MIME Types

Multipurpose Internet Mail Extensions (MIME) was originally designed to allow non plain text content in mail messages. It is also used in web browsers on non windows systems (Mac and UNIX) to map incoming data to programs. Web servers send the mime type in the header for files and the browser uses this to determine what program to use to display the file contents. This is configured under Edit > Preferences > Receiving FIles >Helpers on UNIX and Mac. In windows from a my compuer or windows explorer window select View > Folder Options > File Types.
RFC 1521 - MIME (Multipurpose Internet Mail Extensions) says in Appendix E 
  "In order to ensure that the set of such values is
   developed in an orderly, well-specified, and public manner, MIME
   defines a registration process which uses the Internet Assigned
   Numbers Authority (IANA) as a central registry for such values."

See Also: 
Media Types at IANA
Helpers and Plug-In's, 

RFC 1341  Mechanisms for Specifying and Describing the Format
of Internet Message Bodies
List at NTT/Verio
List at Duke
mediaTypes at dsi

Intro See: MIME Types at Netscape Programmers Guide, MIME types are defined by three attributes: language (lang), encoding (enc), and content-type (type). At least one of these attributes must be present for each type. The most commonly used attribute is type.

type=application, text, audio, image, video, message, model, multipart
Other types: magnus-internal, wwwserver, drawing, model,
enc=x-gzip, x-compress, x-uuencode

type=magnus-internal - By convention, all values of type that require the server to do something other than just send the requested resource to the client start with magnus-internal/.

 Mime types for common applications (e.g. MS Office) have changed
several times.  Only MS Word was registered (by someone other than
Microsoft) with IANA, so the others are unofficial.  At the end of
1995 a convention of preceding unofficial names with x- was adopted. 
So Mime types like application/msexcel which was in common use at
the time changed to application/x-msexcel. A new convention was
adopted in 1997.

Note: application/msword does not change because msword is an officially
      registered mime type.

Changes at the end of 1997
   OLD             NEW
 x-msexcel      vnd.ms-excel
 x-mspowerpoint vnd.ms-powerpoint
 x-msproject    vnd.ms-project 
 x-framemaker   vnd.framemaker
 x-mif          vnd.mif
 x-mshelp       winhlp

application/msword           .doc,.dot    MS Word (Windows format) (1)
application/vnd.framemaker   .frm,.mif,.fm3,.fm4,.mk    FrameMaker (2)
application/vnd.ms-excel     .xls,.xlc    MS Excel (spreadsheet, chart)
application/sylk             .slk        (.SYLK) Symbolic Link
                                   WingZ/Excel/Lotus (old MultiPlan format)
application/vnd.ms-powerpoint .ppt        MS Powerpoint
application/x-xsb             .xsb,.sb    Superbook
text/x-sgml                   .sgm       (.SGML) Standard Generalized Markup Lang.
                                (Future versions of Superbook should read SGML)
application/x-notes            .ntf,nsf    Lotus Notes 
application/vnd.lotus-organizer .or2        Lotus Organizer
application/pdf                .pdf        Portable Document Format (Adobe Acrobat)
application/vnd.ms-project     .mpt,.mpp   MS Project
application/x-coreldrw         .cdr        Corel Draw
application/winhlp             .hlp        Windows Help
image/tiff                     .tif  *       *               *  

(1)  We recommend storing Word Docs as Word for Windows format (.doc)
     rather than Mac format (.mcw) for better portability of graphics.
(2) .fm which was used from FrameMaker 3 conflicted with .fm which
    was already used for FileMaker Pro.  Don Pratt proposed using
    .fm3 for FrameMaker 3

  See Notes on adding viewers
Defaults:                    (1)              Air    NCSA    Microsoft
                           Official Netscape  Mosaic Server  WWW Server
image/gif               .gif   *       *       *       *        *
image/jpeg   .jpg,.jpeg,.jpe   *       *       *       *        *
audio/basic         .au,.snd   *       *       *       *        *
audio/x-wav             .wav           *               *        *
audio/wav         .wave,.wav                   *
video/quicktime     .qt,.mov   *       *       *       *
video/mpeg         .mpeg,.mpg  *       *       *       *        *
video/x-msvideo          .avi          *               *        *
video/msvideo            .avi                  *
video/avi                .avi                  *
text/richtext            .rtx  *       *(W)            *
text/x-sgml              .sgm                          *
appl./postscript .ps,.eps,.ai  *       *       *       *        *
application/rtf          .rtf  *       *               *        *
application/x-rtf        .rtf                  *
application/msword       .doc  *                       *        *
application/mac-binhex40 .hqx  *       *               *        *
application/macbinhex40  .hqx  *       *               *        *
application/x-macbinary  .bin          *
application/octet-stream .bin  *                       *
application/octet-stream .exe  *       *
application/x-msdownload .exe                                   *
application/x-stuffit    .sit          *
application/x-tar        .tar          *               *
application/x-gtar       .gtar         *               
application/x-troff-man  .man          *(W)            *

Defaults:                    (1)              Air    NCSA    Microsoft
                           Official Netscape  Mosaic Server  WWW Server

appl./x-compressed .zip,z,gz           *(M)            
appl./zip                .zip  *                       *        *
appl./x-compress         .Z            *(W)            *
appl./x-zip-compressed   .zip          *(W)            x  
appl./x-gzip             .gz           *(W)            x 
appl./x-gzip-compressed  .gz           *(W)            x  
image/pict               .pict         *
image/targa       .targa,.tga                 *
image/tiff         .tiff,.tif  *       *               *        *
image/x-xbitmap          .xbm          *               *
image/x-win-bmp          .bmp                  *
image/x-MS-bmp           .bmp          *
image/x-mspaint          .bmp                                   *
image/x-msmetafile       .wmf                                   *
image/x-wmf              .wmf                                   *
image/ief                .ief          *(W)
image/x-rgb              .rgb          *(W)
image/x-portable-anymap  .pnm          *(W)
image/x-portable-bitmap  .pbm          *(W)
image/x-portable-graymap .pgm          *(W)
image/x-portable-pixmap  .ppm          *(W)
image/x-xwindowdump      .xwd          *(W)
image/x-xpixmap          .xpm          *(W)
image/x-xbitmap          .xbm          *(W)
image/x-cmu-raster       .ras          *(W)
audio/aiff         .aiff,.aif          
audio/x-aiff       .aiff,.aif          *               *
audio/x-midi             .mid                  *
appl/x-ns-proxy-autoconfig  .pac       *(W)
appl/x-javascript   .js,.ls,.mocha     *(W)
appl/x-tcl               .tcl          *(W)
appl/x-sh                .sh           *(W)
appl/x-csh               .csh          *(W)
appl/x-cpio              .cpio         *(W)
appl/x-shar              .shar         *(W)
appl/fractals            .fif          *(W)
appl/x-texinfo           .texi         *(W)
appl/x-dvi               .dvi          *(W)
appl/x-latex             .latex        *(W)
appl/x-tex               .tex          *(W)
New with Explorer 4
image/x-png                   png             Portable Network Graphics
application/pdf               pdf   Portable Document Format (Adobe)
application/x-msdownload      exe                                   *

                                              x - In srm.conf on server
                                   (W/M)- Windows/Mac version of Netscape only

(1) The official list  of registered MIME (Media) types is at
   Non-standard  MIME types should begin with an x.  e.g. x-tar
   See below for other official/standard MIME types

Other common UNIX types in conf/srm.conf and conf/mime.types on httpd servers.

application/x-dvi               dvi   TeX DVI (Device Independent)
See Also:
File Name Extension in Default httpd config. in ver. 2.2 2/94
and in Tony Sanders (sanders@bsdi.com) list at

 standard MIME types are marked `*'
 non-standard types with security concerns are marked `=' 
Content-Type:                                   Description
*application/andrew-inset                       Andrew-inset
*application/atomicmail                         Atomicmail
*application/dca-rft                            IBM Doc Content Arch
*application/dec-dx                             Digital Doc Transfer
*application/news-message-id                    RFC 1036
*application/news-transmission                  RFC 1036
*application/octet-stream       bin             Uninterpreted Binary Data
*application/oda                oda
*application/pdf                pdf		Portable Document Format (Adobe)
*application/postscript         ai eps ps       PostScript
*application/remote-printing                    RFC 1486
*application/rtf                rtf             RTF
*application/slate                              Slate
*application/wita                               Wang Info Transfer
=application/x-csh              csh             CSH Script (major danger)
=application/x-dvi              dvi             TeX DVI (Device Independent)
 application/x-hdf              hdf             NCSA HDF data file
=application/x-latex            latex           LaTeX Source
 application/x-netcdf           nc cdf          Unidata netCDF data file
=application/x-sh               sh              SH Script (major danger)
=application/x-tcl              tcl             TCL Script (major danger)
=application/x-tex              tex             TeX Source
=application/x-texinfo          texinfo texi    Texinfo
=application/x-troff            t tr roff       Troff
=application/x-troff-man        man             Troff w/MAN Macros
=application/x-troff-me         me              Troff w/ME Macros
=application/x-troff-ms         ms              Troff w/MS Macros
 application/x-wais-source      src             WAIS Source
*application/zip                zip             PKZIP
=application/x-bcpio            bcpio           Old Binary CPIO
=application/x-cpio             cpio            IEEE Std1003.2 (``POSIX'') CPIO
=application/x-gtar             gtar            Gnu Tar
=application/x-shar             shar            Sh Shar
=application/x-sv4cpio          sv4cpio         SVR4 CPIO
=application/x-sv4crc           sv4crc          SVR4 CPIO w/CRC
=application/x-tar              tar             4.3BSD Tar 
=application/x-ustar            ustar           IEEE Std1003.2 (``POSIX'') Tar
 application/x-mif                              Maker Interchange Format
*audio/basic                    au snd          8-bit u-law [PCM] / 8000 Hz
 audio/x-aiff                   aif aiff aifc
 audio/x-wav                    wav             MS Windows+ WAVE format
 audio/x-pn-realaudio           ram             Real Audio Player
 audio/x-mpeg                   mp2             MPEG Audio
*image/gif                      gif             Graphics Interchange Format
*image/ief                      ief             Image Exchange Format
*image/jpeg                     jpeg jpg jpe
*image/tiff                     tiff tif        Tagged Image File Format
 image/x-cmu-raster             ras
 image/x-portable-anymap        pnm             PBM Anymap Format
 image/x-portable-bitmap        pbm             PBM Bitmap Format
 image/x-portable-graymap       pgm             PBM Graymap Format
 image/x-portable-pixmap        ppm             PBM Pixmap Format
 image/x-portable-??            png             Portable Network Graphics
 image/x-png                    png             Portable Network Graphics
 image/x-rgb                    rgb
 image/x-xbitmap                xbm             X Bitmaps
 image/x-xpixmap                xpm             X Pixmap format
 image/x-xwindowdump            xwd             X Window Dump (xwd)
 image/g3fax                    g3f             Group III FAX
 image/cgm                      cgm             Computer Graphics Metafile 
                                              - Harvard Graphics (object) 

 text/html                      html htm        HTML
*text/plain                     txt             Plain Text
 text/plain                     bas             BASIC program
 text/plain                     c               C program
*text/richtext                  rtx             MIME Richtext format
 text/enriched                                  a refinement of "text/richtext"
*text/tab-separated-values      tsv             Tab Separated Values
 text/x-setext                  etx             Structure Enchanced Text
*video/mpeg                     mpeg mpg mpe    Motion Picture Experts Group
*video/quicktime                qt mov          QuickTime
 video/x-msvideo                avi             Microsoft Video for Windows
 video/x-sgi-movie              movie           SGI "movieplayer" movie
 video/vdo                      vdo             VDOLive 
 www/*                                          Reserved Internal WWW type
 application/x-msaccess         mdb
 application/x-mscardfile       crd
 application/x-msclip           clp
 application/x-msmediaview      m13
 application/x-msmediaview      m14
 application/x-msmoney          mny
 application/x-mspif            pif         Program Information File (Windows)
 application/x-mspowerpoint     ppt
 application/x-mspublisher      pub
 application/x-msschedplus      cal
 application/x-msterminal       trm
 application/x-msworks          wks
 application/x-mswrite          wri
 application/mathmetica         ma          Mathmetica Notebook
 application/envoy              evy         Novell Formatted Doc. Distr. format
 application/vis5d              v5d         5-D data set visualization
+model/iges                     igs         IGES CAD Object
+model/mesh                     msh         2 and 2-D visualization
 x-world/x-vrml                 wrl         VRML Virtual Reality Modeling Lang.
+ model is a new mime type still under review as of 2/1/96