The description of the computer, input devices, output devices, internal memory and external storage devices is self-explanatory. E-mail me with any questions if you are unclear about anything. Computer classifications are changing rapidly. Students often confuse external memory size and RAM size . You should understand the difference and the importance of each type of memory for different business purposes.
External memory refers to permanent storage.
Your hard drive, a floppy disk, magnetic tapes, etc. are all examples of external memory. RAM on the other hand is volatile. If you lose power before a document is saved to an external storage device, the document is lost. RAM is a temporary storage location. You should understand every item of it.