memory allocation failure (listner control log)

All,
I would like to know how much of sga area gets allocated to each session at login. We are running oracle 7.3 with the default instance initorcl.ora set for LARGE default options.. There is 64MB of memory on the NT box and every time the number of sessions exceeds 15, the new connection fails and listner log shows a malloc failure. Has anyone experienced this?
Is adding more memory the only solution? If not how do I control the amount of memory each session takes up.

Thanks in advance. Received on Wed Dec 04 1996 - 00:00:00 CET