Identifying Font Files

Differences between Mac and PC files
The PC and Mac differ in the way they store files. On a Mac each file can have two parts called forks. The data fork holds data (text, images, etc.). The resource fork holds resources (icons, fonts, menus, sounds, etc.). There are actually two files linked to one name in the file system. PCs only have one file linked to each name. Macs also have two four character fields stored with the name for each file. They are called the type and creator. The type field tells the Mac software what type of file it is. The creator is a unique signature identifying a program on the Mac. This field tells the Mac OS what program to launch if the files icon is clicked. PCs identify files with a file name extension. This is the characters after a period at the end of the file name. It used to be limited to three characters from the DOS days, but it can now be larger on current Windows versions. This tells Windows both what type of file it is and what program to launch if the icon is clicked. Unlike the Mac, you have to tell Windows what program goes with what extension (this can also be done automatically by a setup program). OS X seems to be moving away from using resource forks as heavily as OS Classic. It also can use file name extensions like Windows and Linux in addition to a file type and creator. This makes files more portable and easier to transmit over networks.

Font Information Table
The table below contains information about the various font types on each platform.

Platform	Font Type	Icon	Number of Files Required	Name extension or Mac type*	File Location for installed fonts**	Notes
Windows	TrueType		1	.ttf	\Windows\Fonts \Winnt\Fonts
	PostScript Type 1		2	.pfb – Font file .pfm – Metric file	\Windows\Fonts \Winnt\Fonts \psfonts	Both .pfb and .pfm must have the same base name. Windows will automatically create the .pfm if a pair of .afm and .inf files with the same base name are used to install the the .pfb.
	OpenType		1	.otf – PostScript outlines .ttf – TrueType outlines	\Windows\Fonts \Winnt\Fonts
Mac OS Classic	Non-Suitcase TrueType		1	No extension Mac type is tfil	System:Fonts
	TrueType in Suitcase		1	No extension Mac type is FFIL	System:Fonts	A suitcase may contain multiple TrueType and/or bitmap screen fonts. CrossFont will not be able to convert one that has only screen fonts.
	PostScript Type 1	Printer Font (Icon may vary with font maker) or  Display Font or Display Font Suitcase	2	No extension Printer Font Mac type is LWFN Display Font type is ffil Suitcase Mac type is FFIL	System:Fonts	Printer and display font files might not reside in the same folder.
Mac OS X (starting with OS X 10.5 icons may only show a font sample)	Windows style TrueType		1	.ttf	…/Library/Fonts	This icon is also shown for OpenType fonts with TrueType outlines.
	OpenType		1	.otf	…/Library/Fonts	This icon is only shown for OpenType fonts with PostScript outlines.
	Resource fork TrueType Suitcase		1	No extension Mac type is FFIL	…/Library/Fonts	A suitcase may contain multiple TrueType and/or bitmap screen fonts. CrossFont will not be able to convert one that has only screen fonts.
	Data fork TrueType Suitcase		1	.dfont	…/Library/Fonts
	Non-Suitcase TrueType		1	No extension Mac type is tfil	…/Library/Fonts
	PostScript Type 1	Printer Font Display Font Suitcase	2	No extension Printer Font Mac type is LWFN Suitcase Mac type is FFIL	…/Library/Fonts
Linux	TrueType		1	.ttf	various
	PostScript Type 1		2	.pfa – Font file .afm – Metric file	various	The .pfa and .afm for Linux are ASCII text versions of the Windows .pfb and .pfm files.

Table Footnotes:
*    Extensions for Windows fonts may not be visible for installed fonts or if Windows is configured not to show extensions. Mac file types are not shown by the OS, a special utility may be required to see them.
**  Some applications may handle fonts themselves instead of using the operating system. In this case font files may be stored in folders elsewhere on the file system.