List and explain the key characteristics of a computer family.

Similar or identical instruction set: In many cases, the same set of machine instructions is supported on all members of the family. Thus, a program that executes on one machine will also execute on any other.  

1. Similar or identical operating system: The same basic operating system is available for all family members. 
    Increasing speed: The rate of instruction execution increases in going from lower to higher family members. 
   
    Increasing Number of I/O ports: In going from lower to higher family members.  
   
   Increasing memory size: In going from lower to higher family members. 
   
    Increasing cost: In going from lower to higher family members.