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.
4K resolution
Some 4K resolutions, like 38402160 are often casually referred to as "2160p". This name follows from the previous naming convention used by HDTV and SDTV formats, which refer to a format by the number of pixels/lines along the vertical axis (such as "1080p" for 19201080 progressive scan, or "480i" for the 480-line interlaced SDTV formats) rather than the horizontal pixel count (≈4000 or "4K" for 38402160).