Multiple host support for remote expansion apparatus
View Patent ↗A data processing assembly includes one or more hosts connected to one or more I/O Expansion Drawers. Assignment state information is stored on the Expansion Drawer to convey the assignment state of Expansion Drawer(s) resources to the hosts. The host retrieves the assignment state and, from it, determines, for each Expansion Buss cable connected to the host, the number of Expansion Cards in the Expansion Drawer to configure. A change in the number of Expansion Cards in the expansion apparatus may necessitate a change in the assignment state, which can be electronically accommodated (as opposed to a manual reconfiguration). Similarly, a failure of an Expansion Buss cable is addressed by electronically reassigning resources to another host or to the same host over a different Expansion Buss cable without the need for further manual intervention. The assembly is capable of verifying correct cable connection between a host and the Expansion Drawer.
1. An expansion drawer configured to connect, via a first expansion bus cable, to a first host of a first platform type and to connect, via a second expansion bus cable, to a second host of a second platform type, the expansion drawer comprising:
a first expansion card;
an expansion drawer controller configured to communicate with the first and second hosts and further configured to set an assignment state for the first expansion card, wherein the assignment state is indicative of whether the first host or the second host may configure the first expansion card; and
a storage resource of the expansion drawer containing the assignment state indicative of an assignment status of the first expansion card and an availability of the first expansion card;
wherein the first host is enabled to retrieve the assignment status of the first expansion card from the storage resource and determine whether to configure the first expansion card depending upon information in the assignment status of the first expansion card,
wherein the first host is configured not to retain the assignment state across boot cycles of the first host, and
wherein the first host acquires, from the expansion drawer, the assignment state at boot time of the first host.
2. The expansion drawer of claim 1 , further comprising a second expansion card, wherein the assignment state is further indicative of an assignment status of the second expansion card wherein the assignment status of the second expansion card is indicative of whether the first host or second host may configure the second expansion card.
3. The expansion drawer of claim 2 , wherein the controller is further configured to prevent the first and second hosts from contending to configure the same expansion card.
4. The expansion drawer of claim 2 , wherein the expansion drawer may assume a first configuration state in which the first and second expansion cards are configured by a first host, and a second configuration state in which the first and second expansion cards are configured by different hosts.
5. The expansion drawer of claim 1 , wherein the controller is configured to enable the first host to configure the second expansion card.
6. The expansion drawer of claim 5 , wherein the controller is configured to enable the first host to configure the second expansion card responsive to a failure of the first expansion bus.
7. The expansion drawer of claim 1 , wherein the expansion drawer is configured to support a daisy chain connection to a second expansion drawer wherein the first host is enabled to configure expansion cards in each of the expansion drawers.
8. The expansion drawer of claim 1 , wherein the controller is enabled to manage dynamic changes in the number of available expansion drawers and expansion cards.
9. The expansion drawer of claim 1 , wherein the controller is configured to provide a replacement host substituted for the first host retrieves with the assignment information thereby enabling the replacement host to configure the expansion cards.