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by Dinesh Thakur

In terms of computing’s history, we’re just beginning to scratch the surface of the lifestyle applications of touch-sensitive gadgets. In this article, we’ll take a look at two of the most important touch-based input technologies used in computers, smartphones, laptops, and tablets.



 
by Dinesh Thakur

Whether you’re looking to replace a failed drive or upgrading to get more capacity and faster access times, installing a hard drive is simple. Just follow these steps to insert, secure, and power a new HDD in your desktop PC.



 
by Dinesh Thakur

There are three types of storage that we can use for our files: HDDs, SSDs, and cloud-based storage. In some cases, we have the option of foregoing one type in favor of another when looking for more capacity, faster load times, or dynamically shifting capacities. Read on to determine which applications are best suited to which storage types.

 
by Dinesh Thakur

The principle form of electronic MEMORY used in computers prior to the invention of semiconductor memory chips. It consisted of thousands of tiny rings called cores, made from a magnetic FERRITE material and each threaded onto three fine copper wires: the whole formed a two-dimensional mesh much like a knitted textile.



 
by Dinesh Thakur

A type of RAM that add ERROR DETECTION AND CORRECTION circuitry to automatically detect and correct a single BIT ERROR in any of the chip. Such errors are often induced, for example, by stray alpha particles emitted from minute amounts of radioactive elements in the chips' packaging.



 
by Dinesh Thakur

A type of ROM chip that can be erased and reprogrammed. The process of programming an EPROM is often called BURNING, and the box into which it is plugged to program it an EPROM burner.



 
by Dinesh Thakur

VRAM (pronounced "vee ram") stands for video random access memory, or video RAM. This is a special type of memory used on some video adapters to speed up the display of images on the screen. VRAM costs more than regular RAM (DRAM, dynamic RAM), but it does make the screen snappier.



 
by Dinesh Thakur

A RAM disk is not really a disk at all-it is memory (RAM, in the form of memory chips) that has been set aside pretending to be a disk. As long as the power is on, you can use a RAM disk just like a real disk drive-you can copy files to and from the RAM disk, display the RAM disk's directory or folder on your screen, and run any programs you've stored there. A RAM disk may be an external SCSI device that looks similar to a regular external hard disk (but is very expensive and is slowed down by the limitations of the SCSI connection), or it may be a lot of extra memory that you set aside with special RAM-disks of software, or it may be a memory card that you add to your computer.



 
by Dinesh Thakur

Understanding RAM on a PC gets pretty complicated, especially if you're using DOS instead of Windows. If your system is working okay already, don't bother with this information because it's pretty technical. But if you're running out of memory-if certain programs won't run or you can't create large files-you need some background knowledge before you march down and buy more memory. You may already have enough!



 
by Dinesh Thakur

Most dot matrix printers have a print buffer, a special chunk of memory for temporary storage. When you print a document, the computer sends out the necessary information faster than the printer can print it. If the printer has a buffer, the information the printer can't deal with immediately goes into the buffer, where it waits until the printer is ready for it. As soon as the entire document is in the buffer, you can use your computer again for other work, while the printer takes its time to print the "buffered" information. The larger the print buffer, the more it can hold and the faster you get your screen back.



 
by Dinesh Thakur

In humans, the memory is mind warehouse , where are stored for a later use the various components experience. The memory of a computer somewhat similar but more limited at its possibilities.



 
by Dinesh Thakur

By allowing ordinary people (that's me) to produce printed documents that look almost like they were professionally published, and to do it all in their own home or office, laser printers represent a true technological revolution. The first relatively affordable laser printers were the Apple LaserWriter and the Hewlett-Packard LaserJet. Prices have dropped like a rock and quality is way up since those machines came out, but the basic technology remains the same.

 
by Dinesh Thakur

IBM Disc Electronics or Integrated Drive Electronics is more commonly known as ATA or Parallel ATA (PATA) and is a standard interface for IBM compatible hard drives.

 
by Dinesh Thakur

Density is a term used to describe the type and amount of storage area on a floppy disk. A disk is covered with particles of magnetic 'dust' that can store pieces of data. The larger the particles, the fewer the disk can hold and therefore the less information it can store. On a high-density disk, the particles are smaller; the disk can store more information because more particles can be packed in more densely. High density is not the same as "double density," which is an earlier technology still currently used that packs only about half as much data onto a floppy disk.



 
by Dinesh Thakur

Firmware is a category or class of memory chips which contain information that is permanent (meaning it isn't erased when you shut off your computer or when the power suddenly goes out on a dark and stormy night). The best examples of firmware are theROM chips in your computer that contain programs installed at the factory. Firmware cannot be altered, per se, but in some cases the whole chip can be completely replaced by a technician when it becomes outdated or obsolete.



 
by Dinesh Thakur

Fatal error!? Why do they do this to us? Why can't they just say, "Oh, excuse me, but your system has a serious problem. The trouble may just be temporary, and if you'll turn off the computer and try again, maybe everything will work fine."



 
by Dinesh Thakur

In the vast majority of pcs sold these days, extended memory is the type of memory over and above the first megabyte (which is the conventional memory). A PC must have at least an 80286 microprocessor (meaning that an 80386 or 80486 will work, too) to use extended memory. But even then, DOS doesn't recognize extended memory-to use it, your software has to incorporate a DOS extender.



 
by Dinesh Thakur

Expansion slots are the long, narrow openings aligned in rows on your computer's main circuit board (the motherboard) where you plug in add in boards to give your computer new capabilities. The slots are openings within short plastic projections that stick up from the motherboard. The walls of an expansion slot are lined with metal contacts to match the contacts on the add-in board that you insert.



 
by Dinesh Thakur

Expanded memory, also known as EMS, is a combination of hardware and software that allows an IBM PC or compatible to use more memory (normally, DOS limits pc-type computers to one megabyte). 



 
by Dinesh Thakur

DRAM stands for dynamic random access memory. DRAM is a technical term for a type of random access memory (RAM) that can retain its contents only for a very brief period (measured in milliseconds) and must therefore be continually refreshed by reading its contents at short intervals.



 
by Dinesh Thakur

The resolution of a printer or a scanner is measured in dots per inch, abbreviated "dpi." If a printer has a resolution of, say, 300 dots per inch, that means in one inch there are 300 dots in a row across, and 300 dots in a row down. The more dots per inch, the smaller the dot has to be, of course. You can logically understand, then, that the higher the dpi, the smoother the printed image will appear to be.



 
by Dinesh Thakur

A disk drive (or diskette drive, depending on what you want to call the disk) is the part of the computer that takes the disks you insert and spins them. There are many different types of disks, so there are many types of disk drives. The one you will probably see most commonly is the floppy disk drive; actually, all you see is the slot where you insert the disk-the drive mechanism itself is inside the computer. 



 
by Dinesh Thakur

The disk controller is circuitry on the computer's motherboard or on a plug-in circuit board that controls the operation of your hard disk drive, floppy disk drives, or both. When the computer wants to transfer data to or from the disk, it tells the disk controller. The controller in turn sends electronic commands to the disk drive making the disk spin and move its magnetic heads to the proper location on the disk. The controller then transfers the data between the computer and the disk drive. The computer's OPERATING SYSTEM and BIOS issue commands directly to the controller to BOOT the computer and to access files stored on the disks. 



 
by Dinesh Thakur

A disk is a thin, circular object used to store computer data (well, the actual disk itself is round, but it is stored in either a square, paper envelope or a square, hard plastic case). The disk goes into a disk drive which spins the disk very rapidly, allowing information to be located and transferred to or from the disk quickly.



 
by Dinesh Thakur

The term dirty ROMS is backwards-derived from the 32-bit clean ROMS that were built into later Macintoshes. That is, they didn't plan to make dirty ROMs. A ROM is a read-only memory chip built inside the computer. It contains permanent and unalterable software to help run the computer.



 
by Dinesh Thakur

DAT stands for digital audio tape. It refers to a type of tape recording technology, originally developed for music, which represents music on tape with numbers (digitally) rather than as analog sound waves (see digitize and A-to-D conversion). High-fidelity digital music requires a system that can record a great deal of data at high speed, and DAT technology measures up. Since the same requirements pertain to backing up a hard disk, DAT technology has been adapted for use with computers.



 
by Dinesh Thakur

Data transfer rate (sometimes just called "data rate") simply refers to just how fast data can get from one place to another-"one place to another" meaning between a computer and a peripheral (an external piece of hardware connected to the computer) or one modem to another modem, or even from one internal part of a computer to another internal part.



 
by Dinesh Thakur

When personal computers first came out, daisywheel printers were the only type of affordable printer that could print sharp-enough text for important documents like business communications or college papers. Daisywheel printers work by pounding raised, fully-formed letters made of metal or plastic against the paper through a ribbon, just like a typewriter.



 
by Dinesh Thakur

The cycle time of a computer is the time required to change the information in a set of registers. This is also sometimes called the state transition time. The register cycle time of a processor is sometimes referred to as the internal cycle time, clock time, or simply cycle time. Main memory cycle time is usually several times the internal cycle time.



 
by Dinesh Thakur

Auxiliary memory is the lowest-cost, highest-capacity, and slowest-access storage in a computer system. It is where programs and data are kept for long-term storage or when not in immediate use. Such memories tend to occur in two types-sequential access (data must be accessed in a linear sequence) and direct access (data may be accessed in any sequence). The most common sequential storage device is the magnetic tape, whereas direct-access devices include rotating drums, disks, CD-ROMs and DVD-ROMs.



 
by Dinesh Thakur

Memory mapping is the translation between the logical address space and the physical memory. The objectives of memory mapping are (1) to translate from logical to physical address, (2) to aid in memory protection (q.v.), and (3) to enable better management of memory resources. Mapping is important to computer performance, both locally (how long it takes to execute an instruction) and globally (how long it takes to run a set of programs). In effect, each time a program presents a logical memory address and requests that the corresponding memory word be accessed, the mapping mechanism must translate that address into an appropriate physical memory location. The simpler this translation, the lower the implementation cost and the higher the performance of the individual memory reference.



 
by Dinesh Thakur

The speed of a dot matrix or daisy wheel printer (or any printer that prints one character at a time) is measured in characters per second, or cps. A warning: the cps rating that a printer manufacturer puts in an ad is always much faster than the printer's actual speed.



 
by Dinesh Thakur

Without special help, DOS recognizes a maximum of 640 kilobytes of RAM (random access memory) for use in running your programs. That 640K is referred to as conventional memory to distinguish it from other types of memory (upper, expanded, and extended) that have been invented to overcome DOS'S 640Klimitation. See RAM for a comparison of the different types of memory used in PCs.



 
by Dinesh Thakur

A typical hard disk is built right into your computer or is housed in a box nearby-and you never see the actual hard disk or take it out of its container. A cartridge hard disk, though, is removable. It works kind of like a giant floppy disk in that it slips into a slot in a special kind of removable hard drive case (actually, it's more like sliding a video tape into a VCR). A typical cartridge hard disk holds 44 megabytes (there are also 88s), costs as little as $40, and is about as big as a cheese sandwich with no lettuce. The drive (the case) that you put the cartridge into costs from $450 to $1000.But once you have the hard drive, buying a new cartridge is the cheapest way to increase the amount of hard disk space you have.



 
by Dinesh Thakur

A cache card is a board you install inside your computer, specifically designed to temporarily store frequently used information that the computer would otherwise have to get from the disk. A cache card can dramatically increase the speed of many tasks because getting information from a cache card is much, much faster than getting the information from a disk.



 
by Dinesh Thakur

This is a special area of very high-speed memory linked directly to the computer's central processing unit (CPU, the main processor, or chip, that runs the machine). The processor can access information in this cache much more quickly than it can get to data stored in the main memory area. The cache circuits monitor the data used by the processor, keeping a copy of the most recently and most frequently used information in the cache. Since programs are likely to access several items of related data that are near each other, the cache will even try to anticipate the processor's needs by copying data stored near the requested data in main memory. When the processor requests data from main memory, the cache first checks to see if it already has a copy, in which case the cache provides the data. Otherwise the main memory retrieves the data.



 
by Dinesh Thakur

A cache (pronounced "cash") is a temporary holding area in the computer's memory where the computer stores information that is used repeatedly. The computer can access the information much more quickly from the cache than if the information was stored in the usual place (which might be on a disk or in a part of the computer's memory that takes longer to access). The term cache can also be used as a verb-"to cache" means to place information in the cache.



 
by Dinesh Thakur

Byte Striping: A technique for speeding up the retrieval of data stored on an ARRAY of hard disks. The data stream is divided up into, say, 4-byte portions, and the bytes from each such portion are written to four different drives: this effectively quadruples the data rate since the four drives can be written to or read from simultaneously. Byte striping is covered by the RAID4 and 5 specifications, and driver software to accomplish it is built into, for example, WINDOWS NT and WINDOWS 2000.

 
by Dinesh Thakur

Byte Ordering: The direction in which a computer's PROCESSOR reads the BYTES that make up each WORD stored in its memory. Some machines are designed to read the byte at the lower address first, so that OC 77 is read as OC77hor 3191decimal, while others read the higher address first, so that OC 77 is read as 770Ch or 30476 decimal A difference in byte ordering represents the greatest possible degree of incompatibility, since not only can two such computers not execute each other's programs, but they cannot even agree on the value of any particular instruction or data item.



 
by Dinesh Thakur

Burst-Mode, Burst-Transfer Mode: A mode of data access supported by many devices – from DISK DRIVE controllers to RAM chips-in which, once the first of a sequence of desired data items has been located, the following items can be retrieved at a faster rate than usual by simply reading from consecutive locations.



 
by Dinesh Thakur

Buffered Seek: A mode of hard disk operation in which a sequence of commands to perform SEEKS operations are collected and executed all together rather than one at time. This saves time compared to non-buffered modes in which one seek must be executed before the next command can be accepted. All modern SCSI and ATA drives have buffered seek built into their internal mechanism.

 
by Dinesh Thakur

Buffer Definition: A buffer is an area of memory (RAM) reserved for temporary storage. For instance, you've probably noticed that you can quickly type a bunch of commands on the keyboard, and then just sit back and watch your computer carry out the commands one after another. This is because the computer stores the keys you pressed in a buffer-after doing one command; it goes back to the buffer to get the next one in line.



 
by Dinesh Thakur

A type of computer memory from which items may be retrieved by matching some part of their content, rather than by specifying their ADDRESS (hence also called associative or content-addressable memory.) Associative memory is much slower than RAM, and is rarely encountered in mainstream computer designs.



 
by Dinesh Thakur

Associative Cache: A type of CACHE designed to solve the problem of cache CONTENTION that plagues the DIRECT MAPPED CACHE. In a fully associative cache, a data block from any memory address may be stored into any CACHE LINE, and the whole address is used as the cache TAG: hence, when looking for a match, all the tags must be compared simultaneously with any requested address, which demands expensive extra hardware. However, contention is avoided completely, as no block need ever be flushed unless the whole cache is full, and then the least recently used may be chosen.



 
by Dinesh Thakur

A high speed expansion slot introduced by Intel to speed up 3D graphics operations in Pentium based PCs. AGP provides a 32-bit wide POINT-TO-POINT data channel that enables a graphics card's processor to directly access the PC's system memory, bypassing the PCI system bus and the main CPU- bulky graphics data such as texture maps can be delivered straight to the GRAPHICS PROCESSOR at up to 533megabits per second (Mbps).



 
by Dinesh Thakur

Address

In the Earlier programming Language, a programmer would assign instructions and data to locations in memory, and instructions would refer to absolute locations in memory.



 
by Dinesh Thakur

Hard Disk Access time is the total elapsed time between the initiation of a particular request for data and receipt of the first bit of that data.

Direct access devices (Hard Disk Drive) require varying times to position a disk head over a particular record. In the case of a moving-head disk drive, this involves positioning the comb (head assembly, as in Fig.) to the designated cylinder, plus rotation of the selected track to the desired record. Comb-movement times for a typical medium-sized disk drive are shown in Fig.



 
by Dinesh Thakur

In computing, an access method is a program or a hardware mechanism that moves data between the computer and an outlying device such as a hard disk (or other form of storage) or a display terminal.



 
by Dinesh Thakur

Storage Device is a device for recording (storing) information (data). Recording can be done using virtually any form of energy.storage device is a hardware device capable of storing information. There are two storage devices used in computers; a primary storage device such as computer RAM and a secondary storage device such as a computer hard disk drive.



 
by Dinesh Thakur

Printers are Output devices used to prepare permanent Output devices on paper. Printers can be divided into two main categories :

 
by Dinesh Thakur

Read Only Memory (ROM) is an example of nonvolatile memory.  ROM is a class of storage medium used in computers and other electronic devices. Read Only Memory (ROM), also known as firmware, is an integrated circuit programmed with specific data when it is manufactured. The instructions for starting the computer are housed on Read only memory chip.



 
by Dinesh Thakur

CISC (Complex Instruction Set Computer) : It was developed by Intel. CISC is a type of design for the computers. CISC based computer will have shorter programs which are made up of symbolic machine language.



 
by Dinesh Thakur

Random Access Memory (RAM) is the best known form of Computer Memory. The Read and write (R/W) memory of a computer is called RAM. The User can write information to it and read information from it.With Ram any location can be reached in a fixed ( and short) amount of time after specifying its address.



 
by Dinesh Thakur

Flash Memory (sometimes called "Flash RAM") is a type of RAM that, like a ROM, retains its contents when the power supply is removed, but whose contents can be easily erased by applying a short pulse of higher voltage. This is called flash erasure, hence the name. Flash memory is currently both too expensive and too slow to serve as MAIN MEMORY, but is used as removable storage cards for digital cameras and pocket computers.



 
by Dinesh Thakur

Until now you may have not seriously considered using a printer. After all, if you do not use your personal computer to play or to calculate your family budget you do not really need a hard copy of what is displayed on the screen.



 
by Dinesh Thakur

The devices which are used to input the data and the programs in the computer are known as "Input Devices". or  Input device can read data and convert them to a form that a computer can use. Output Device can produce the final product of machine processing into a form usable by humans. It provides man to machine communication. Some of the I/O devices are explained below:



 
by Dinesh Thakur

All Optical media (CD, DVD, Blu-Ray etc.) have pits and lands. These are microscopic and represent the binary information of the data stored on the disc. A land is reflective and reflects the laser into a sensor to register it as a I, but when the light hits a pit, it shatters and no reflection is received, thus a O is registered



 
by Dinesh Thakur

Register are used to quickly accept, store, and transfer data and instructions that are being used immediately by the CPU, there are various types of Registers those are used for various purpose. Among of the some Mostly used Registers named as AC or Accumulator, Data Register or DR, the AR or Address Register, program counter (PC), Memory Data Register (MDR) ,Index register,Memory Buffer Register.



 
by Dinesh Thakur

When a Process is executed by the CPU and when a user Request for another Process then this will create disturbance for the Running Process. This is also called as the Interrupt.



 
by Dinesh Thakur

Some Random Access Memory (RAM) chips have built-in error-checking functions that use a process called parity. Chips that use parity have an extra bit for every eight bits of data. In the parity process, as the eight bits receive binary data (data represented by 1s and 0s), the chip adds all the 1s, and if that total is odd, the extra bit is set to 1.



 
by Dinesh Thakur

A device for storing digital information that is fabricated by using integrated circuit technology. Also known as integrated-circuit memory; large-scale integrated memory; memory chip; semiconductor storage; transistor memory.



 
by Dinesh Thakur

Primary Storage, also known as main storage or memory, is the main area in a computer in which data is stored for quick access by the computer's processor. Information must be transferred to primary storage. On today's smaller computers, especially personal computers and workstations, the term random access memory (RAM) - or just memory - is used instead of primary, main storage, core memory, or immediate access storage, internal storage, and the hard disk, diskette, CD, and DVD collectively describe secondary storage or auxiliary storage.



 
by Dinesh Thakur

In computing, Sequential Access Memory (SAM) is a class of data storage devices that read their data in sequence. This is in contrast to random access memory (RAM) where data can be accessed in any order. Sequential access devices are usually a form of magnetic memory.



 
by Dinesh Thakur

Bubble memory is a type of non-volatile computer memory that uses a thin film of a magnetic material to hold small magnetized areas, known as bubbles or domains, each storing one bit of data. Andrew Bobeck invented the Bubble Memory in 1970. His development of the magnetic core memory and the development of the twistor memory put him in a good position for the development of Bubble Memory.



 
by Dinesh Thakur

Optical Mark Recognition (OMR) is the technology of electronically extracting intended data from marked fields, such as checkboxes and fill-in fields, on printed forms. It is generally distinguished from OCR by the fact that a recognition engine is not required. This requires the image to have high contrast and an easily-recognizable or irrelevant shape.



 
by Dinesh Thakur

Magnetic Ink Character Recognition(MICR) is a technique that enables special characters printed in magnetic ink to be read and input rapidly to a computer. When a document that contains this ink needs to be read, it passes through a machine, which magnetizes the ink and then translates the magnetic information into characters.



 
by Dinesh Thakur

OCR stands for optical character recognition, a wonderful and marvellous technology. It enables you to convert previously printed text material into information your computer can understand, without having to retype it. Have you ever had a story or an article or a magazine clipping that you wanted to have in your computer, but the thought of retyping the entire thing was overwhelming? Or just boring? That's what OCR is for.



 
by Dinesh Thakur

A computer device, such as a CD-ROM drive or printer, which is not part of the essential computer, i.e., the memory and microprocessor. Peripheral devices can be external -- such as a mouse, keyboard, printer, monitor, external Zip drive or scanner -- or internal, such as a CD-ROM drive, CD-R drive or internal modem. Internal peripheral devices are often referred to as integrated peripherals. Linkage between the CPU and the users is provided by Peripheral devices.



 
by Dinesh Thakur

A printer is an output device that prints characters, symbols, and perhaps graphics on paper. The printed output is generally referred to as hardcopy because it is in relatively permanent form. Softcopy refers to temporary images such as those displayed on a monitor. Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper. Impact printers have contact; nonimpact printers do not.



 
by Dinesh Thakur

Line Printers :- Line Printer can Print One Line at a Time. The line printer is a form of high speed impact printer. They can Print 300 to 3000 Lines per Minute. So that they are very fast. Large Computer system typically use Line Printer. The Line Printers are of two Types.



 
by Dinesh Thakur

A Hard Disk Drive also called HDD (hard drive) or hard disk is a non-volatile. The harddisk is the primary storage unit of the computer. This is where your data, programs and the Windows system that is used to make your computer are physically saved in a digital form (string composed of 0s and 1s). There hard disk capacity is expressed in gigabytes (GB). More hard drive will have a large capacity, the more you can install programs or store documents in your computer.



 
by Dinesh Thakur

As we know that the Main Memory Stores the data in a Temporary Manner means all the data will be loss when the Power switched off. And all the data will be loss when the power goes switched off.

So that we uses the Secondary Storage devices those are used for Storing the data in a Permanent Manner means all the Data will remain Stored whether the Power is Switched on or Switched off means the Power Will never effect on the System. For storing the data in a Permanent Manner we uses the Magnetic Storage Devices. There are also Some Advantages of Secondary Storage Devices.



 
by Dinesh Thakur

DDRAM: - Short for Double Data Rate-Synchronous DRAM, a type of SDRAM that supports data transfers on both edges of each clock cycle (the rising and falling edges), effectively doubling the memory chip's data throughput. DDR-SDRAM also consumes less power, which makes it well suited to notebook computers. DDR-SDRAM is also called SDRAM II And DDRAM.



 
by Dinesh Thakur

There are two types of relational integrity rules

Entity Integrity: - No attribute participating in the primary key of a base relation allowed containing any nulls. Primary key performs the unique identification function in a relational model. Thus a null primary key value within a base relation would be like saying that there was some entity that had no known identity. An entity that cannot be identified is a contradiction in terms, hence the name entity integrity.