CompTIA IT Fundamentals FC0-U51; File Extensions
.doc/.docx
Microsoft Word files .docx files are newer and support more features than older .doc files.
.flac
Open source compression format; not widely supported.
.png
Portable Network Graphics; designed as a lossless compression format to replace gif. Very common on websites.
.rtf
Rich text format. A fairly basic document format developed by Microsoft and generally more compatible than .doc files.
.scexe
Self-extracting firmware updates that HP produce, commonly associated with Linux machines.
.exe
Short for "executable," it tells the OS to run the program. Most Windows desktop programs use this extension.
.jar
Short for Java archive; similar in format to .zip files. Usually used to distribute software programmed in the Java language.
.bmp
Short for bitmap. One of the oldest and simplest image formats, usually for lower quality pictures.
.tar
Short for tape archive, it's a format used in UNIX and Linux environments. It's not compressed; a compressed .tar file would have the extension .tar.gz.
.tiff
Tagged Image File Format; uses lossless compression, which preserves better image quality than JPEG or GIF.
.zip
The most common compression format, supported by most compression software.
.mpg
These are compressed files commonly found on the internet. Most video players can handle .mpg files.
.mp4
This is an MPEG-4 file, or just a newer and better version of .mpg. Again, most video players can handle these files. It has the advantage over .flv of being supported natively on most mobile devices.
.mp3
This is short for MPEG-1 Audio Layer-3, and it's an audio-only compression format. It compresses files into about one-twelfth their original size yet maintains near-CD quality sound.
.m4a
This stands for MPEG-4 Audio, and it uses the same compression as .aac. Some media players wont play this file unless they are renamed to .mp4.
.wav
Waveform Audio File format; These are uncompressed files, and as such they have the best sound quality. They are the largest.
.wmv
Windows Media Player
.aac
Advanced Auto Coding; produces better quality than .mp3, at about the same file size. This is the file format used by iTunes.
.avi
Audio Video interleave; Typically uses less compression than other formats. These files tend to be more universally supported than .wmv files.
.txt
Basic text file. Almost all word processors will open this, from the basic Notepad in Windows to Microsoft Word, and most other commercial and free apps as well. Generally, very few configuration options (such as fonts or inserting images) are available.
.bat
Batch file. Used to execute multiple commands from the Windows command prompt (cmd.exe) within one file.
.jpg
Called a j-peg, and sometimes you will see files with a .jpeg extension. The JPEG extension defines how images are compressed and stored. Very commonly used by digital cameras.
.7z
Compression files generated by the 7-Zip program.
.gz
Compression files generated by the gzip program, which is mostly found on UNIX and LINUX systems. .gzip is the replacement for the compress utility.
.rar
Compression format introduced by WinRAR.
.iso
Disk image archive files for optical media, such as CD-ROMs
.app
Executes a program within OS X (as .exe does in Windows)
.flv
Flash Video; competing technology to .mp4, and requires a flash player plug in to play. Still a common format on Youtube and Google video.
.msi
For installation and removal of software within Windows. Opening an .msi file actually launches msiexec.exe, which reads the .msi file and does what it says. .msi files use Windows installer, so think of it as a standing for "Microsoft Installation."
.gif
Graphics Interchangeable Format; uses a different compression standard than JPEG. Commonly used on websites.
.dmg
Mac OS X disk image files
