Specifications

Library Configuration
Library configuration on multiple machine environments should base on
application characteristics. How frequently the machines change job
determines the optimal library configuration.
On one end of the spectrum, the local library configuration is the most robust,
low-risk and flexible but require the most work to keep all the machines in
sync. To propagate any change make on one machine user must copy the
Board Setups and their libraries to other machines.
On the other end of the spectrum, user can setup all the machines to use a
single central library located on the network server. With this configuration any
changes to Devices automatically propagate to all the machine's Board
Setups. The limitation with this approach is that at any one time only one
machine can be in Supervisor Mode to make change to a Board Setup. This
library configuration is also somewhat risky, for example if the network is
down none of the machine can inspect board. Since there is only one copy of
the library shared amongst all machines, if the library is corrupted it affects all
the machines.
It is possible to configure library between the two extremes, for example you
can setup central library configuration but have a separate central library on
each machine. You can also create batch file to automate the update process
on local library configurations.
When multiple machines share a central library. The software uses a text file
called owner.txt to regular access to the library. All machines that share the
library must have full access right (read/write) to the central library and the
owner.txt file. The access control logic is simple. When a machine e.g.
machine A wish to modify the library (i.e. when it tries to enter the Supervisor
Mode.) It will first read the owner.txt file to see if some other machine is
editing the library. If no other machine is editing the library i.e. Owner=NONE,
machine A would write its machine ID into the owner field of the Owner.txt file.
For example machine B now try to enter Supervisor Mode, it examine the
owner.txt file and find Machine A is listed as owner. It would then, inform the
user that machine A is editing the central library and therefore cannot enter
Supervisor Mode. Machine B would only enter Supervisor Mode if machine A
return to Operator Mode or exit the AOI software.