Difference between magnetic tape and magnetic disk
It is the oldest strong device being used as a secondary storage media.It is discovered by Fritz pflemer in 1928 in Germany.
A magnetic tape consist of a plastic ribbon.This plastic ribbon is coated with a storage media of iron oxide or chromium dioxide.The data can be recorded over the storge media in the form of invisible magnetized or non magnetized spot i.e, either 1 or 0.It is surounded within a reel like audio or video cassete.Data from the magnetic tape can be erased for infinite time.When new data are written i a particular storage are then if that storage area contains some existing data they are erased.
Length of the ribbon varies from 50 ft to 2400 ft.
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| difference between magnetic tape and magnetic disk |
Storage organization of magnetic tape:
A magnetic tap is divided into certain number of tracks.If a six bit coding format is used to store the data then the number of tracks required in the tape reel is 7.If 8 bit coding is used then the
the number of tracks required is 9.The extra bit is used for checking errors which can store 1 bit of data.
The tracks are again divided into vertical columns which are called frames.The intersection of frame and track are called a cell which can store 1 bit of data.
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| difference between magnetic tape and magnetic disk |
In magnetic tape the records are stored sequentially one after another.To know the end of the record the tape is left back after the end of a record ,then the next record is stored,This blank space indicates end of a particular record.This record is called inter record gap.
The length of this gap is basically 0.5 inches.In some cases several records are combined into a block gap is maintained to indicate the end of a block.This technique is used in a situation more number of record is required to store having smaller record length.
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| difference between magnetic tape and magnetic disk |
