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Universitatea "Titu Maiorescu" Bucuresti
Facultatea de Informatica
The History of Computers
The first computer mouse was invented in 1963 by Douglas Engelbart at the Stanford Research Institute. (He is also one of the inventors of hypertext.) The first mouse used two wheels positioned at a 90-degree angle to each other to keep track of the movement (see picture below). The ball mouse wasn't invented until 1972, and the optical mouse was invented circa 1980 although it didn't come to popular use until much later.Douglas Engelbart never received any royalties for his invention and his patent had run out by the time the mouse became commonplace in the era of home PCs.
The trackball was actually invented 11 years BEFORE the mouse, in 1952. It was invented by Tom Cranston and Fred Longstaff as part of a computerized battlefield information system called DATAR, initiated by the Canadian Navy. It used a standard five-pin bowling ball as its trackball, which is smaller than the more common 10-pin bowling ball.
Well, perhaps that should be "movable" computer. The IBM 5100 Portable Computer was introduced in 1975, weighed 25 kg (55 lb), was the size of a small suitcase and needed external power to operate. It held everything in the same unit, packing in a processor, ROM (several hundreds of KB) and RAM (16-64 KB), a five-inch CRT display, keyboard and a tape drive, which was an amazing feat at the time. It also came with built-in BASIC and/or APL. The different models of the IBM 5100 sold for $8,975 - $19,975.
The first laptop computer (or notebook) was the Grid Compass 1100 (called the GRiD) and was designed in 1979 by a British industrial designer, Bill Moggridge. The computer didn't start selling until 1982, then featuring a 320×200 screen, an Intel 8086 processor, 340 KB of magnetic bubble memory (a now obsolete, non-volatile memory type) and a 1200 bps modem. It weighed 5 kg (11 lb) and cost $8-10,000. The GRiD was mainly used by NASA and the US military.
The IBM Personal Computer was introduced in 1981 as the IBM 5150. The platform became so pervasive in the 80s that although the term "personal computer" had been in use since the early 70s, a PC became synonymous with an IBM PC-compatible computer.
During its development, the IBM 5150 had been internally referred to as "Project Chess" and was created by a team of 12 people headed by Don Estridge and Larry Potter. To speed up development and cut costs, IBM had decided to use off-the-shelf parts, something that they normally wouldn't do.
The first IBM PC had an Intel 8088 processor, 64 KB of RAM (extendible to 256 KB), a floppy disk drive (which could be used to boot the computer with a rebranded version of MS-DOS (PC-DOS)) and a CGA or monochrome video card. The machine also had a version of Microsoft BASIC in ROM. On the first IBM PC the optional 10 MB hard disk drive could only be installed if the original power supply was replaced (the original one was too weak).
The first Apple personal computers (Apple I) were designed and hand-built by Steve Wozniak. The Apple I went on sale in 1976 for the price of $666.66. Only about 200 units were produced. The Apple I was basically just a motherboard with a processor, a total of 8KB of RAM, a display interface and some additional functionality. To have a working computer, the buyer would have to add a power supply, a keyboard and a display (and a case to keep mount it all in).
Arguably the first (writable) random access memory was Magnetic Core Memory (also called Ferrite-Core Memory) and was invented in 1951 as a result of work done by An Wang at Harvard University's Computation Lab and Jay Forrester at MIT.
Core memory was a family of related technologies that used the magnetic properties of materials to give them a similar functionality to transistors. They stored their information using the polarity of tiny, magnetic ceramic rings with wires threaded through them. Unlike today's RAM, core memory could keep its information even after the power was turned off.
Core memory was common until it was replaced by integrated silicon RAM chips in the 1970s. The "core" in core memory is why a memory dump is called a "core dump" even today.
The IBM Model 350 Disk File was the first hard disk drive and was part of the IBM 305 RAMAC computer that IBM started delivering in 1956 (mainly intended for business accounting). It had 50 24-inch discs that together could store about 4.4 MB of data. The Model 350 spun at 1200 rpm, had a data transfer rate of 8,800 characters per second and an access time of approximately one second.
And since the Web is such an integral part of today's computer experience, we couldn't help but include another first: The first web server was a NeXT workstation that Tim Berners-Lee used when he invented the World Wide Web at CERN. The first web page was put online on August 6, 1991.
A personal computer (PC) is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator. PCs include any type of computer that is used in a 'personal' manner. This is in contrast to the batch processing or time-sharing models which allowed large expensive mainframe systems to be used by many people, usually at the same time, or large data processing systems which required a full-time staff to operate efficiently. It is also in contrast with the more recent trend of controlling software availability through an intervening third party such as the Apple App Store.
A personal computer may be a desktop computer , a laptop , a tablet PC , or a handheld PC (also called a palmtop). The most common microprocessors in personal computers are x86 -compatible CPUs. Software applications for personal computers include word processing spreadsheets databases Web browsers and e-mail clients, games , and myriad personal productivity and special-purpose software applications. Modern personal computers often have connections to the Internet , allowing access to the World Wide Web and a wide range of other resources.
A PC may be used at home or in an office. Personal computers may be connected to a local area network (LAN), either by a cable or a wireless connection.
While early PC owners usually had to write their own programs to do anything useful with the machines, today's users have access to a wide range of commercial and non-commercial software, which is provided in ready-to-run or ready-to-compile form. Since the 1980s, Microsoft and Intel have dominated much of the personal computer market, first with MS-DOS and then with the Wintel platform.
By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person.
In the 1970s Hewlett Packard introduced fully BASIC programmable computers that fit entirely on top of a desk, including a keyboard, a small one-line display and printer. The Wang 2200 of 1973 had a full-size cathode ray tube (CRT) and cassette tape storage. The IBM 5100 in 1975 had a small CRT display and could be programmed in BASIC and APL. These were generally expensive specialized computers sold for business or scientific uses. The introduction of the microprocessor, a single chip with all the circuitry that formerly occupied large cabinets, led to the proliferation of personal computers after 1975.
Early personal computers - generally called microcomputers - were sold often in kit form and in limited volumes, and were of interest mostly to hobbyists and technicians. Minimal programming was done with toggle switches to enter instructions, and output was provided by front panel lamps. Practical use required peripherals such as keyboards, computer terminals , disk drives, and printers.
Through the late 1970s and into the 1980s, computers were developed for household use, with software for personal productivity, programming and games. One such machine, the Commodore 64 , totaled 17 million units sold, making it the best-selling single personal computer model of all time. Somewhat larger and more expensive systems (although still low-cost compared with minicomputers and mainframes ) were aimed at office and small business use. Workstations are characterized by high-performance processors and graphics displays, with large local disk storage, networking capability, and running under a multitasking operating system.
Eventually due to the influence of the IBM-PC on the personal computer market, personal computers and home computers lost any technical distinction. Business computers acquired color graphics capability and sound, and home computers and game systems users used the same processors and operating systems as office workers. Mass-market computers had graphics capabilities and memory comparable to dedicated workstations of a few years before. Even local area networking, originally a way to allow business computers to share expensive mass storage and peripherals, became a standard feature of personal computers used at home.
In 1982 'The Computer' was named Machine of the Year by Time Magazine
Single unit PCs (also known as all-in-one PCs) are a subtype of desktop computers, which combine the monitor and case of the computer within a single unit. The monitor often utilizes a touchscreen as an optional method of user input, however detached keyboards and mice are normally still included. The inner components of the PC are often located directly behind the monitor, and many are built similarly to laptops.
A laptop computer or simply laptop, also called a notebook computer or sometimes a notebook, is a small personal computer designed for portability. Usually all of the interface hardware needed to operate the laptop, such as USB ports (previously parallel and serial ports), graphics card, sound channel, etc., are built in to a single unit. Laptops contain high capacity batteries that can power the device for extensive periods of time, enhancing portability.
Once the battery charge is depleted, it will have to be recharged through a power outlet. In the interest of saving power, weight and space, they usually share RAM with the video channel, slowing their performance compared to an equivalent desktop machine.
One main drawback of the laptop is sometimes, due to the size and configuration of components, relatively little can be done to upgrade the overall computer from its original design. Internal upgrades are either not manufacturer recommended, can damage the laptop if done with poor care or knowledge, or in some cases impossible, making the desktop PC more modular. Some internal upgrades, such as memory and hard disks upgrades are often easy, a display or keyboard upgrade is usually impossible. The laptop has the same access as the desktop to the wide variety of devices, such as external displays, mice, cameras, storage devices and keyboards, which may be attached externally through USB ports and other less common ports such as external video.
Netbooks (also called mini notebooks or subnotebooks) are a rapidly evolving category of small, light and inexpensive laptop computers suited for general computing and accessing web-based applications; they are often marketed as 'companion devices,' that is, to augment a user's other computer access. Walt Mossberg called them a 'relatively new category of small, light, minimalist and cheap laptops.' By August 2009, CNET called netbooks 'nothing more than smaller, cheaper notebooks.'
Tablet PC
A tablet PC is a notebook or slate-shaped mobile computer, first introduced by Pen computing in the early 90s with their PenGo Tablet Computer and popularized by Microsoft. Its touchscreen or graphics tablet/screen hybrid technology allows the user to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse.
As technology and functionality continue to progress, prototype tablet computers will continue to emerge. The Microsoft Courier, a personal business device, has two 7' monitors that support multi-touch gestures, Wi-Fi capabilities and has a built-in camera. The device looks to be a replacement to traditional planners while offering what most digital planners cannot, two pages and large writing spaces. This particular device, however, has been recently abandoned and the market is currently being led by the popular iPad from Apple Inc.
A pocket PC is a hardware specification for a handheld-sized computer (personal digital assistant) that runs the Microsoft Windows Mobile operating system. It may have the capability to run an alternative operating system like NetBSD or Linux. It has many of the capabilities of modern desktop PCs
Currently there are tens of thousands of applications for handhelds adhering to the Microsoft Pocket PC specification, many of which are freeware. Some of these devices also include mobile phone features. Microsoft compliant Pocket PCs can also be used with many other add-ons like GPS receivers barcode readers, RFID readers, and cameras. In 2007, with the release of Windows Mobile 6, Microsoft dropped the name Pocket PC in favor of a new naming scheme. Devices without an integrated phone are called Windows Mobile Classic instead of Pocket PC. Devices with an integrated phone and a touch screen are called Windows Mobile Professional.
Mass-market consumer computers use highly standardized components and so are simple for an end user to assemble into a working system. A typical desktop computer consists of a computer case which holds the power supply motherboard hard disk and often an optical disc. External devices such as a video monitor or visual display unit keyboard, and a pointing device are usually found in a personal computer.
The motherboard connects all processor, memory and peripheral devices together. The RAM, graphics card and processor are mounted directly onto the motherboard. The central processing unit microprocessor chip plugs into a socket. Expansion memory plugs into memory sockets. Some motherboards have the video display adapter, sound and other peripherals integrated onto the motherboard. Others use expansion slots for graphics cards, network cards, or other I/O devices. Disk drives for mass storage are connected to the mother board with a cable, and to the power supply through another cable. Usually disk drives are mounted in the same case as the motherboard; formerly, expansion chassis were made for additional disk storage.
The graphics and sound card can have a break out box to keep the analog parts away from the electromagnetic radiation inside the computer case. For really large amounts of data, a tape drive can be used or (extra) hard disks can be put together in an external case.
The keyboard and the mouse are external devices plugged into the computer through connectors on an I/O panel on the back of the computer. The monitor is also connected to the I/O panel, either through an onboard port on the motherboard, or a port on the graphics card.
The hardware capabilities of personal computers can sometimes be extended by the addition of expansion cards connected via an expansion bus. Some standard peripheral buses often used for adding expansion cards in personal computers as of 2005 are PCI AGP (a high-speed PCI bus dedicated to graphics adapters), and PCI Express. Most personal computers as of 2005 have multiple physical PCI expansion slots. Many also include an AGP bus and expansion slot or a PCI Express bus and one or more expansion slots, but few PCs contain both buses.
A computer case is the enclosure that contains the main components of a computer. Cases are usually constructed from steel or aluminum, although other materials such as wood and plastic have been used. Cases can come in many different sizes, or form factors. The size and shape of a computer case is usually determined by the form factor of the motherboard that it is designed to accommodate, since this is the largest and most central component of most computers. Consequently, personal computer form factors typically specify only the internal dimensions and layout of the case. Form factors for rack-mounted and blade servers may include precise external dimensions as well, since these cases must themselves fit in specific enclosures.
Currently, the most popular form factor for desktop computers is ATX , although microATX and small form factors have become very popular for a variety of uses. Companies like Shuttle Inc. and AOpen have popularized small cases, for which FlexATX is the most common motherboard size.
The central processing unit, or CPU, is that part of a computer which executes software program instructions. In older computers this circuitry was formerly on several printed circuit boards, but in PCs is a single integrated circuit. Nearly all PCs contain a type of CPU known as a microprocessor. The microprocessor often plugs into the motherboard using one of many different types of sockets. IBM PC compatible computers use an x86-compatible processor, usually made by Intel AMD VIA Technologies or Transmeta. Apple Macintosh computers were initially built with the Motorola 680x0 family of processors, then switched to the PowerPC series (a RISC architecture jointly developed by Apple Computer IBM and Motorola), but as of 2006, Apple switched again, this time to x86-compatible processors by Intel. Modern CPUs are equipped with a fan attached via heat sink
The motherboard, also referred to as systemboard or mainboard, is the primary circuit board within a personal computer. Many other components connect directly or indirectly to the motherboard. Motherboards usually contain one or more CPUs, supporting circuitry - usually integrated circuits (ICs) - providing the interface between the CPU memory and input/output peripheral circuits, main memory, and facilities for initial setup of the computer immediately after power-on (often called boot firmware or, in IBM PC compatible computers, a BIOS). In many portable and embedded personal computers, the motherboard houses nearly all of the PC's core components. Often a motherboard will also contain one or more peripheral buses and physical connectors for expansion purposes. Sometimes a secondary daughter board is connected to the motherboard to provide further expandability or to satisfy space constraints.
A PC's main memory is fast storage that is directly accessible by the CPU, and is used to store the currently executing program and immediately needed data. PCs use semiconductor random access memory (RAM) of various kinds such as DRAM, SDRAM or SRAM as their primary storage. Which exact kind depends on cost/performance issues at any particular time. Main memory is much faster than mass storage devices like hard disks or optical discs, but is usually volatile, meaning it does not retain its contents (instructions or data) in the absence of power, and is much more expensive for a given capacity than is most mass storage. Main memory is generally not suitable for long-term or archival data storage.
Mass storage devices store programs and data even when the power is off; they do require power to perform read and write functions during usage. Although flash memory has dropped in cost, the prevailing form of mass storage in personal computers is still the hard disk
The disk drives use a sealed head/disk assembly (HDA) which was first introduced by IBM's 'Winchester' disk system. The use of a sealed assembly allowed the use of positive air pressure to drive out particles from the surface of the disk, which improves reliability.
If the mass storage controller provides for expandability, a PC may also be upgraded by the addition of extra hard disk or optical disc drives. For example, BD-ROMs DVD-RWs, and various optical disc recorders may all be added by the user to certain PCs. Standard internal storage device connection interfaces are PATA Serial ATA SCSI
The video card - otherwise called a graphics card, graphics adapter or video adapter - processes and renders the graphics output from the computer to the computer display, and is an essential part of the modern computer. On older models, and today on budget models, graphics circuitry tended to be integrated with the motherboard but, for modern flexible machines, they are supplied in PCI AGP, or PCI Express format.
When the IBM PC was introduced, most existing business-oriented personal computers used text-only display adapters and had no graphics capability. Home computers at that time had graphics compatible with television signals, but with low resolution by modern standards owing to the limited memory available to the eight-bit processors available at the time.
A visual display unit (or monitor) is a piece of electrical equipment, usually separate from the computer case, which displays viewable images generated by a computer without producing a permanent record. The word 'monitor' is used in other contexts; in particular in television broadcasting, where a television picture is displayed to a high standard. A computer display device is usually either a cathode ray tube or some form of flat panel such as a TFT LCD. The monitor comprises the display device, circuitry to generate a picture from electronic signals sent by the computer, and an enclosure or case. Within the computer, either as an integral part or a plugged-in Expansion card, there is circuitry to convert internal data to a format compatible with a monitor. The images from monitors originally contained only text, but as Graphical user interfaces emerged and became common, they began to display more images and multimedia content.
In computing, a keyboard is an arrangement of buttons that each correspond to a function, letter, or number. They are the primary devices of inputting text. In most cases, they contain an array of keys specifically organized with the corresponding letters, numbers, and functions printed or engraved on the button. In English, the most common layout is the QWERTY layout, which was originally used in typewriters. They have evolved over time, and have been modified for use in computers with the addition of function keys, number keys, arrow keys, and OS specific keys. Often, specific functions can be achieved by pressing multiple keys at once or in succession, such as inputting characters with accents or opening a task manager. Programs use keyboard shortcuts very differently and all use different keyboard shortcuts for different program specific operations, such as refreshing a web page in a web browser or selecting all text in a word processor.
A Mouse on a computer is a small, slideable device that users hold and slide around to point at, click on, and sometimes drag objects on screen in a graphical user interface using a pointer on screen. Almost all Personal Computers have mice. It may be plugged into a computer's rear mouse socket, or as a USB device, or, more recently, may be connected wirelessly via a USB antenna or Bluetooth antenna. In the past, they had a single button that users could press down on the device to 'click' on whatever the pointer on the screen was hovering over. Now, however, many Mice have two or three buttons(possibly more); a 'right click' function button on the mouse, which performs a secondary action on a selected object, and a scroll wheel, which users can rotate using their fingers to 'scroll' up or down. The scroll wheel can also be pressed down, and therefore be used as a third button. Some mouse wheels may be tilted from side to side to allow sideways scrolling. Different programs make use of these functions differently, and may scroll horizontally by default with the scroll wheel, open different menus with different buttons, among others. These functions may be user defined through software utilities.
Computer software is a general term used to describe a collection of computer programs procedures and documentation that perform some tasks on a computer system. The term includes application software such as word processors which perform productive tasks for users, system software such as operating systems, which interface with hardware to provide the necessary services for application software, and middleware which controls and co-ordinates distributed systems
Software applications for word processing Internet browsing, Internet faxing e-mail and other digital messaging, multimedia playback, computer game play and computer programming are common. The user of a modern personal computer may have significant knowledge of the operating environment and application programs, but is not necessarily interested in programming nor even able to write programs for the computer. Therefore, most software written primarily for personal computers tends to be designed with simplicity of use, or 'user-friendliness' in mind. However, the software industry continuously provide a wide range of new products for use in personal computers, targeted at both the expert and the non-expert user.
An operating system (OS) manages computer resources and provides programmers with an interface used to access those resources. An operating system processes system data and user input, and responds by allocating and managing tasks and internal system resources as a service to users and programs of the system. An operating system performs basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating computer networking and managing files.
Common contemporary desktop OSs are Microsoft Windows (92.78% market share), Mac OS X (5.12%), Linux (0.95%), Solaris and FreeBSD. Windows, Mac, and Linux all have server and personal variants. With the exception of Microsoft Windows, the designs of each of the aforementioned OSs were inspired by, or directly inherited from, the Unix operating system. Unix was developed at Bell Labs beginning in the late 1960s and spawned the development of numerous free and proprietary operating systems.
