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Computer Science IGCSEPDF 36
142 pagesrevision 46930
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Solid State (Flash Memory)
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Solid-state uses electronic circuits to store 0s and 1s.
Eg Solid State Drives, USB
Uses NAND and NOR gates to control the flow of electrons
and store data persistently.
Solid-state (flash memory) is made of tiny cells, each storing
one bit (1 or 0).
Each cell has a transistor that acts as an on/off switch.
The transistor has two main parts:
○ Control gate: top layer; connects to the circuit and
controls current flow.
○ Floating gate: holds a charge like a tiny battery, between
two oxide insulating layers.
To store data: a high voltage pushes electrons through the
oxide onto the floating gate.
To erase data: voltage is reversed, pulling electrons off the
floating gate.
Advantages
Disadvantages
Durability - No moving parts
Capacity - Medium/high storage
Speed - Very fast read/write access
Portability - Small and no moving parts
Cost - Very high per gigabyte
Reliability - Limited read/write cycles