Hewlett-packard Development Company, L.p.

Compaq Computer Corporation, Inc.

Compaq Information Technologies Group, L.p.

Jerome J Johnson

Gary J Piccirillo

Robert A Lester

John Edward Larson

Phillip M Jones

Michael J Collins

John MacLaren

Kenneth T Chin

Benjamin H Clark

Clarence K Coffee

Christian H Post

Jeffery L Galloway

Patrick Lee Ferguson

Ho M Lai

Eric Rose

Jeffrey C Stevens

C Kevin Coffee

Siamak Tavallaei

Jeffrey S Autor

Tim W Majni

Anisha Anand

Bret D Roscoe

Dan Fink

Sompong Paul Olarig

Kenneth A Jansen

Paul A Santeler

Ronald Timothy Horan

Gregory N Santos

Clarence Coffee

A computer system includes a plurality of memory modules that contain semiconductor memory, such as DIMMs. The system includes a host/data controller that utilizes an XOR engine to store data and parity information in a striped fashion on the plurality of memory modules to create a redundant array of industry standard DIMMs (RAID). The host/data controller also interleaves data on a plurality of channels associated with each of the plurality of memory modules. The system implements error interrupt control, ECC error reporting, cartridge error power down procedures in response to command errors, storage of error information in unused segments of each DIMM, hot-pug procedure indicator and remote tagging capabilities of memory cartridges and DIMMs.

Error indication in a raid memory system

A computer system includes a plurality of memory modules that contain semiconductor memory, such as DIMMs. The system includes a host/data controller that utilizes an XOR engine to store data and parity information in a striped fashion on the plurality of memory modules to create a redundant array of industry standard DIMMs (RAID). The host/data controller also interleaves data on a plurality of channels associated with each of the plurality of memory modules. To optimize memory bandwidth and reduce memory latency, various techniques are implemented in the present RAID system. Present techniques include providing dual memory arbiters, sorting read cycles by chip select or bank address, providing programmable upper and lower boundary registers to facilitate programmable memory mapping, and striping and interleaving memory data to provide a burst length of one.

Memory latency and bandwidth optimizations

A computer system includes a plurality of memory modules that contain semiconductor memory, such as DIMMs. The system includes a host/data controller that utilizes an XOR engine to store data and parity information in a striped fashion on the plurality of memory modules to create a redundant array of industry standard DIMMs (RAID). The host/data controller also interleaves data on a plurality of channels associated with each of the plurality of memory modules.

Method for supporting multi-level striping of non-homogeneous memory to maximize concurrency

The control logic for a hot-pluggable memory cartridge for use in a redundant memory system. To implement a hot-pluggable memory cartridge in a redundant memory system, control logic to control the sequence of events for powering-up and powering-down a memory cartridge is provided.

Hot replace power control sequence logic

A technique for resynchronizing a memory system. More specifically, a technique for resynchronizing a plurality of memory segments in a redundant memory system after a hot-plug event. After a memory cartridge is hot-plugged into a system, the memory cartridge is synchronized with the operational memory cartridges such that the memory system can operate in lock step. A refresh counter in each memory cartridge is disabled to, generate a first refresh request to the corresponding memory segments in the memory cartridge. After waiting a period of time to insure that regardless of what state each memory cartridge is in when the first refresh request is initiated all cycles have been completely executed, each refresh counter is re-enabled, thereby generating a second refresh request. The generation of the second refresh request to each of the memory segments provides synchronous operation of each of the memory cartridges.

Memory module resync

A method of adding memory capacity to a computer system. The computer system comprises a redundant memory system including a plurality of memory cartridges. By powering-down a memory cartridge, adding an additional memory module to the memory cartridge, and powering-up the memory cartridge for each memory cartridge in the system, the system can transition from a redundant mode of operation to a non-redundant mode of operation for each power-down, thus allowing the computer system to remain functional during the addition of the memory module. Alternatively, memory cartridges with higher memory capacity than those currently present in the computer system can be used to replace existing memory cartridges in the computer system, using the same techniques.

Hot-upgrade/hot-add memory

A computer system includes a plurality of memory modules that contain semiconductor memory, such as DIMMs. The system includes a host/data controller that utilizes an XOR engine to store data and parity information in a striped fashion on the plurality of memory modules to create a redundant array of industry standard DIMMs (RAID). To optimally run back to back cycles to the memory modules, a technique for providing de-rating parameters such that unnecessary latencies designed into the memory devices can be removed while the system is executing requests. By removing any unnecessary latency, cycle time and overall system performance can be improved.

Memory auto-precharge

A system and technique for correcting data errors in a memory device. More specifically, data errors in a memory device are corrected by scrubbing the corrupted memory device. Generally, a host controller delivers a READ command to a memory controller. The memory controller receives the request and retrieves the data from a memory sub-system. The data is delivered to the host controller. If an error is detected, a scrub command is induced through the memory controller to rewrite the corrected data through the memory sub-system. Once a scrub command is induced, an arbiter schedules the scrub in the queue. Because a significant amount of time can occur before initial read in the scrub write back to the memory, an additional controller may be used to compare all subsequent READ and WRITE commands to those scrubs scheduled in the queue. If a memory location is rewritten with new data prior to scheduled scrub corresponding to the same address location, the controller will cancel the scrub to that particular memory location.

Real-time hardware memory scrubbing

Method for supporting multi-level stripping of non-homogeneous memory to maximize concurrency

A computer system includes a plurality of memory modules that contain semiconductor memory, such as DIMMs. The system includes a host/data controller that utilizes an XOR engine to store data and parity information in a striped fashion on the plurality of memory modules to create a redundant array of industry standard DIMMs (RAID). The system supports DIMMs having X4 and X8 configurations. The system also transitions between various states, including a redundant state and a non-redundant state, to facilitate &ldquo;hot-plug&rdquo; capabilities utilizing its removable memory cartridges.

Raid memory

A method of replacing a memory module in a computer system. Specifically, a method for replacing a memory module in a segment of a redundant memory system, without powering-down the memory system.

Hot-replace of memory

A technique for resynchronizing a memory system. More specifically, a technique for resynchronizing a plurality of memory segments in a redundant memory system after a hot-plug event. After a memory cartridge is hot-plugged into a system, the memory cartridge is synchronized with the operational memory cartridges such that the memory system can operate in lock step. A refresh counter in each memory cartridge is disabled to generate a first refresh request to the corresponding memory segments in the memory cartridge. After waiting a period of time to insure that regardless of what state each memory cartridge is in when the first refresh request is initiated all cycles have been completely executed, each refresh counter is re-enabled, thereby generating a second refresh request. The generation of the second refresh request to each of the memory segments provides synchronous operation of each of the memory cartridges.

Growing community of inventors

Spring, TX, United States of America

Jerome J Johnson