Secondary storage - computer architecture, Computer Engineering

Secondary storage:

Secondary storage (or external memory) differs from primary storage in that aspect it is not accessible by the CPU directly. The computer typically uses its input/output channels to access secondary storage and transfers the needed data by using intermediate area in primary storage. Secondary storage does not drop the data when the device is powered down-it is non-volatile memory. Per unit, it is normally also an order of magnitude less costly than primary storage. Thus, modern computer systems normally have an order of magnitude more secondary storage than primary storage and data is hold for a longer time there.

 In modern computers, hard disk drives are generally used as secondary storage. Time taken to access a particular given byte of information stored on a hard disk is normally a few thousandths of particular second or just milliseconds. But, the time taken to access a given byte of information stored in RAM is measured in billionths of a second, or nanoseconds. It illustrates very important access-time difference which distinguishes solid-state memory from rotating magnetic storage devices: hard disks are typically regarding a million times slower than memory. Rotating optical storage devices, like DVD and CD drives, have even longer access times. Having disk drives, once the disk read/write head reaches the appropriate placement and the data of interest rotates under it then subsequent data on the track are very fast to access. Consequently, in order to hide the initial seek time and rotational latency that data are transferred to and from disks in big contiguous blocks.

When data exist in disk, block access to hide latency offers wish in designing efficient external memory algorithms. Sequential or Block access on disks is orders of magnitude faster than random access, and various sophisticated paradigms have been developed to design efficient algorithms based on the block and sequential access. Another way to reduce the I/O bottleneck is to utilize multiple disks in parallel in order to increase the bandwidth amongst primary and secondary memory.

Some other instance of secondary storage technologies are: flash memory (for instance USB flash drives or keys), punched cards, magnetic tape, paper tape, ,  standalone RAM disks, and Iomega Zip drives ,floppy disks.

 

Posted Date: 10/13/2012 6:04:26 AM | Location : United States







Related Discussions:- Secondary storage - computer architecture, Assignment Help, Ask Question on Secondary storage - computer architecture, Get Answer, Expert's Help, Secondary storage - computer architecture Discussions

Write discussion on Secondary storage - computer architecture
Your posts are moderated
Related Questions
Describe architecture of WAP gateway. WAP GATEWAY : It is a very unique product giving semi-automatic redirection of HTML documents to WAP compatible mobile phones. Wir

The following are the difference among Activity and Sequence Diagrams: A sequence diagram represents the way of processes implement in a sequence. For example, the order of op

Program Level : It is the next level consisting of independent programs for parallelism. Coarse Granularity  size is used at this level containing ten thousands of instructions.

Write a ‘C’ functions to arrange the elements of an integer array in such a way that all the negative elements are before the positive elements. The array is passed to it as an arg

Q. Illustrate why does a tea kettle sing? Answer:- There is a little attachment with a hole in it which acts as a whistle. It is inserted into the spout of the kettle as w

What Is The Difference Between ViewState and SessionState? View State persist the values of controls of certain page in the client (browser) when post back operation done. When

Instruction Set Architecture:                             Instruction set architecture cycle-it is smallest unit of time in a processor. superscalar processor

What are various types of Shift Registers ? Ans: Kinds of Shift Registers: (i) SISO that is Serial-In Serial-Out Shift Register (ii) SIPO that is Serial-In P

What are the 3 segments of the default route, that is there in an ASP.NET MVC application? Ans)  Segment 1st - Controller Name Segment 2nd - Action Method Name Segment 3r

Q. What is Hypercube Network? The hypercube architecture has played a significant role in development of parallel processing and is quite influential and popular. The highly sy