Hardware

Stating the purpose of a CPU.

A CPU (central processing unit) is the brain of a processing unit. Surprisingly its job is to process data, the CPU has two main components.

The control unit - uses electrical signals to direct the system to execute the instructions in stored programs.
The ALU - arithmetic and logic unit - carries out all of the arithmetic and logic operations, including: addition; subtraction and comparisons.

When a computer turns on it starts an endless cycle this is the fetch, decode, execute cycle. the program the CPU needs to access is stored in the ROM (read only memory), the CPU FETCHES, the next instruction, DECODES it and EXECUTES it before repeating the process

the speed of this cycle is determined by an electronic clock chip. This chip uses a constant vibrating crystal that keeps a constant rate, the clock speed is measures in hertz (Hz) or cycles per second. the computer synchronises all processes at this speed. While the CPU can process data very quickly, getting data from the memory can be quite slow in comparison. to overcome the this, when the first instruction of a program is requested by the CPU, the remaining instructions are copied to the into the cache memory. the cache memory has access times a lot closer to the CPU -a lot faster than main memory-  so to improve performance the CPU will begin there.

Secondary storage

Secondary storage includes the most widely used flash memory, this isn't as widely used as much as hard drives due to economy reasons. But it beats it in many aspects, firstly, portability. this is very helpful as it can be carries around so you can securely transfer large data's from place to place that are too big to email. Secondly, is is more durable compared to primary storage drives, this is because they tend to have no moving parts unlike normal a normal pc's hard drive. Thirdy, speed, usb's storage devices are quicker at transferring memory, especially in an SSD as its transfer time is next to nothing.Lastly a flash usb it less likely to be effected by hardware deteriation over time,  but is likely to be damaged because it is portable. 

the ssd (first image is a 120gb for £50)
this flash drive (second image is 8gb for £5)