QBASIC     

QBasic , a short form of   Quick Beginners All purpose Symbolic Instruction Code  is an
integrated development environment and
interpreter for a variety of BASIC programming languages which are based on QuickBASIC . Code entered into the IDE is compiled to an
intermediate representation , and this IR is immediately interpreted on demand within the IDE. [1] It can run under nearly all versions of
DOS and 32-bit versions of Windows , or through emulation via DOSBox / DOSEMU on Linux,
FreeBSD , and 64-bit versions of Windows. [2] (QBasic is a DOS program and requires DOS or a DOS emulator. Windows XP comes with an emulator called DOS Virtual Machine, subsequent versions of Windows require an emulator such as DosBox.) For its time, QBasic provided a state-of-the-art IDE, including a
debugger with features such as on-the-fly expression evaluation and code modification. It supports various inbuilt functions.

Paradigm Procedural
Developer Microsoft
First appeared 1991; 27 years ago
OS MS-DOS , Windows 95, Windows 98,
Windows Me, PC DOS, OS/2 ,
eComStation
License Part of the operating system (a variety of closed-source licenses)
Website wwwmicrosoft.com
Influenced by
QuickBASIC, GW-BASIC

History
QBasic was intended as a replacement for GW-BASIC . It was based on the earlier QuickBASIC 4.5 compiler but without QuickBASIC's compiler and linker elements. Version 1.0 was shipped together with MS-DOS 5.0 and higher, as well as
Windows 95 , Windows NT 3.x , and Windows NT 4.0 . IBM recompiled QBasic and included it in PC DOS 5.x, as well as OS/2 2.0 onwards. [7]
eComStation, descended from OS/2 code, includes QBasic 1.0 . QBasic 1.1 is included with MS-DOS 6.x, and, without EDIT , in Windows 95, Windows 98 and Windows Me . Starting with
Windows 2000 , Microsoft no longer includes QBasic with their operating systems, [8] but can still be obtained for use on newer versions of Windows.
QBasic (as well as the built-in MS-DOS Editor ) is backwards-compatible with DOS releases prior to 5.0 (down to at least DOS 3.20). However, if used on any 8088 / 8086 computers, or on some
80286 computers, the QBasic program may run very slowly, or perhaps not at all, due to DOS memory size limits. Until MS-DOS 7, MS-DOS Editor and Help required QBasic: the
EDIT.COM and HELP.COM programs simply started QBasic in editor and help mode only, and these can also be entered by running
QBASIC.EXE with the /EDITOR and /QHELP switches (i.e., command lines
QBASIC /EDITOR and QBASIC /QHELP ).