tcr The .tcr filename extension is a compressed text file format for eBooks and text associated with eBook reader software developed by Psion, a London based techonology company. The format has its beginnings in the early 90's and was designed for use on the PDAs released by the company, particularly the Series 3 handheld PDA. Though the format is proprietary and was intended for exclusive use on Psion devices, today, a few eBook reader applications can open files encoded in this format. As PDAs eventually lost there popularity, the format was discontinued when Psion eventually pulled out of the PDA market.
pdb The .pdb filename extension refers to the program database file format authored by Microsoft. The format is used for storing debugging information about executable files and programming libraries or DLL files. The pdb format was designed to ease the debugging process of executables and program modules by decoupling the debugging information from the end of the program or class library itself to allow the integrated debugger and linker to access the pdb files directly. It doing so, the PDB format facilitates the stepping into/out of runtime libraries. The format and its internals remain the proprietary asset of Microsoft.