Method for executing discovery and status update polling procedures of networked devices
In a system of networked devices such as printers managed by a computer connected to them by a network, a method is described for executing device discovery and device status update at independent time intervals using a SNMP broadcast method while eliminating thread safety risk. Device discovery and status update are executed as subroutines within a main routine and each subroutine has its own decrement counter. The entire routine is repeated one cycle every time unit. In each cycle, the decrement counters are evaluated. If a counter is a positive value, the corresponding subroutine is skipped and the counter is decremented by one. If a counter is zero, the corresponding subroutine is executed and its counter is reset to the user-specified time interval afterwards.
1. A method implemented on a computer for managing a plurality of devices, the computer being connected to the devices via a network, the method comprising:
(a) evaluating a first time counter;
(b) if the first time counter is a first target value, executing a first subroutine and resetting the first time counter to a first reset value, the first subroutine including making SNMP (Simple Network Management Protocol) calls onto the network and receiving responses from one or more of the devices to gather a first type of information;
(c) if the first time counter is one of a first plurality of non-target values, skipping the first subroutine and adjusting the first time counter toward the first target value;
(d) evaluating a second time counter;
(e) if the second time counter is a second target value, executing a second subroutine and resetting the second time counter to a second reset value, the second subroutine including making SNMP calls onto the network and receiving responses from one or more of the devices to gather a second type of information;
(f) if the second time counter is one of a second plurality of non-target values, skipping the second subroutine and adjusting the second time counter toward the second target value;
(g) sleeping for a pre-defined time period; and
(h) repeating steps (a) through (g),
wherein each of the first time counter and the second time counter is evaluated once and only once between two consecutive sleeping steps.
2. The method of claim 1 , wherein the devices are printers, wherein the first subroutine is a printer discovery subroutine, and wherein the second subroutine is a printer status update subroutine.
3. The method of claim 1 , wherein step (b) further comprises setting the second time counter to the second target value.
4. The method of claim 1 , further comprising:
(i) if the first time counter is a third value, the third value being different from the first target value and the first plurality of non-target values, skipping the first subroutine without changing the first time counter.
5. The method of claim 4 , further comprising, before step (a): setting the first time counter to the third value.
6. The method of claim 1 , further comprising, before step (a): setting the first time counter to the first target value.
7. A computer program product comprising a non-transitory computer usable medium having a computer readable program code embedded therein for controlling a computer, the computer being connected to a plurality of devices via a network, the computer readable program code configured to cause the computer to execute a process for managing the plurality of devices, the process comprising:
(a) evaluating a first time counter;
(b) if the first time counter is a first target value, executing a first subroutine and resetting the first time counter to a first reset value, the first subroutine including making SNMP (Simple Network Management Protocol) calls onto the network and receiving responses from one or more of the devices to gather a first type of information;
(c) if the first time counter is one of a first plurality of non-target values, skipping the first subroutine and adjusting the first time counter toward the first target value;
(d) evaluating a second time counter;
(e) if the second time counter is a second target value, executing a second subroutine and resetting the second time counter to a second reset value, the second subroutine including making SNMP calls onto the network and receiving responses from one or more of the devices to gather a second type of information;
(f) if the second time counter is one of a second plurality of non-target values, skipping the second subroutine and adjusting the second time counter toward the second target value;
(g) sleeping for a pre-defined time period; and
(h) repeating steps (a) through (g),
wherein each of the first time counter and the second time counter is evaluated once and only once between two consecutive sleeping steps.
8. The computer program product of claim 7 , wherein the devices are printers, wherein the first subroutine is a printer discovery subroutine, and wherein the second subroutine is a printer status update subroutine.
9. The computer program product of claim 7 , wherein step (b) further comprises setting the second time counter to the second target value.
10. The computer program product of claim 7 , where the process further comprises:
(i) if the first time counter is a third value, the third value being different from the first target value and the first plurality of non-target values, skipping the first subroutine without changing the first time counter.
11. The computer program product of claim 10 , wherein the method further comprises, before step (a): setting the first time counter to the third value.
12. The computer program product of claim 7 , wherein the method further comprises, before step (a): setting the first time counter to the first target value.