摘要:
When a disk controller receiving an access from a host computer to a disk device is connected with a disk connection device, if a relevant disk is used by another disk controller, positioning data for seek, set file mask and set sector are queued in a common memory. When the relevant disk becomes free, the disk controller reads the queued information and requires the disk device for positioning. A request of a reconnection with the host computer is issued from the disk controller informed by the disk unit, which has finished positioning at the position specified by the positioning data, search of an aimed record and a read/write operation of transmitted data are effected without any new intervening of an access program of the host computer.
摘要:
A method for controlling to keep off defects in a magnetic disk apparatus while has a plurality of magnetic disks and defect position information is recorded in each of tracks on each magnetic disk to keep off a defect in writing records in each track. Positional information about defects on all the tracks belonging to a cylinder of the magnetic disk apparatus is recorded in each of the tracks, and records are written in each of the tracks while keeping off the defects on the basis of the recorded positional information about the defects.
摘要:
In a control unit having a external storage device, a method for selecting a loading method of data stored in the cache memory into the cache memory in accordance with an access pattern to the data, and an apparatus therefor are disclosed. The selection of the loading method is selection of control mode or procedure in accordance with the loading method, and it is attained by a learn function.
摘要:
There is disclosed an error recovery apparatus and method for a data processing system having (1) a peripheral unit, for instance, a magnetic disc unit, for storing data in a plurality of blocks each having a unique address, (2) a main memory for storing data read from the peripheral units, and (3) a controller for controlling the transfer of the data blocks from the peripheral unit to the main memory by execution of a single channel command word (CCW) chain. When an uncorrectable error occurs in the transfer of a second or subsequent data block of the plurality of data blocks (not the first data block), the processor produces a new CCW chain to re-read the data block in error in addition to all the data blocks subsequent to the data blocking error and store these data blocks in the memory under the control of the new CCW chain.
摘要:
A method of emulating an original record format for a new rotating storage device, including the steps of;(a) determining an original angular position (.alpha.) of a record according to a first recording format;(b) determining a desirable angular position (.beta.) for recording according to a second recording format having a higher recording density than that of the first recording format;(c) subtracting the desirable angular position from the original angular position to obtain a difference between the angles (.alpha.-.beta.); and(d) incrementing a gap length immediately before the data field of the record when the angular position exceeds a value corresponding to one unit of segment.
摘要:
An interrupt control system having a plurality of access paths includes a control memory for storing control information for controlling all of the access paths. When an error occurs on a path, a control unit controlling the respective access paths refers to and updates the control memory to execute a channel reconnection without using the path on which the error has occurred, and then executes a retry command to carry out an error recovery operation.
摘要:
A control system for a disk cache memory is disposed between a main memory unit and a disk unit for storing a record of data from the disk unit. The control system is designed such that when an input/output instruction is issued from a CPU while data loading is being performed from the disk unit to the cache memory, it interrupts the data loading once so that an input/output instruction from the CPU can be executed, thereby considerably reducing the time of wait for execution of the input/output instruction.
摘要:
The present invention relates to a computer system having a disk cache unit between a disk unit and the main storage unit. Ordinarily, the data transfer processing is carried out between the disk unit and the disk cache unit and between the disk cache unit and the main storage unit in this case under control of a director. The present invention is characterized by enabling these two data transfer operations to be executed in parallel and to prevent the director from becoming the bottleneck of the processing due to the concentrated processing requests. For this purpose, the present invention provides for a data transfer between the disk cache unit and a disk unit while a data transfer is taking place between the main storage unit and the disk cache unit.
摘要:
An external memory device subsystem and a data recording device, which issue a command specifying a plurality of tracks (surfaces) in a rotary type memory device prior to a read or write instruction being issued from the data processing unit of higher rank to the rotary type memory device through a control unit; selects sequentially the plurality of individual tracks (surfaces) previously specified when executing a read or write command after the receipt of the command; and in this way can read/write continuously without wait time interruptions when data is discontinuous.
摘要:
An external memory device subsystem and a data recording device, which issue a command specifying previously a plurality of tracks in a rotary type memory device prior to a read or write instruction issued from the data processing unit of higher rank to the rotary type memory device through a control unit; select continuously the plurality of tracks previously specified, at executing a read or write command after the execution of the command; and in this way can read/write continuously without wait time for rotation a plurality of tracks distant from each other within the same cylinder.