초록 ▼

A so-called “roll mode”technique provides block transfer with a disk-type of direct-access data-storage device (DASD). A set of chained commands for accessing record areas enables rapidly accessing a plurality of records within a given DASD cylinder of tracks. The rotational position of the surfaces

A so-called “roll mode”technique provides block transfer with a disk-type of direct-access data-storage device (DASD). A set of chained commands for accessing record areas enables rapidly accessing a plurality of records within a given DASD cylinder of tracks. The rotational position of the surfaces is checked. The command within the chain, irrespective of its location, having the closest logical rotational proximity to the instant rotational position of the surfaces is selected as the first command in the chain. The chain is executed beginning at the indicated rotational position selected command through the end of the chain and then wrapped to the beginning of the original chain and continuing on until the command immediately preceding the rotational position selected command has been executed.

대표청구항 ▼

A data-storage system adapted to be connected to a host processor and having a high-speed data cache and slow-speed backing store, means for transferring data signals between said data cache and backing store, said cache and store each having a large plurality of addressable data storage registers,

A data-storage system adapted to be connected to a host processor and having a high-speed data cache and slow-speed backing store, means for transferring data signals between said data cache and backing store, said cache and store each having a large plurality of addressable data storage registers, said backing store including a disk storage apparatus having a plurality of recording surfaces with a transducer head for each of the surfaces with one track of each surface being scanned by a respective transducer at a given instant, such tracks constituting a cylinder of data tracks, said apparatus having means for indicating rotational position of the data stored on the tracks with respect to said transducers; the improvement comprising: first means for receiving from said host and memorizing an intent signal signifying sequential data blocks and a storage extend for storing such blocks; data-transfer means for transferring data signals between said host and said cache and memorizing that blocks of data signals defined by said intent signal were transferred with the host; second means connected to said data-transfer means and being connectable to said host for receiving peripheral commands from said host and responsive to said intent signal and a request for any of said sequential blocks to actuate said data-transfer means for transferring data signals between said backing store and said data cache within all of such identified sequential blocks up to a predetermined maximum number of such identified sequential blocks; and means in said data-transfer means including internal command word (hereinafter termed ICW) chain means for establishing a series of commands for accessing predetermined ones of said blocks stored in tracks within one of said cylinders of data and arranging said commands into a chain of commands for transferring said predetermined ones of said blocks in a predetermined sequence; means for sensing the instant rotational position of said tracks of a first encountered block with respect to said heads and determining the rotational position of said first encountered block; means coupled to said sensing means and said ICW chain means for selecting a command in said chain of commands irrespective of its position in said sequence as the first command to be executed in accordance with the comparison of said rotational position and said expected rotational position of said predetermined ones of said blocks; and means coupled to said selecting means for executing the chain of commands beginning with said rotationally selected command through the end of the chain, thence to the beginning of the chain and to the command in said sequence that immediately precedes said rotationally selected command whereby a plurality of records within said cylinder on any of said tracks are accessed with a minimal latency delay due to rotation of said disk record surfaces.