by Dinesh Thakur Category: Memory

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 Category: Memory

Definition: Flash memory (Known as Flash Storage) is a type of non-volatile storage memory that can be written or programmed in units called “Sector” or a “Block.” Flash Memory is EEPROM (Electronically Erasable Programmable Read-Only Memory) means that it can retain its contents when the power supply removed, but whose contents can be quickly erased and rewritten at the byte level 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.

 
by Dinesh Thakur Category: Memory

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 Category: Memory

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 Category: Memory

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.

While sequential access memory is read in sequence, accesses can still be made to arbitrary locations by "seeking" to the requested location. This operation, however, is often relatively inefficient (see seek time, rotational latency).

Magnetic sequential access memory is typically used for secondary storage in general-purpose computers due to their higher density at lower cost compared to RAM, as well as resistance to wear and non-volatility. Examples of SAM devices still in use include hard disks, CD-ROMs and magnetic tapes. Historically, drum memory has also been used.




 
by Dinesh Thakur Category: Memory

Definition: Auxiliary memory (also referred to as secondary storage) is the non-volatile memory lowest-cost, highest-capacity, and slowest-access storage in a computer system. It is where programs and data kept for long-term storage or when not in immediate use.

Such memories tend to occur in two types-sequential access (data must access in a linear sequence) and direct access (data may access in any sequence). The most common sequential storage device is the hard disk drives, whereas direct-access devices include rotating drums, disks, CD-ROMs, and DVD-ROMs.It used as permanent storage of data in mainframes and supercomputers.



 
by Dinesh Thakur Category: Memory

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.

 
by Dinesh Thakur Category: Memory

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 Category: Memory

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 Category: Memory

Definition of parity memory: 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.The most common data error-checking and validation technique is the Vertical Redundancy Check (VRC) often called a parity check.

 

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About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.



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