Service software are the utility programs, Library programs and Device drivers that make the life of a user a bit easier. They help to manage hardware, software, and data resources in a better way.
DOS (Disk Operating System) are simple text command operating systems. It uses CLI (command line interface). DOS used a text based interface that required text and codes to operate. Text is used as the basic input system commands. DOS is unable to run multiple processes at the same time. The highest amount of storage size available is 2GB.
Windows is a range of graphical interface operating systems that are developed and sold by Microsoft. It uses GUI (graphical user interface). Windows uses graphics, images and text. Uses a mouse for all operating system input. Windows is a multitasking operating system; allowing more than one process to work simultaneously. Window systems offer storage space up to 2 terabyte.
Next, learn about Difference between Main memory and Secondary memory.