Suspension and restart of input/output operations

Claim 2

In an input/output control mechanism including a channel and a control unit, said channel including means for executing a start I/O instruction to initiate a particular I/O operation the improvement comprising: means at said control unit for registering a manifestation indicating that an I/O operation is suspended to thereby hold said control unit in a suspended state; means in said channel for executing a restart instruction whereby said channel is set in such a state that said channel can resume the I/O operation; means at said channel for sending a predetermined command to said control unit to resume said operation; and means at said control unit operative in response to said predetermined command and to said registering means for resuming said input/output operation at the point of suspension, whereby a previously started I/O operation may be suspended during the execution of a channel program upon the occurrence of some condition requiring a delay before the operation can be continued.

Claim 3

The combination according to claim 1 wherein said channel includes means for signalling said control unit that said I/O operation is to be suspended and wherein said registering means responds to said signalling means for placing said control unit in said suspended state.

Claim 4

In an input/output control mechanism, including a channel and a control unit, in which a previously started I/O operation started by executing a start I/O instruction within a main program is suspended during the execution of a channel program upon the occurrence of some condition requiring a delay before the operation can be continued, said channel including means for signalling said control unit that said operation is to be suspended, the inprovement comprising: means at said control unit responsive to said signalling means for registering a manifestation indicating that the I/O operation is suspended to thereby hold said control unit in a suspended state until said channel receives an instruction from the main program to restart the operation; means in said channel for decoding a restart instruction and for setting said channel in such a state that said channel can resume the I/O operation; means at said channel for selecting and addressing said control unit and for sending said control unit a predetermined command; and means at said control unit connected to said registering means operative upon receipt of said command and in response to said manifestation indicating the previously retained suspended condition for resuming said input/output operation at the point of suspension.

Claim 5

In an input/output control mechanism, including a channel and a control unit, in which a previously started I/O operation started by executing a start I/O instruction within a main program is suspended during the execution of a channel program upon the occurrence of some condition requiring a delay before the operation can be continued, said channel including means for signalling said control unit that said operation is to be suspended, the inprovement comprising: means at said control unit responsive to said signalling means for registering a manifestation indicating that the I/O operation is suspended to thereby hold said control unit in a suspended state until said channel receives an instruction from the main program to restart the operation; means in said channel for decoding a restart instruction and for setting said channel in such a state that said channel can resume the I/O operation; means at said channel for selecting and addressing said control unit and for sending said control unit a predetermined command; and means at said control unit connected to said registering means operative upon receipt of said command and in response to said manifestation indicating the previously retained suspended condition for resuming said input/output operation at the point of suspension.

Claim 6

For use with a channel of the type in which an input/output operation is started by a first instruction, including means in said channel for signalling to indicate suspension of said operation and means in said channel for executing a second instruction for restarting said operation; a control unit comprising: means responsive to commands received from said channel for executing said commands to control a device; means responsive to the signalling means in said channel for registering a manifestation indicating that said operation is to be suspended; means for resuming the execution of said command; and means responsive to said registering means and a command received from said channel during the execution of said second instruction for generating a signal for resuming said suspended operation.

Claim 7

For use with a channel of the type in which an input/output operation is started by a first instruction, including means in said channel for signalling to indicate suspension of said operation and means in said channel for executing a second instruction for restarting said operation; a control unit comprising: means responsive to commands received from said channel for executing said commands to control a device; means responsive to the signalling means in said channel for registering a manifestation indicating that said operation is to be suspended; means for resuming the execution of said command; and means responsive to said registering means and a command received from said channel during the execution of said second instruction for generating a signal for resuming said suspended operation.

Claim 8

For use with a channel of the type in which input/output operations are carreid out in response to a channel program comprised of a list of channel command words (CCW''s) obtained by said channel from a storage, and in which address means in said channel specify the address of a CCW in said storage; said channel including means for executing a start I/O instruction to intitiate a particular I/O operation; further means in said channel for signalling to indicate suspension of said operation; and means in said channel for executing a restart instruction for restarting the suspended operation and for sending a predetermined command, a control unit comprising: command execution control means responsive to commands received from said channel for executing said commands to control a device, said control means including means for suspending and resuming the execution of said commands; means at said control unit responsive to the signalling means in said channel for registering a manifestation indicating that said operation is suspended; and means responsive to said registering means and said predetermined command received from said channel for resuming said suspended operation.

Claim 9

For use with a channel of the type in which input/output operations are carreid out in response to a channel program comprised of a list of channel command words (CCW''s) obtained by said channel from a storage, and in which address means in said channel specify the address of a CCW in said storage; said channel including means for executing a start I/O instruction to intitiate a particular I/O operation; further means in said channel for signalling to indicate suspension of said operation; and means in said channel for executing a restart instruction for restarting the suspended operation and for sending a predetermined command, a control unit comprising: command execution control means responsive to commands received from said channel for executing said commands to control a device, said control means including means for suspending and resuming the execution of said commands; means at said control unit responsive to the signalling means in said channel for registering a manifestation indicating that said operation is suspended; and means responsive to said registering means and said predetermined command received from said channel for resuming said suspended operation.

Claim 10

For use with controlling apparatus capable of executing a start I/O instruction for initiating an I/O operation in a peripheral device, a peripheral device controller comprising in combination: suspend latch and control means; selection logic means adapted to connect said controller to said controlling apparatus for receiving commands and control signals from said controlling apparatus; command execution control means connected to said selection logic means responsive to commands from said controlling apparatus for effecting an I/O operation; said suspended latch and control means responsive to said selection logic means for initiating suspension of said I/O operation in response to control signals from said controlling apparatus and resume suspended operation control means connected to said selection logic means, responsive to said selection logic means for initiating the resumption of a suspended I/O operation in response to a command from said controlling apparatus and signals received from said selection logic means.

Claim 11

For use with controlling apparatus capable of executing a start I/O instruction for initiating an I/O operation in a peripheral device, a peripheral device controller comprising in combination: suspend latch and control means; selection logic means adapted to connect said controller to said controlling apparatus for receiving commands and control signals from said controlling apparatus; command execution control means connected to said selection logic means responsive to commands from said controlling apparatus for effecting an I/O operation; said suspended latch and control means responsive to said selection logic means for initiating suspension of said I/O operation in response to control signals from said controlling apparatus and resume suspended operation control means connected to said selection logic means, responsive to said selection logic means for initiating the resumption of a suspended I/O operation in response to a command from said controlling apparatus and signals received from said selection logic means.

Claim 12

For use with controlling apparatus capable of executing a start I/O instruction for initiating an I/O operation in a peripheral device, a peripheral device controller comprising in combination: status generating means; suspend latch and control means; selection logic means adapted to connect said controller to said controlling apparatus for receiving commands and control signals from said controlling apparatus; command execution control means connected to said selection logic means responsive to commands from said controlling apparatus for effecting an I/O operation; means at said status generating means responsive to signals from said command execution control means and from said suspend latch and control means for indicating to said controlling apparatus the status of said peripheral device controller; said suspend latch and control means responsive to said selection logic means for initiating suspension of said I/O operation in response to control signals from said controlling apparatus and for setting zero status in said status generating means; resume suspended operation control means connected to said selection logic means, responsive to said selection logic means and a command from said controlling apparatus for initiative the resumption of a suspended operation in response to said command and signals received from said selection logic and sequence control means; and means connected to said status generating means and said selection logic means responsive to said selection logic means for supplying said status indicia to said controlling apparatus.

Claim 13

For use with controlling apparatus capable of executing a start I/O instruction for initiating an I/O operation in a peripheral device, a peripheral device controller comprising in combination: status generating means; suspend latch and control means; selection logic means adapted to connect said controller to said controlling apparatus for receiving commands and control signals from said controlling apparatus; command execution control means connected to said selection logic means responsive to commands from said controlling apparatus for effecting an I/O operation; means at said status generating means responsive to signals from said command execution control means and from said suspend latch and control means for indicating to said controlling apparatus the status of said peripheral device controller; said suspend latch and control means responsive to said selection logic means for initiating suspension of said I/O operation in response to control signals from said controlling apparatus and for setting zero status in said status generating means; resume suspended operation control means connected to said selection logic means, responsive to said selection logic means and a command from said controlling apparatus for initiative the resumption of a suspended operation in response to said command and signals received from said selection logic and sequence control means; and means connected to said status generating means and said selection logic means responsive to said selection logic means for supplying said status indicia to said controlling apparatus.