Data transfer between devices maintaining state data

1. A method for performing transfers between a writer device and a reader device, wherein the writer device and the reader device are each coupled to a common bus, comprising:

a host device creating a transfer session between the writer device and the reader device, wherein the host device is separate and distinct from the writer device and the reader device, wherein each of the host device, the writer device, and the reader device independently maintains state data of the transfer session, wherein the state data comprises an enabled state and a disabled state, and wherein after said creating the transfer session, the state data of the transfer session maintained by each device is in the disabled state;

the host device enabling a direct transfer of data between the writer device and the reader device, wherein said enabling comprises the host device notifying at least one of the reader device or the writer device of a state change from the disabled state to the enabled state, and wherein after said enabling, data is transferred directly between the writer device and the reader device without involving the host device; and

the host device disabling the direct transfer of data between the writer device and the reader device, wherein said disabling comprises the host device notifying at least one of the reader device or the writer device of a state change from the enabled state to the disabled state, and wherein after said disabling, the direct transfer of data between the writer device and the reader device is stopped.

2. The method of claim 1 , wherein said enabling is performed in response to at least one of the reader device or the writer device changing from the disabled state to the enabled state.

3. The method of claim 1 , wherein said disabling is performed in response to at least one of the reader device or the writer device changing from the enabled state to the disabled state.

4. The method of claim 3 , wherein said disabling is performed before completion of the direct transfer of data.

5. The method of claim 4 , wherein the writer device comprises a flushing state, wherein the writer device enters the flushing state before the disabled state, wherein, in the flushing state, the writer device continues to transfer remaining buffered data to the reader device, and wherein, after the remaining buffered data is transferred, the writer device enters the disabled state.

6. The method of claim 1 , wherein the state data further comprises an unlinked state, wherein prior to said initiating, the writer device and the reader device are in the unlinked state, and wherein the method further comprises:

the host device closing the transfer session, wherein said closing the transfer session comprises the host device notifying the reader device and the writer device of a state change to the unlinked state.

7. The method of claim 1 , wherein the transfer session comprises a peer to peer streaming session.

8. The method of claim 1 , wherein the writer device comprises a data acquisition device, and wherein the data comprises acquisition data of the data acquisition device.

9. A non-transitory computer accessible memory medium comprising program instructions for performing transfers between a writer device and a reader device, wherein the writer device and the reader device are each coupled to a common bus, and wherein the program instructions are executable by a processor of a host device to:

create a transfer session between the writer device and the reader device, wherein the host device is separate and distinct from the writer device and the reader device, wherein each of the host device, the writer device, and the reader device independently maintains state data of the transfer session, wherein the state data comprises an enabled state and a disabled state, and wherein after said creating the transfer session, the state data of the transfer session maintained by each device is in the disabled state;

enable a direct transfer of data between the writer device and the reader device, wherein said enabling comprises notifying at least one of the reader device or the writer device of a state change from the disabled state to the enabled state, and wherein after said enabling, data is transferred directly between the writer device and the reader device without involving the host device; and

disable the direct transfer of data between the writer device and the reader device, wherein said disabling comprises notifying at least one of the reader device or the writer device of a state change from the enabled state to the disabled state, and wherein after said disabling, the direct transfer of data between the writer device and the reader device is stopped.

10. The memory medium of claim 9 , wherein said enabling is performed in response to at least one of the reader device or the writer device changing from the disabled state to the enabled state.

11. The memory medium of claim 9 , wherein said disabling is performed in response to at least one of the reader device or the writer device changing from the enabled state to the disabled state.

12. The memory medium of claim 11 , wherein said disabling is performed before completion of the direct transfer of data.

13. The memory medium of claim 12 , wherein the writer device comprises a flushing state, wherein the writer device enters the flushing state before the disabled state, wherein, in the flushing state, the writer device continues to transfer remaining buffered data to the reader device, and wherein, after the remaining buffered data is transferred, the writer device enters the disabled state.

14. The memory medium of claim 9 , wherein the state data further comprises an unlinked state, wherein prior to said initiating, the writer device and the reader device are in the unlinked state, and wherein the program instructions are further executable to:

close the transfer session, wherein said disabling the transfer session comprises notifying the reader device and the writer device of a state change to the unlinked state.

15. The memory medium of claim 9 , wherein the transfer session comprises a peer to peer streaming session.

16. The memory medium of claim 9 , wherein the writer device comprises a data acquisition device, and wherein the data comprises acquisition data of the data acquisition device.

17. A host device for performing transfers between a writer device and a reader device, wherein the host device is separate and distinct from the writer device and the reader device, comprising:

a processor;

one or more ports coupled to the processor, wherein the one or more ports are configured to couple to the reader device and the writer device over a common bus; and

a memory medium coupled to the processor, wherein the memory medium stores program instructions executable by the processor to:

create a transfer session between the writer device and the reader device, wherein each of the host device, the writer device, and the reader device independently maintains state data of the transfer session, wherein the state data comprises an enabled state and a disabled state, and wherein after said creating the transfer session, the state data of the transfer session maintained by each device is in the disabled state;

enable a direct transfer of data between the writer device and the reader device, wherein said enabling comprises notifying at least one of the reader device or the writer device of a state change from the disabled state to the enabled state, and wherein after said enabling, data is transferred directly between the writer device and the reader device without involving the host device; and

disable the direct transfer of data between the writer device and the reader device, wherein said disabling comprises notifying at least one of the reader device or the writer device of a state change from the enabled state to the disabled state, and wherein after said disabling, the direct transfer of data between the writer device and the reader device is stopped.

18. The host device of claim 17 , wherein said enabling is performed in response to at least one of the reader device or the writer device changing from the disabled state to the enabled state.

19. The host device of claim 17 , wherein said disabling is performed in response to at least one of the reader device or the writer device changing from the enabled state to the disabled state.

20. A system for performing transfers between a writer device and a reader device, comprising:

a host device;

a reader device coupled to the host device over a bus; and

a writer device coupled to the host device over the bus;

wherein the host device is separate and distinct from the writer device and the reader device; and

wherein the host device is configured to:

create a transfer session between the writer device and the reader device, wherein each of the host device, the writer device, and the reader device independently maintains state data of the transfer session, wherein the state data comprises an enabled state and a disabled state, and wherein after said creating the transfer session, the state data of the transfer session maintained by each device is in the disabled state;

enable a direct transfer of data between the writer device and the reader device, wherein said enabling comprises notifying at least one of the reader device or the writer device of a state change from the disabled state to the enabled state, and wherein after said enabling, data is transferred directly between the writer device and the reader device without involving the host device; and

disable the direct transfer of data between the writer device and the reader device, wherein said disabling comprises notifying at least one of the reader device or the writer device of a state change from the enabled state to the disabled state, and wherein after said disabling, the direct transfer of data between the writer device and the reader device is stopped.