Primary and secondary storage

Primary and secondary storage

1. Primary storage

   • RAM
     • RAM stands for Random Access Memory
       • It's called this because the computer doesn't have to go through all the data in specific order to find what the user wants it can go straight to the wanted data
     • RAM is volatile meaning the data that is stored will be lost if the power is cut off
     • RAM stores programs and data are stored when they are currently in use
     • They are typically larger in capacity compared to ROM
     • RAM can be written and read from
   • ROM
     • ROM stands for Read Only Memory
     • ROM is non-volatile meaning the data is saved when the power is cut off
       • Its purpose is to contain the boot up/ BIOS instructions so the computer can start up
     • ROM can only be read from
     • Has a smaller memory capacity
   • primary storage are storage that have direct access to the processor

2. Secondary storage

   • Magnetic storage
     • Hard drives/HDD
     • A storage device that uses magnets to record data on rotating metal plates
     • Advantages - Larger storage capacity, Fairly inexpensive, Fast access to read and write data
     • Disadvantage - Data can be lost or altered by magnetic fields / mechanical problems, The moving parts can get damaged
   • Flash/solid-state storage
     • SSD, memory sticks
     • Uses flash memory to store data
       • Flash memory - Uses storage transistors which contain logic gates. Electrons and positive and negative charges are used to write and erase data to and from the flash memmory
     • Advantages - More robust and Faster boot-up, due to no moving parts, Faster read and write speeds
     • Disadvantages - Expensive to manufacture, Limited number of times that the data can be written and read from
   • Optical storage
     • CD, DVD and Blu-ray
     • Uses a lens and a light beam to read and write data on the disk
     • Advantages - Small and light, Cheap to manufacture, Fairly Durable - safe to store data for a long time
     • Disadvantage - Storage capacity is small compared to others, Disk such as Blu-ray needs a specialized drive to read and write to and from the disk
   • Storage that isn't under the direct control of the CPU