Magnetic-core memory was the predominant form of random-access computer memory for 20 years between about 1955 and 1975.
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17 Facts About Magnetic-core memory
2.
Core Magnetic-core memory uses toroids of a hard magnetic material (usually a semi-hard ferrite) as transformer cores, where each wire threaded through the core serves as a transformer winding.
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3.
Core Magnetic-core memory was driven from the market gradually between 1973 and 1978.
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4.
Devol's magnetic Magnetic-core memory was further refined via 5 additional patents and ultimately used in the first Industrial Robot.
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5.
The first core Magnetic-core memory of was installed on Whirlwind in the summer of 1953.
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6.
Forrester has since observed, "It took us about seven years to convince the industry that random-access magnetic-core memory was the solution to a missing link in computer technology.
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7.
Cost of complete core Magnetic-core memory systems was dominated by the cost of stringing the wires through the cores.
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8.
The cost of core Magnetic-core memory declined sharply over the lifetime of the technology: costs began at roughly per bit and dropped to roughly per bit.
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9.
The properties of materials used for Magnetic-core memory cores are dramatically different from those used in power transformers.
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10.
The magnetic material for a core Magnetic-core memory requires a high degree of magnetic remanence, the ability to stay highly magnetized, and a low coercivity so that less energy is required to change the magnetization direction.
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11.
The core Magnetic-core memory contents are retained even when the Magnetic-core memory system is powered down.
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12.
Core Magnetic-core memory controllers were designed so that every read was followed immediately by a write.
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13.
Early core Magnetic-core memory systems had cycle times of about 6 µs, which had fallen to 1.
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14.
Core Magnetic-core memory is non-volatile storage—it can retain its contents indefinitely without power.
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15.
For example, the Space Shuttle IBM AP-101B flight computers used core Magnetic-core memory, which preserved the contents of Magnetic-core memory even through the Challengers disintegration and subsequent plunge into the sea in 1986.
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16.
Diagnosing hardware problems in core Magnetic-core memory required time-consuming diagnostic programs to be run.
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17.
The procedure was seldom needed, as core Magnetic-core memory proved to be very reliable compared to other computer components of the day.
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