AutoCAD is a software application for computer-aided design

Computer-aided design

Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...

 (CAD) and drafting

Technical drawing

Technical drawing, also known as drafting or draughting, is the act and discipline of composing plans that visually communicate how something functions or has to be constructed.Drafting is the language of industry....

 in both 2D

2D computer graphics

2D computer graphics is the computer-based generation of digital images—mostly from two-dimensional models and by techniques specific to them...

 and 3D

3D computer graphics

3D computer graphics are graphics that use a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering 2D images...

. It is developed and sold by Autodesk, Inc. First released in December 1982, AutoCAD was one of the first CAD programs to run on personal computer

Personal computer

A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

s, notably the IBM PC

IBM PC

The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...

. At that time, most other CAD programs ran on mainframe computer

Mainframe computer

Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

s or mini-computers

Minicomputer

A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...

 that were connected to a graphics computer terminal

Computer terminal

A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...

 for each user.
AutoCAD derived from a program called Interact, which was written in a proprietary language (SPL) and ran on the Marinchip Systems 9900 computer (Marinchip was owned by Autodesk co-founders John Walker

John Walker (programmer)

John Walker is a computer programmer and a co-founder of the computer-aided design software company Autodesk, and a co-author of early versions of AutoCAD, a product Autodesk originally acquired from programmer Michael Riddle...

 and Dan Drake.)

When Marinchip Software Partners (later renamed Autodesk) formed, they decided to re-code Interact in C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

 and PL/1 They chose C because it seemed to be the biggest upcoming language.