RADIX 50[1][2][3] or RAD50[3] (also referred to as RADIX50,[4] RADIX-50[5] or RAD-50), is an uppercase-only character encoding created by Digital Equipment Corporation (DEC) for use on their DECsystem, PDP, and VAX computers.
For its similarities to the SQUOZE character encoding scheme used in IBM's SHARE Operating System for representing object code symbols, DEC's variant was also sometimes called DEC Squoze,[7] however, IBM SQUOZE packed six characters of a 50-character alphabet plus two additional flag bits into one 36-bit word.
Where RADIX 50 was used for filenames stored on media, the code points represent the $, %, * characters, and will be shown as such when listing the directory with utilities such as DIR.
Some early documentation for the RT-11 operating system considered the code point 29 to be undefined.
[3] The use of RADIX 50 was the source of the filename size conventions used by Digital Equipment Corporation PDP-11 operating systems.