🎞️ What are Magnetic Tapes?
🧩 The Context:
In early computer systems, once the punch cards were read, the data and programs were stored and transferred using magnetic tapes, because tapes could hold much more data and were reusable, unlike punch cards.
🧲 What is a Magnetic Tape?
A magnetic tape is a thin strip of plastic coated with magnetic material used to store data sequentially. Think of it like an old cassette tape, but for computers.
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Data is written linearly (start → end)
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It uses a read/write head to magnetize regions to represent bits (0s and 1s)
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It’s a sequential access device, meaning to read data in the middle, you have to go through everything before it
📦 How it was used in Batch OS:
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The OS would read punch cards and store job input onto magnetic tape.
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The tape would then be loaded into the system to process jobs in sequence.
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Output was either stored on another magnetic tape or printed on a line printer.
This reduced manual work and increased speed compared to handling stacks of physical punch cards directly.
⚙️ Key Characteristics:
| Feature | Value |
|---|---|
| Access type | Sequential |
| Capacity | Higher than punch cards |
| Speed | Slower than modern disks |
| Usage | Input/output & backup storage |
| Durability | Rewritable but fragile |
🚀 Modern Legacy:
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Still used today in backup systems and cold storage due to low cost and long shelf life.
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Technologies like LTO (Linear Tape-Open) are descendants.
🧠 Interview Line:
“Magnetic tapes were sequential-access storage devices used in batch systems to store and process jobs efficiently after reading input from punch cards.”