Unidirectional byte error detecting codes for computer memory systems

Codes are developed for detecting unidirectional errors in t bytes simultaneously (t-UBED) while also providing all unidirectional error detection (AUED). These classes of codes differ from purely all unidirectional error detecting codes in that the errors in one byte may be of the form 1→0, while in another byte they may be of the form 0→1. The codes utilize 2 B for parity check information. As an example, a code providing 3-UBED+AUED protection for up to 12 information bytes of 8 b each can be constructed