Network Terms "J"

.JRS file

Exchange 2007's database engine is referred to as the Extensible Storage Engine (ESE). ESE is a transactional database that writes information into RAM memory and into a log file. Once it is in the log file, it will be written to disk. There are a number of files used to store information:

• An .edb file is located in the actual database itself. All of a user's messages, folders, public folders, contacts, appointment information, etc. is all stored on the .edb file. An .edb file size can exceed multiple GB.

• A .log file is an ESE transaction log file. All .log files are 1 MB.

• A .jrs file is a reserve log file which is used to commit any transactions that are still in memory in the event of the server running out of disk space. All .jrs files are 1 MB.

• A .chk file is used to identify which log files have been committed to the database. The size of .chk file varies from 2-3 KB.

The ESE takes the following steps to write information into database files:

1. The ESE writes a message into memory RAM when it arrives at the server.

2. At the same time that information is written to RAM, it's written into the current .log file. All current log files are named E00.log. The information is written in a sequential format until the log file is full. When the log file is full, it will be renamed.

3. Once it has been committed to the log file, the information is written to the .edb file.

4. The checkpoint file is updated to indicate that the transaction log that has been committed to the database.

Java

A programming language designed to let programmers create applications for the Internet. Java applications do not depend on a particular operating system or hardware platform to run.

Journaling

Journaling is the ability to record and retain all communications in an organization.