pdf The .pdf file format extension was developed by Adobe systems in 1993 as a means of presenting documents in a consistent manner across different platforms, hardware, operating systems, and applications. The format was not released as an open source document format until 2008, though minimal proprietary technologies still controlled by Adobe Systems exist in the format. Every .pdf document carries with it the necessary meta information required to properly reconstruct the text, fonts, and graphics used to produce the document. This ensures that documents will be viewed in exactly the same way the author intended regardless of the device used to open the document. From conception to date, Adobe Systems has continued to support the format adding features with every iteration of the standard including hardened algorithms for document encryption and privacy. Today, many freely available readers exist allowing you to open and view .pdf documents and create or convert other file formats such as .jpeg and .doc into .pdf documents.
pcx The Picture Exchange file format, shortened PCX, with the .pcx filename extension is an image file format developed by ZSoft Corporation. It was initially released in 1985 as a lossless bitmap image format and for a time was the default file format for PC paintbrush. The format is now largely superseded by other formats given the target platforms for the software associated with the format are no longer in production, i.e. MS DOS and Windows 1.0.