GAL, Routing Group, Stm files, Eseutil & ininteg - what are they used for?

GAL:

 This address list contains all mail-enabled users, contacts, groups, or rooms in the organization. During setup, Exchange creates various default address lists. The most familiar address list is the GAL. By default, the GAL contains all recipients in an Exchange organization. In other words, any mailbox-enabled or mail-enabled object in an Active Directory forest that has Exchange installed is listed in the GAL. For ease of use, the GAL is organized by name, not by email address

Routing Group:

A routing group is a logical collection of servers used to control mail flow and public folder referrals. In a routing group, all servers communicate and transfer messages directly to one another

STM Files:

The .stm or streaming media file is used in conjunction with the .edb file to comprise the Exchange database. Both files together make up the database, and as such, they should always be treated as a single entity. Typically, if you perform an action on the .edb file, such as with Exchange Server Database Utilities (Eseutil), the .stm file is automatically included.

EseUtil:

You can use the Eseutil utility to defragment the information store and directory in Microsoft Exchange Server

ininteg  ( I think you mean isinteg)

You can use the Isinteg.exe tool to check and to fix the integrity of the information store databases including the private information store, Priv.edb, and the public information store, Pub.edb.