The "core" of a computer is the CPU and in general this is just a programmable calculator that begins to operate as soon as it is turned on and continues until it is turned off.
Simplistically, a CPU's job can be summarised as three repeated steps: Fetch the next instruction from memory, Decode what this instruction asks you to do, Carry out this instruction. The FETCH program concentrates on letting students (and teachers) explore this cycle in detail. The screen is a "standard" Babbage screen but the app only lets you step through the operation with single instructions, not run whole programs.
At a Glance
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