Fujitsu Corporation

Hitoshi Matsushima

Tohru Kobayashi

Shoichi Murano

Jun Ishikawa

Tadashi Kumasawa

Jun Katayama

A disk controlling apparatus creates sense data indicating the contents of an error and writes it into an intermediate buffer provided within the disk controlling apparatus together with the record normally read when a key portion or a data portion constituting a record is not normally read. The disk controlling apparatus searches the intermediate buffer for desired record, reads and informs an error while taking the sense data into consideration for each record. The disk controlling apparatus stores a write address in a memory at the time of writing data, and when data are normally written the write address is eliminated from the memory, while holding the address when data are not normally written. At the time of reading data, if the address which agrees with the read address is stored in the memory, the disk controlling apparatus reports an error to a host apparatus. The disk controlling apparatus further calculates the busy ratio indicating the rate at which each channel adapter is used for I/O processing, and data is transmitted and received to and from the host apparatus through the channel adapter which has the lowest busy ratio.

Disk controlling method and apparatus for transferring a record from a

The invention relates to a disk track emulation system and method, whereby, when a disk device is replaced by a new disk device having a disk track with a data format different from that of the conventional device, a program in a conventional host device can be used as it is, in the same way as in the conventional disk device, without reforming the program. To maintain the a compatibility, using the characteristic that the data format is divided by a unit called a cell having a constant number of bytes, and writing, into a home address area and a count area in the new data format, cell position data with the new data format, and compatible cell position data with respect to the conventional data format in which the compatibility should be maintained.

System and method for emulating disk tracks to maintain data format

A data transfer system in a device control apparatus for controlling data transfer between a channel of a central processing unit and a device, comprising: a channel transfer circuit for transferring data to the channel and for receiving data from the channel; a device transfer circuit for transferring data to the device and for receiving data from the device, and an intermediate memory for temporarily storing transfer data from the channel or from the device transfer circuit only when the transfer rate determined by the channel is different from the transfer rate determined by the device.

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Kawasaki, Japan

Hitoshi Matsushima