how to restore postgre 8.3 from data directory

Hi!

I need to restore the postgre 8.3 from a data directory
/var/lib/postgresql/8.3/main which has the following content:

$ ls -l

drwx------ 5 postgres postgres 4096 oct 14 11:53 base
drwx------ 2 postgres postgres 4096 oct 14 12:10 global
drwx------ 2 postgres postgres 4096 oct 14 11:53 pg_clog
drwx------ 4 postgres postgres 4096 oct 14 11:53 pg_multixact
drwx------ 2 postgres postgres 4096 oct 14 11:53 pg_subtrans
drwx------ 2 postgres postgres 4096 oct 14 11:53 pg_tblspc
drwx------ 2 postgres postgres 4096 oct 14 11:53 pg_twophase
-rw------- 1 postgres postgres 4 oct 14 11:53 PG_VERSION
drwx------ 3 postgres postgres 4096 oct 14 11:53 pg_xlog
-rw------- 1 postgres postgres 133 oct 14 12:05 postmaster.opts
lrwxrwxrwx 1 root root 31 oct 14 11:53 root.crt ->
/etc/postgresql-common/root.crt
lrwxrwxrwx 1 root root 36 oct 14 11:53 server.crt ->
/etc/ssl/certs/ssl-cert-snakeoil.pem
lrwxrwxrwx 1 root root 38 oct 14 11:53 server.key ->
/etc/ssl/private/ssl-cert-snakeoil.key

I'm tried to replace this directory with the directory of my backup, but I
had no success on startup.

Is it possible restore postgre from a data source (I don't have any dump)

Thanks, ALberto