Rich_1020's

computer help

files!

FILE NAME EXTENTIONS

I'll update this listing as I go along,for now there are at leats 200 file extentions here.

An extension is the part of a filename after the (last) period. It usually tells both humans and operating systems what type of file it is. There must be thousands of filename extensions in use, ranging from the very common ones, found across operating systems (such as .c for C source) to, at the other extreme end, extensions used by one application (.3gr, .bps, .kye).

t = text files. These contain mainly ASCII: characters A-Z, a-z, 0-9, and punctuation (together codes 32-126), as well as "control characters" (such as code 13 and/or 10 for linebreaks). They can be read by text editors on any platform, if you download them "as ASCII" (which means linebreaks are translated to the proper code for your platform). Text files may contain codes above 126 for accented letters, symbols etc. in various incompatible ways. There is a cross-platform standard extension to ASCII using codes 161-255, Latin-1.

b = binary files, which can be programs, pictures, or many other things. The bytes in a binary file can take any possible value (0-255). Often every single bit counts, so these files must be downloaded "as binary" (that means literally, avoiding the linebreak translation done for ASCII files). Programs from one platform (PC, Mac, UNIX etc.) will not work on another platform. Pictures, sound and movie clips etc. will work across platforms, if you have software that can understand the particular format.

[DOS], [Win], [*NIX] etc. = platform. It's not really possible (or even desirable) to restrict the list to a single operating system. Many files (e.g. picture formats) are exchanged freely cross-platform. On the other hand, some extensions refer to file types that, by their nature, occur on only one operating system. The current list reflects a bias towards PC compatibles, but extensions from any source are welcome!

Makemaze > a construction like this indicates that the named program can make files of this type, while
> Maze indicates that the named program reads files of this type.
Many file types are traditional and are produced by many programs, and understood by many more. The listing will only mention programs if the file type is specific to one (or a few) programs.

floorplan of maze = description of the contents or purpose of files of this type.

Characters used in extension entries

? = any character e.g. .wk? = .wks, .wk1, ...
# = any decimal digit e.g. .#86 = .286, .386, ...
any other = itself, literally

Common abbreviations used

cf. = compare
e.g. = for example
ext. = extension
temp. = temporary
trad. = traditional(ly)
&c. = etcetera



.a t [any] assembly source.
.a86 t [DOS] assembly source intended for > A86.
.aio ? [any] APL I/O file.
.ann b [Win] > Windows Help > user's annotations to a helpfile.
.apl ? [any] APL workspace.
.app (1) b [Gem] application.
.app (2) b [Win] > Gupta SQLWindows > application.
.arc b [DOS] LZArc > compressed archive.
.asc t [any] ASCII text.
.asm t [DOS] assembly source e.g. > MASM, > TASM.
.aux (1) t [any] > LaTeX > auxiliary file recording cumulative values of section counters, &c.
.aux (2) b/t [any] any kind of auxiliary file. .b t [any] BASIC source
.bak b/t [DOS] backup: copy of old file when a file is changed
.bas (1) t [any] BASIC source
.bas (2) b [any] fast-loading font bases > MetaFont
.bat t [DOS] batch file
.bbl b [any] BibTeX > bibliography
.bcm b [DOS, Win] MS Works > backup of .wcm, comms script
.bdb b [DOS, Win] MS Works > backup of .wdb, database
.bib t [any] bibliography source database > BibTeX
.bin b [any] any binary, e.g. executable independent of operating system
.bks b [DOS, Win] MS Works > backup of .wks, worksheet
.blg t [any] BibTeX > log
.bmk b [Win3] > winhelp > user's bookmarks in a helpfile
.bmp (1) b [Win2, OS/2] bitmap (with BITMAPCOREHEADER and RGBTRIPLEs), uncompressed
.bmp (2) b [Win3+] bitmap (with BITMAPINFOHEADER and RGBQUADs), either uncompressed or same as .rle
.bps b [DOS, Win] MS Works > backup of .wps, word processor text
.bsc b [DOS] MS C nmake > replacement of .sbr source browser data
.bst t [any] bibliography style file > BibTeX
.btm t [DOS] fast executing memory-loaded batch file > 4DOS
.bug (1) t [DOS] trad. tongue-in-cheek ext. for scripts > debug
.bug (2) t [any] list of bugs
.c t [any] C source
.cal (1) b [DOS] spreadsheet > SuperCalc >
.cal (2) b [Win3] appointment diary from the > calendar > applet
.cdr ? [Win, ?] a vector picture format > CorelDraw >
.ce b [DOS] from Digital Vision's scanner board Computer Eyes > IFF bitmap, same as .iff
.cfg ? [any] configuration in proprietory format (various apps)
.cgm ? [???] a vector picture format
.ch ? [any] change file for Tangle, Weave, MFT (MetaFont source formatter)
.chk b/t [DOS] chkdsk > reconstructed file, cf ._dd
.chr t [any] pxtoch > readable form of .pxl > chtopx, cf. .pxl
.clp b [Win] saved clipboard contents from the > clipbrd > applet
.cmd (1) b [OS/2] batch file
.cmd (2) ? [any] dBASE command
.cnf ? [any] configuration in proprietory format (various apps, e.g. emTeX's dvidrv)
.cob t [any] COBOL source
.cod b [any] FORTRAN compiled code
.com (1) b [CP/M, DOS] executable. Both CP/M for 80x86 systems and DOS load 256 byte "Program Prefix Segment" (jump vectors into system, program arguments etc.) at cs:0, and the file at cs:0100h, with cs = ds = es = ss. Many DOS COMs are not CP/M compatible though, making system calls directly (not via the PSP jump vectors). Note: DOS determines whether a file is COM or EXE format from file contents, not name. Cf. .exe
.com (2) b [IBM DOS] ibmbio.com & ibmdos.com are disk-based BIOS and DOS, cf. .sys (2)
.cpi b [DOS] character pixel information (screen fonts for various codepages)
.cpl b [Win3] Control Panel item (actually a dll)
.cpp t [any] C++ source, also .cxx
.crd b [Win] cardfile from the > card > applet
.cur b [Win] file with (group of) mouse cursor shape(s)
.cut b [DOS?] Dr. Halo bitmap format
.cvf b [DOS] compressed volume file > SuperStor >
.cxx t [any] C++ source, also .cpp
.dat b/t [any] data (various apps)
.dbf ? [any] dBASE database file
.dbg b [DOS etc.] MS C > debug info > CodeView
.dbt (1) t [any] dBASE text
.dbt (2) ? [Win] > Gupta SQLWindows > temp. file
.def t [Win] module definition file > link
.dib (1) b [Win2, OS/2] device independent bitmap, like .bmp (1)
.dib (2) b [Win3+] device independent bitmap, like .bmp (2), but the DIB format is slightly freeer than BMP in that it can also be color planed.
.diff ? [*NIX] differences between versions, to update software
.dir ? [DOS] > SideKick > directory
.diz t [any] file_id.diz is small description zipped up with software on many BBSes
.dlg (1) t [Win] MS Win SDK's dlgedit > dialog box description, to be included in .rc file > rc (resource compiler)
.dlg (2) t [DOS] emTeX's dvidrv, dviscr, dvidot > printer driver log
.dll b [Win, OS/2] dynamic link library
.doc (1) t [any] software documentation
.doc (2) t [any] version of .sty with added comments > LaTeX
.doc (3) b [DOS, Win] > MS Word > document
.dos b/t [Win95] DOS7 system files, inactive when using Win95 GUI, but copied to io.sys, msdos.sys, config.sys, autoexec.bat when booting up to naked DOS7 prompt
.dot (1) b [DOS, Win] > MS Word > document template
.dot (2) t [DOS] parameters for emTeX's dot matrix printer driver > dvidot
.drv b [Win] device driver
.dsc t [DOS] description, e.g. mime decoder munpack > text portion of mime message
.dtp b [Gem, Win] desktop publishing file > TimeWorks Publisher, aka PublishIt >
.dvi t [any] (La)TeX > device-independent output
.dxf ? [any] vector picture format used by CAD apps .eps b [any] Encapsulated PostScript (vector graphic, may contain bitmapped preview).
.eps b [any] output for Epson compatible printer, printed to file.
.err t [any] error messages, e.g. A86 >.
.exe (1) t [DOS] executable (loaded at cs:0100, after Program Segment Prefix).
First 256 bytes of file is EXE header, containing info about segments used, first two characters MZ or ZM. Executable code starts at file offset 0x0100 (cs:0200 in memory). Segment registers cs and ds contain different values (cf. .com). Note: DOS determines whether an executable is a COM or an EXE by its contents, not the extension!
This format also includes what are actually (self-extracting) compressed archives.
.exe (2) b [Win] executable. Contains DOS compatible EXE header causing it to run small "stub" program under DOS and exit. Contains also extended header with information on the code and "resources" in the program.
.exe (3) b [OS/2] any of various types of OS/2 executable. .f t [*NIX] Fortran source.
.f77 t [*NIX] Fortran77 source.
.fli b [DOS] font library for emTex's > dvidrv.
.flt ? [Win] ??
.fmt (1) b [any] fast loading format >TeX (a format is e.g. plain TeX, LaTeX, &c.).
.fmt (2) ? [any] screen format > dBASE >.
.fnt b [Win2+] font resource file. Such a file can be incorporated into a program using > rc.exe like other resource files such as *.cur, *.ico, *.bmp . Can also be used to make a standalone font file (see .fon).
.fon b [Win2+] non-TrueType font file. Unlike *.fnt files, a *.fon file shows up as fonts actually available to the user. Consists of a DLL without code and without data, to which *.fnt resources have been added using rc.exe >.
.for t [any] FORTRAN source.
.fot b [Win3.1+] auxiliary file for a *.ttf font file, allows the TrueType font to be accessed by routines originally intended for *.fon files.
.frm (1) ? [any] report form > dBASE >.
.frm (2) t [any] order.frm = order form in ASCII text, as supplied with various shareware. .gf b [any] MetaFont > font file.
.gft ? [any] MetaFont's GFType >.
.gid b [Win95] Windows 95 .hlp files contain a cross-reference index to help topics in a way that earlier .hlp files do not. The first time Windows 95 opens an old style .hlp file, it creates such an index in a separate .gid file.
.gif b [any] CompuServe Graphics Information File. A bitmap format, max 256 colors. Can have multiple images and embedded text. First six characters of file GIF87a or GIF89a, type 89a designates one color as transparent.
Largely abandoned in the mid nineties, after Unisys acquired the patent for the LZW compression algorithm used, and decided to enforce it in a way that made it difficult for shareware developers to comply.
.glo t [any] auxiliary file for \glossary > LaTeX >.
.grp b [Win 3] describes items in > Program Manager > group. Converted to folders under "\Windows\Start Menu" by > Grpconv.exe on Win95 installation (you can also run this manually on groups imported later). .h t [any] "header file", auxiliary C source file containing declarations.
.hlp (1) t [DOS] any help file in ASCII text.
.hlp (2) b [DOS] helpmake.exe > compressed hyperlink help file as used by > several Microsoft development tools.
.hlp (3) b [Win] hypertext help file displayed by > winhelp.exe (Windows help system), e.g. as a result of user selecting a help item from an application's menu. With or without internal compression.
.hpj (1) b [any] output for HP LaserJet, printed to file.
.hpj (2) t [DOS, Win] help jobfile: list of source files and settings for > hc.exe, the Windows SDK helpfile compiler.
.hpp t [any] header file for C++, cf .h, .hxx.
.htm t [DOS, Win3] see .html
.html t [any] files in HyperText Markup Language, a form of SGML used as source for web pages.
.hxx t [any] header file for C++, cf .h, .hpp. .icn t [SunOS] icon (64x64, mono), file can contain comments.
.ico b [Win] file containing an icon image, or several alternative ones for different screen resolutions. Limited to 32x32 in 16 colors (with mask for transparency) up to Win 3.*, to 64x64 and 256 colors under Win95.
Executables and DLL's can also contain icon images.
.idx t [any] index entries > LaTeX >.
.ind t [any] index entries > makeindx > (for TeX and LaTeX)
.iff b [Amiga, DOS &c.] an extremely flexible graphics format, allows all sorts of things besides to be stored. Also called .ce, .lbm etc. in DOS.
.img b [Gem &c.] image file (a bitmap format) for > Ventura Publisher >.
.imp ? [any] Pascal implementation.
.inc (1) t [any] assembly language include file.
.inc (2) t [any] include file for Pascal.
.inf b [Win] information for installing e.g. drivers, for Windows > install.exe.
.ini (1) t/b [any] initialisation data for various programs.
.ini (2) t [Win] user preferences and settings for a Windows application, reading and writing such files is managed by Windows at the request of applications (they can also be edited by hand).
.int ? [any] Pascal interface. .jif b [any] for JFIF compliant JPEG (a graphics format), nowadays usually given the .jpeg extension.
.jor ? [Windows] journal, a > Gupta SQLWindows > format.
.jpe b [DOS, Win3] see .jpeg.
.jpeg b [any] JPEG, graphics format with an optional amount of lossy compression designed by the Joint Photographic Experts Group.
.jpg b [DOS, Win3] see .jpeg. .kye t [Win3] Play level for > kye, a game. .lbl ? [any] label > dBASE >.
.lbm b [DOS] > Electronic Arts' Deluxe Paint > IFF image (see .iff).
.lib b [any] Library of common functions for e.g. I/O handling. When you write in a high-level anguage such as C, C++, Pascal, you can call these functions. After your code is compiled, > link searches the libraries and links the relevant code into your program, relocating the addresses.
A DOS or Windows library contains a header and one or more modules, essentially in .obj format. You can make your own libraries with lib > from .obj files generated e.g. by an assembler or compiler. A module is included by > link as a whole, so different functions should only be together in one module if they share code, or are always needed together anyway.
.lnk b [Win95] Shortcut for a Windows application (cf. .pif for DOS apps under Windows). A shortcut acts as an entry in a folder (desktop, start menu or any other folder) that forms a link to a program or document that lives in (usually) another folder.
.lof t [any] auxiliary file for \listoffigures > LaTeX >.
.log t [any] any log of activity, e.g. TeX >, LaTeX >, MetaFont >, DrWatson > &c.
.lot t [any] auxiliary file for \listoftables > LaTeX >.
.lst t [any] any sort of list(ing) in ASCII text. .m ? [any] native format of > Mathematica >.
.mac b [Mac &c.] bitmap format > MacPaint > (576x720 mono, comes in two flavors: with or without header).
.mak t [any] Makefile for > make utils (e.g. nmake.exe). Used in integrated development environments. Specifies what development tools to use for certain (types of) files, and a dependency tree for source files, intermediate files, and final program, so the make util can decide (based on the time stamp of files) what work needs to be (re)done when source files are edited.
.map (1) t [DOS, Win] link > listing of segments and publics (data, functions).
.map (2) t [DOS, Win] list of colors for > Fractint >.

.maz (1) t [DOS] Makemaze > Maze floorplan of maze.


.mdm ? [DOS,Win] modem info (Access).
.me (1) t [any] read.me = shareware documentation (English).
.me (2) t [any] lees.me = shareware dokumentatie (Nederlands).
.mem ? [any] memory > dBASE >.
.mf t [any] font source > MetaFont.
.mfj t [any] MetaFont job, batch input > MFJob.
.mft t [any] style file for > MFT (MetaFont source formatter).
.mi t [any] legge.mi = documentazione per shareware (Italiano).
.mid b [Win] MIDI file (sound).
.mnu b [DOS] menu (various, e.g. Access).
.moi t [any] lisez.moi = documentation pour shareware (Français).
.msg (1) t [any] message in ASCII text.
.msg (2) t [DOS,Win] file with CompuServe forum or mail messages with standard message headers, > TapCIS >, > OzCIS >, > OzWin > &c.
.msg (3) ? [DOS] message (SideKick).
.msp b [Win2] a mono bitmap format > Microsoft Paint >.
.mve b [Win3] icon movie > IconDoIt. .ncd b [DOS] > Norton ChangeDirectory > treeinfo.ncd = internal tree data in root dir (re-generated when a new directory is encountered, also when ncd is run with /r option).
.ndx ? [any] > dBASE > index.
.not t [DOS] note in ASCII text. .o b [*NIX] compiler or assembler > object > link.
.obj b [DOS, Win] compiler or assembler > object > link.exe.
.old (1) t [DOS] A86 > original source, when it inserts error messages in source.
.old (2) t [Win3] backup of old system files by install.exe >.
.out b [*NIX] compiler > a.out = trad. name for compiler output. when no name specified.
.ovl b [DOS, OS/2] program overlay.
.ovr b [DOS] program overlay. .p t [*NIX] Pascal source.
.pal (1) b [Win] > Paintbrush > color palette.
.pal (2) b [?] color palette accompanying .cut file.
.pas t [DOS] Pascal source.
.pcc b [Win] > Zsoft Paintbrush > cutout.
.pcx b [Win] > Zsoft Paintbrush > bitmap format.
.pgm b [DOS] program overlay.
.pic b [?] > PC Paint > bitmap graphic format.
.pic b [?] a Lotus vector graphic format.
.pif (1) b [Win3] (545 bytes) > PIFEdit > program information file for running DOS app. in > Windows.
_default.pif is used for programs without PIF of their own.
.pif (2) b [Win95] (900+ bytes, usu. 967) Shortcut to DOS app., edited with > Properties dialog box >. If the properties of the DOS executable itself are edited (rather than those of a shortcut) this automatically produces a PIF file (shortcut) in the same folder. Cf. also .lnk.
.pk b [any] compressed font for > TeX (incl. > LaTeX).
.pkt t [any] PKType > readable contents of .pk (TeX font).
.pl t [any] readable form of .tfm (TeX font metric).
.poo t [any] string pool for > INITeX or > INIMF.
.prd b [DOS] printer driver e.g. for > Microsoft Works.
.prg b [Gem] executable program.
.pro t [any] Prolog source.
.pub ? [?] > PageMaker > publication.
.pxl ? [any] pixel data of TeX font > printer- or screen driver. .q ? [Win95] schedule.q = queue for Win95 fax.
.qsn t [DOS] QuickScan data for > TapCIS >.
.qtc b [Win] QuickTime for Windows component. .ras b [SunOS] raster image (a bitmap format).
.rc t [Win] source for > rc.exe, the Windows SDK "resource" compiler. Resources are things like bitmaps, icons, dialog boxes, menus &c. embedded in an EXE or DLL. See also .dlg (1).
.reg t [Win] Registry data, can be edited as text and imported (merged) into the registry with > regedit.exe > which can also export (branches of) the registry in this format.
.rle (1) b [any] a CompuServe runlength encoded (compressed) bitmap graphics format.
.rle (2) b [Win] Runlength encoded (compressed) bitmap graphics format, two types of encoding (for 16 and 256 color files). This type can also have extension .bmp .
.rot t [Mac, DOS] 3-d image for > Rotater or > rotate.
.rtf t [DOS, Win, Mac] Rich Text Format, a format containing text with embedded control sequences. Also used as sources for help topics, as listed in a .hpj file. .sbr ? [DOS, Win] source browser for Microsoft C (zero-length if there is a .bsc .
.scn t [DOS] laid-out screenful of text.
.scr (1) t [any] any kind of script (comms, debug, Access, &c.).
.scr (2) b [Win] screen saver (coded as a special kind of executable).
.shg b [Windows] Segmented hypergraphic made by > shed.exe > (in Windows SDK), a compressed bitmap with clickable fields to be incorporated by > hc.exe (also Windows SDK) into a Windows .hlp file.
.spl ? [Win] > Gupta SQLWindows > spooler.
.sql ? [Win] > Gupta SQLWindows > data.
.sts t [DOS] settings and status for project in Microsoft C > PWB >.
.sty t [any] > LaTeX style file.
.sty t/b [any] style sheet for various desktop publishing programs.
.sub t [DOS] font substitution list for emTeX's > dvidrv.
.syd t [Win] config.syd, autoexec.syd, win.syd, system.syd = backup copy of two DOS system files and two Windows INI files when edited using sysedit.exe >.
.sym (1) b [DOS, Win] symbol table for debugging (Microsoft C link.exe > cv[w].exe).
.sym (2) b [DOS] symbol table for debugging (A86 >).
.sys (1) t/b [any] any kind of system file.
.sys (2) b [DOS] io.sys & msdos.sys = disk-based BIOS and DOS -- cf. .com (2).
.sys (3) t [DOS] config.sys = system configuration (loads device drivers).
.sys (4) b [DOS] country.sys & keyboard.sys = system data.
.sys (5) b [DOS] others: device drivers installed through config.sys . .t t [*NIX] ASCII text.
.tex t [any] source for > TeX (including > LaTeX).
.tmp t/b [any] temporary file of any kind.
.txt t [any] ASCII text.
.tfm ? [any] TeX font metric, font dimensioning info for > TeX (incl. > LaTeX).
.tga b [any] Truevision Targa (a number of uncompressed, runlength compressed, or otherwise compressed graphics formats).
.tif b [any] TIFF = Tagged Image File Format (any of 5 graphics formats).
.toc t [any] auxiliary file for \tableofcontents in > LaTeX >.
.ttf b [Win3.1+] TrueType font.
.tun b [Win] mouse cursor tune for > IconDoIt. .ub b [DOS] > UBasic > program.
.ubb b [DOS] User-supplied machine-language program (actually a COM) to be incorporated in a > UBasic program.
.ubd b [DOS] Auxiliary file for some UBasic programs (data file?).
.umb t [DOS] config.umb, autoexec.umb = backup copies of original system files when MemMaker > edits your system files. MemMaker is a tool supplied with MS DOS 6 that can find the most efficient addresses to put device drivers &c. to maximise free memory (UMB comes from Upper Memory Blocks, where it puts a lot of stuff).
.und t [DOS] Listing of undefined symbols, by A86 > assembler.
.url t [Win95] Short textfile containing an URL (Universal Resource Locator), in other words a web address. .vs? b [Win] various file types for > Visio >, a tool to draw diagrams.
.vxd b [Win] virtual device drivers. .wav b [Win] waveform of a soundbite.
.wcm t [DOS, Win] comms script for > Microsoft Works >.
.wdb b [DOS, Win] database for > Microsoft Works >.
.web t [any] WEB source for > Tangle or > Weave.
.wk# b [DOS, Win] various versions of worksheet (spreadsheet) for > Lotus 123 >.
.wks b [DOS, Win] original spec for worksheet used by spreadsheet programs like > Lotus 123 >, > AsEasyAs >, > MS Works > (in a semi-compatible way: can be read across apps with some loss of display formatting).
.wmf b [Win] Windows metafile (graphic specified by sequence of GDI operations).
.wpg b [DOS] WordPerfect Graphics (a bitmap and/or vector image format).
.wps b [DOS, Win] word processing document for > Microsoft Works >.
.wri b [Win] word processing document for > Write >. Note: under Win95, these files are associated with a stub write.exe that calls Wordpad, but Wordpad saves the document in Word .doc format. .xl? b [DOS, Win, Mac &c.] various > Excel > file types (this entry needs expanding). .yes t [Win] agreemnt.yes = licence agreement of Spam Hater, a tool to track down the sender of unsolicited nuisance bulk emails that disguise their origin, and to respond effectively. Recommended. .zip (1) b [many] PKZip v1 > compressed archive, version 1 format > any PKUnzip version.
.zip (2) b [many] PKZip v2 > compressed archive, version 2 format > PKUnzip v 2 only.
Note: it's a good idea to always unzip with -d option, in case the ZIP contains a directory tree (without this option all the files end up in the same directory).

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