What is it?
A computer is a general purpose logic machine where the logic is programmable. Data is manipulated and decisions can be made according
to the program. A program is a series of instructions that are stored in a memory device. The simplest heart of a computer is the ALU - the Arithmetic and
Logic Unit, but this is typically, now, just a tiny part of the Central Processing Unit (CPU) chip. The key elements of a computer are the processor (CPU or ALU),
memory and I/O (Input/ Output). In order for the computer to interact with the environment it is in, it needs to have
some way of communicating with it - that is the I/O. This could be a keyboard and screen as in a typical desktop computer. A computer program typically stores
information, as variables, in its memory. This information relates to the internal state of the program (e.g. where it is in the program, or the value of a counter),
or a model of the problem or the environment the program is designed to interwork with. So the computer needs to be able to read from and write to its memory, although some of its memory
may be read only (e.g. fixed data like a name or a fixed program (often called firmware on a dedicated embedded computer)
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