4K (computer virus)
4k is a computer virus which infects COM files and EXE files. The virus was one of the first to employ stealth tactics. Infected systems will hang, after September 22 every year, which is also the date of birth Bilbo Baggins, a character from "The Lord of the Rings". The code was intended to display the message "Frodo Lives", but hangs in all known variants.
5K resolution
Some photographic still cameras such as DSLRs can exceed 5K resolution when capturing still images, but not when capturing video. For example, the Canon EOS 5D Mark IV announced in August 2016 has a maximum resolution of 67204480 pixels (around 30 megapixels in a 3:2 aspect ratio) which is used for high resolution still images, but it can only capture video at a maximum of 40962160 and a framerate of 30 Hz.