1991 software

text editor, improved version of Vi

computer program for data encryption, primarily in email (PGP)

media player and media library application by Microsoft

QuickTime (or QuickTime Player, referred to officially as QuickTime X in Mac OS X Snow Leopard) is an extensible multimedia architecture created by Apple, which supports playing, streaming, encoding, and transcoding a variety of digital media formats. The term QuickTime also refers to the QuickTime Player front-end media player application, which is built-into macOS, and was formerly available for Windows.

WinZip is a trialware file archiver and compressor for Microsoft Windows, macOS, iOS and Android. It is developed by WinZip Computing (formerly Nico Mak Computing), which is owned by Alludo. The program can create archives in Zip file format, unpack some other archive file formats and it also has various tools for system integration.

QBasic is an integrated development environment (IDE) and interpreter for a variety of dialects of BASIC which are based on the QuickBASIC compiler and the QuickBASIC Interpreter. Code entered into the IDE is an intermediate representation (IR), and this IR is immediately executed on demand within the IDE.

3D computer graphics software

anti-virus software

Apple Macintosh operating system version series

software reverse engineering tool

open source collection of about 80 command-line tools for manipulating geographic and Cartesian data sets

ViolaWWW is a discontinued web browser, the first to support scripting and stylesheets for the World Wide Web (WWW). It was first released in 1991/1992 for Unix and acted as the recommended browser at CERN, where the WWW was invented, but eventually lost its position as most frequently used browser to Mosaic.

text editor in MS-DOS and Windows 9x

Oracle Corporation's flagship software development product for the Solaris and Linux operating systems

extent-based file system

Multi-platform command-line web browser

software

NcFTP is an FTP client program which debuted in 1991 as the first alternative FTP client. It was created as an alternative to the standard UNIX ftp program, and offers a number of additional features and greater ease of use.

sound software development kit for video games