AppLocker feature, it will be possible to prevent certain applications from running.
The DirectAccess feature allows you to establish a secure connection to the server in the background, unlike VPN, which requires user interaction. DirectAccess can also apply group policies before a user logs on.
The probability of getting viruses, worms, trojans into the Windows 7 system is 25% lower than in Windows Vista, and 20% lower than in Windows Vista SP2. In addition, many viruses simply do not run on the 64-bit version of Windows 7.
Sandbox.
Windows 7 uses a sandbox mode, the implementation of which was discussed during alpha and beta testing (under development by Longhorn). Access to low-level sockets for unmanaged code, as well as direct access to the file system, hardware abstraction layer (HAL), full access to a memory address, is prohibited. All access to external applications, files and protocols is controlled by the operating system.
New Aero interface features
Aero Peek function
shake
A new Aero Shake feature has been added to the Windows Aero interface, allowing you to minimize all inactive applications with a mouse movement. To activate it, just grab the title of the window and shake it a little.
Peek
The Aero Peek feature allows you to display thumbnails of windows when you hover your mouse over the taskbar icon, switch between application windows with a simple click on the icon, drag and drop different windows and applications on the taskbar, view the desktop with one hover to a special area of the screen, and much more.
Snap
Similar to the Shake feature, the Aero Snap feature allows you to rotate a window half-screen, full screen, or just the vertical axis by moving the mouse.
FreeBSD is a UNIX-like operating system that is freely available on the Internet. It is widely used in ISPs, embedded devices, and anywhere else where reliability is important. The FreeBSD operating system is the result of over thirty years of continuous development, research and development. The story began with the BSD project in 1979. BSD is the grandmother of FreeBSD. Years ago, AT&T needed its own custom business software. However, she did not have the right to intrude into the computer industry and therefore could not sell her software. As a result, AT&T provided various pieces of software and its source code to universities at a very low cost. Universities have been able to save money by using this software instead of commercially priced software, and university students have access to great technology. They could read the source code and study how it worked. In return, AT&T received a free playground for experimentation and a generation of computer scientists who grew up on AT&T hardware. Everyone was happy. The UNIX system was the most famous software distributed under this license plan. The original UNIX system had a lot of shortcomings compared to modern operating systems. However, thousands of students had access to the source code, and hundreds of teachers needed interesting projects for their students. When programs did not behave as expected, or there were some bugs in the operating system itself, then everyone who worked on the system day after day had the opportunity and incentive to correct these deficiencies. Thanks to their efforts, the UNIX system was soon improved to include many features that we now take for granted. Students added the ability to control the launch of programs (task management, job control). The UNIX S51K file system brought system administrators to tears, so they replaced it with the Fast File System, the features of which have migrated to all modern file systems. Over the years, a large number of useful programs have been written that have gradually replaced entire blocks of the UNIX operating system. The Computer Systems Research Group (CSRG) at the University of California, which was involved in these improvements, became the central repository for UNIX code improvements. The CSRG collected the changes, evaluated them, packaged them, and distributed the builds free of charge to all holders of a valid AT&T UNIX license. In addition, CSRG has collaborated with the Defense Advanced Research Projects Agency (DARPA) to implement various features in UNIX, such as the TCP/IP protocol stack. The resulting software collection was called the Berkeley Software Distribution, or BSD. BSD users took software, improved it, and then brought their work back to BSD. Today we consider this to be the standard for open source software development, but in 1979 it became revolutionary. The development took a long time. Looking at the copyright information of the old BSD system, you can see the following: Copyright 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994 The Regents of the University of California. All rights reserved. Yes, 15 years of work is a lifetime in software development. How many parts of the operating system not only continue to be used, but are actively developed after
15 years? In fact, so many changes were made to the original BSD system that over the years there has been an almost complete replacement of the original UNIX code with code created by the CSRG staff and their contributors. There is very little left of the AT&T product. Eventually funding for the CSRG stopped and it became apparent that the BSD project was coming to an end. In 1992, after some controversy in the bowels of the University of California, the BSD code was released to the general public. This transfer of rights is called the BSD license.
8.1 BSD license
The BSD code was made available to the public on perhaps the most liberal terms in the history of software development. Today, the main provisions of the license look like this:
* Do not claim that you wrote this code.
* Don't blame us for bugs in the code.
* Do not use our name to promote your product.
This means that you can do whatever you want with the BSD sources. (The original BSD license required mentioning the use of code released under the BSD license, but this requirement was later removed.) It doesn't even require you to share your changes with the authors of the original code! Anyone is free to include BSD code in proprietary, free, and open source products. The BSD code can be printed on punched cards and covered with them on the lawn. Would you like to release 10,000 BSD CDs and give them to your friends? Please. Sometimes when discussing the BSD license, not "copyright" is mentioned, but "copycenter" (copy center) - "take this license to a copy center and print several copies for yourself." It's no surprise that some companies, like Sun Microsystems, have seized on it so much—it's free, reliable, and a large number of graduates have experience with it.
BSDi was even created specifically to take advantage of BSD UNIX. The AT&T/CSRG/BSDi Race Even in the heyday of CSRG, work on UNIX at AT&T never stopped. AT&T took the BSD UNIX bits they distributed, integrated it with their UNIX system, and then passed the result back on to the universities that made those improvements. This approach worked well until AT&T broke up and the resulting companies were allowed to compete in the software market. AT&T had one significant property: a high-end operating system that had been fine-tuned by thousands of people around the world. This operating system had many useful features, such as small but powerful commands, a modern file system, job control capabilities, and the TCP/IP protocol stack. AT&T formed its subsidiary, Unix Systems Laboratories (USL), which began to successfully sell UNIX to enterprises for a lot of money, while maintaining relationships with universities, which provided it with such an improved operating system.
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Purpose and functions of the operating system.
OS purpose- organization of the computing process in the computing system, rational distribution of computing resources between individual tasks to be solved; providing users with numerous service tools that facilitate the process of programming and debugging tasks. The operating system plays the role of a kind of interface (Interface - a set of hardware and software necessary to connect peripheral devices to a PC) between the user and the aircraft, i.e. The OS provides the user with a virtual aircraft. This means that the OS largely forms the user's idea of the capabilities of the aircraft, the convenience of working with it, and its throughput. Different operating systems on the same technical means can provide the user with different opportunities for organizing a computing process or automated data processing.
OS features:
1) Job scheduling. Processor usage.
2) Providing programs with means of communication and synchronization.
3) Memory management.
4) File system management.
5) Input-output control.
6) Ensuring security.
Types of user interfaces of operating systems
According to the type of user interface, text (linear), graphic and speech operating systems are distinguished.
A user interface is a set of ways in which a user interacts with an application. The user interface includes the user's communication with the application and the language of communication.
Text OS
Linear operating systems implement a command line interface. The main control device in them is the keyboard. The command is typed on the keyboard and displayed on the display screen. The command is terminated by pressing the Enter key. To work with operating systems that have a text interface, you need to master the command language of this environment, i.e. a set of commands whose structure is determined by the syntax of this language.
The first true operating systems had a text interface. It is currently also used on servers and users' computers.
Graphic OS
Such operating systems implement an interface based on the interaction of active and passive graphical on-screen controls. The control devices in this case are the keyboard and mouse. The active control element is the mouse pointer - a graphical object, the movement of which on the screen is synchronized with the movement of the mouse. Passive controls are graphical application controls (on-screen buttons, icons, radio buttons, checkboxes, dropdowns, menu bars, etc.).
An example of a purely graphical operating system is the operating system of the Windows family. The start screen of such operating systems is a system object called the desktop. The desktop is a graphical environment that displays objects (files and directories) and controls.
In graphic operating systems, most operations can be performed in many different ways, for example, through the menu bar, through the toolbar, through the window system, etc. Since operations are performed on an object, it must first be selected (highlighted).
The basis of the graphical user interface is an organized system of windows and other graphical objects, during the creation of which developers strive for the maximum standardization of all elements and methods of work.
Window - this is a framed rectangular area on the monitor screen in which applications, a document, a message are displayed. A window is active if the user is currently working with it. All operations performed in graphical operating systems occur either on the desktop or in a window.
Speech OS
In the case of a SILK interface(from English speech - speech, image - image, language - language, knowledge - knowledge) - on the screen, according to a speech command, there is a movement from one search image to another.
It is assumed that when using the public interface, you will not need to understand the menu. Screen images will unambiguously indicate the further path of moving from one search image to another along semantic semantic links.
Job scheduling.
Task Scheduler - Microsoft Management Console (MMC) snap-in, which includes additional help topics for advanced users.
A task scheduler is a program or service of the operating system that launches other programs depending on various criteria, such as:
the arrival of a certain time
the operating system enters a certain state (idle, hibernate, etc.)
an administrative request has been received through the user interface or through the remote administration tools.
Microsoft Windows
In versions of Windows up to and including XP, this service was provided mainly for the needs of the end user. Starting with Windows Vista, this service is actively used by the operating system itself for maintenance (defragmentation of hard disk partitions, component testing, file indexing, etc.).
Cron- task scheduler daemon in UNIX-like operating systems.
Organization of input-output.
When the processor encounters an I/O-related instruction while executing a program, it executes it by passing the appropriate instructions to the I/O controller. With programmable I/O, this device performs the requested action and then sets the appropriate bits in the I/O status registers. The I/O controller no longer sends any signals to the processor, including interrupt signals. Thus, it is the processor's responsibility to periodically check the status of the I/O module; it must keep checking until the I/O operation is complete.
Backoff Processor
A very rare option and not quite unambiguously interpreted. BOFF# (Back Off) - a signal of unconditional disconnection of the processor from the bus. On this signal, the processor gives up control of the bus in the next cycle, interrupting the current cycle. At the end of the "BOFF#" signal, the processor restarts the interrupted bus cycle. Possible values of the option:
"Disabled" (or "No"),
"Enabled" (or "Yes").
Based on the foregoing, we can assume that the option refers to the unconditional transfer of bus control to another device, i.e. without setting different waiting intervals, certain control transfer conditions, etc. This will be discussed in more detail below (the topic of "arbitration"). It is clear that in order to use the specified signal, the option must be enabled.
The option may be called "Backoff CPU".
Base I/O Address
Option to set the base address of the device. I/O addresses are input/output addresses, also called system and peripheral device ports. In fact, these are "mailboxes" through which programs and devices exchange messages and data. Each address is allocated one byte of system memory. Since 386 systems there are 65536 such addresses, although most of them are never used.
The base I/O address is the first address in the address space given to the device. For example, most network adapters use an address range of 20h, and for COM 1, a range of addresses from 3F8h to 3FFh is reserved, which are used for various tasks, such as setting speed, parity, etc. The entire I/O address range is 0000-FFFFh.
No specific values are given for this option. And in terms of content, the option is more "suitable" for materials on the distribution of resources of various devices. But the option is placed in this place deliberately to emphasize that I / O addresses belong not only to memory, but also to the central processor. After all, control procedures begin from it, and they are produced through the I / O ports.
If you look at the "Ports" chapter, you can pay attention to the fact that the available addresses are already "assigned" to system or peripheral devices. But when programming an input / output device, and this may be an expansion card, it is quite acceptable to use "traditional" addresses or unused ones. In some cases, the use of unused addresses, which is associated, for example, with the absence of a device, does not necessarily lead to conflicts.
The "Extended I/O Decode" option discussed above showed us some of the nuances and even complexities of decoding I/O addresses. The "PCI I/O Start Address" option, intended generally for PCI devices, nevertheless allows ISA devices to create an additional address area and thus avoid "unpleasant overlays".
Branch Target Buffer
Just a rare feature, rather in the sense of uniqueness, rather than the frequency of occurrence in different BIOS versions. What is this about? BTB (Branch Target Buffer) is a CPU block responsible for dynamic branch prediction. This takes into account which jump addresses were previously selected. This is the most important node of a modern processor (see special literature).
It turns out that with the help of this option it is possible to refuse ("Disabled") the use of the mechanism for predicting branches, branching of processor commands or enable it ("Enabled"). It remains to be added that enabling the option improves system performance.
CPU ADS# Delay 1T or Not
Option to set delay for ADS# signal. A few preliminary words. ADS# (Address Status) - address strobe entered by the initiator of the exchange as an indicator of the validity of the address. The signal operates on the system bus and can be output both from the processor side and from the chipset side. The transmission of the address and the address strobe occurs simultaneously, since the system bus has its own dedicated line for the address strobe. It is clear that ADS# is a standard signal of processors.
The presented option also indicates the possibility of no delay, which increases the speed characteristics of data exchange in the system. In fact, this option allows you to set the time during which the processor (or chipset, memory controller) will wait from the chipset (processor) for a data address status signal, which determines the speed of lazy writing on the system bus. It is clear that we are also talking about data transfer to the PCI interface. The default value does not need to be changed. However, when installing a faster processor, the speed can be increased, i.e. remove delay.
The option placed in the header has two values: "1T", "No Delay".
But the option "Cyrix M2 ADS# delay" offered the standard "Enabled" and "Disabled". The "Latency from ADS# status" option offered numerical values in system bus cycles: "2T" (default), "3T".
It must be understood that by setting the "delay time", we thereby determine the temporal characteristics of the write cycles. And taking into account the fact that the use of a delayed write buffer leads, as a rule, to the formation of small packets (in double words or in two DWs). Therefore, by setting the value to "3T", we get 5 system clocks for each double word. The arithmetic here is simple. 3 delay cycles, one address cycle and one data reading cycle.
CPU BIST Enable
In some chipsets, starting from the 430th series, specialized BIST registers have been used. They didn't carry a lot of work. If the system (chipset + processor) supports the Built-In Self Test function, then the BIST register stores the "Start BIST" or "Completion Code" commands in its bits. If the "system" does not support BIST functions, then setting the option to "Enabled" will have no effect, and the corresponding register bits will be set to "0".
Built-in and, importantly, a full-fledged BIST self-test mechanism was implemented in Pentium III processors. It provided constant control over freezes and crashes in microcode, large programmable logic arrays, and also provided testing of the instruction (instruction) cache and data cache, TLB buffers (Translation Lookaside Buffer - paging buffer) and ROM memory segments. Within 10-30 ms (the time is related to the internal frequency of the processor core), about two thirds of all internal processor blocks are covered by internal testing. As soon as the test is completed, the processor switches to operating mode, and the results of the test are recorded in the EAX register.
CPU Drive Strength
This and not entirely clear option determines the intensity (strength), or rather, the duration of the signals during data transfer from the chipset to the processor. The parameter is measured in system cycles. The higher the value of the parameter, the longer the duration of the signals, and the use of this "BIOS Setup" option may be useful for "overclocking" processors. But not for every system, increasing the values of the option can lead to maintaining the stability of the "overclocked" processor. The option values are: 0, 1, 2, 3.
It remains to add that this option requires further clarification.
CPU Fast String
- (fast string operations). Enabling this parameter ("Enabled") allows using some specific features of the architecture of the Pentium Pro processor family (Pentium II, Deschutes, etc.), in particular, the ability to cache operations with strings. It is only necessary to understand that the conditions for enabling this mechanism must also be met in the user program itself. These conditions are specified in the documentation for any processor of this family. It is recommended to leave the parameter in the "Enabled" state.
CPU Line Read Multiple
In this option, we are talking about reading the so-called processor. "full cache" lines. When the "cache" line is full of data, it is 32 bytes (eight double words). Since the line is "full", the system knows exactly how long the data on the line will be read. This system will require 4 cycles, after which a new address will be set. Therefore, the system does not need a signal about the end of the data transfer, and the system will not be waiting for such a signal, being free to solve other problems. When this option is enabled ("Enabled"), the processor will be able to read data simultaneously from several "full cache" lines. The default is "Disabled".
The option may be called "CPU Multiple Reads".
The functions listed below do not contain multiplicity properties, but their placement in this place is more than justified. Here are their names: "Allow Full Line Reads", "Full Cache Line Reads", "CPU Line Read". Each of them, through "Disabled" or "Enabled", prohibits or allows the use of "full" reading lines.
The "CPU-to-PCI Read-Line" option is set to "On" and "Off", but the differences don't end there. An option under this name was introduced and optimized to work with Intel OverDrive processors. Therefore, an increase in CPU efficiency can only be achieved with these processors. Otherwise, the option should be disabled.
CPU Read Multiple Prefetch
Option to enable/disable the multiple prefetch mode. The meaning of the prefetch process is that the processor, selecting the desired instruction (for example, from the PCI bus or memory), simultaneously starts reading the next one, thereby initiating the next process. This is facilitated by the fact that the chipset can have four read lines. For example, the first chipsets supporting Pentium Pro processors (Intel 450KX/GX, both codenamed Orion) had 4 such read lines. Multiple prefetching, on the other hand, allows multiple instruction fetching operations to be performed simultaneously, which significantly increases system performance. The default is "Disabled".
The option may also be called "CPU Multiple Read Prefetch".
If we are not talking about "multiple" operations, then the option can be called "CPU Line Read Prefetch", "CPU Read Prefetch".
I/O Space Access
This option allows access to the entire I/O address space via "Enabled". Rare BIOS does without strange options.
Processor Number Features
An option to set automatic reading and output of information about the built-in serial number of the Pentium III processor in the BIOS of motherboards that support its installation. To implement this feature, of course, the value of the parameter as "Enabled" is required. In all other cases, the value is set to "Disabled". It is also installed by default.
The option may be called "Processor S/N".
In "Phoenix BIOS" there is a similar option called "CPU Serial Number", and in "AMI BIOS" - "Processor Serial Number".
Why is serial number information needed? Let's say for external programs. One example is reading processor information when browsing the Internet. Naturally, this violates the privacy and rights of the user. At one time, this problem was quite vigorously discussed.
OS file system.
The file system is part of the OS, including:
1) The collection of all files on the disk.
2) Sets of data structures used to manage files.
3) A complex of system software tools that implement various operations on files.
FS functions:
1) File naming.
2) Programming interface for applications.
3) Mapping the logical model of the file system to the physical organization of data storage.
4) Resilience of the file system to power failures.
File types:
1) Ordinary files are files containing information of an arbitrary nature that the user enters into them, or resulting from the operation of system and user programs.
2) Directories are a special type of files containing system help information about a set of files that are grouped by users according to some informal attribute.
3) Special files are files associated with system I/O devices that are used for the mechanism of access to individual files and external devices.
Modern file systems support other types of files: symbolic links; named pipelines; memory-mapped files, etc.
Microsoft is still shipping its LAN Manager network OS. A large number of ISVs license this OS and maintain their own versions of LAN Manager as part of their networking products. These companies include well-known firms such as AT&T and Hewlett-Packard. LAN Manager requires OS/2 operating system to be installed on the file server, workstations can run under DOS, Windows or OS/2. OS/2 is an operating system that implements true multitasking, running in protected mode on x86 and higher microprocessors. LAN Manager uses a 32-bit version of the OS/2 file system called HPFS, which is optimized to run on a file server by caching directories and data. LAN Manager is the first network operating system designed to support a client-server environment. The key components of LAN Manager are the redirector and the server. LAN Manager is particularly effective in supporting the client-server architecture for database management systems. LAN Manager allows OS/2 workstations to support peer-to-peer network service. This means that the workstation can act as a database server, print server or communication server. The limitation is that only one user other than the owner of this workstation has access to this peer-to-peer service.
To work in a small network, Microsoft offers a compact operating system that does not require significant hardware or software costs, Windows for Workgroups. This operating system allows you to organize a network according to the "peer-to-peer" scheme, while there is no need to purchase a special computer to work as a network server. This operating system is especially suitable for networking tasks in teams whose members used Windows 3.1 extensively in the past. Windows for Workgroups achieves high network processing performance by making all network drivers 32-bit virtual drivers.
Computers with the image of a seven-color apple have long ceased to be a curiosity. They can now be found almost everywhere - in publishing houses, advertising agencies, design studios. The high popularity of Apple computers among layout designers and designers can be explained by many reasons, but everyone notes the high quality, user-friendly interface and reliability of the equipment of this brand. The company is approaching the new millennium confidently occupying a worthy place among the largest computer manufacturers. New developments based on the PowerPC 750 (G3) processors have already gained well-deserved popularity, and Apple is preparing to release even more powerful models of computers equipped with a reliable and convenient MacOS operating system. One of the latest models - iMac - has become a hit of the season, breaking all sales records. Distinctive features of this computer - high computing power, ease of installation and configuration, elegant design at low cost.
The original philosophy for developing Unix is to distribute functionality into several small pieces, programs.
This was originally a requirement coming from the hardware that Unix was originally running on. For some strange reason, the resulting operating system turned out to be quite useful on other hardware. You can achieve new functionality and new features relatively easily by putting small parts (programs) together in a new way. If new utilities appear (and they do), you can build it into your old toolkit. Unfortunately, Unix programs are getting bigger and more feature-rich these days, but some flexibility and interoperability still remains. For example, when I wrote this document, I used these programs extensively; fvwm for managing "windows", emacs for editing text, LaTeX for formatting it, xdvi for viewing formatted text, dvips for preparing it for printing, and finally lpr for printing. If I find a better new dvi viewer tomorrow, I can use it instead of the old one without changing the rest of the settings.
network OS.
Network OS - designed for processing, storing and transmitting data in an information network.
Tasks:
Resource sharing;
Network administration.
Are divided into:
Network OS for servers;
Network OS for users.
Network OS is the basis of any computer network.
Under network OS:
In a broad sense: is understood as a set of operating systems of individual computers interconnected for the purpose of exchanging messages and sharing resources according to common rules - protocols. These protocols provide the main functions of the network: object addressing; the functioning of the services; data security; network management.
In a narrow sense: A network OS is the operating system of a single computer that provides it with the ability to work on a network.
They are divided into classes:
Peer-to-peer (the same OS is installed);
Dual-rank (more commonly referred to as dedicated server networks).
Deadlock situations.
Deadlock (clinch, deadlock)- a situation that will never be resolved, i.e. the process is waiting for a resource, but it will not be allocated to it.
OS in a deadlocked state ("hanging") - when several processes are in a deadlocked state.
A simple deadlock in the OS:
Let there be 2 processes A and B, which before starting work are provided with resources P1 and P2, respectively. At some point in time, process A needed P2, and process B needed P1, but they will not get them, because they are held by previous processes => there is a simple deadlock in the OS.
OS deadlock prevention rules:
Before a process can begin its work, it must be provided with all the required resources.
In the event that during its operation it needed an additional resource, it needs to return all previously allocated OS resources and then request all the required resources with this additional resource.
Infinite postponing of the process.
In a system where processes have to wait until it allocates the required resource to it, a situation may arise that processes with a higher priority will come, requiring the same resource - a situation of infinitely postponing a process.
In some operating systems, this situation is prevented by increasing the priority ("senescence" of the process) in order for it to be provided with the required resource, after which the priority is reduced to the previous level.
Resource management.
The idea that an OS is primarily a system that provides a user-friendly interface is consistent with a top-down view. Another view, from the bottom up, gives an idea of the OS as some kind of mechanism that controls all parts of a complex system. Modern computing systems consist of processors, memory, timers, disks, tape drives, network communications equipment, printers, and other devices. In accordance with the second approach, the function of the OS is to allocate processors, memory, devices, and data among processes that compete for these resources. The OS must manage all the resources of the computer in such a way as to ensure maximum efficiency of its functioning. The efficiency criterion can be, for example, the throughput or reactivity of the system. Resource management involves solving two common tasks that do not depend on the type of resource:
resource planning- that is, determining to whom, when, and for divisible resources and in what quantity, it is necessary to allocate this resource;
resource status tracking- that is, maintaining operational information about whether the resource is occupied or not, and for divisible resources - how much of the resource has already been distributed, and how much is free.
To solve these common resource management tasks, different operating systems use different algorithms, which ultimately determines their appearance as a whole, including performance characteristics, scope, and even user interface. So, for example, the processor control algorithm largely determines whether the OS is a time-sharing system, a batch processing system, or a real-time system.
Types of operating systems. The concept of the operating system.
Operating system (OS) - a set of system and control programs designed for the most efficient use of all resources of a computer system (CS) (Computing system - an interconnected set of computer hardware and software designed to process information) and ease of working with it.
Batch processing operating systems.
A batch processing operating system is a system that processes a batch of jobs, i.e. multiple jobs prepared by the same or different users. Interaction between the user and his job during processing is either impossible or extremely limited. Under the control of the batch processing operating system, the computer can operate in single-program and multi-program modes.
Time sharing operating systems.
Such systems provide simultaneous service to many users, allowing each user to interact with his task in a dialogue mode. The effect of simultaneous service is achieved by dividing the processor time and other resources between several computing processes that correspond to individual user tasks. The operating system provides the computer to each computing process for a small interval of time; if the computational process has not completed by the end of the next interval, it is interrupted and placed in the waiting queue, giving way to the computer to another computational process. The computer in these systems operates in a multiprogram mode.
The time sharing operating system can be used not only to serve users, but also to control technological equipment. In this case, the “users” are individual control units of the actuating devices that are part of the technological equipment: each unit interacts with a certain computing process for a time interval sufficient to transfer control actions to the actuating device or receive information from sensors.
Operating systems of real time.
These systems guarantee the prompt execution of requests within a specified time interval. Requests can come from users or from devices external to the computer, with which the systems are connected by data transmission channels. In this case, the speed of computational processes in the computer must be consistent with the speed of processes occurring outside the computer, i.e., consistent with the course of real time. These systems organize the control of computing processes in such a way that the response time to a request does not exceed the specified values. The required response time is determined by the properties of the objects (users, external devices) serviced by the system. Real-time operating systems are used in information retrieval systems and process equipment control systems. Computers in such systems operate more often in multitasking mode.
Dialog operating systems.
These operating systems are widely used in personal computers. These systems provide a convenient form of dialogue with the user through the display when entering and executing commands. To execute frequently used sequences of commands, i.e. tasks, the interactive operating system provides the possibility of batch processing. Under the control of the interactive operating system, the computer usually operates in a single-program mode.
Among the numerous types and categories of software, operating systems are at the very top of the hierarchy. These are large-scale and complex types of programs that act directly as a layer between the hardware of a computer or any other device and individual applications that help the user perform specific tasks.
The operating system must take control of all the basic activities of the computer, as well as all peripheral devices. However, it cannot be said that the OS exists only for PCs as such. Any complex electronic device that performs and calculates operations using a processor will need an operating system. Now there are special types of tablet computers, etc.
The operating system is necessary so that the user can manage all processes. This is a kind of shell that provides quick and convenient access to the main or device. It acts as an environment for launching other applications and programs. Types are divided, first of all, by their properties and capabilities, as well as by the type of device for which they are intended.
OS features
As already mentioned, any one takes control of the "iron" stuffing of a computer or any other device, controls the distribution of memory and processor performance. One of the main tasks is the input and output of information, since any computer must work with new data.
There are types of operating systems with different types of file systems, as well as methods for processing processes, interacting with other machines, using RAM. For the user himself, the interface remains noticeable first of all, the popularity of a particular OS, as well as the implemented methods, depends on how convenient it is.
We must not forget that the OS itself also takes up some of the available resources - RAM, processor power and disk space. Accordingly, the best operating system is one that has high functionality, but at the same time remains undemanding to resources.
There are many varieties of operating systems, each of which has certain features that depend on the tasks. For example, some types of operating systems are designed to work in multi-user networks, others are designed for one user and one computer (OS Windows).
In relation to the user, categories such as convenience, interface, ease of administration, openness, cost, bit depth, etc. can be distinguished.
Using his authority, the user can either remove the operating system or install a new one. However, it will be more difficult to do this, since additional features will need to be used. The operating system cannot delete itself.
In the situation that has developed today, it is possible to distinguish varieties of OS for a home computer and for mobile devices. In the first case, the leader is OS Windows from Microsoft. In the second case, the situation is somewhat different, for a long time there was no specific leader, but now it is a product from OC Android. It is a fairly user-friendly operating system, with free code, and supported by a large number of content and software developers. In addition, the popularity of Apple devices explains the fact that the percentage of iOS is quite high. However, there are a huge number of other operating systems for computers and mobile devices that simply did not gain such high popularity or, for some reason, their development was suspended.
A couple of years ago, on one forum, while participating in a heated debate on whose swamp is better, I published a post that will reveal the topic of this article. I bring it below:
A small digression about Windows and Linux. Here you understand what's the matter: Windows is a combination of the system core, as well as utility programs and scripts that perform certain operations and tasks. On this OS, you do not have the right to modify or remove scripts and system software...
When you, for example, change the cursor to Windows, the job of changing the cursor is performed by a script that is already in the system by default. A graphical interface is written for the script (this is a separate program), which is also by default and which also cannot be selected, changed, or deleted. You press a button (graphical interface), thereby launching a script and the cursor changes. For Windows, there is one version of the cursor change program. Everything. You have no right to change it.
There can be a lot of such programs on Linux, an example of this can be graphical environments for Linux "a. Only I know about a dozen. So with the rest of the programs. You yourself choose which programs to install. But the point is that Linux gives you a FULL freedom of action.That is, you choose and install yourself.If you want to see naked Windows, take a look at DOS.Convenient?
Therefore, if something is missing, you need to look for a ready-made solution and install it yourself into the system. If there is no solution, it must be written or asked by an enthusiast. Linux is a designer, you must take it for granted if you are going to use this OS. There are builds like Ubuntu, where they have already screwed a lot, but they also screwed a lot of unnecessary things to please everyone. And they forgot to ask Do you need it? . Therefore, when using such assemblies, questions like How to remove all unnecessary often arise? .
Just think: you were bought a typewriter as a child (for example) and you were satisfied, because you were bought what you wanted. You didn't have any complaints. Now remember the children's designers, no matter what, Lego, pieces of iron with bolts, etc. You wanted a designer, they bought it for you. You played it, collected something there, who wanted what. Did you have any claims to the designer that he was not immediately a remote-controlled car? Is a car with a remote control and a box with a designer the same thing? No, guys, these are different toys!
Linux is essentially a constructor. And if you come across an assembly in which the car has five wheels, do not rush to make claims to the author. He felt more comfortable that way. He cannot know what is more convenient specifically for you, he judges by himself. If you don't like the fifth wheel, turn it off. And in general, if you want everything to work perfectly, remember the saying: If you want to do well, do it yourself! .
End of article.
Conclusions and arguments in favor of Linux
Choose for yourself what you need more - convenience and comfort or complete freedom of action. Unfortunately, you will not get both at once for ideological reasons of the creators of these operating systems. And to make it easier to decide, you can watch a video on the topic of the article. In the video, I am trying to install problematic software on both OSes. At the same time, Windows is treacherously silent, and Linux gives comprehensive information:
Other operating systems
Naturally, the world of computer technology does not end with Windows and Linux. There is also an unknown macOS. But it is overly pretentious and expensive, with its own set of software, hardware, ideology, and is not suitable for everyone. They are also not limited. There are quite a few other operating systems for various platforms, both commercial and free (free):
- Haiku (free version of BeOS)
The most prominent representative of the disk OS is the MS-DOS system from Microsoft, which appeared in 1981. Currently, there are versions 6.22 and 7.0 (as part of Windows 9x), as well as its varieties from other developers (DR DOS, PC DOS). Today, this OS is almost forgotten, it is relevant for computers with x286 and x386 processors. It has a text user interface and, as a result, requires knowledge of the syntax for writing commands. It is a 16-bit single-tasking operating system.
Windows operating system
In our country, this OS is the most widespread. The rest of this section briefly introduces the different operating systems that appear on the market in chronological order.
Windows 3.1 replaced MS-DOS. It had a graphical user interface that makes it easy for users to work. It was a single-tasking and 16-bit system. Windows 3.1 for Workgroups was peer-to-peer and focused on workgroups.
Windows 95 is a versatile high-performance multi-tasking and multi-threaded operating system. Unlike the Windows 3.1 shell, this operating system does not require a DOS operating system to be installed on the computer. This is a 32-bit operating system with advanced networking capabilities that provides efficient information exchange between individual programs and provides the user with ample opportunities for working with multimedia, processing text, graphics, audio and video information.
This operating system provides a user experience on the network, providing built-in support for file sharing and protection measures, the ability to share printers, fax machines and other shared resources. Windows 95 allows you to send messages by e-mail, fax, supports remote access. The protected mode used in Windows 95 does not allow the application program to disrupt the system in the event of a failure, reliably protects applications from accidental interference of one process with another, and provides a certain resistance to viruses.
Windows 98 is different from Windows 95 the fact that in it the OS is combined with the Internet Explorer browser through an interface made in the form of a Web browser. In addition, it has improved compatibility with new computer hardware, it is equally convenient for use on both desktop and laptop computers.
Windows 2000 is a family of operating systems for business use on computers ranging from laptops to servers.
Windows 2000 Professional is a robust desktop and laptop operating system that can be used by businesses of all sizes. Based on NT technology, it provides superior reliability and improved manageability, making it easy to administer workstations. Integrated Internet capabilities and broad support for mobile computers and hardware devices make it easy for business users to connect to and work on the Internet anywhere, anytime.
And finally, the most current version of Windows today is Windows XP, which is also a family:
- Windows XP Home Edition is designed for home PC users with a new look and feel that makes everyday tasks easier and more efficient. Users have access to improved capabilities for working with digital images and music, both when working on a local PC, and when sharing them over the Internet;
- designed for corporate users, Windows XP Professional provides a high level of scalability and reliability. At the same time, among its distinctive features, a higher level of security can be distinguished, including the ability to encrypt files and folders in order to protect corporate information, support for mobile devices for offline work, and connecting to computers remotely. Built-in support for high-performance multiprocessor systems, the ability to work with Microsoft Windows Server servers will be necessary to solve business problems;
- Windows XP 64-Bit Edition is designed for the 64-bit Intel Itanium processor family. It provides support for additional memory, increases the speed of I / O operations, expands the possibilities for calculating floating point variables. This is a fairly powerful platform for technical and analytical development, as well as financial and statistical analysis.
Unix operating system
The Unix operating system was created at Bell Telephone Laboratories. It is a multitasking OS that can handle a very large number of users at the same time. One powerful server can serve the requests of a large number of users. This requires the administration of only one system. In addition, the system is capable of performing a large number of different functions, in particular, as a computing server, as a database server, as a network server that supports the most important network services, etc.
Despite the diversity UNIX versions, the basis of the entire family are fundamentally the same architecture and a number of standard interfaces. Having at your disposal a set of utilities, each of which solves a narrow specialized task, you can construct complex complexes from them.
Operating system Linux
In 1991, Finnish student Linus Torvalds e-mailed the first prototype of his OS and urged everyone who liked it or not to respond to his work. From that moment on, many programmers began to support Linux by adding device drivers, developing various applications, etc. Nowadays, Linux is a very powerful and free system.
Linus Torvalds did not develop the operating system itself, but its core, connecting existing components. Third-party companies, seeing good prospects for the development of their business, soon began to saturate the OS with utilities and application software. The disadvantage of this approach is the lack of a unified and well-thought-out procedure for installing the system, and this is still one of the main deterrents for the wider distribution of Linux. And, nevertheless, this OS from year to year wins an increasing market share from the well-known world manufacturers of network operating systems.
