O Level Computer Certification Course

Nowadays , computers had become one of the part in our daily life . Computers can make our jobs become easier . They can be used for communicational purposes (internet), to store and calculate data and to write up massive documents multiple times while only needing to write it up once.

A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks. A computer system is a "complete" computer that includes the hardware, operating system (main software), and peripheral equipment needed and used for "full" operation. This term may also refer to a group of computers that are linked and function together, such as a computer network or computer cluster.

A broad range of industrial and consumer products use computers as control systems. Simple special-purpose devices like microwave ovens and remote controls are included, as are factory devices like industrial robots and computer-aided design, as well as general-purpose devices like personal computers and mobile devices like smartphones. Computers power the Internet, which links hundreds of millions of other computers and users.

Early computers were meant to be used only for calculations. Simple manual instruments like the abacus have aided people in doing calculations since ancient times. Early in the Industrial Revolution, some mechanical devices were built to automate long tedious tasks, such as guiding patterns for looms. More sophisticated electrical machines did specialized analog calculations in the early 20th century. The first digital electronic calculating machines were developed during World War II. The first semiconductor transistors in the late 1940s were followed by the silicon-based MOSFET (MOS transistor) and monolithic integrated circuit (IC) chip technologies in the late 1950s, leading to the microprocessor and the microcomputer revolution in the 1970s. The speed, power and versatility of computers have been increasing dramatically ever since then, with transistor counts increasing at a rapid pace (as predicted by Moore's law), leading to the Digital Revolution during the late 20th to early 21st centuries.

Conventionally, a modern computer consists of at least one processing element, typically a central processing unit (CPU) in the form of a microprocessor, along with some type of computer memory, typically semiconductor memory chips. The processing element carries out arithmetic and logical operations, and a sequencing and control unit can change the order of operations in response to stored information. Peripheral devices include input devices (keyboards, mice, joystick, etc.), output devices (monitor screens, printers, etc.), and input/output devices that perform both functions (e.g., the 2000s-era touchscreen). Peripheral devices allow information to be retrieved from an external source and they enable the result of operations to be saved and retrieved.

The two important parts of a computer are: It responds to a specific instruction set in a well-defined manner and it can execute a stored list of instructions called a program. There are four main actions in a computer: inputting, storing, outputting and processing.

Modern computers can do billions of calculations in a second. Being able to calculate many times per second allows modern computers to multi-task, which means they can do many different tasks at the same time. Computers do many different jobs where automation is useful. Some examples are controlling traffic lights, vehicles , security systems, washing machines and digital televisions.

Computers can be designed to do almost anything with information. Computers are used to control large and small machines which in the past were controlled by humans. Most people have used a personal computer in their home or at work. They are used for things such as calculation, listening to music, reading an article, writing etc.

Computers are controlled with user interfaces. Input devices which include keyboards, computer mice, buttons, and touch screens .

Computer programs are designed or written by computer programmers. A few programmers write programs in the computer's own language called machine code. Most programs are written using a programming language like C, C++, Java. These programming languages are more like the language with which one talks and writes every day. The compiler converts the user's instructions into binary code (machine code) that the computer will understand and do what is needed.

Computers come in different forms, but most of them have a common design.

• All computers have a CPU.

• All computers have some kind of data bus which lets them get inputs or output things to the environment.

• All computers have some form of memory. These are usually chips (integrated circuits) which can hold information.

• Many computers have some kind of sensors, which lets them get input from their environment.

• Many computers have some kind of display device, which lets them show output. They may also have other peripheral devices connected.

A computer has several main parts. When comparing a computer to a human body, the CPU is like a brain. It does most of the thinking and tells the rest of the computer how to work. The CPU is on the Motherboard, which is like the skeleton. It provides the basis for where the other parts go, and carries the nerves that connect them to each other and the CPU. The motherboard is connected to a power supply, which provides electricity to the entire computer. The various drives (CD drive, floppy drive, and on many newer computers, USB flash drive) act like eyes, ears, and fingers, and allow the computer to read different types of storage, in the same way that a human can read different types of books. The hard drive is like a human's memory, and keeps track of all the data stored on the computer. Most computers have a sound card or another method of making sound, which is like vocal cords, or a voice box. Connected to the sound card are speakers, which are like a mouth, and are where the sound comes out. Computers might also have a graphics card, which helps the computer to create visual effects, such as 3D environments, or more realistic colors, and more powerful graphics cards can make more realistic or more advanced images, in the same way a well trained artist can.

Most importantly, know what you want to use it for and set aside a realistic budget.

• Your budget
  The first thing that most of us are constrained to is budget so this is the first thing you should consider. We always want the best but we need to be grounded on what we can afford. So Get a budget and stick to it.
  
  

• Laptop or Desktop?
  The next thing you should be looking at is your requirements. Do you need a laptop or desktop? What is the machine going to be used for? Once you have done this go back to number one and see if these are compatible often they are not first time round. You either need to adjust your budget or adjust your goals to make them more compatible with each other.

Now its time to look at the computer.
There are many things to consider when actually buying the computer, here I will list the most important so you can choose wisely.

2. The Processor
This is the most important factor when choosing a computer nowadays and there are many factors in processor choice the main thing is that in my opinion Intel are at the moment making the best chips and their core 2 duo range is the best so go for one in this family and you will be ok.

3. RAM (Computer Memory)
Essentially, the more rams you have, the more browsers and applications you can open. 4Gb is the most basic nowadays. 8GB is the sweet spot for most people. If you are a gamer, photo or video editor, or planning to do CAD/CAM work, you need at least 16GB of Ram. Make sure you get windows vista 64bit as your operating system.

6. Hard Drive
This is the next piece you should tackle. Computers today usually come with 250GB and 750GB of space in the hard drive. As more people are storing their information online on cloud storage, you may want to rethink of buying a huge hard drive space.

Where to get free cloud storage;

• Google provides the 1st 15GB of free & monthly fee of $1.99 for 100GB and $9.99 for 1 terabyte.

• Mega provides free 50GB

• pCloud provides free 10GB

• MediaFire provides 10GB

• Dropbox provides 2GB

7. Graphics
Now all computers come with some form of graphics built in. But my recommendation is to go with something a little better possibly from NVIDIA or AMD. They make your computer resolution better. AMD cards are good for mining while NVidia is good for Adobe programs.

8. Computer Software
Most computers comes with microsoft software. The latest is Windows 10.

9. Anti-Virus Software
The last thing to do with the actual computer is a good virus and spy ware package. Don’t be under any illusion this is possibly the most important part of protecting your computer. It will get attacked at some point be prepared when it does.

10. Your Computer Lifeline, Internet
Finally the internet, get a good internet provider broadband at least. No computer is complete without a good internet.

A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program. This contrasts with external components such as main memory and I/O circuitry,[1] and specialized processors such as graphics processing units (GPUs).

The form, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory) and execution of instructions by directing the coordinated operations of the ALU, registers and other components.

Most modern CPUs are implemented on integrated circuit (IC) microprocessors, with one or more CPUs on a single metal-oxide-semiconductor (MOS) IC chip. Microprocessors chips with multiple CPUs are multi-core processors. The individual physical CPUs, processor cores, can also be multithreaded to create additional virtual or logical CPUs.[2]

An IC that contains a CPU may also contain memory, peripheral interfaces, and other components of a computer; such integrated devices are variously called microcontrollers or systems on a chip (SoC).

Array processors or vector processors have multiple processors that operate in parallel, with no unit considered central. Virtual CPUs are an abstraction of dynamical aggregated computational resources.

Random-access memory (RAM; /ræm/) is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code.[1][2] A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media (such as hard disks, CD-RWs, DVD-RWs and the older magnetic tapes and drum memory), where the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.

RAM contains multiplexing and demultiplexing circuitry, to connect the data lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, and RAM devices often have multiple data lines and are said to be "8-bit" or "16-bit", etc. devices.[clarification needed]

In today's technology, random-access memory takes the form of integrated circuit (IC) chips with MOS (metal-oxide-semiconductor) memory cells. RAM is normally associated with volatile types of memory (such as dynamic random-access memory (DRAM) modules), where stored information is lost if power is removed, although non-volatile RAM has also been developed.[3] Other types of non-volatile memories exist that allow random access for read operations, but either do not allow write operations or have other kinds of limitations on them. These include most types of ROM and a type of flash memory called NOR-Flash.

The two main types of volatile random-access semiconductor memory are static random-access memory (SRAM) and dynamic random-access memory (DRAM). Commercial uses of semiconductor RAM date back to 1965, when IBM introduced the SP95 SRAM chip for their System/360 Model 95 computer, and Toshiba used DRAM memory cells for its Toscal BC-1411 electronic calculator, both based on bipolar transistors. Commercial MOS memory, based on MOS transistors, was developed in the late 1960s, and has since been the basis for all commercial semiconductor memory. The first commercial DRAM IC chip, the Intel 1103, was introduced in October 1970. Synchronous dynamic random-access memory (SDRAM) later debuted with the Samsung KM48SL2000 chip in 1992.

A video card (also called a graphics card, display card, graphics adapter, or display adapter) is an expansion card which generates a feed of output images to a display device (such as a computer monitor). Frequently, these are advertised as discrete or dedicated graphics cards, emphasizing the distinction between these and integrated graphics. At the core of both is the graphics processing unit (GPU), which is the main part that does the actual computations, but should not be confused with the video card as a whole, although "GPU" is often used as a metonymic shorthand to refer to video cards.

Most video cards are not limited to simple display output. Their integrated graphics processor can perform additional processing, removing this task from the central processor of the computer.[1] For example, Nvidia and AMD (previously ATI) produced cards that render the graphics pipelines OpenGL and DirectX on the hardware level.[2] In the later 2010s, there has also been a tendency to use the computing capabilities of the graphics processor to solve non-graphic tasks, which can be done through the use of OpenCL and CUDA. Video cards can also be used for AI training.[3][2]

Usually, the graphics card is made in the form of a printed circuit board (expansion board) and inserted into an expansion slot, universal or specialized (AGP, PCI Express).[4] Some have been made using dedicated enclosures, which are connected to the computer via a docking station or a cable. These are known as eGPUs.

A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is also sometimes called a solid-state device or a solid-state disk,[1] even though SSDs lack the physical spinning disks and movable read–write heads used in hard disk drives (HDDs) and floppy disks.[2]

Compared with electromechanical drives, SSDs are typically more resistant to physical shock, run silently, and have quicker access time and lower latency.[3] SSDs store data in semiconductor cells. As of 2019, cells can contain between 1 and 4 bits of data. SSD storage devices vary in their properties according to the number of bits stored in each cell, with single-bit cells ("Single Level Cells" or "SLC") being generally the most reliable, durable, fast, and expensive type, compared with 2- and 3-bit cells ("Multi-Level Cells/MLC" and "Triple-Level Cells/TLC"), and finally quad-bit cells ("QLC") being used for consumer devices that do not require such extreme properties and are the cheapest per Gigabyte of the four. In addition, 3D XPoint memory (sold by Intel under the Optane brand), stores data by changing the electrical resistance of cells instead of storing electrical charges in cells, and SSDs made from RAM can be used for high speed, when data persistence after power loss is not required, or may use battery power to retain data when its usual power source is unavailable.[4] Hybrid drives or solid-state hybrid drives (SSHDs), such as Apple's Fusion Drive, combine features of SSDs and HDDs in the same unit using both flash memory and a HDD in order to improve the performance of frequently-accessed data.[5][6][7] Bcache allows to achieve a similar effect purely in software, using combinations of dedicated regular SSDs and HDDs.

SSDs based on NAND Flash will slowly leak charge over time if left for long periods without power. This causes worn-out drives (that have exceeded their endurance rating) to start losing data typically after one year (if stored at 30 °C) to two years (at 25 °C) in storage; for new drives it takes longer.[8] Therefore, SSDs are not suitable for archival storage. 3D XPoint is a possible exception to this rule; it is a relatively new technology with unknown long-term data-retention characteristics.

SSDs can use traditional HDD interfaces and form factors, or newer interfaces and form factors that exploit specific advantages of the flash memory in SSDs. Traditional interfaces (e.g. SATA and SAS) and standard HDD form factors allow such SSDs to be used as drop-in replacements for HDDs in computers and other devices. Newer form factors such as mSATA, M.2, U.2, NF1,[9][10] XFMEXPRESS[11] and EDSFF (formerly known as Ruler SSD)[12][13] and higher speed interfaces such as NVM Express (NVMe) over PCI Express (PCIe) can further increase performance over HDD performance.[4]

SSDs have a limited lifetime number of writes, and also slow down as they reach their full storage capacity.

In computing, BIOS (/ˈbaɪɒs, -oʊs/, BY-oss, -⁠ohss; an acronym for Basic Input/Output System and also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is firmware used to perform hardware initialization during the booting process (power-on startup), and to provide runtime services for operating systems and programs.[1] The BIOS firmware comes pre-installed on a personal computer's system board, and it is the first software to run when powered on. The name originates from the Basic Input/Output System used in the CP/M operating system in 1975.[2][3] The BIOS originally proprietary to the IBM PC has been reverse engineered by some companies (such as Phoenix Technologies) looking to create compatible systems.[4] The interface of that original system serves as a de facto standard.

The BIOS in modern PCs initializes and tests the system hardware components, and loads a boot loader from a mass storage device which then initializes an operating system. In the era of DOS, the BIOS provided BIOS interrupt calls for the keyboard, display, storage, and other input/output (I/O) devices that standardized an interface to application programs and the operating system. More recent operating systems do not use the BIOS interrupt calls after startup.[5]

Most BIOS implementations are specifically designed to work with a particular computer or motherboard model, by interfacing with various devices especially system chipset. Originally, BIOS firmware was stored in a ROM chip on the PC motherboard. In modern computer systems, the BIOS contents are stored on flash memory so it can be rewritten without removing the chip from the motherboard. This allows easy, end-user updates to the BIOS firmware so new features can be added or bugs can be fixed, but it also creates a possibility for the computer to become infected with BIOS rootkits. Furthermore, a BIOS upgrade that fails may brick the motherboard.

Unified Extensible Firmware Interface (UEFI) is a successor to the legacy PC BIOS, aiming to address its technical limitations.

Windows 10 is a major release of the Windows NT operating system developed by Microsoft. It is the successor to Windows 8.1, released nearly two years earlier, and was released to manufacturing on July 15, 2015, and broadly released for the general public on July 29, 2015.[21] Windows 10 was made available for download via MSDN and Technet, as a free upgrade for retail copies of Windows 8 and Windows 8.1 users via the Windows Store, and to Windows 7 users via Windows Update. Windows 10 receives new builds on an ongoing basis, which are available at no additional cost to users, in addition to additional test builds of Windows 10, which are available to Windows Insiders. Devices in enterprise environments can receive these updates at a slower pace, or use long-term support milestones that only receive critical updates, such as security patches, over their ten-year lifespan of extended support.[22][23]

Windows 10 received mostly positive reviews upon its original release. Critics praised Microsoft's decision to provide a desktop-oriented interface in line with previous versions of Windows, contrasting the tablet-oriented approach of Windows 8, although Windows 10's touch-oriented user interface mode was criticized for containing regressions upon the touch-oriented interface of its predecessor. Critics also praised the improvements to Windows 10's bundled software over Windows 8.1, Xbox Live integration, as well as the functionality and capabilities of the Cortana personal assistant and the replacement of Internet Explorer with Microsoft Edge. However, media outlets have been critical of the changes to operating system behaviors, including mandatory update installation, privacy concerns over data collection performed by the OS for Microsoft and its partners, and adware-esque tactics used to promote the operating system on its release.[24]

Microsoft initially aimed to have Windows 10 installed on over one billion devices within three years of its release;[22] that goal was ultimately reached almost five years after release on March 16, 2020.[25] By January 2018, Windows 10 surpassed Windows 7 as the most popular version of Windows worldwide.[26] As of June 2021, it is estimated that 79% of Windows PCs,[26] 58% of all PCs (the rest being older Windows versions and other operating systems such as macOS and Linux), and 24% of all devices (including mobile, tablet and console)[27] are running Windows 10.

An application program (app or application for short) is a computer program designed to carry out a specific task other than one relating to the operation of the computer itself,[1] typically to be used by end-users. Word processors, media players, and accounting software are examples. The collective noun refers to all applications collectively.[2] The other principal classifications of software are system software, relating to the operation of the computer, and utility software ("utilities").

Applications may be bundled with the computer and its system software or published separately and may be coded as proprietary, open-source, or projects.[3] The term "app" often refers to applications for mobile devices such as phones.

Software is a collection of instructions and data that tell a computer how to work. This is in contrast to physical hardware, from which the system is built and actually performs the work. In computer science and software engineering, computer software is all information processed by computer systems, including programs and data. Computer software includes computer programs, libraries and related non-executable data, such as online documentation or digital media. Computer hardware and software require each other and neither can be realistically used on its own.

At the lowest programming level, executable code consists of machine language instructions supported by an individual processor—typically a central processing unit (CPU) or a graphics processing unit (GPU). A machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. For example, an instruction may change the value stored in a particular storage location in the computer—an effect that is not directly observable to the user. An instruction may also invoke one of many input or output operations, for example displaying some text on a computer screen; causing state changes which should be visible to the user. The processor executes the instructions in the order they are provided, unless it is instructed to "jump" to a different instruction, or is interrupted by the operating system. As of 2015, most personal computers, smartphone devices and servers have processors with multiple execution units or multiple processors performing computation together, and computing has become a much more concurrent activity than in the past.

The majority of software is written in high-level programming languages. They are easier and more efficient for programmers because they are closer to natural languages than machine languages.[1] High-level languages are translated into machine language using a compiler or an interpreter or a combination of the two. Software may also be written in a low-level assembly language, which has strong correspondence to the computer's machine language instructions and is translated into machine language using an assembler.

Microsoft Windows, commonly referred to as Windows, is a group of several proprietary graphical operating system families, all of which are developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. Active Microsoft Windows families include Windows NT and Windows IoT; these may encompass subfamilies, (e.g. Windows Server or Windows Embedded Compact) (Windows CE). Defunct Microsoft Windows families include Windows 9x, Windows Mobile and Windows Phone.

Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces (GUIs).[5] Microsoft Windows came to dominate the world's personal computer (PC) market with over 90% market share, overtaking Mac OS, which had been introduced in 1984.

Apple came to see Windows as an unfair encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh (eventually settled in court in Microsoft's favor in 1993). On PCs, Windows is still the most popular operating system in all countries.[6][7] However, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android,[8] because of the massive growth in sales of Android smartphones. In 2014, the number of Windows devices sold was less than 25% that of Android devices sold. This comparison, however, may not be fully relevant, as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows (that are comparable to competitors) show one third market share, similar to that for end user use.

As of May 2021, the most recent version of Windows for PCs, tablets and embedded devices is Windows 10, version 21H1. The most recent version for server computers is Windows Server, version 20H2.[9] A specialized version of Windows also runs on the Xbox One and Xbox Series X/S video game consoles.

macOS (/ˌmækoʊˈɛs/;[10] previously Mac OS X and later OS X) is a proprietary graphical operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS, after Windows NT.[11][12]

macOS succeeded the classic Mac OS, a Macintosh operating system with nine releases from 1984 to 1999. During this time, Apple cofounder Steve Jobs had left Apple and started another company, NeXT, developing the NeXTSTEP platform that would later be acquired by Apple to form the basis of macOS.

The first desktop version, Mac OS X 10.0, was released in March 2001, with its first update, 10.1, arriving later that year. Releases from Mac OS X 10.5 Leopard[13] and thereafter are UNIX 03 certified.[14] Apple's mobile operating system, iOS, has been considered a variant of macOS.[15]

A prominent part of macOS's original brand identity was the use of Roman numeral X, pronounced "ten" as in Mac OS X and also the iPhone X, as well as code naming each release after species of big cats, or places within California.[16] Apple shortened the name to "OS X" in 2012 and then changed it to "macOS" in 2016 to align with the branding of Apple's other operating systems, iOS, watchOS, and tvOS. After sixteen distinct versions of macOS 10, macOS Big Sur was presented as version 11 in 2020, and macOS Monterey was presented as version 12 in 2021.

macOS has supported three major processor architectures, beginning with PowerPC-based Macs in 1999. In 2006, Apple transitioned to the Intel architecture with a line of Macs using Intel Core processors. In 2020, Apple began the Apple silicon transition, using self-designed, 64-bit ARM-based Apple M1 processors on new Mac computers.

Linux (/ˈlinʊks/ (listen) LEEN-uuks or /ˈlɪnʊks/ LIN-uuks[9]) is a family of open-source Unix-like operating systems based on the Linux kernel,[10] an operating system kernel first released on September 17, 1991, by Linus Torvalds.[11][12][13] Linux is typically packaged in a Linux distribution.

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy.[14][15]

Popular Linux distributions[16][17][18] include Debian, Fedora, and Ubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise Server. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions intended for servers may omit graphics altogether, or include a solution stack such as LAMP. Because Linux is freely redistributable, anyone may create a distribution for any purpose.[19]

Linux was originally developed for personal computers based on the Intel x86 architecture, but has since been ported to more platforms than any other operating system.[20] Because of the dominance of the Linux-based Android on smartphones, Linux also has the largest installed base of all general-purpose operating systems.[21][22][23][24] Although it is used by only around 2.3 percent of desktop computers,[25][26] the Chromebook, which runs the Linux kernel-based Chrome OS, dominates the US K–12 education market and represents nearly 20 percent of sub-$300 notebook sales in the US.[27] Linux is the leading operating system on servers (over 96.4% of the top 1 million web servers' operating systems are Linux),[28] leads other big iron systems such as mainframe computers, and is the only OS used on TOP500 supercomputers (since November 2017, having gradually eliminated all competitors).[29][30][31]

Linux also runs on embedded systems, i.e. devices whose operating system is typically built into the firmware and is highly tailored to the system. This includes routers, automation controls, smart home technology (like Google Nest),[32] televisions (Samsung and LG Smart TVs use Tizen and WebOS, respectively),[33][34][35] automobiles (for example, Tesla, Audi, Mercedes-Benz, Hyundai, and Toyota all rely on Linux),[36] digital video recorders, video game consoles, and smartwatches.[37] The Falcon 9's and the Dragon 2's avionics use a customized version of Linux.[38]

Linux is one of the most prominent examples of free and open-source software collaboration. The source code may be used, modified and distributed commercially or non-commercially by anyone under the terms of its respective licenses, such as the GNU General Public License.[19]

90% of all cloud infrastructure is powered by Linux including supercomputers and cloud providers.[39] 74% of smartphones in the world are Linux-based.

Windows 10 makes its user experience and functionality more consistent between different classes of device and addresses most of the shortcomings in the user interface that were introduced in Windows 8.[43][44][67] Windows 10 Mobile, the successor to Windows Phone 8.1, shared some user interface elements and apps with its PC counterpart.[68]

Windows 10 supports universal apps, an expansion of the Metro-style first introduced in Windows 8. Universal apps can be designed to run across multiple Microsoft product families with nearly identical code‍—‌including PCs, tablets, smartphones, embedded systems, Xbox One, Surface Hub and Mixed Reality. The Windows user interface was revised to handle transitions between a mouse-oriented interface and a touchscreen-optimized interface based on available input devices‍—‌particularly on 2-in-1 PCs, both interfaces include an updated Start menu which incorporates elements of Windows 7's traditional Start menu with the tiles of Windows 8. Windows 10 also introduced the Microsoft Edge web browser, a virtual desktop system, a window and desktop management feature called Task View, support for fingerprint and face recognition login, new security features for enterprise environments, and DirectX 12.

The Windows Runtime app ecosystem was revised into the Universal Windows Platform (UWP).[35][69][70] These universal apps are made to run across multiple platforms and device classes, including smartphones, tablets, Xbox One consoles, and other devices compatible with Windows 10. Windows apps share code across platforms, have responsive designs that adapt to the needs of the device and available inputs, can synchronize data between Windows 10 devices (including notifications, credentials, and allowing cross-platform multiplayer for games), and are distributed through the Microsoft Store (rebranded from Windows Store since September 2017).[71] Developers can allow "cross-buys", where purchased licenses for an app apply to all of the user's compatible devices, rather than only the one they purchased on (e.g., a user purchasing an app on PC is also entitled to use the smartphone version at no extra cost).[36][72][73]

The ARM version of Windows 10 allows running applications for x86 processors through software emulation.

On Windows 10, Microsoft Store serves as a unified storefront for apps, video content, and eBooks.[74] Windows 10 also allows web apps and desktop software (using either Win32 or .NET Framework) to be packaged for distribution on Microsoft Store. Desktop software distributed through Windows Store is packaged using the App-V system to allow sandboxing

Microsoft Office, or simply Office, is a family of client software, server software, and services developed by Microsoft. It was first announced by Bill Gates on August 1, 1988, at COMDEX in Las Vegas. Initially a marketing term for an office suite (bundled set of productivity applications), the first version of Office contained Microsoft Word, Microsoft Excel, and Microsoft PowerPoint. Over the years, Office applications have grown substantially closer with shared features such as a common spell checker, OLE data integration and Visual Basic for Applications scripting language. Microsoft also positions Office as a development platform for line-of-business software under the Office Business Applications brand. On July 10, 2012, Softpedia reported that Office was being used by over a billion people worldwide.[11]

Office is produced in several versions targeted towards different end-users and computing environments. The original, and most widely used version, is the desktop version, available for PCs running the Windows and macOS operating systems. Microsoft also maintains mobile apps for Android and iOS. Office on the web is a version of the software that runs within a web browser.

Since Office 2013, Microsoft has promoted Office 365 as the primary means of obtaining Microsoft Office: it allows the use of the software and other services on a subscription business model, and users receive feature updates to the software for the lifetime of the subscription, including new features and cloud computing integration that are not necessarily included in the "on-premises" releases of Office sold under conventional license terms. In 2017, revenue from Office 365 overtook conventional license sales. Microsoft also rebranded most of their standard Office 365 editions into Microsoft 365 to emphasize their current inclusion of products and services.

The current on-premises, desktop version of Office is Office 2019, released on September 24, 2018.

OpenOffice.org (OOo), commonly known as OpenOffice, is a discontinued open-source office suite, now fully replaced by Apache OpenOffice. OpenOffice.org was an open-sourced version of the earlier StarOffice, which Sun Microsystems acquired in 1999 for internal use.

OpenOffice included a word processor (Writer), a spreadsheet (Calc), a presentation application (Impress), a drawing application (Draw), a formula editor (Math), and a database management application (Base).[9] Its default file format was the OpenDocument Format (ODF), an ISO/IEC standard, which originated with OpenOffice.org. It could also read a wide variety of other file formats, with particular attention to those from Microsoft Office.

Sun open-sourced the OpenOffice suite in July 2000 as a competitor to Microsoft Office,[10][11] releasing version 1.0 on 1 May 2002.[1]

In 2011, Oracle Corporation, the then-owner of Sun, announced that it would no longer offer a commercial version of the suite[12] and donated the project to the Apache Foundation.[13][14]

Apache renamed the software Apache OpenOffice.[15] Other active successor projects include LibreOffice (the most actively developed[16][17][18]) and NeoOffice (commercial, and available only for macOS).

OpenOffice.org was primarily developed for Linux, Microsoft Windows and Solaris, and later for OS X, with ports to other operating systems. It was distributed under the GNU Lesser General Public License version 3 (LGPL); early versions were also available under the Sun Industry Standards Source License (SISSL).

Core apps and services

• Microsoft Word is a word processor included in Microsoft Office and some editions of the now-discontinued Microsoft Works. The first version of Word, released in the autumn of 1983, was for the MS-DOS operating system and introduced the computer mouse to more users. Word 1.0 could be purchased with a bundled mouse, though none was required. Following the precedents of LisaWrite and MacWrite, Word for Macintosh attempted to add closer WYSIWYG features into its package. Word for Mac was released in 1985. Word for Mac was the first graphical version of Microsoft Word. Initially, it implemented the proprietary .doc format as its primary format. Word 2007, however, deprecated this format in favor of Office Open XML, which was later standardized by Ecma International as an open format. Support for Portable Document Format (PDF) and OpenDocument (ODF) was first introduced in Word for Windows with Service Pack 2 for Word 2007.[13]

• Microsoft Excel is a spreadsheet editor that originally competed with the dominant Lotus 1-2-3 and eventually outsold it. Microsoft released the first version of Excel for the Mac OS in 1985 and the first Windows version (numbered 2.05 to line up with the Mac) in November 1987.

• Microsoft PowerPoint is a presentation program used to create slideshows composed of text, graphics, and other objects, which can be displayed on-screen and shown by the presenter or printed out on transparencies or slides.

• Microsoft OneNote is a notetaking program that gathers handwritten or typed notes, drawings, screen clippings and audio commentaries. Notes can be shared with other OneNote users over the Internet or a network. OneNote was initially introduced as a standalone app that was not included in any Microsoft Office 2003 edition. However, OneNote eventually became a core component of Microsoft Office; with the release of Microsoft Office 2013, OneNote was included in all Microsoft Office offerings. OneNote is also available as a web app on Office on the web, a freemium (and later freeware) Windows desktop app, a mobile app for Windows Phone, iOS, Android, and Symbian, and a Metro-style app for Windows 8 or later.

• Microsoft Outlook (not to be confused with Outlook Express, Outlook.com or Outlook on the web) is a personal information manager that replaces Windows Messaging, Microsoft Mail, and Schedule+ starting in Office 97; it includes an e-mail client, calendar, task manager and address book. On the Mac OS, Microsoft offered several versions of Outlook in the late 1990s, but only for use with Microsoft Exchange Server. In Office 2001, it introduced an alternative application with a slightly different feature set called Microsoft Entourage. It reintroduced Outlook in Office 2011, replacing Entourage.[14]

• Microsoft OneDrive is a file hosting service that allows users to sync files and later access them from a web browser or mobile device.

• Skype for Business is an integrated communications client for conferences and meetings in real-time; it is the only Microsoft Office desktop app that is neither useful without a proper network infrastructure nor has the "Microsoft" prefix in its name.

• Microsoft Teams is a platform that combines workplace chat, meetings, notes, and attachments. Microsoft announced that Teams would eventually replace Skype for Business.

Microsoft Word is a word processor developed by Microsoft. It was first released on October 25, 1983,[6] under the name Multi-Tool Word for Xenix systems.[7][8][9] Subsequent versions were later written for several other platforms including IBM PCs running DOS (1983), Apple Macintosh running the Classic Mac OS (1985), AT&T UNIX PC (1985), Atari ST (1988), OS/2 (1989), Microsoft Windows (1989), SCO Unix (1990), and macOS (2001).

Commercial versions of Word are licensed as a standalone product or as a component of Microsoft Office 365, or Microsoft 365 Premium subscription, Windows RT or the discontinued Microsoft Works suite.

In 1981, Microsoft hired Charles Simonyi, the primary developer of Bravo, the first GUI word processor, which was developed at Xerox PARC.[10] Simonyi started work on a word processor called Multi-Tool Word and soon hired Richard Brodie, a former Xerox intern, who became the primary software engineer.[10][11][12]

Microsoft announced Multi-Tool Word for Xenix[10] and MS-DOS in 1983.[13] Its name was soon simplified to Microsoft Word.[7] Free demonstration copies of the application were bundled with the November 1983 issue of PC World, making it the first to be distributed on-disk with a magazine.[7][14] That year Microsoft demonstrated Word running on Windows.[15]

Unlike most MS-DOS programs at the time, Microsoft Word was designed to be used with a mouse.[13] Advertisements depicted the Microsoft Mouse, and described Word as a WYSIWYG, windowed word processor with the ability to undo and display bold, italic, and underlined text,[16] although it could not render fonts.[7] It was not initially popular, since its user interface was different from the leading word processor at the time, WordStar.[17] However, Microsoft steadily improved the product, releasing versions 2.0 through 5.0 over the next six years. In 1985, Microsoft ported Word to the classic Mac OS (known as Macintosh System Software at the time). This was made easier by Word for DOS having been designed for use with high-resolution displays and laser printers, even though none were yet available to the general public.[18] It was also notable for its very fast cut-and-paste function and unlimited number of undo operations, which are due to its usage of the piece table data structure.[19]

Following the precedents of LisaWrite and MacWrite, Word for Mac OS added true WYSIWYG features. It fulfilled a need for a word processor that was more capable than MacWrite.[20] After its release, Word for Mac OS's sales were higher than its MS-DOS counterpart for at least four years.[10]

The second release of Word for Mac OS, shipped in 1987, was named Word 3.0 to synchronize its version number with Word for DOS; this was Microsoft's first attempt to synchronize version numbers across platforms. Word 3.0 included numerous internal enhancements and new features, including the first implementation of the Rich Text Format (RTF) specification, but was plagued with bugs. Within a few months, Word 3.0 was superseded by a more stable Word 3.01, which was mailed free to all registered users of 3.0.[18] After MacWrite Pro was discontinued in the mid-1990s, Word for Mac OS never had any serious rivals. Word 5.1 for Mac OS, released in 1992, was a very popular word processor owing to its elegance, relative ease of use and feature set. Many users say it is the best version of Word for Mac OS ever created.[18][21]

In 1986, an agreement between Atari and Microsoft brought Word to the Atari ST[22] under the name Microsoft Write. The Atari ST version was a port of Word 1.05 for the Mac OS[23][24] and was never updated.

The first version of Word for Windows was released in 1989. With the release of Windows 3.0 the following year, sales began to pick up and Microsoft soon became the market leader for word processors for IBM PC-compatible computers.[10] In 1991, Microsoft capitalized on Word for Windows' increasing popularity by releasing a version of Word for DOS, version 5.5, that replaced its unique user interface with an interface similar to a Windows application.[25][26] When Microsoft became aware of the Year 2000 problem, it made Microsoft Word 5.5 for DOS available for download free. As of February 2021, it is still available for download from Microsoft's web site.[27] In 1991, Microsoft embarked on a project code-named Pyramid to completely rewrite Microsoft Word from the ground up. Both the Windows and Mac OS versions would start from the same code base. It was abandoned when it was determined that it would take the development team too long to rewrite and then catch up with all the new capabilities that could have been added at the same time without a rewrite. Instead, the next versions of Word for Windows and Mac OS, dubbed version 6.0, both started from the code base of Word for Windows 2.0.[21]

With the release of Word 6.0 in 1993, Microsoft again attempted to synchronize the version numbers and coordinate product naming across platforms, this time across DOS, Mac OS, and Windows (this was the last version of Word for DOS). It introduced AutoCorrect, which automatically fixed certain typing errors, and AutoFormat, which could reformat many parts of a document at once. While the Windows version received favorable reviews (e.g., from InfoWorld[28]), the Mac OS version was widely derided. Many accused it of being slow, clumsy and memory intensive, and its user interface differed significantly from Word 5.1.[21] In response to user requests, Microsoft offered Word 5 again, after it had been discontinued.[29] Subsequent versions of Word for macOS are no longer direct ports of Word for Windows, instead featuring a mixture of ported code and native code.

Microsoft Excel is a spreadsheet developed by Microsoft for Windows, macOS, Android and iOS. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications (VBA). It has been a very widely applied spreadsheet for these platforms, especially since version 5 in 1993, and it has replaced Lotus 1-2-3 as the industry standard for spreadsheets. Excel forms part of the Microsoft Office suite of software.

Basic operation

Main article: Spreadsheet

Microsoft Excel has the basic features of all spreadsheets,[6] using a grid of cells arranged in numbered rows and letter-named columns to organize data manipulations like arithmetic operations. It has a battery of supplied functions to answer statistical, engineering, and financial needs. In addition, it can display data as line graphs, histograms and charts, and with a very limited three-dimensional graphical display. It allows sectioning of data to view its dependencies on various factors for different perspectives (using pivot tables and the scenario manager).[7][8] A PivotTable is a powerful tool that can save time when it comes to data analysis.[9] It does this by simplifying large data sets via PivotTable fields that are also known as "the building blocks of PivotTables."[10] It has a programming aspect, Visual Basic for Applications, allowing the user to employ a wide variety of numerical methods, for example, for solving differential equations of mathematical physics,[11][12] and then reporting the results back to the spreadsheet. It also has a variety of interactive features allowing user interfaces that can completely hide the spreadsheet from the user, so the spreadsheet presents itself as a so-called application, or decision support system (DSS), via a custom-designed user interface, for example, a stock analyzer,[13] or in general, as a design tool that asks the user questions and provides answers and reports.[14][15] In a more elaborate realization, an Excel application can automatically poll external databases and measuring instruments using an update schedule,[16] analyze the results, make a Word report or PowerPoint slide show, and e-mail these presentations on a regular basis to a list of participants. Excel was not designed to be used as a database.[citation needed]

Microsoft allows for a number of optional command-line switches to control the manner in which Excel starts.[17]

Functions

See also: Microsoft Power Fx

Excel 2016 has 484 functions.[18] Of these, 360 existed prior to Excel 2010. Microsoft classifies these functions in 14 categories. Of the 484 current functions, 386 may be called from VBA as methods of the object "WorksheetFunction"[19] and 44 have the same names as VBA functions.[20]

With the introduction of LAMBDA, Excel will become Turing complete.[21]

Macro programming

VBA programming

Main article: Visual Basic for Applications

Use of a user-defined function sq(x) in Microsoft Excel. The named variables x & y are identified in the Name Manager. The function sq is introduced using the Visual Basic editor supplied with Excel.

Subroutine in Excel calculates the square of named column variable x read from the spreadsheet, and writes it into the named column variable y.

The Windows version of Excel supports programming through Microsoft's Visual Basic for Applications (VBA), which is a dialect of Visual Basic. Programming with VBA allows spreadsheet manipulation that is awkward or impossible with standard spreadsheet techniques. Programmers may write code directly using the Visual Basic Editor (VBE), which includes a window for writing code, debugging code, and code module organization environment. The user can implement numerical methods as well as automating tasks such as formatting or data organization in VBA[22] and guide the calculation using any desired intermediate results reported back to the spreadsheet.

VBA was removed from Mac Excel 2008, as the developers did not believe that a timely release would allow porting the VBA engine natively to Mac OS X. VBA was restored in the next version, Mac Excel 2011,[23] although the build lacks support for ActiveX objects, impacting some high level developer tools.[24]

A common and easy way to generate VBA code is by using the Macro Recorder.[25] The Macro Recorder records actions of the user and generates VBA code in the form of a macro. These actions can then be repeated automatically by running the macro. The macros can also be linked to different trigger types like keyboard shortcuts, a command button or a graphic. The actions in the macro can be executed from these trigger types or from the generic toolbar options. The VBA code of the macro can also be edited in the VBE. Certain features such as loop functions and screen prompt by their own properties, and some graphical display items, cannot be recorded but must be entered into the VBA module directly by the programmer. Advanced users can employ user prompts to create an interactive program, or react to events such as sheets being loaded or changed.

Macro Recorded code may not be compatible with Excel versions. Some code that is used in Excel 2010 cannot be used in Excel 2003. Making a Macro that changes the cell colors and making changes to other aspects of cells may not be backward compatible.

VBA code interacts with the spreadsheet through the Excel Object Model,[26] a vocabulary identifying spreadsheet objects, and a set of supplied functions or methods that enable reading and writing to the spreadsheet and interaction with its users (for example, through custom toolbars or command bars and message boxes). User-created VBA subroutines execute these actions and operate like macros generated using the macro recorder, but are more flexible and efficient.

History

From its first version Excel supported end-user programming of macros (automation of repetitive tasks) and user-defined functions (extension of Excel's built-in function library). In early versions of Excel, these programs were written in a macro language whose statements had formula syntax and resided in the cells of special-purpose macro sheets (stored with file extension .XLM in Windows.) XLM was the default macro language for Excel through Excel 4.0.[27] Beginning with version 5.0 Excel recorded macros in VBA by default but with version 5.0 XLM recording was still allowed as an option. After version 5.0 that option was discontinued. All versions of Excel, including Excel 2010 are capable of running an XLM macro, though Microsoft discourages their use.[28]

Charts

Graph made using Microsoft Excel

Excel supports charts, graphs, or histograms generated from specified groups of cells. It also supports Pivot Charts that allow for a chart to be linked directly to a Pivot table. This allows the chart to be refreshed with the Pivot Table.[29] The generated graphic component can either be embedded within the current sheet or added as a separate object.

These displays are dynamically updated if the content of cells changes. For example, suppose that the important design requirements are displayed visually; then, in response to a user's change in trial values for parameters, the curves describing the design change shape, and their points of intersection shift, assisting the selection of the best design.

Add-ins

Additional features are available using add-ins. Several are provided with Excel, including:

• Analysis ToolPak: Provides data analysis tools for statistical and engineering analysis (includes analysis of variance and regression analysis)

• Analysis ToolPak VBA: VBA functions for Analysis ToolPak

• Euro Currency Tools: Conversion and formatting for euro currency

• Solver Add-In: Tools for optimization and equation solving