XTND was a document import/export system developed by

Claris Claris International Inc., formerly FileMaker Inc., is a computer software development company formed as a subsidiary company of Apple Computer (now Apple Inc.) in 1987. It was given the source code and copyrights to several programs that were ...

for their products on the

Apple Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and software en ...

. Products supporting XTND placed an additional popup menu in the open and save dialogs, allowing users to read and write documents of any supported format. The name is a four-letter contraction of ''extend'', the Mac using four-letter identifiers in its

system resource In computing, a system resource, or simple resource, is any physical or virtual component of limited availability within a computer system. All connected devices and internal system components are resources. Virtual system resources include fi ...

files. XTND was first introduced in 1989 with MacWrite II, Claris CAD 2.0 and with FileMaker Pro in 1991. The system proved popular and became a major selling point for Claris products, which were otherwise considered somewhat "low end". The system was soon used by a number of other products as well, and became fairly common during the early 1990s. In 1992 Claris gave the system to Apple, who eventually re-branded it as a basic part of the Mac OS known as the Translation Manager. They also added Macintosh Easy Open which offered to open unknown documents using software installed on the machine and converting it using XTND. A developer's guide, ''XTND Programmer's Guide'', was published in 1991 along with the ''XTND Developer's Kit 1.3'', which was placed on their

FTP The File Transfer Protocol (FTP) is a standard communication protocol used for the transfer of computer files from a server to a client on a computer network. FTP is built on a client–server model architecture using separate control and data ...

site. XTND broke on the Power Macs, but an extension-to-the-extension released in 1993 fixed that for a time. By the 1995/96 time frame it appears Apple had already abandoned the entire system. XTND consisted of a simple runtime engine that listed, loaded and managed a series of "translators". The translators were stored in resource files placed in the Mac's System folder, allowing them to be found and used by any program supporting the XTND system. Almost all of the actual logic was located in the translators, the runtime simply handed off filenames and parameters to code stored inside. Claris supplied translators for word-processors like MacWrite,

Microsoft Word Microsoft Word is a word processing software developed by Microsoft. It was first released on October 25, 1983, under the name ''Multi-Tool Word'' for Xenix systems. Subsequent versions were later written for several other platforms includin ...

AppleWorks AppleWorks was an integrated office suite containing a word processor, database, and spreadsheet. It was developed by Rupert Lissner for Apple Computer, originally for the Apple II platform and launched in 1984, and was later reworked for the Ma ...

, AppleWorks GS,

WriteNow WriteNow was one of the two original word processor application software, applications developed for the launch of the Apple Macintosh in 1984, and was the primary word processor for computers manufactured by NeXT. WriteNow was purchased from T/ ...

, WordPerfect,

WordStar WordStar is a word processor application for microcomputers. It was published by MicroPro International and originally written for the CP/M-80 operating system, and later written also for MS-DOS and other 16-bit PC OSes. Rob Barnaby was the sol ...

, as well as translators for various spreadsheets, graphics and databases formats. A major technical problem with XTND was that the conversion process was "opaque". The system ran code in the translators which had no way to provide feedback to the user or ask questions. This made it difficult to distinguish if a long conversion was still processing or if the process locked. Program freezes were a common occurrence as the code base aged. The converters themselves varied widely in quality. For example, the

extension was particularly prone to errors.

References

* Apple Computer Inc., ''XTND Programmer's Guide'', 1991. Classic Mac OS software {{mac-software-stub