alu

Arithmetic Logic Unit (ALU)

The ALU is an internal part of the processor which is used for all mathematical and logical operations. The basic operations of an ALU include adding and multiplying binary values, as well as performing logical operations such as AND, OR and XOR. The algorithms for performing these mathematical and logical operations are hard coded (stored permanently) within the ALU.

Cache (L2)

L2 Cache (pronounced cash) is a special block of memory inside the processor (in the same chip) which offers faster data retrieval, typical sizes are 128KB, 256KB and 512KB.
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note: Some processors (generally older) utilise external L2 cache.
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The data that the processor stores in its cache memory will be data that is frequently used (such as a certain algorithm), the processor will also guess what data may be required and store this data in its cache. This guessing may be successful or it may not, the success rate is known as a hit rate. For instance, if the hit rate was 94% then it would mean that 94 out of every 100 attempts the processor correctly identified and stored a block of data which was needed, the other 6 times the data was never used.