Kak-nastroit-interfejs-v-Linux.jpg' alt='Car Computer Software Linux' title='Car Computer Software Linux' />Computer data storage WikipediaMemory device redirects here. For tricks used to aid human memory, see mnemonic. Gi. BPATA hard disk drive HDD from 1. GB SDLT tape cartridge, an example of off line storage. When used within a robotic tape library, it is classified as tertiary storage instead. Computer data storage, often called storage or memory, is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. Car Computer Software Linux' title='Car Computer Software Linux' />Computerworld covers a range of technology topics, with a focus on these core areas of IT Windows, Mobile, Appleenterprise, Office and productivity suites. A driverless car sometimes called a selfdriving car, an automated car or an autonomous vehicle is a robotic vehicle that is designed to travel between destinations. The central processing unit CPU of a computer is what manipulates data by performing computations. In practice, almost all computers use a storage hierarchy,1 4. CPU and slower but larger and cheaper options farther away. ALT-Linux-3.jpg' alt='Car Computer Software Linux' title='Car Computer Software Linux' />Generally the fast volatile technologies which lose data when off power are referred to as memory, while slower persistent technologies are referred to as storage however, memory is sometimes also used when referring to persistent storage. In the Von Neumann architecture, the CPU consists of two main parts The control unit and the arithmetic logic unit ALU. The former controls the flow of data between the CPU and memory, while the latter performs arithmetic and logical operations on data. FunctionalityeditWithout a significant amount of memory, a computer would merely be able to perform fixed operations and immediately output the result. It would have to be reconfigured to change its behavior. This is acceptable for devices such as desk calculators, digital signal processors, and other specialized devices. Von Neumann machines differ in having a memory in which they store their operating instructions and data. Such computers are more versatile in that they do not need to have their hardware reconfigured for each new program, but can simply be reprogrammed with new in memory instructions they also tend to be simpler to design, in that a relatively simple processor may keep state between successive computations to build up complex procedural results. Most modern computers are von Neumann machines. Data organization and representationeditA modern digital computer represents data using the binary numeral system. Look to Cray for all computing technology. Learn about our products and how they deliver superior results through performance, scalability and adaptability. The keyboard is a device used to input text into a computer or other device. A keyboard typically connects wirelessly or via USB. Heres more. Quantum Computer Systems Inc. Business Information Solutions. Software Solutions. Multimedia VoIP. Networking. Text, numbers, pictures, audio, and nearly any other form of information can be converted into a string of bits, or binary digits, each of which has a value of 1 or 0. The most common unit of storage is the byte, equal to 8 bits. A piece of information can be handled by any computer or device whose storage space is large enough to accommodate the binary representation of the piece of information, or simply data. For example, the complete works of Shakespeare, about 1. Data are encoded by assigning a bit pattern to each character, digit, or multimedia object. Many standards exist for encoding e. ASCII, image encodings like JPEG, video encodings like MPEG 4. HbpZ1yWnBa4/UpRcRn5uK1I/AAAAAAAAAhE/G1JJ9zJEiec/s1600/LinuxVersions.jpg' alt='Car Computer Software Linux' title='Car Computer Software Linux' />When your driving, you need to keep your eyes on the ROAD. By adding bits to each encoded unit, redundancy allows the computer to both detect errors in coded data and correct them based on mathematical algorithms. Errors generally occur in low probabilities due to random bit value flipping, or physical bit fatigue, loss of the physical bit in storage of its ability to maintain a distinguishable value 0 or 1, or due to errors in inter or intra computer communication. A random bit flip e. A bit, or a group of malfunctioning physical bits not always the specific defective bit is known group definition depends on specific storage device is typically automatically fenced out, taken out of use by the device, and replaced with another functioning equivalent group in the device, where the corrected bit values are restored if possible. The cyclic redundancy check CRC method is typically used in communications and storage for error detection. A detected error is then retried. Data compression methods allow in many cases such as a database to represent a string of bits by a shorter bit string compress and reconstruct the original string decompress when needed. This utilizes substantially less storage tens of percents for many types of data at the cost of more computation compress and decompress when needed. Analysis of trade off between storage cost saving and costs of related computations and possible delays in data availability is done before deciding whether to keep certain data compressed or not. For security reasons certain types of data e. Hierarchy of storageeditGenerally, the lower a storage is in the hierarchy, the lesser its bandwidth and the greater its access latency is from the CPU. This traditional division of storage to primary, secondary, tertiary and off line storage is also guided by cost per bit. In contemporary usage, memory is usually semiconductor storage read write random access memory, typically DRAM dynamic RAM or other forms of fast but temporary storage. Storage consists of storage devices and their media not directly accessible by the CPU secondary or tertiary storage, typically hard disk drives, optical disc drives, and other devices slower than RAM but non volatile retaining contents when powered down. Historically, memory has been called core memory, main memory, real storage or internal memory. Meanwhile, non volatile storage devices have been referred to as secondary storage, external memory or auxiliaryperipheral storage. Blackjack Multi Advisor Serial Mom. Primary storageeditPrimary storage also known as main memory or internal memory, often referred to simply as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. Any data actively operated on is also stored there in uniform manner. Historically, early computers used delay lines, Williams tubes, or rotating magnetic drums as primary storage. By 1. 95. 4, those unreliable methods were mostly replaced by magnetic core memory. Core memory remained dominant until the 1. This led to modern random access memory RAM. It is small sized, light, but quite expensive at the same time. The particular types of RAM used for primary storage are also volatile, i. As shown in the diagram, traditionally there are two more sub layers of the primary storage, besides main large capacity RAM Processor registers are located inside the processor. Each register typically holds a word of data often 3. CPU instructions instruct the arithmetic logic unit to perform various calculations or other operations on this data or with the help of it. Registers are the fastest of all forms of computer data storage. Processor cache is an intermediate stage between ultra fast registers and much slower main memory. It was introduced solely to improve the performance of computers. Most actively used information in the main memory is just duplicated in the cache memory, which is faster, but of much lesser capacity. On the other hand, main memory is much slower, but has a much greater storage capacity than processor registers. Multi level hierarchical cache setup is also commonly usedprimary cache being smallest, fastest and located inside the processor secondary cache being somewhat larger and slower. Main memory is directly or indirectly connected to the central processing unit via a memory bus. It is actually two buses not on the diagram an address bus and a data bus. The CPU firstly sends a number through an address bus, a number called memory address, that indicates the desired location of data. Then it reads or writes the data in the memory cells using the data bus.