International Business Machines Corporation

Jack E Reeder

Patrick Allen Buckland

John W Irwin

Gary Robert Lyons

A new drive installation to a multiple drive, drive group begins with a start command issued by the drive group controller to a new drive. The command is then propagated to every other drive. A successful completion reply is propagated back to the first drive and then to the controller. The controller transfers managing control to the new drive and the new drive reads the first data segment it needs; i.e., in a sixth drive addition to a five drive group, this is data segment six on drive one. The segment read by the new drive (drive six) is placed in the segment stack on the first drive (segment six of Drive,is read and Drive,places segment six on its segment stack). The process is repeated with each drive in the RAID device, in order. All drives consider their segment stack to determine if they have locations to read. As a segment is read on a drive, the segment is placed into the drive's segment stack and removed from the source drive as the segment is written to the target drive. After a few operations, multiple drives are reading and writing segments to target drives in parallel. The access to the controller is minimal and the functions are taking place in parallel, thereby reducing the drive group transactions with the controller and speeding up the installation process.

Method and apparatus for reducing processor operations when adding a new drive to a raid-6 drive group

A method and system for controlling the display of data in a data processing system that includes a main processor, a memory subsystem, and an Input/Output subsystem which includes an I/O Channel Controller for managing traffic on an I/O bus having an attached co-processor and a plurality of I/O devices including display devices with different reserved I/O address space. The main processor can establish different display modes for displays having different reserved I/O address space, which generally indicates different display types. In one mode, a display is assigned exclusively to the main processor and attempted data transfers by the co-processor to that display are suppressed. In a second mode, a display is time-shared between processors by establishing a virtual video buffer in main memory which is written into by one processor when the other processor has control of the display device. The contents of the virtual and real buffer are swapped whenever the display is reassigned to the other processor. In the third mode, co-processor data in the virtual buffer can be 'windowed' onto the display device when it is assigned to the main processor. In the fourth mode, a display assigned to the co-processor displays data being run by code that is written to the displayed on a display device with a different pel resolution. The main processor does a pel conversion operation on the data in the process of transferring the data from the virtual buffer to the real buffer.

Logical arrangement for controlling use of different system displays by

A method and system for controlling the display of data in a data processing system that includes a main processor, a memory subsystem, and an Input/Output subsystem which includes an I/O Channel Controller for managing traffic on an I/O bus having an attached co-processor and a plurality of I/O devices including display devices with different reserved I/O address space. The main processor can establish different display modes for displays having different reserved I/O address space, which generally indicates different display types. In one mode, a display is assigned exclusively to the main processor and attempted data transfers by the co-processor to that display are suppressed. The display control means is based on logic circuitry associated with the co-processor for trapping instructions having addresses within the range of those reserved for the display devices. The logic enables normal writes and reads to the video buffer to be suppressed or relocated to the virtual buffer, depending on the mode established by the main processor. A circular queue is established in memory to enable the main processor to selectively individually update the video buffer with the changes that have been made to the virtual buffer.

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Round Rock, TX, United States of America

Jack E Reeder