Applies To
Express Software Manager version 4.x through 5.x

Summary
This technical note provides information on the Inventory process and features in Express Software Manager 4.x through 5.x. Information on the Express Software Manager two-pass architecture, primary and secondary gathering, and Update Database feature is included.

Understanding the Two-Pass Architecture
Express Inventory uses a two-pass architecture that is designed to be low-impact and decrease the amount of time needed to gather file information.

Two-Pass Architecture Sequence
Typically, the Express Inventory client collects data in the following sequence:

First pass: The Express Inventory client retrieves basic file information (installation path, file name, size, date, and time stamp). If the Express Knowledgebase recognizes a file, no further passes are needed on that file.

First database update: The Express Inventory client adds recognized files to the Auto-Added files list and marks unrecognized files for a second pass.

Second pass: The Express Inventory client calculates a Cyclic Redundancy Check (CRC) on the first 1000 bytes of each file and retrieves version information on each file that was not recognized by the Express Knowledgebase.

Subsequent database updates: The Express Inventory client adds all .exe and .com files, with version information, to the Auto-Added files list.

First Pass
The first pass gathers the file name, file size, date, time stamp, and installation path for the file extensions specified on the Inventory tab in Library Properties (for example, .exe, .com and .dll files). The information gathered from the inventory scan and the Year 2000 compliance check, if enabled, is stored in an I<n>.inv file. Each machine generates a unique I<n>.inv file, which is stored in the application library folder on the server.

Database Updates
During an Update Database operation, Express processes the files that were gathered by the Express Inventory client in the first pass.

Note: Even if the workstation has not been completely scanned, the files that have been gathered in the first pass are processed by the Update Database operation.

If an inventoried file is not already in the Files list in Express Console, the Update Database operation attempts to find an exact match in the Express Knowledgebase based on file name and file size. If an exact match is found, the recognized .exe or .com file is added to the Auto-Added files list in the Application Wizard. The system administrator must then configure the Auto-Added files to view applications in Express Reports.

All files that are not matched in the Express Knowledgebase are marked for a second pass.

For more information about running an Update Database operation, see the Starting an Update Database Operation section of this technical note.

Second Pass
Specific files that require a second pass are identified in the I<n>.inv file for the machine on which the files are located. Once a file has been marked for a second pass, the Express Inventory client must be run again on the machine where that file was first found. During this pass, the Express Inventory client retrieves version information and calculates a CRC on the first 1000 bytes of each file.

Note: Even if that file exists elsewhere on the network, only the original computer where it was found can perform a second pass on that file.

After the second pass and a subsequent update of the database, all of the .exe and .com files are added to the Auto-Added files list with additional information (such as version string) to help with identification. Only files with .exe or .com extensions are added to the Auto-Added files list after the second pass.

Understanding Primary and Secondary Gathering
Primary and secondary gatherings are used to schedule the Express Inventory client. The primary and secondary gathering schedules can be configured in the Express Console (click the Inventory tab in Library Properties). Scanning continues as scheduled until the workstation has been completely scanned.

Note: If you are using Express 4.5 or higher and you run the Express Inventory client with the -O switch, the settings in the Library Properties dialog box will be ignored. The Express Inventory client will run until all of the inventory data (first and second pass) has been gathered.

Primary Gathering Settings
The default primary gathering setting is high-impact gathering with a 10-second time limit, but you can configure limits based on time, the number of directories or files scanned, or a percentage of the disk.

A high-impact scan requires more of the system resources, but takes less time. Using the two-pass architecture described above, the primary scan will run the Express Inventory client for ten seconds (or the configured value). If the workstation has not been fully scanned at the end of the primary gathering period, a secondary gathering will occur at the time set on the Inventory tab. If the workstation is completely scanned during the primary gathering, scanning will be performed again when the next complete scan is scheduled (by default, in one month).

Secondary Gathering Settings
The default secondary gathering resumes high-impact scanning after 30 minutes. Subsequent scanning will occur at the scheduled interval (for example, every 30 minutes) for the same gathering time as primary scanning (for example, 10 seconds) until the workstation is completely inventoried.

Files that were not identified in the first pass and were not matched to files in the Express Knowledgebase (see Understanding the Two-Pass Architecture), will be scanned first during the secondary scanning. If there is additional time after scanning second-pass files, scanning of first-pass files will continue. The secondary gathering always scans second-pass files first, before scanning new or unscanned files.

Note: If the database is not updated after the primary gathering, second-pass files may not yet be identified when the Express Inventory client resumes. If second-pass files are identified after the Express Inventory client has scanned the complete workstation, secondary gathering will scan these files the next time the Express Inventory client runs.

Starting an Update Database Operation
Files that are detected by the Express Inventory client and matched in the Express Knowledgebase are moved to the Auto-Added files list by the Update operation. A database update can be started in any of the ways listed below. The most convenient way to perform updates, however, is to schedule them to run automatically using the Express Library Manager service.

• Configure the Express Library Manager service to schedule automatic database updates and consolidations. A Consolidate operation always attempts to update every library involved in the consolidation.

• In Express Console, click the Files folder in the left pane. (You will be prompted to update if the prompt has not been turned off in Console Options.)

• In Express Console, click the Machines folder in the left pane. (You will be prompted to update if the prompt has not been turned off in Console Options.)

• From the Tools menu in Express Console, select Library, and click Update database.

Related Technical Notes

1294	Running Express Software Manager Inventory Client from a Server
1560	Understanding the Inventory Process in Express Software Manager 6.0
9989	Express Software Manager 6.0 Technical Notes
9991	Express Software Manager Technical Notes (5.x or lower)