An Operating System (OS) is the software that acts as an intermediary between hardware and application software. It manages hardware resources and provides services for programs to run, enabling interaction between the user, applications, and the hardware. Examples include Windows, Linux, and macOS.

OCR stands for Optical Card Reader. It is a technology used to convert different types of documents, such as scanned paper documents or images, into editable and searchable data by recognizing characters and text.

To convert the decimal number 56 into binary:

1. Divide the number by 2 and record the remainders:

   • 56 ÷ 2 = 28 remainder 0
   • 28 ÷ 2 = 14 remainder 0
   • 14 ÷ 2 = 7 remainder 0
   • 7 ÷ 2 = 3 remainder 1
   • 3 ÷ 2 = 1 remainder 1
   • 1 ÷ 2 = 0 remainder 1

2. Write the remainders from bottom to top: 111000.

Computers are commonly classified into categories like Supercomputers, Microcomputers, and Minicomputers based on their size, power, and application. Mainfirm is not a recognized classification of computers. Instead, the term Mainframe exists, referring to large, powerful computers used in enterprises.

Printers are categorized into types such as Inkjet, Daisy Wheel, and Dot Matrix, based on their printing technology. Droll is not a type of printer; it is likely a typo or a non-existent term in this context.