Abstract: A method, apparatus and system for restarting an emulated mainframe IOP, such as a failed or hung emulated mainframe IOP within an emulated mainframe commodity computer. The method includes a rescue process that polls a home location for Restart Request information. In response to receiving Restart Request information, the rescue process is configured to shut down the existing emulated mainframe IOP, start a new emulated mainframe IOP, and reset the home location. The Restart Request information can be provided to the home location by the mainframe computer being emulated. Alternatively, the rescue mechanism can use an interface management card instructed to restart the commodity computer hosting the failed or hung IOP, e.g., from a maintenance service and/or a maintenance program residing in an active commodity computer coupled to the commodity computers hosting one of several emulated mainframe IOPs.

Abstract: A method, apparatus and system for transmitting multiple I/O requests from an input/output processor (IOP) to an I/O device. The IOP is configured with multiple I/O threads, each having a corresponding active I/O, that allow a queuing thread to coordinate the transfer of multiple I/O requests at a time from the output of the device queue to the active I/Os and their I/O threads. The queuing thread and a promotion algorithm are configured to consider the promotion of one or more I/O requests ahead of other I/O requests in the device queue, based on a set of promotion requirements. After processing by the I/O threads, multiple I/O requests are transferred at a time from the multiple active I/Os to the I/O device. Promotion of I/O requests based on the promotion requirements improves processing efficiency by making better use of the multiple I/O thread processing resources.

Abstract: A method, apparatus and system for restarting an emulated mainframe IOP, such as a failed or hung emulated mainframe IOP within an emulated mainframe commodity computer. The method includes a rescue process that polls a home location for Restart Request information. In response to receiving Restart Request information, the rescue process is configured to shut down the existing emulated mainframe IOP, start a new emulated mainframe IOP, and reset the home location. The Restart Request information can be provided to the home location by the mainframe computer being emulated. Alternatively, the rescue mechanism can use an interface management card instructed to restart the commodity computer hosting the failed or hung IOP, e.g., from a maintenance service and/or a maintenance program residing in an active commodity computer coupled to the commodity computers hosting one of several emulated mainframe IOPs.

Abstract: A method and system for communicating information regarding input/output (IO) processing in a shared access to memory environment is disclosed. A central processing unit (CPU) and an input/output processor (IOP) are configured to write to and read from predetermined memory locations to manage the detection, performance, and completion of IOs. The CPU and the IOP may read from and write to memory as desired.