In modern computers, hard disk drives are usually used as secondary storage. The time taken to access a given byte of information stored on a hard disk is typically a few thousandths of a second, or milliseconds. By contrast, the time taken to access a given byte of information stored in random access memory is measured in billionths of a second, or nanoseconds. This illustrates the significant access-time difference which distinguishes solid-state memory from rotating magnetic storage devices: hard disks are typically about a million times slower than memory. Rotating optical storage devices, such as CD and DVD Drives, have even longer access times. With disk drives, once the disk read/write head reaches the proper placement and the data of interest rotates under it, subsequent data on the track are very fast to access. As a result, in order to hide the initial seek time and rotational latency, data are transferred to and from disks in large contiguous blocks.
When data reside on disk, block access to hide latency offers a ray of hope in designing efficient external memory algorithms. Sequential or block access on disks is orders of magnitude faster than random access, and many sophisticated paradigms have been developed to design efficient algorithms based upon sequential and block access. Another way to reduce the I/O bottleneck is to use multiple disks in parallel in order to increase the bandwidth between primary and secondary memory.[3]
Some other examples of secondary storage technologies are: flash memory (e.g. USB flash drives or keys), floppy disks, magnetic tape, paper tape, punched cards, standalone RAM disks, and Iomega Zip drives.
The secondary storage is often formatted according to a file system format, which provides the abstraction necessary to organize data into files and directories, providing also additional information (called metadata) describing the owner of a certain file, the access time, the access permissions, and other information.
Most computer operating systems use the concept of virtual memory, allowing utilization of more primary storage capacity than is physically available in the system. As the primary memory fills up, the system moves the least-used chunks (pages) to secondary storage devices (to a swap file or page file), retrieving them later when they are needed. As more of these retrievals from slower secondary storage are necessary, the more the overall system performance is degraded.
write detail note on secondary storage devices
falls
Secondary memory, also called auxiliary memory or mass storage, consists of devices not directly accessible by the CPU. Hard drives, floppy disks, tapes, and optical disks are widely used for secondary storage. The input and output of these devices is much slower than for the semiconductor devices that provide the computer's primary memory. Although access times (i.e., the time to read or write information) are slow as compared to that of primary memory, secondary memory devices have important features that are unmatched by primary memory. First, most secondary storage devices are capable of containing much more information than is feasible for primary memory (hence the use of the term "mass storage" as a synonym for secondary memory). A second, and essential, feature of secondary memory is that it is non-volatile. This means that data is stored with or without electrical power being supplied to the device, as opposed to RAM, which can retain its data only so long as electrical power is present.
Secondary devices? Secondary devices? You might as well ask "what are the benefits of using tertiary ideas?" The question is the type of question, that a complete cretin with a toilet paper degree would write. Probably was.
CD-R
cd-r and dvd-rw
Well, the categories which storage devices are under, are PRIMARY and SECONDARY storage.Primary storage is elctronic storage which is directly connected to the computer. Unlike the primary storage, the secondary storage is not directly connected to the CPU. But, te secondary has more advantages and one big disadvantage which was just mentioned.
floppy disks are read/write storage devices, they are a backing store, a non-volatile long term storage which will not lose data when power is lost.Random access storage is the original term for RAM, the random access memory term was used a a marketing term and has stuck since.Another AnswerYES - floppy disk are Random Access storage devices.
Commonly CD Read Write are used for reliable data storage as these devices offer a lot of capacity and reliability. One has to be careful with CD to ensure that these devices are protected from scratches, sunlight and dust.
External devices are used for storage just like internal devices but with the added bonus of being portable and not requiring space inside your computer. This usually comes at the sacrifice of access time or write times. Depends on the interface used for the external device.
Since all storage devices are hardware and are therefore vulnerable to the unpredictability of mechanical or electronic device failures. The closest approximation to stable storage are database systems that write data to multiple storage devices at the same time. If one device crashes, the data is still available from another device.
Write Once Read Many (WORM) is technology that includes CD-R, DVD + or - R discs and also a magnetic tape cartridge type of storage.