| Variable | Enabling Range | State Transformation | Remarks |
|---|---|---|---|
| Avail(Avail) | = 0 | not modified | |
| Failed(Failed) | = 1 | v'=v | Action performs identity function! |
| C1WaitsForServer(C1WaitsForServer) | = 1 | v'=v+1 | |
| C1WaitsForUser(C1WaitsForUser) | = 0 | not modified | |
| C2WaitsForServer(C2WaitsForServer) | = 0 | v'=v+1 | |
| C2WaitsForUser(C2WaitsForUser) | = 0 | not modified | |
| C1InService(C1InService) | = 0 | not modified | |
| C2InService(C2InService) | = 1 | v'=v-1 | |
| Sidle(Sidle) | = 0 | v'=v+1 |