The TWG recognizes that the use of short filenames has many disadvantages. The most vexing is that it results in the creation of dozens of different files with exactly the same name. At a typical site, |cmr10.pk| will be the filename for Computer Modern Roman 10 pt at 5–10 magnifications for 2–3 modes. (Section 2.4 discusses duplicate filenames in general.)
To minimize this problem, the TDS strongly recommends |PK| files contain enough information to identify precisely how they were created: at least the mode, base resolution, and magnification used to create the font.
This information is easy to supply: a simple addition to the local modes used for building the fonts with METAFONT will automatically provide the required information. If you have been using a local modes file derived from (or that is simply) |modes.mf| (see Appendix D), the required information is already in your |PK| files. If not, a simple addition based on the code found in |modes.mf| can be made to your local modes file and the |PK| files rebuilt.