Channel-To-Channel Deadlock Prevention
Original Publication Date: 1985-Nov-01
Included in the Prior Art Database: 2005-Feb-19
A classical restriction of Channel-to-Channel Adapters (CTCAs) is that multiple CTCAs must not be connected to the same I/O interfaces on two different channels. If this restriction is violated, then only one CTCA per interface must be enabled at any one time. A potential deadlock can occur if two CTCAs are enabled and connected to both a single channel interface on a first system, and also to a single channel interface on a second system, and these two systems attempt to simultaneously interleave communications to each other through both CTCAs. Instantaneous communication through both CTCAs is impossible because of only two channel paths available.