36 lines
1.5 KiB
Markdown
36 lines
1.5 KiB
Markdown
---
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tags: [computer-history, storage]
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created: Monday, September 23, 2024
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---
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# Magnetic tape
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Used for data storage in early digital computers (broadly from the
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[UNIVAC](./The_History_of_Computing_Swade.md)) era until the mini-computer era.
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While the UNIVAC was not the first to use magnetic tape, it popularised the
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method due to its success and high profile.
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It worked as follows. The tape was a long, narrow strip of plastic coated with a
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magnetic material. Data is recorded on the the tape by magnetising tiny
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particles on its surface. It was first used in the 1920s for audio recording.
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Data is accessed in a linear, sequential manner. To reach a specific piece of
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data, you often need to wind through all the preceding data
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It was used for long term storage rather than RAM memory due to its sequential
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nature. It stored data and program instructions that would be read into the
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machine's memory. Data was also written out to magenetic tape, in order to store
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and further process results.
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It could store more data than punched cards and its sequential nature
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accommodated batch processing well. However its sequential nature meant it was
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slow at retreiving specific pieces of data as it would have to cycle through all
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the values stored on the tape.
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It developed from open-reel tapes to cartridges and cassettes. It was superseded
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by hard disk drives and solid state drives.
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