It happened again. Suddenly I lost the ability to locally access a
database. This is firebird 2.1 running on Ubuntu 10.04.

If I try and access the database using isql I get "Permission denied."
However, "ls -l" shows I have ownership and rights to the file. I can
even dump the file. It seems firebird is trying to access some other
file besides the database when I try to connect to the database. When I
reboot the machine I have normal access again. The firebird log file
contains absolutely nothing.

ted@migmar11:~/dbs$ isql exp_dm
Statement failed, SQLCODE = -902
operating system directive open failed
-Permission denied
Use CONNECT or CREATE DATABASE to specify a database
SQL> quit;
ted@migmar11:~/dbs$ ls -l exp_dm
-rw-rw---- 1 ted ted 1531904 2012-12-12 15:12 exp_dm
ted@migmar11:~/dbs$ hexdump -C exp_dm |head
00000000 01 00 39 30 7c 10 00 00 00 00 00 00 00 00 00 00
|..90|...........|
00000010 00 20 0b 80 03 00 00 00 00 00 00 00 ce 0f 00 00 |.
..............|
00000020 cf 0f 00 00 d0 0f 00 00 00 00 02 00 af db 00 00
|................|
00000030 4c 85 d0 17 a6 00 00 00 00 00 00 00 13 00 01 00
|L...............|
00000040 01 00 66 00 00 00 00 00 01 00 00 00 cf 0f 00 00
|..f.............|
00000050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
|................|
00000060 06 04 20 4e 00 00 00 00 00 00 00 00 00 00 00 00 |..
N............|
00000070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
|................|
*
00002000 02 00 39 30 4b 00 00 00 00 00 00 00 bb 00 00 00
|..90K...........|
ted@migmar11:~/dbs$