Do you mean portfast ?
Assuming you do -
1) for trunk connections between switches no you should not enable portfast. There is a "spanning-tree portfast trunk" command which can be used on trunks but you would use this primarily for connections from devices like firewalls, routers or servers connecting with a trunk link.
2) No it does not disable STP it simply allows the port to bypass the listening and learning stages and transition to forwarding immediately.
Jon
