Linux
Linux
The Linux kernel is a Unixlike computer operating system kernel. The Linux kernel is a widely used operating system kernel world-wide; theLinux operating system is based on it and deployed on both traditional computer systems, usually in the form of Linux distributions, and onembedded devices such as routers. The Android operating system fortablet computers and smartphones is also based atop the Linux kernel. The Linux kernel was initially conceived and created in 1991 by Finnishcomputer science student Linus Torvalds, for his personal computer and with no cross-platform intentions, but has since expanded to support a huge array of computer architectures, more than any other operating system or kernel. Linux rapidly attracted developers and users who adapted code from other free software projects for use with the new operating system. The Linux kernel has received contributions from nearly 12,000 programmers from more than 1,200 companies, including some of the largest software and hardware vendors. The Linux kernel API, the application programming interface (API) through which user programs interact with the kernel, is meant to be very stable and to not break userspace programs (some programs, such as those with GUIs, rely on other APIs as well). As part of the kernel's functionality, device drivers control the hardware; "mainlined" device drivers are also meant to be very stable. However, the interface between the kernel and loadable kernel modules (LKMs), unlike in many other kernels and operating systems, is not meant to be very stable by design. The Linux kernel, developed by contributors worldwide, is a prominent example of free and open source software. Day-to-day development discussions take place on the Linux kernel mailing list (LKML). The Linux kernel is released under the GNU General Public License version 2 (GPLv2), with some firmware images released under various non-free licenses.
History
History
In April 1991, Linus Torvalds, a 21-year-old student at the University of Helsinki, Finland started working on some simple ideas for an operating system. He started with a task switcher in Intel 80386 assembly language and a terminal driver. After that, many people contributed code to the project. Early on, the MINIX community contributed code and ideas to the Linux kernel. At the time, the GNU Project had created many of the components required for a free operating system, but its own kernel, GNU Hurd, was incomplete and unavailable. The BSD operating system had not yet freed itself from legal encumbrances. Despite the limited functionality of the early versions, Linux rapidly accumulated developers and users. By September 1991, Linux version 0.01 was released on the FTP server (ftp.funet.fi) of the Finnish University and Research Network (FUNET). It had 10,239 lines of code. In October 1991, Linux version 0.02 was released.[16] In December 1991, Linux 0.11 was released. This version was the first to be self-hosted - Linux 0.11 could be compiled by a computer running Linux 0.11. A newsgroup known as alt.os.linux was starWhen he released version 0.12 in February 1992, Torted, and on 19 January 1992, the first post to valds adopted the GNU General Public License (GPL) alt.os.linux was made. On 31 March 1992, over his previous self-drafted license, which had not alt.os.linux became comp.os.linux. permitted commercial redistribution. The X Window System was soon ported to Linux. In March 1992, Linux version 0.95 was the first to be capable of running X. This large version number jump (from 0.1x to 0.9x) was due to a feeling that a version 1.0 with no major missing pieces was imminent. However, this proved to be somewhat overoptimistic, and from 1993 to early 1994, 15 development versions of version 0.99 appeared. On 14 March 1994, Linux 1.0.0 was released, with 176,250 lines of code. In March 1995, Linux 1.2.0 was released (310,950 lines of code).
Architecture Architecture Linux kernel is a monolithic kernel. Device drivers and kernel extensions run in kernel space (ring 0 in many CPU architectures), with full access to the hardware, although some exceptions run in user space, for example filesystems based on FUSE. The graphics systemmost people use with Linux does not run within the kernel, in contrast to that found in Microsoft Windows. Unlike standard monolithic kernels, device drivers are easily configured as modules, and loaded or unloaded while running the system. Also unlike standard monolithic kernels, device drivers can be pre-empted under certain conditions. This latter feature was added to handle hardware interrupts correctly, and to improve support for symmetric multiprocessing. By choice, the Linux kernel has no Binary Kernel Interface.
The hardware is also incorporated into the file hierarchy. Device drivers interface to user applications via an entry in the /dev or / sysdirectories. Process information as well is mapped to the file system through the / proc directory. Linux kernel supports true preemptive multitasking (both in user modeand kernel mode), virtual memory, shared libraries, demand loading, shared copy-on-write executables (via KSM), memory management, the Internet protocol suite, and threading.
Distributions Distributions Debian Is composed entirely of free and open-source software, most of which is under the GNU General Public License, and packaged by a group of individuals known as the Debian project. At each point in time the Debian project offers three branches named "stable", "testing" and "unstable". The Debian Stable distribution is one of the most popular for personal computers and network servers, and has been used as a base for several other Linux distributions. Debian was first announced in 1993 by Ian Murdock, and the first stable release was made in 1996. The development is carried out over the Internet by a team of volunteers guided by a project leader and three foundational documents. New distributions are updated continually, and the next candidate is released after a time-based freeze. As one of the earliest Linux distributions, it was envisioned that Debian was to be developed openly in the spirit of Linux and GNU. This vision drew the attention and support of the Free Software Foundation, which sponsored the project from November 1994 until November 1995. Upon the ending of FSF sponsorship, the Debian project formed the non-profit organisation Software in the Public Interest.
Debian is primarily a Linux distribution with access to online repositories that contain over 37,500 software packages. Debian officially contains only free software, but non-free software can be downloaded from the Debian repositories and installed. Debian includes popular free programs such as LibreOffice, Iceweasel web browser, Evolution mail, K3b disc burner, VLC media player, GIMP image editor andEvince document viewer. Debian is a popular choice for web servers. The cost of developing all of the packages included in Debian 5.0 Lenny (323 million lines of code) has been estimated to be about US$ 8 billion, using one method based on the COCOMO model. As of 2014, Ohloh estimates that the codebase(78 million lines of code) would cost about US$ 1.5 billion to develop, using a different method based on the same model.
Distributions Distributions Ubuntu is a Debian-based Linuxoperating system, with Unity as its default desktop environment. It is based on free software and named after the Southern African philosophy of ubuntu (literally, "human-ness"), which often is translated as "humanity towards others" or "the belief in a universal bond of sharing that connects all humanity".
Development of Ubuntu is led by UK-based Canonical Ltd., a company owned by South African entrepreneur Mark Shuttleworth. Canonical generates revenue through the sale of technical support and other services related to Ubuntu. The Ubuntu project is publicly committed to the principles of opensource software development; people are encouraged to use free software, study how it works, improve upon it, and distribute it.
A default installation of Ubuntu contains a wide range of software that includes LibreOffice, Firefox, Thunderbird, Transmission, and several lightweight games such as Sudoku and chess. Many additional software packages, including titles no longer in the default installation such as Evolution, GIMP, Pidgin, andSynaptic, are accessible from the built in Ubuntu Software Center as well as any other APT based package managementtool. Execution of Microsoft Office and other Microsoft Windows applications can be facilitated via the Wine compatibility package or through the use of a virtual machine such as VirtualBox or VMware Workstation. Ubuntu's goal is to be secure "out-of-the box". By default user's programs run with low privileges and cannot corrupt the operating system or other user's files. For increased security, the sudo tool is used to assign temporary privileges for performing administrative tasks, which allows the root account to remain locked and helps prevent inexperienced users from inadvertently making catastrophic system changes or opening security holes.
Distributions Distributions OpenSUSE is a general purpose operating system built on top of the Linux kernel, developed by the communitysupported openSUSE Project and sponsored by SUSE and a number of other companies.[5] On 4 November 2003, Novell announced the acquisition of SuSE Linux AG at a price of US$210 million. After Novell acquired SUSE Linux in January 2004, the company used openSUSE as a logo, but typically is referred to as OpenSuse by contemporary technical publications. Novell decided to release the SUSE Linux Professional product as a 100% open sourceproject. In 2011, The Attachmate Group acquired Novell and split Novell andSUSE into two autonomous subsidiary companies. SUSE offers products and services around SUSE Linux Enterprise—their commercial offering that is based on openSUSE Linux. The openSUSE Project community, sponsored by SUSE, develops and maintains SUSE Linux distributions components. openSUSE Linux is the successor to "SUSE Linux Professional". Beyond the distribution, the openSUSE Project provides a web portal for community involvement. The community developing openSUSE collaboratively with its corporate sponsors through the Open Build Service, writing documentation, designing artwork, fostering discussion on open mailing lists and in Internet Relay Chat channels, and improving the openSUSE site through its wiki interface. openSUSE aims to offer a stable base and allow users to use the Open Build Service to get additional or more up to date software, or even a rolling release version with the name Tumbleweed. Moreover, the system should be flexible and make it easy to re-purpose for specific goals like running a web- or mail server. Like most Linux distributions, openSUSE includes both a default graphical user interface (GUI) and a command line interface option. During installation, the user may choose among KDE SC, GNOME, LXDE and Xfce GUIs. openSUSE supports thousands of software packages across the full range of Free software / open source development.
Distributions Distributions Mandrake Mandrakelinux or Mandrake Linux and the Brazilian distributionConectiva Linux) is a Linux distribution distributed by Mandriva. It uses the RPM Package Manager. The product lifetime of Mandriva Linux releases is 18 months for base updates (Linux, system software, etc.) and 12 months for desktop updates (window managers, desktop environments, web browsers, etc.). Server products receive full updates for at least 5 years after their release. The last release was the 2011 version released in August that year. Most Mandriva Linux developers who were laid off went to Mageia.
The first release was based on Red Hat Linux (version 5.1) and K Desktop Environment 1 in July 1998. It has since moved away from Red Hat's distribution and has become a completely separate distribution in its own right. Mandriva now includes a number of original tools, mostly to ease system configuration. Mandriva Linux is the brainchild ofGaĂŤl Duval, who wanted to focus on ease of use for new users. This goal was met as Mandrake Linux gained a reputation as "one of the easiest to install and userfriendly Linux distributions". At this time Internet Explorer held a dominant share of the web browser market, and Microsoft a near monopoly in operating systems. Web browsers for Linux were limited to Mozilla, followed by a variety of poorly performing Linux-specific browsers such as Konqueror or Galeon. Mandrake Linux earned praise as a Linux distribution that users could use all the time, without dual booting into Windows for compatibility with web sites or software unavailable under Linux. CNET called the user experience of Mandrake Linux 8.0 the most polished available at that time. Duval became the co-founder of Mandrakesoft, but was laid off from the company in 2006 along with many other.
Distributions Distributions Knnopix Knoppix is an operating systembased on Debian designed to be run directly from a CD / DVD (Live CD) or a USB flash drive (Live USB), one of the first of its kind for any operating system. Knoppix was developed by Linux consultant Klaus Knopper. When starting a program, it is loaded from the removable medium and decompressed into a RAM drive. The decompression istransparent and on-thefly. Although Knoppix is primarily designed to be used as a Live CD, it can also be installed on a hard disk like a typical operating system. Computers that support booting from USB devices can load Knoppix from a live USB flash drive or memory card.
There are two main editions of Knoppix: the traditional Compact Disc (700 megabytes) edition and the DVD (4.7 gigabytes) "Maxi" edition. Each of these main editions have two language-specific editions: English and German. Knoppix mostly consists of free and open source software, but also includes some proprietary software, so long as it fulfils certain conditions. Knoppix can be used to copy files easily from hard drives with inaccessible operating systems. To quickly and more safely use Linux software, the Live CD can be used instead of installing another OS.
Prior to Knoppix 3.8.2, any documents or settings a user created would disappear upon reboot. This lack of permanence then made it necessary to save documents directly to a hard drive partition, over the network, or to some removable media, such as a USB flash drive. It was also possible to set up a "persistent home directory", where any documents or settings written to the user's home directory would automatically be redirected to a hard drive or removable media, which could be automatically mounted on bootup. A single file, knoppix.img, was cached on the rewritable media and used to simulate a file system into which files were written for later use. This allowed the user to transparently write to their home directory.
Distributions Distributions Fedora is an operating system based on the Linux kernel, developed by the community-supported Fedora Project and owned by Red Hat. Fedora contains software distributed under a free and open source license and aims to be on the leading edge of such technologies. Linus Torvalds, founder of the Linux kernel, uses Fedora on all of his computers. Fedora has a reputation for focusing on innovation, integrating new technologies early on and working closely with upstream Linux communities. Making changes upstream instead of specifically in Fedora ensures that the changes are available to all Linux distributions. Fedora has a relatively short life cycle: version X is supported only until 1 month after version X+2 and with approximately 6 months between versions, this means that a version of Fedora is supported for approximately 13 months. This promotes leading-edge software because it frees developers from some backward compatibility restraints, but it also makes Fedora a poor choice for product development, which usually requires long -term vendor-support. Fedora users can upgrade from version to version using FedUp.
The name of Fedora derives from Fedora Linux, a volunteer project that provided extra software for the Red Hat Linux distribution, and from the characteristic fedora hat used in Red Hat's "Shadowman" logo. Warren Togami began Fedora Linux in 2002 as an undergraduate project, intended to provide a single repository for well-tested third-party software packages so that non-Red Hat software would be easier to find, develop, and use. The key of Fedora Linux and Red Hat Linux was that Fedora's repository development would be collaborative with the global volunteer community. Fedora Linux was eventually absorbed into the Fedora Project, carrying with it this collaborative approach. Before Fedora 7, Fedora was called Fedora Core after the name of one of the two main software repositories - Core and Extras. Fedora Core contained all the base packages that were required by the operating system, as well as other packages that were distributed along with the installation CD/DVDs, and was maintained only by Red Hat developers. Fedora Extras, the secondary repository that had been included since Fedora Core 3, was community-maintained and not distributed along with the installation CD/DVDs. Upon the release of Fedora 7, the distinction between Fedora Core and Fedora Extras was eliminated.
8 WindowsWindows 8
Windows 8 is a personal computer operating system developed byMicrosoft as part of the Windows NT family of operating systems. Development of Windows 8 started before the release of its predecessor, Windows 7, in 2009. It was announced at CES 2011, and followed by the release of three pre-release versions from September 2011 to May 2012. The operating system was released to manufacturing on August 1, 2012, and was released for general availability on October 26, 2012.
Windows 8 introduced major changes to the operating system's platform and user interface to improve its user experience on tablets, where Windows was now competing with mobile operating systems, including Android and iOS. In particular, these changes included a touchoptimized Windows shell based on Microsoft's "Metro" design language, the Start screen (which displays programs and dynamically updated content on a grid of tiles), a new platform for developing appswith an emphasis on touchscreen input, integration with online services (including the ability to sync apps and settings between devices), andWindows Store, an online store for downloading and purchasing new software. Windows 8 added support for USB 3.0, Advanced Formathard drives, near field communications, and cloud computing. Additional security features were introduced, such as builtin antivirus software, integration with Microsoft SmartScreen phishing filtering service and support for UEFI Secure Boot on supported devices with UEFI firmware, to prevent malware from infecting the boot process.
Windows 8 was released to a mixed reception. Although reaction towards its performance improvements, security enhancements, and improved support for touchscreen devices was positive, the new user interface of the operating system was widely criticized for being potentially confusing and difficult to learn (especially when used with a keyboard and mouse instead of a touchscreen). Despite these shortcomings, 60 million Windows 8 licenses have been sold through January 2013, a number which included both upgrades and sales toOEMs for new PCs. On October 17, 2013, Microsoft released Windows 8.1. It addresses some aspects of Windows 8 that were criticized by reviewers and early adopters and incorporates additional improvements to various aspects of the operating system.
8 WindowsWindows 8 New and Changed Features New features and functionality in Windows 8 include a faster startup through UEFIintegration and the new "Hybrid Boot" mode (which hibernates the Windows kernelon shutdown to speed up the subsequent boot), a new lock screen with a clock and notifications, and the ability for enterprise users to create live USB versions of Windows (known as Windows To Go). Windows 8 also adds native support for USB 3.0 devices, which allow for faster data transfers and improved power management with compatible devices, and hard disk 4KB Advanced Format support, as well as support fornear field communication to facilitate sharing and communication between devices.
Task Manager has been redesigned, including a new processes tab with the option to display fewer or more details of running applications and background processes, a heat map using different colors indicating the level of resource usage, network and disk counters, grouping by process type (e.g. applications, background processes and Windows processes), friendly names for processes and a new option which allows users to search the web to find information about obscure processes. Additionally, the Blue Screen of Death has been updated with a simpler and modern design with less technical information displayed.
Windows Explorer, which has been renamed File Explorer, now includes a ribbon in place of the command bar. File operation dialog boxes have been updated to provide more detailed statistics, the ability to pause file transfers, and improvements in the ability to manage conflicts when copying files. A new "File History" function allows incremental revisions of files to be backed up to and restored from a secondary storage device, while Storage Spaces allows users to combine different sized hard disks into virtual drives and specify mirroring, parity, or no redundancy on a folder-by-folder basis.
New security features in Windows 8 include two new authentication methods tailored towards touchscreens (PINs and picture passwords), the addition of antivirus capabilities to Windows Defender (bringing it in parity with Microsoft Security Essentials). SmartScreen filtering integrated into Windows, Family Safety offers Parental controls, which allows parents to monitor and manage their children's activities on a device with activity reports and safety controls. Windows 8 also provides integrated system recovery through the new "Refresh" and "Reset" functions, including system recovery from USB drive. Windows 8's first security patches would be released on November 13, 2012; it would contain three fixes deemed "critical" by the company
8 WindowsWindows 8 Hardware Requeriments Requirement
Processor
Minimum 1 GHz clock rate IA-32 or x64 architecture Support for PAE, NX andSSE2 [119][120]
Recommended
x64 architecture Second Level Address Translation (SLAT) support for Hyper-V
Memory (RAM)
IA-32 edition: 1 GB x64 edition: 2 GB
4 GB
Graphics Card
DirectX 9 graphics device WDDM 1.0 or higher driver
DirectX 10 graphics device
Display screen
N/A
Input device
Keyboard and mouse
Hard disk space
IA-32 edition: 16 GB x64 edition: 20 GB
Other
N/A
1024Ă—768 pixels multi-touch display screen
N/A
UEFI v2.3.1 Errata B with Microsoft Windows Certification Authority in its database Trusted Platform Module (TPM) Internet connectivity
8 WindowsWindows 8 Editions & Pricings Windows 8 is available in four editions: one simply named Windows 8 is intended for mainstream consumers. Windows 8 Pro contains additional features aimed towards power users and professional environments. Windows 8 Enterprisecontains additional features aimed towards business environments, and is only available through volume licensing. Windows RT is only available pre-loaded on new ARMbased devices built specifically for the OS. Windows Media Center is not included by default in any edition of Windows 8, but is available for purchase as an add-on for Windows 8 Pro, or as part of a "Pro Pack" upgrade for the basic version of Windows 8 which also includes the Pro upgrade. The Windows Media Center add-on was offered for free until January 31, 2013. Microsoft has offered an upgrade program for those purchasing new PCs pre-loaded with Windows 7 Home Basic, Home Premium, Professional, or Ultimate between June 2, 2012 and January 31, 2013—in which users could digitally purchase a Windows 8 Pro upgrade for US$14.99.[131] Several PC manufacturers have offered rebates and refunds on Windows 8 upgrades obtained through the program on select models, such as Hewlett-Packard (in the U.S. and Canada on select models), and Acer (in Europe on selected Ultrabook models).
Users of previous versions of Windows can purchase an upgrade to Windows 8 Pro online (using a download that can be optionally made into DVD or USB install media), or through boxed copies at retail on DVD. Microsoft offered Windows 8 Pro upgrades at a discounted price of US$39.99 online, or $69.99 for retail box DVD from its launch until January 31, 2013; afterward the Windows 8 price has been $119.99 and the Pro price $199.99. The "Full" and "OEM" SKUs that typically exist for previous versions of Windows (which can be installed on a computer with no existing operating system) were replaced by a specialized "System Builder" SKU under Windows 8, intended to be used by original equipment manufacturers and on homebuilt computers. Aside from the "System Builder" version, all retail copies of Windows 8 could only be used for upgrades.
8 WindowsWindows 8 Upgraded Versions An upgrade to Windows 8 known as Windows 8.1 was officially announced by Microsoft on May 14, 2013. Following a presentation devoted to the upgrade at Build 2013, a public beta version of the upgrade was released on June 26, 2013. Windows 8.1 was released to OEM hardware partners on August 27, 2013, and released publicly as a free download through Windows Store on October 17, 2013.Volume license customers and subscribers to MSDN Plus and TechNet Plus were initially unable to obtain the RTM version upon its release; a spokesperson said the policy was changed to allow Microsoft to work with OEMs "to ensure a quality experience at general availability. However, after criticism, Microsoft reversed its decision and released the RTM build on MSDN and TechNet on September 9, 2013. The upgrade addressed a number of criticisms faced by Windows 8 upon its release, with additional customization options for the Start screen, the restoration of a visible Start button on the desktop, the ability to snap up to four apps on a single display, and the ability to boot to the desktop instead of the Start screen. Windows 8's stock apps were also updated, a newBing-based unified search system was added, SkyDrive was given deeper integration with the operating system, and a number of new stock apps, along with a tutorial, were added. Windows 8.1 also added support for 3D printing, Miracast media streaming, NFC printing, and Wi -Fi Direct
Microsoft markets Windows 8.1 as an "update" rather than as a "service pack" or "upgrade". However, Microsoft's support lifecycle policy treats Windows 8.1 similarly to previous Windows service packs: it is part of Windows 8's support lifecycle, and upgrading to 8.1 is required to maintain access to mainstream support and Windows updates after January 12, 2016. Retail and OEM copies of Windows 8, Windows 8 Pro, and Windows RT can be upgraded through Windows Store free of charge. However, volume license customers, TechNet or MSDN subscribers and users of Windows 8 Enterprise must acquire a standalone installation media for 8.1 and install through the traditional Windows setup process, either as an in-place upgrade or clean install. This requires an 8.1-specific product key.