CSpotRun was an early PalmDOC file viewer written by Bill Clagett for displaying text files in the Palm doc format originated by Aportis. It was free, and open source under the GNU Public License, with C source code available.
CSpotRun was tiny (22K) and fast, well suited for early devices with limited RAM and no expansion capability. It would decompress and display Palm doc files in memory, with selectable fonts (from the built in system fonts provided, and a configurable toolbar where the user could place frequently used functions. The display could be rotated, and line spacing was adjustable. It could also auto-scroll for reading with no page operations required.
It lacked support for document categories and could not view files on an expansion card. (It was developed before expansion card support was added to PalmOS.) Bookmarks and an encryption library for reading DRM protected documents were added by third parties.
CSpotRun is still available from the author's site, but has not been developed or maintained since 2004.
It may be found here: http://www.32768.com/bill/palmos/cspotrun/index.html