The CPU, The RAM, and The ROM

The CPU, The RAM, and The ROM

1. The CPU

   • The CPU or central processing unit is essentially the brain of the computer as it carries out all the complex calculations that are required to run the computer. It does this by performing one simple task many times a second: the fetch decode execute cycle.
   • CPU Performance is measured in clock speed and is how many time a second the CPU can carry out the fetch decode execute cycle. 1HZ means the FDE cycle can be carried out once per second which is pretty slow as today's CPUs have an average clock speed of about 3.5 GHz which means the FDE cycle can be carried out 3.5 billion times a second. The clock speed can be affected by the number of cores the CPU has or how large the cache is.

2. The ROM

   • The ROM or Read-Only Memory is a form of permanent data storage meaning when the power is cut the data is still stored there and so is called non-volatile memory. The ROM cannot have data written to it or be deleted from it so it stores critical programs like the the boot up software and the BIOS.

3. The RAM

   • The RAM or Random Access Memory is a form of temporary or volatile(meaning when the power is cut the RAM will immediately lose everything on it) memory. It is much quicker for the CPU to access data from the RAM than from the hard disk directly.

4. Virtual memory

   • Virtual Memory is used when RAM is running low so the OS(operating system) use some of the hard disk as Ram as well. Virtual memory is slower than than the main storage but still quicker than the hard disk. It is volatile and acts just like the normal RAM but is on the hard disk.