Hi Moaz,
Sorry, I cannot understand what is "modification of log for negative numbers".
I have done some searching and got some information on SQL server.
FileSizeLimitMb paramenter:
Specifies an upper limit on trace log size. The file is measured in megabytes. Valid values are 0 to a maximum integer. The default value is 32. If you specify 0 or a negative number, the report server treats the value as 1.
More details in the following article:
Report Server Service Trace Log
http://technet.microsoft.com/en-us/library/ms156500.aspx
If your question relates to SQL server, I suggest asking SQL server Forum for help.
For your convenience:
http://social.technet.microsoft.com/Forums/sqlserver/en-US/home?category=sqlserver
If you have quesion on Exchange Server, please describe this issue in details.
Thanks
Mavis
Mavis Huang
TechNet Community Support
