Method and means for limiting duration of input/output (I/O) requests

Claim 1

An apparatus for limiting duration of an I/O (input/output) request performed by an I/O supervisor to a data set resident in an I/O device in a data processing system comprising a main processor having a processor clock and said I/O device attached to said main processor, said apparatus comprising: a) request-based interval establishment means for setting an I/O request time limit in a request time limit field located in said data processing system, and turning ON a request limit indicator in a request limit indicator field located in said data processing system, for said I/O request; b) data-set-based interval establishment means for setting a maximum data-set duration for said I/O request to said data-set in a data-set-based time limit field located in said data processing system, and turning ON a data-set limit indicator in a data-set indicator field located in said data processing system, for said I/O request; c) workload-based interval establishment means for setting a maximum workload duration for said I/O request originating in an indicated address space in a workload-based time limit field located in said data processing system, and turning ON a workload limit indicator in a workload indicator field located in said data processing system, for said I/O request; d) device-based interval establishment means for setting a maximum I/O duration for said I/O request to said I/O device in a device-based time limit field located in said data processing system, and turning ON a device limit indicator in a device indicator field located in said data processing system, for said I/O request; e) error detection means for detecting an I/O error for said I/O device and generating an error indication; f) error recovery means, responsive to said error indication for calculating said total I/O request time value for said I/O request, for comparing said total I/O request time value, calculated by said error recovery means, to a minimum of said I/O request time limit, said maximum data-set duration, said maximum workload duration, and said maximum device duration, and for restarting said I/O request only if said total I/O request time value for said I/O request is less than a minimum of said I/O request time limit, said maximum data-set duration, said maximum workload duration, and said maximum device duration, said time limit and durations being considered in deriving said minimum only if said request, data-set, workload, and device indicators are ON, respectively, said total I/O request time value being calculated by said error recovery means with respect to an initial start time for said I/O request; g) scan means for calculating said total I/O request time value, for comparing said total I/O request time value, calculated by said scan means, to a minimum of said I/O request time limit and said maximum data-set duration, and for terminating said I/O request, if said total I/O request time value, calculated by said scan means, is greater than a minimum of said I/O request time limit and said maximum data-set duration, said maximum workload duration, and said maximum device duration time limit and durations being considered in deriving said minimum only if said request, data-set, workload, and device indicators are ON, respectively.

Claim 2

An apparatus for limiting duration of an I/O (input/output) request performed by an I/O supervisor to a data set resident in an I/O device in a data processing system comprising a main processor having a processor clock and said I/O device attached to said main processor, said apparatus comprising: a) request-based interval establishment means for setting an I/O request time limit in a request time limit field located in said data processing system, and turning ON a request limit indicator in a request limit indicator field located in said data processing system, for said I/O request; b) data-set-based interval establishment means for setting a maximum data-set duration for said I/O request to said data-set in a data-set-based time limit field located in said data processing system, and turning ON a data-set limit indicator in a data-set indicator field located in said data processing system, for said I/O request; c) workload-based interval establishment means for setting a maximum workload duration for said I/O request originating in an indicated address space in a workload-based time limit field located in said data processing system, and turning ON a workload limit indicator in a workload indicator field located in said data processing system, for said I/O request; d) device-based interval establishment means for setting a maximum I/O duration for said I/O request to said I/O device in a device-based time limit field located in said data processing system, and turning ON a device limit indicator in a device indicator field located in said data processing system, for said I/O request; e) error detection means for detecting an I/O error for said I/O device and generating an error indication; f) error recovery means, responsive to said error indication for calculating said total I/O request time value for said I/O request, for comparing said total I/O request time value, calculated by said error recovery means, to a minimum of said I/O request time limit, said maximum data-set duration, said maximum workload duration, and said maximum device duration, and for restarting said I/O request only if said total I/O request time value for said I/O request is less than a minimum of said I/O request time limit, said maximum data-set duration, said maximum workload duration, and said maximum device duration, said time limit and durations being considered in deriving said minimum only if said request, data-set, workload, and device indicators are ON, respectively, said total I/O request time value being calculated by said error recovery means with respect to an initial start time for said I/O request; g) scan means for calculating said total I/O request time value, for comparing said total I/O request time value, calculated by said scan means, to a minimum of said I/O request time limit and said maximum data-set duration, and for terminating said I/O request, if said total I/O request time value, calculated by said scan means, is greater than a minimum of said I/O request time limit and said maximum data-set duration, said maximum workload duration, and said maximum device duration time limit and durations being considered in deriving said minimum only if said request, data-set, workload, and device indicators are ON, respectively.

Claim 3

An apparatus for limiting duration of an I/O (input/output) request performed by an I/O supervisor to a data set resident in an I/O device in a data processing system comprising a main processor having a processor clock and said I/O device attached to said main processor, said apparatus comprising: a) interval establishment means for setting a time limit in a time limit field located in said data processing system for said I/O request; b) error detection means for detecting an I/O error for said I/O device and generating an error indication; c) error recovery means, responsive to said error indication, for restarting said I/O request only if a total I/O request time value for said I/O request is less than said time limit, said error recovery means comprising first I/O request time approximation means for estimating said total I/O request time value including error recovery time and comparing said estimated I/O request time value to said time limit; d) scan means for terminating said I/O request, if said total I/O request time value is greater than said time limit, said scan means comprising second I/O request time approximation means for estimating said total I/O request time value including error recovery time and comparing said estimated I/O request time value to said time limit.

Claim 4

An apparatus for limiting duration of an I/O (input/output) request performed by an I/O supervisor to a data set resident in an I/O device in a data processing system comprising a main processor having a processor clock and said I/O device attached to said main processor, said apparatus comprising: a) interval establishment means for setting a time limit in a time limit field located in said data processing system for said I/O request; b) error detection means for detecting an I/O error for said I/O device and generating an error indication; c) error recovery means, responsive to said error indication, for restarting said I/O request only if a total I/O request time value for said I/O request is less than said time limit, said error recovery means comprising first I/O request time approximation means for estimating said total I/O request time value including error recovery time and comparing said estimated I/O request time value to said time limit; d) scan means for terminating said I/O request, if said total I/O request time value is greater than said time limit, said scan means comprising second I/O request time approximation means for estimating said total I/O request time value including error recovery time and comparing said estimated I/O request time value to said time limit.