All questions related to installations, configurations and maintenance of Advanced Host Monitor (including additional tools such as RMA for Windows, RMA Manager, Web Servie, RCC).
Manual says "logical operators [and, or, not, <, >, >=, <=, ==, <>]".
No, HostMonitor does not support xor. I have added your request into "to do" list
HostMonitor can accept 64K string (65536 characters). Windows edit control has its own limitations. I think it is 2Gb for Windows NT and 32K for Windows 9x/ME