A family of Microsoft relational database management systems designed for ease of use.
Environ can have questionable reliability, in the sense that is can be reset through code. You be better using http://access.mvps.org/access/api/api0008.htm
As for your delema, you'd use this function in your form or directly in VBA, not in your table. One way or another, no one should ever be entering any information directly in a table, so set it up through the data entry form. One way would be using the Open event, or Current event where you could assign the value to a control:
Me.ControlName = fOSUserName()