run postgres 8.3

I installed the 8.3 postgres
the amount of giving the command:
bash-3.2$ /usr/local/postgres_8.3/bin/initdb -D /base/data

the result is:

The files belonging to this database system will be owned by user
"postgres".
This user must also own the server process.

The database cluster will be initialized with locale en_US.UTF-8.
The default database encoding has accordingly been set to UTF8.
The default text search configuration will be set to "english".

initdb: directory "/base/data" exists but is not empty
If you want to create a new database system, either remove or empty
the directory "/base/data" or run initdb
with an argument other than "/base/data".

but do not raise your service