hello all:
ultra 2 ORACLE 8.1.7.4
when I start the database, the warring in the alert.log
WARNING: Not enough physical memory for SHM_SHARE_MMU segment of size 0x00000000
0ae44000

the /etc/system
set semsys:seminfo_semmap=250
set semsys:seminfo_semmni=1000
set semsys:seminfo_semmns=5000
set semsys:seminfo_semmsl=500
set semsys:seminfo_semmnu=500
set semsys:seminfo_semume=100

set shmsys:shminfo_shmmax=209715200set
shmsys:shminfo_shmmni=100
set shmsys:shminfo_shmseg=200
set shmsys:shminfo_shmmin=1
set msgsys:msginfo_msgmni=50
set msgsys:msginfo_msgmnb=16384

the initial.ora
DB_BLOCK_SIZE=8192
DB_BUFFERS=12800
LOG_BUFFER=32768
SHARED_POOL_SIZE =50MB

please help me analyse the problem and present the solution!
Thanks in advance