A low-cost, low-capacity version of the hard disk was popularized by the microcomputer. Although the popular IBM format only holds 1,44 megabytes, a number of manufacturers have developed diskette drives that can store from to megabytes per stiffy.
An alternative development is the removable disk cartridge, which is similar in structure to an internal hard drive but provides portability, making it useful for backup purposes. While disk and optical storage have overtaken magnetic tape as the most popular method of storing data in a computer, tape is still used occasionally — in particular for keeping archive copies of important files.
The main drawback of magnetic tape is that it is not very efficient for accessing data in any way other than strictly sequential order. As an illustration, compare a CD player which can skip to any track almost instantly with a music tape recorder which has to wind the tape all the way through if one wants to listen to a song near the end. In computer terms, the ability to access any record, track, or even part within a song directly is called the direct access method. In the case of the tape recorder one may have to wind laboriously through the tape until one reaches the song required — this is referred to as the sequential access method.
The high-density diskette and recordable optical disk have all but eroded the marginal cost advantage that tape storage enjoyed. This technology is therefore disappearing fast. Similar to disk storage, information is stored and read from a circular disk. However, instead of a magnetic read head, a tiny laser beam is used to detect microscopic pits burnt onto a plastic disk coated with reflective material.
In contrast to hard disks, data is not stored in concentric cylinders but in one long continuous spiral track. The widespread use of music compact discs has made the technology very pervasive and cheap. The drive reader units themselves have also dropped in price and are now hardly more than the cost of a diskette drive. A standard CD-ROM can store megabytes of data and the data can be transferred at many megabytes per second, though accessing non-sequential data takes much longer.
Data cannot be recorded onto the disk. The low cost and relatively large capacity makes the CD-ROM ideally suited to the distribution of software. They are also ideal for the low-cost distribution of large quantities of information such as product catalogues, reference materials, conference proceedings, databases, etc. It is indispensable for the storage of multimedia where traditional textual information is supplemented with sound, music, voice, pictures, animation, and even video clips.
The limitation of the read-only format lead to the development of low-cost recordable optical disks. The CD-R drive unit takes a blank optical disk and burns data onto it using a higher-powered laser.
This disk can then be read and distributed as an ordinary CD-ROM, with the advantage that the data is non-volatile i. The rapid drop in the cost of drive units and blank recording media less than R2 per CD-R is making this a very competitive technology for data backup and small-scale data distribution. Although the megabytes initially seemed almost limitless, many multimedia and video applications now require more storage. By combining the increased storage capacity with sophisticated data compression algorithms, a DVD disc can easily store 10 times as much as a CD, sufficient for a full-length high-quality digital motion picture with many simultaneous sound tracks.
Even the DVD is not sufficient storage capacity and currently two optical technologies have been developed to increase storage capacity even further. A promising research area involves the use of holographic disk storage whereby data is stored in a three-dimensional manner.
Though in its infancy, early prototypes promise a many-fold increase in storage capacity and it could become the answer to the ever increase storage requirements of the next decade. The final stage of information processing involves the use of output devices to transform computer-readable data back into an information format that can be processed by humans. As with input devices, when deciding on an output device you need to consider what sort of information is to be displayed, and who is intended to receive it.
One distinction that can be drawn between output devices is that of hardcopy versus softcopy devices. Hardcopy devices printers produce a tangible and permanent output whereas softcopy devices display screens present a temporary, fleeting image. The desk-based computer screen is the most popular output device.
A strong magnetic field guides the particle stream to form the text or graphics on your familiar monitor. CRTs vary substantially in size and resolution. The screen resolution depends on a number of technical factors.
A technology that has received much impetus from the fast-growing laptop and notebook market is the liquid crystal display LCD. LCDs have matured quickly, increasing in resolution, contrast, and colour quality. Their main advantages are lower energy requirements and their thin, flat size. Organic light-emitting diodes OLED can generate brighter and faster images than LED technology, and require thinner screens, but they have less stable colour characteristics, making them more suitable for cellular telephone displays than for computers.
Another screen-related technology is the video projection unit. Originally developed for the projection of video films, the current trend towards more portable LCD-based lightweight projectors is fuelled by the needs of computer-driven public presentations. They are rapidly replacing the flat transparent LCD panels that needed to be placed on top of an overhead projection unit.
Though the LCD panels are more compact, weigh less and are much cheaper, their image is generally of much poorer quality and less bright.
Printers are the most popular output device for producing permanent, paper-based computer output. Although they are all hardcopy devices, a distinction can be made between impact and non-impact printers.
With impact printers, a hammer or needle physically hits an inked ribbon to leave an ink impression of the desired shape on the paper. The advantage of the impact printer is that it can produce more than one simultaneous copy by using carbon or chemically-coated paper. Non-impact printers, on the other hand, have far fewer mechanically moving parts and are therefore much quieter and tend to be more reliable.
Computer data storage, often called storage or memory, refers to computer components and recording media that retain digital data. Data storage is a core function and fundamental component of computers. The price of solid-state drives SSD , which store data on flash memory, has dropped a lot in recent years, making them a better choice than ever to add to a computer to make booting up and accessing files faster.
Input and output devices are typically housed externally to the main computer chassis. The following are either standard or very common to many computer systems. In the s and s more and more departments started to use cheaper and dedicated systems for specific purposes like process control and laboratory automation.
A supercomputer is superficially similar to a mainframe, but is instead intended for extremely demanding computational tasks. As of November , the fastest supercomputer in the world is the Tianhe-2, in Guangzhou, China. The term supercomputer does not refer to a specific technology. Rather it indicates the fastest computers available at any given time. In mid , the fastest supercomputers boasted speeds exceeding one petaflop, or trillion floating point operations per second.
Super computers are fast but extremely costly so they are generally used by large organizations to execute computationally demanding tasks involving large data sets. Super computers typically run military and scientific applications.
Although they cost millions of dollars, they are also being used for commercial applications where huge amounts of data must be analyzed. For example, large banks employ supercomputers to calculate the risks and returns of various investment strategies, and healthcare organizations use them to analyze giant databases of patient data to determine optimal treatments for various diseases and problems incurring to the country.
Hardware — any physical device or equipment used in or with a computer system anything you can see and touch. Output device — a piece of hardware device that receives information from a computer. Examples: monitor, printer, scanner, speaker, display screen tablet, smartphone … , projector, head phone, etc.
Internal hardware Internal hardware devices or internal hardware components — any piece of hardware device that is located inside the computer. Hard disk drives work by writing binary data onto spinning magnetic disks called platters that rotate at high speeds, while a solid-state drive stores data by using static flash memory chips. Find out more about computer storage and how solid state drives work. Especially important for 3D rendering, the GPU does exactly what its name suggests and processes huge batches of graphic data.
As opposed to the basic on-board graphic capabilities that PC motherboards supply, dedicated graphics cards interface with the motherboard via an expansion slot to work almost exclusively on graphic rendering. This also means you can upgrade your graphics card if you want to get a bit more performance from your PC. Not only this, but modern GPUs fulfil a broad computational workload beyond just rendering, making them an extension to the central processing unit.
A power supply unit, commonly abbreviated as PSU, does more than just supply your computer with power. It is the point where power enters your system from an external power source and is then allocated by the motherboard to individual component hardware.
Not all power supplies are made equally however, and without the right wattage PSU your system will fail to work. Computers that are used for highly intensive tasks such as graphic design or gaming will require more powerful components and thus will need a bigger PSU to cater to this additional need.
Not only do you guard yourself against system failure, you also future-proof yourself against needing a new PSU when you upgrade to more powerful PC components. Understanding your computer and its hardware components can prove very useful when the time comes to upgrade or replace any parts, or when building a computer. Should a problem arise with the internal workings of your computer, you will have a better understanding of the importance of each component, the need for them to be in good working condition and how to go about solving any issues.
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