External relations of Guernsey both islands retain their independence with regards to domestic affairs but internationally, the islands would be regarded as one state. A Guernsey-Jersey double taxation agreement was first signed in 1956. In 1998 Guernsey and Jersey electricity companies formed the Channel Islands Electricity Grid to operate and manage the submarine cables between Europe and the Channel Islands. Guernsey has formed part of the British–Irish Council since it was formed in 1999, as does Jersey. Meetings take place twice a year, in 2004, 2010 and 2014 the meetings have taken place in Guernsey. Its stated aim is to "promote the harmonious and
SIMMON virtual machine for testing of a single guest program running there. CP-40 supported many virtual machines for time-sharing production work. CP-40 evolved by many stages into the present VM/CMS operating system. SIMMON was a useful test vehicle for many years. SIMMON was designed to dynamically include independently developed programs (test tools) for testing the target guest program. The SIMMON kernel maintained control over the hardware (and the guest) and coordinated invocation of the test tools. Two modes of operation were provided: In this mode, each instruction in the guest program was simulated without ever passing control directly to the guest.