Virus Scan Before upload of File

In case of uploading File in Server for permanent storage virus scan should be done .Now the question is where virus is checking?I mean to say is there any temporary storage where virus scaning is going on and if no virus found then only it moves to permanent storage. If it something like that,then where the temporary storage reside? In same Server where permanent storage reside? or in some other place?

After virus scan is there any report file generating? If i want to throw message to client browser in case of virus found, from where i will extract the report/status of virus scan.

Generally, in the local computers, the path is C:\WINDOWS\Temp_avast4_

Generally, in the local computers, the path is C:\Program files\Alwil Software\Avast4\DATA\chest

Again, in the local computers, the path is C:\Program files\Alwil Software\Avast4\DATA\report

You can use the alert options.