Components of Central Processing Unit (CPU)
A CPU has following components:
1. Datapaths (such as ALUs and pipelines)
2. Control unit: logic which controls the datapaths
3. Memory components such as register files, caches
4. Clock circuitry such as clock drivers, PLLs, clock distribution networks
5. Pad transceiver circuitry
6. Logic gate cell library which is used to implement the logic

Phase-locked Loop(PLL)
A phase-locked loop or phase lock loop (PLL) is a control system that generates a signal that has a fixed relation to the phase of a "reference" signal. A phase-locked loop circuit responds to both the frequency and the phase of the input signals, automatically raising or lowering the frequency of a controlled oscillator until it is matched to the reference in both frequency and phase. A phase-locked loop is an example of a control system using negative feedback.

Pad transceiver circuitry
A transceiver circuit for an integrated circuit having a pad located therein, a receiving circuit connected to the pad for receiving digital data signals therefrom, a transmitting circuit connected to the pad for transmitting digital data signals to the pad, characterized by output resistance control means connected to said transmitting circuit and arranged to dynamically retain said output resistance of the transmitting circuit at a constant value during data signal transmission from said transmitting circuit.

Logic gate cell library
A standard cell library is a collection of low level logic functions such as AND, OR, INVERT, flip-flops, latches and buffers. These cells are realized as fixed height, variable width full custom cells. The key aspect with these libraries is that they are of a fixed height, which enables them to be placed in rows, easing the process of automated digital layout.

How Computer Cache works

Lets take a library as an example to understand how caching works. Imagine a large library but with only one librarian (the standard one CPU setup). The first person comes into the library and asks for a book titled "Lord of the Rings". The librarian goes off follows the path to the bookshelves (Memory Bus) retrieves the book and gives it to the person. The book is returned to the library once its finished with. Now without cache the book would be returned to the shelf. When the next person arrives and asks for "Lord of the Rings", the same process happens and takes the same amount of time.

But, if this library had a cache system then once the book was returned it would have been put on a shelf at the librarians desk. This way once the second person comes in and asks for "Lord of the Rings", the librarian only has to reach down to the shelf and retrieve the book. This significantly reduces the time it takes to retrieve the book. Back to computing this is the same idea, the data in the cache is retrieved much quicker. The computer uses its logic to determine which data is the most frequently accessed and keeps them books on the shelf so to speak.

Similarly, more level of caching desk (computer cache) can be possible which indeed the case for the modern computer systems architecturs.

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