(a) An operating system is a collection of integrated Computer programs that provide recurring services to other programs or the user of a computer.
These services consist of disk and file management, memory management, and device management.
In other words, it manages C.P.U operations, input/output activities, storage resources, diverse support services, and controls various devices.
Operating systems are classified into two.
These are the command line e.g. UNIX and Ms DOS; and graphical user interface e.g. Micro soft Window and Linux.
(b)(i) DOS - Disk Operating System (i) UNIX (ii) LINUX (iv) Microsoft Window
(c) A floppy disk, or diskette is a disk storage medium composed of a disk of thin and flexible magnetic storage medium.sealed in a rectangular plastic carrier lined with fabric that removes dust particles.They are read and written by a Floppy Disk Drive (FDD).
A compact disc is a small.portable.round medium made of molded polymer for electronically recording.storing,and playing back audio,video,text and other information in digital form.
Standard CDs have a diameter of 120 mm and can hold up to 80mins of uncompressed audio or 737mb of data.
(d) 10 REM PERIMETER OF A RECTANGLE
20 INPUT "PERIMETER" P
30 LET P 2"L+B
40 PRINT PERIMETER" P
50 END