Several i device can be used as a secondary storage, but the one selected for a particular application, mainly depends upon how the stored information needs to be access. There are two accessing information sequential or serial access and direct or random access.
Sequential access storage device is one in which the arrival at the location desired may be preceded by sequencing through other location, so that access time varies according to location. in other words, information on a sequential access device can only be retrieved in the same sequence in which it is stored. Sequential processing is quite suitable for such application like preparation of monthly pay slips, or monthly electricity bills etc. where most if not of all the data record need to be processed one after another.
In these application, data record for every employee or customer needs to be processed at scheduled intervals in this case monthly. However while working with a sequential access device, if an address is required which out of order, if can only be reached by searching through all those addresses which are stored before it.
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