[GENERAL] when postgres failed to recover after the crash...

[anypossibility]

I am running postgres postgres version 8.3 on OS X.
The data directory is on network volume.
The network volume was disconnected and server crashed.
Log reported that last know up was 9:30 pm (about 30 min prior to the server 
crash.)
My conf Checkpoint_Segments setting = 3 (not sure if this is all helpful info)
When postgres try to recover from the crash the volume was still not mounted.
Once storage volume is re-connected:
There were index corruptions. I fixed all that with single user mode.
There were also some missing record... 
I understand that some updates were lost because they haven't been written to 
the disk yet hence updates are lost.
However, it seems that record that were created long time ago (but updated 
before the crash occurs) is completely missing (unable to find even after 
reindex is done).
Does this make sense? or Is this impossible and record might be somewhere on 
the disk? 
Thank you very much for your time in advance.