I/O control system and method

Claim 2

An I/O device control system comprising: a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate; a central processing unit; channel means coupled to said central processing unit for requesting operation of an I/O device designated by said central processing unit; I/O control means coupled to said channel means for controlling data transfer between said channel means and said I/O devices, said I/O control means responsive to a request by said channel means that one of said I/O devices be started for issuing a start request to start said one I/O device, said I/O control means including means for calculating a transfer completion time point at which said one I/O device will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and a known amount of data being transferred; and data transfer path means coupled between said I/O control means and I/O devices for transferring data between said channel means and said I/O devices, said data transfer path means being capable of transferring data for only a single I/O device at a time, said I/O control means including means responsive to a request by said channel means that another I/O device be started for starting said another I/O device at such a time that the starting of said another I/O device is completed at the calculated transfer completion time point of said one I/O device.

Claim 3

An I/O device control system according to claim 1, wherein each of said plurality of I/O devices includes a timer, and said I/O control means includes means for setting each of said timers so that at least one of said I/O devices is started after a lapse of a desired time.

Claim 4

An I/O device control system according to claim 2, wherein said I/O control means includes means for calculating a start time point at which said another I/O device is to be started based on the known starting time of said another I/O device and the calculated transfer completion time point of said one I/O device, said I/O control means including means for issuing the start request for said another I/O device via said data transfer path means to said another I/O device when said data transfer path means is not transferring data and said one I/O device has received the issued start request, the another start request setting the timer of said another I/O device for the calculated start time point.

Claim 5

An I/O device control system according to claim 2, further comprising a buffer coupled the said I/O control means for storing therein blocks of data which are successively read out from said I/O devices regardless of whether said data blocks have been requested by said channel means and for successively writing into said I/O devices other blocks of data which have been read out from said channel means and have been stored in said buffer.

Claim 6

An I/O device control system according to claim 4, wherein said known amount of data being transferred is determined such that at least one I/O device is under data transfer at all times during a period starting from the time that said one I/O device completes its data transfer and ending at the time that said one I/O device again starts its data transfer.

Claim 7

An I/O device control system according to claim 5, wherein the amount of each data block is defined by: Vn=4st/(n-1), where Vn is the amount of data in the data block, n is the number of active I/O devices and n≠1, s is the time required for starting an I/O device, and t is the data transfer rate of an I/O device.

Claim 8

An I/O device control system according to claim 1, further comprising means defining a control information path between said I/O control means and each I/O device, and wherein said I/O control means includes means for calculating the start time point of said another I/O device so as to complete the starting of said another I/O device at the calculated transfer completion time point, and means for issuing a start request to said another I/O device via said control information path at the calculated start time point.

Claim 9

An I/O device control system according to claim 7, further comprising a buffer coupled to said I/O control means for storing therein blocks of data which are successively read out from said I/O devices regardless of whether said data blocks have been requested by said channel means and for successively writing into said I/O devices other blocks of data which have been read out from said channel means and have been stored in said buffer.

Claim 10

An I/O device control system according to claim 8, wherein said known amount of data being transferred is determined such that at least one I/O device is under data transfer at all times during a period starting from the time that said one I/O device completes its data transfer and ending at the time that said one I/O device again starts its data transfer.

Claim 11

An I/O device control system according to claim 9 wherein the amount of each data block is defined by: Vn=4st/(n-1), where Vn is the amount of data in the data block, n is the number of active I/O devices and n≠1, s is the time required for starting an I/O device, and t is the data transfer rate of an I/O device.

Claim 12

A data transfer control system for an I/O system, comprising: a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer with a known starting time required for such off-line starting and with a known data transfer rate; a central processing unit; channel means coupled to said central processing unit for requesting operation of an I/O device designated by said central processing unit; I/O control means coupled to said channel means for controlling data transfer between said channel means and said I/O devices, said I/O control means responsive to a request by said channel means that one of said I/O devices be started for issuing a start request to start said one I/O device, said I/O control means including means for calculating a transfer completion time point at which said one I/O device will complete the data transfer, such calculation being based on the known starting time, the known data transfer rate, and a data transfer amount designated by said central processing unit; and data transfer path means coupled between said I/O control means and said I/O devices for transferring data between said channel means and said I/O devices, said data transfer path means being capable of transferring data for only a single I/O device at a time, said I/O control means including means for issuing a start request for starting another I/O device via said data transfer path means during a time period between (a) a data transfer preceeding a data transfer involving said one I/O device and (b) the data transfer involving said one I/O device, in which time period said data transfer path means is not transferring data.

Claim 13

A data transfer control system for an I/O system, comprising: a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer with a known starting time required for such off-line starting and with a known data transfer rate; a central processing unit; channel means coupled to said central processing unit for requesting operation of an I/O device designated by said central processing unit; I/O control means coupled to said channel means for controlling data transfer between said channel means and said I/O devices, said I/O control means responsive to a request by said channel means that one of said I/O devices be started for issuing a start request to start said one I/O device, said I/O control means including means for calculating a transfer completion time point at which said one I/O device will complete the data transfer, such calculation being based on the known starting time, the known data transfer rate, and a data transfer amount designated by said central processing unit; and data transfer path means coupled between said I/O control means and said I/O devices for transferring data between said channel means and said I/O devices, said data transfer path means being capable of transferring data for only a single I/O device at a time, said I/O control means including means for issuing a start request for starting another I/O device via said data transfer path means during a time period between (a) a data transfer preceeding a data transfer involving said one I/O device and (b) the data transfer involving said one I/O device, in which time period said data transfer path means is not transferring data.

Claim 14

An I/O control unit for controlling data transfer via a data transfer path and controlling a plurality of I/O devices, each I/O device having a starting time required for starting of the I/O device, all the starting times being a constant, said I/O control unit comprising: processor means for performing a data transfer process and controlling the driving of the I/O devices; a clock for indicating current time; management information storage means for storing information identifying a time point at which the data transfer path is released from data transfer and identifying the starting times required for starting of the I/O devices; said processor means including means responsive to an I/O request from one of the I/O devices for calculating a start time point of the one I/O device and for issuing a start request to the one I/O device at the calculated start time point, the calculated start time point being based on the identified time point at which the data transfer path is released from data transfer, the current time, and the identified starting time required for starting of one I/O device, whereby following the data transfer completion of another I/O device under data transfer, data transfer for the one I/O device can be started.

Claim 15

An I/O control unit for controlling data transfer via a data transfer path and controlling a plurality of I/O devices, each I/O device having a starting time required for starting of the I/O device, all the starting times being a constant, said I/O control unit comprising: processor means for performing a data transfer process and controlling the driving of the I/O devices; a clock for indicating current time; management information storage means for storing information identifying a time point at which the data transfer path is released from data transfer and identifying the starting times required for starting of the I/O devices; said processor means including means responsive to an I/O request from one of the I/O devices for calculating a start time point of the one I/O device and for issuing a start request to the one I/O device at the calculated start time point, the calculated start time point being based on the identified time point at which the data transfer path is released from data transfer, the current time, and the identified starting time required for starting of one I/O device, whereby following the data transfer completion of another I/O device under data transfer, data transfer for the one I/O device can be started.

Claim 16

An I/O control unit according to claim 12, further comprising a plurality of I/O devices, each of said I/O devices including a timer; and wherein said processor means, issues the start request to the one I/O device while the data transfer path is not transferring data and sets timer of the one I/O device at the calculated start time point.

Claim 17

An I/O control unit according to claim 12, further comprising a plurality of I/O devices, and means defining a control information path between said control unit and said plurality of I/O devices; and wherein said processor means further comprises a timer, means for setting said timer to the calculated start time point, and means for issuing the start request to the one I/O device through said control information path.

Claim 18

An I/O control unit according to claim 12 wherein said processor means includes means for updating the identified time point based on the data transfer time of the I/O devices.

Claim 19

An I/O control unit for controlling an I/O system including a plurality of I/O devices, each I/O device having a timer and having a starting time required for starting of the I/O device, all the starting times being a constant; a buffer coupled to said I/O control unit; a central processing unit; a channel coupled to the central processing unit and to said I/O control unit to access an I/O device designated by the central processing unit; and a data transfer path connecting said I/O control unit with the I/O devices, the data transfer path adapted to allow only one I/O device to be coupled to said I/O control unit at a time; said I/O control unit comprising: first processor means for controlling data transfer between the channel and the buffer; second processor means for controlling data transfer between the buffer and each I/O device; I/O management information storage means for storing information on the I/O devices; buffer management information storage means for storing information on a time point at which the data transfer path is released from data transfer, the number of active I/O devices, and the amount of empty buffer space in the buffer; said first processor means including means responsive to transfer of data between the channel and the buffer for updating the empty buffer space amount and the number of active I/O devices; and means for calculating the amount of data to be loaded from the I/O devices to the buffer and the amount of data to be written in the I/O devices from the buffer; and said second processor means including means for determining the amount of data to be transferred between the buffer and the I/O devices; means for calculating, on the basis of the determined amount, a transfer time point at which the data transfer path is to be released from data transfer; means for updating the stored time point information based on the calculated transfer time point; means for calculating a start time point for one I/O device to which data is to be transferred based on said determined amount; and means for setting the calculated start time point in the timer of the one I/O device.

Claim 20

An I/O control unit for controlling an I/O system including a plurality of I/O devices, each I/O device having a timer and having a starting time required for starting of the I/O device, all the starting times being a constant; a buffer coupled to said I/O control unit; a central processing unit; a channel coupled to the central processing unit and to said I/O control unit to access an I/O device designated by the central processing unit; and a data transfer path connecting said I/O control unit with the I/O devices, the data transfer path adapted to allow only one I/O device to be coupled to said I/O control unit at a time; said I/O control unit comprising: first processor means for controlling data transfer between the channel and the buffer; second processor means for controlling data transfer between the buffer and each I/O device; I/O management information storage means for storing information on the I/O devices; buffer management information storage means for storing information on a time point at which the data transfer path is released from data transfer, the number of active I/O devices, and the amount of empty buffer space in the buffer; said first processor means including means responsive to transfer of data between the channel and the buffer for updating the empty buffer space amount and the number of active I/O devices; and means for calculating the amount of data to be loaded from the I/O devices to the buffer and the amount of data to be written in the I/O devices from the buffer; and said second processor means including means for determining the amount of data to be transferred between the buffer and the I/O devices; means for calculating, on the basis of the determined amount, a transfer time point at which the data transfer path is to be released from data transfer; means for updating the stored time point information based on the calculated transfer time point; means for calculating a start time point for one I/O device to which data is to be transferred based on said determined amount; and means for setting the calculated start time point in the timer of the one I/O device.

Claim 21

An I/O device control system comprising: (a) a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate; (b) channel means for requesting operation of an I/O device; (c) a buffer; and (d) I/O control means coupled to said channel means, to said buffer and to said I/O devices, for controlling data transfer between said I/O devices and said buffer and between said buffer and said channel means, said I/O control means including: (1) means for storing blocks of data which are successively read out from said I/O devices into said buffer regardless of whether said data blocks have been requested by said channel means, and for successively writing into said I/O devices other blocks of data which have been read out from said channel means and have been stored in said buffer; (2) means for calculating a transfer completion time point at which one of said I/O devices will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and a known amount of data being transferred; and (3) means for starting another I/O device at such a time that the starting of said another I/O device is completed not earlier than the calculated transfer completion time point of said one I/O device.

Claim 22

An I/O device control system comprising: (a) a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate; (b) channel means for requesting operation of an I/O device; (c) a buffer; and (d) I/O control means coupled to said channel means, to said buffer and to said I/O devices, for controlling data transfer between said I/O devices and said buffer and between said buffer and said channel means, said I/O control means including: (1) means for storing blocks of data which are successively read out from said I/O devices into said buffer regardless of whether said data blocks have been requested by said channel means, and for successively writing into said I/O devices other blocks of data which have been read out from said channel means and have been stored in said buffer; (2) means for calculating a transfer completion time point at which one of said I/O devices will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and a known amount of data being transferred; and (3) means for starting another I/O device at such a time that the starting of said another I/O device is completed not earlier than the calculated transfer completion time point of said one I/O device.

Claim 23

An I/O device control system according to claim 17, wherein said I/O control means further includes means for starting one of said I/O devices when none of said I/O devices is starting or transferring data.

Claim 24

An I/O device control system comprising: (a) a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate: (b) a central processing unit; (c) channel means coupled to said central processing unit for requesting operation of an I/O device designated by said central processing unit; and (d) I/O control means coupled to said channel means and to said I/O devices for controlling data transfer between said I/O devices and said channel means, said I/O control means responsive to a request by said channel means that one of said I/O devices be started for issuing a start request to start said one I/O device, said I/O control means including: (1) means for calculating a transfer completion time point at which said one I/O device will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and a known amount of data being transferred; and (2) means responsive to a request by said channel means that another I/O device be started for starting said another I/O device at such a time that the starting of said another I/O device is completed not earlier than the calculated transfer completion time point of said one I/O device.

Claim 25

An I/O device control system comprising: (a) a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate: (b) a central processing unit; (c) channel means coupled to said central processing unit for requesting operation of an I/O device designated by said central processing unit; and (d) I/O control means coupled to said channel means and to said I/O devices for controlling data transfer between said I/O devices and said channel means, said I/O control means responsive to a request by said channel means that one of said I/O devices be started for issuing a start request to start said one I/O device, said I/O control means including: (1) means for calculating a transfer completion time point at which said one I/O device will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and a known amount of data being transferred; and (2) means responsive to a request by said channel means that another I/O device be started for starting said another I/O device at such a time that the starting of said another I/O device is completed not earlier than the calculated transfer completion time point of said one I/O device.

Claim 26

An I/O device control system according to claim 19, wherein said I/O control means further includes means for starting one of said I/O devices when none of said I/O devices is starting or transferring data.

Claim 27

An I/O device control system comprising: (a) a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate; (b) channel means for requesting operation of an I/O device; (c) a buffer; and (d) I/O control means coupled to said channel means, to said buffer and to said I/O devices, for controlling data transfer between said I/O devices and said buffer and between said buffer and said channel means, said I/O control means including: (1) means for storing blocks of data which are successively read out from said I/O devices into said buffer regardless of whether said data blocks have been requested by said channel means, and for successively writing into said I/O devices other blocks of data which have been read out from said channel means and have been stored in said buffer; (2) means for calculating a transfer completion time point at which one of said I/O devices will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and an expected amount of data being transferred; and (3) means for starting another I/O device at such a time that the starting of said another I/O device is completed not earlier than the calculated transfer completion time point of said one I/O device.

Claim 28

An I/O device control system comprising: (a) a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate; (b) channel means for requesting operation of an I/O device; (c) a buffer; and (d) I/O control means coupled to said channel means, to said buffer and to said I/O devices, for controlling data transfer between said I/O devices and said buffer and between said buffer and said channel means, said I/O control means including: (1) means for storing blocks of data which are successively read out from said I/O devices into said buffer regardless of whether said data blocks have been requested by said channel means, and for successively writing into said I/O devices other blocks of data which have been read out from said channel means and have been stored in said buffer; (2) means for calculating a transfer completion time point at which one of said I/O devices will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and an expected amount of data being transferred; and (3) means for starting another I/O device at such a time that the starting of said another I/O device is completed not earlier than the calculated transfer completion time point of said one I/O device.

Claim 29

An I/O device control system comprising: (a) a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate: (b) a central processing unit; (c) channel means coupled to said central processing unit for requesting operation of an I/O device designated by said central processing unit; and (d) I/O control means coupled to said channel means and to said I/O devices for controlling data transfer between said I/O devices and said channel means, said I/O control means responsive to a request by said channel means that one of said I/O devices be started for issuing a start request to start said one I/O device, said I/O control means including: (1) means for calculating a transfer completion time point at which said one I/O device will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and an expected amount of data being transferred; and (2) means responsive to a request by said channel means that another I/O device be started for starting said another I/O device at such a time that the starting of said another I/O device is completed not earlier than the calculated transfer completion time point of said one I/O device.

Claim 30

An I/O device control system comprising: (a) a plurality of I/O devices, each I/O device being adapted for off-line starting and for data transfer, with a known starting time required for such off-line starting and with a known data transfer rate: (b) a central processing unit; (c) channel means coupled to said central processing unit for requesting operation of an I/O device designated by said central processing unit; and (d) I/O control means coupled to said channel means and to said I/O devices for controlling data transfer between said I/O devices and said channel means, said I/O control means responsive to a request by said channel means that one of said I/O devices be started for issuing a start request to start said one I/O device, said I/O control means including: (1) means for calculating a transfer completion time point at which said one I/O device will complete data transfer, such calculation being based on the known starting time, the known data transfer rate, and an expected amount of data being transferred; and (2) means responsive to a request by said channel means that another I/O device be started for starting said another I/O device at such a time that the starting of said another I/O device is completed not earlier than the calculated transfer completion time point of said one I/O device.