Computer Software – Programs and Data
Software – Information stored on disk that is used and/or stored on the computer. Software includes:
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Programs contain instructions for the computer (Disk  CPU  Memory)
Data includes information that is input, opened, created, manipulated, etc. (a Document or Image)
Files are documents or data that has been given a name and saved to disk (RAM  CPU  Disk)
Example: We start WORD (a program), type a document (data) and Save it to disk (file)
There are different kinds or types of Software Programs:
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Operating Systems control the hardware and functions of a computer. (Windows, Linux, Novell)
Applications – productivity software that tells the computer (CPU/Memory) what to do when.
(Word, Excel, Internet Explorer, Adobe Reader, Read 180, MicroType, Quicken, Games, etc.)
Utilities are special programs that add features to the OS (Anti-Virus, Backup, Ghost)
The Operating System is first software to be processed on startup. It controls the hardware and its functions so
that other software (Application programs) can communicate effectively with all the computer devices.
Remember the Four Functions of Computer: Input, Processing, Storage and Output.
Example: Letter J input on keyboard, CPU converts it to code, stores it in RAM & outputs it to the screen.
Binary - The numbering system used by computers to store and process information. There are 2 numbers in
this system zero (0) and one (1). In the computer there are millions of microscopic switches. They are either
OFF (absence of a charge) or ON (presence of charge). OFF=0 and ON=1.
Memory Sizes (Terms for RAM, Files, Disks, Systems, etc.)
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Bit
Byte
Kilobyte
Megabyte
Gigibyte
Terabyte
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a single 0 or 1 (represents a switch that is either ON or OFF)
a group of 8 Bits (a pattern that represents a number, character or symbol)
1024 Bytes (Files that we Save are often a number of Kilobytes in size)
1024 Kilobytes (Large files or RAM: like 512 MB Memory)
1024 Megabytes (Hard disks : like 80 GB and some newer computer’s RAM)
1024 Gigibytes (Very large systems: Like NASA, colleges, weather models, etc.)
ASCII Character Set (American Standard Code for Information Interchange) is used to convert characters and
symbols on a keyboard to numbers (so they can be used in different computer platforms). Every character in
ASCII has a unique number. UNICODE is another such system used to represent text in various languages.
Input  Processing  Storage  Output
Capital J  ASCII code 74  1001010 J
Keyboard  CPU RAM  Screen