You have the standard version if you are running Exchange 5.0
Microsoft Knowledge Base Article:
XFOR: Information Store Shuts Down; Database at Maximum Size
The information in this article applies to:
Microsoft Exchange Server, versions 4.0, 5.0, 5.5
The maximum allowed size of a single database in Exchange versions 4.0 and 5.0 is 16 GB (Priv.edb can be 16 GB and Pub.edb can be 16 GB). After the limit is reached, the Exchange database engine stops taking transactions and notifies the information store to shut down.
Microsoft Exchange Server 5.5 Enterprise Edition information store databases are not limited to 16 GB; they are limited only by available hardware.
Microsoft Knowledge Base Article:
XADM: Determining if Exchange Server Enterprise or Standard Edition Is Installed
The information in this article applies to:
Microsoft Exchange Server, version 5.5
SYMPTOMS
There is no distinction in the user interface between Exchange Server Standard and Exchange Server Enterprise editions.
CAUSE
This is by design.
WORKAROUND
To distinguish between Exchange Server Standard and Exchange Server Enterprise, check the Windows NT Event Viewer application event log upon startup.
The following event is logged when the information store starts on an Enterprise edition Exchange Server computer:
Event Id: 1217
Source: MSExchangeIS
Type: Information
Category: General
Description: "Information store with unlimited capacity started"
The Standard edition logs the following event:
Event ID 1216
Source: MSExchangeIS Private
Type: Information
Category: General
Description: Information store with limited storage capacity enabled.
