Winfried W. Wilcke

Storage-class memory: the next storage system technology

The dream of replacing rotating mechanical storage, the disk drive, with solid-state, nonvolatile RAM may become a reality in the near future. Approximately ten new technologies--collectively called storage-class memory (SCM)--are currently under development and promise to be fast, inexpensive, and power efficient. Using SCM as a disk drive replacement, storage system products will have random and sequential I/O performance that is orders of magnitude better than that of comparable disk-based systems and require much less space and power in the data center. In this paper, we extrapolate disk and SCM technology trends to 2020 and analyze the impact on storage systems. The result is a 100- to 1,O00-fold advantage for SCM in terms of the data center space and power required.

Deactivation of carbon electrode for elimination of carbon dioxide evolution from rechargeable lithium–oxygen cells

Carbon has unfaired advantages in material properties to be used as electrodes. It offers a low cost, light weight cathode that minimizes the loss in specific energy of lithium-oxygen batteries as well. To date, however, carbon dioxide evolution has been an unavoidable event during the operation of non-aqueous lithium-oxygen batteries with carbon electrodes, due to the reactivity of carbon against self-decomposition and catalytic decomposition of electrolyte. Here we report a simple but potent approach to eliminate carbon dioxide evolution by using an ionic solvate of dimethoxyethane and lithium nitrate. We show that the solvate leads to deactivation of the carbon against parasitic reactions by electrochemical doping of nitrogen into carbon. This work demonstrates that one could take full advantage of carbon by mitigating the undesired activity.

IBM intelligent Bricks project: petabytes and beyond

This paper provides an overview of the Intelligent Bricks project in progress at IBM Research. It describes common problems faced by data center operators and proposes a comprehensive solution based on brick architectures. Bricks are hardware building blocks. Because of certain properties, defined here, scalable and reliable systems can be built with collections of identical bricks. An important feature is that brick-based systems must survive the failure of any brick without requiring human intervention, as long as most bricks are operational. This simplifies system management and allows very dense and very scalable systems to be built. A prototype storage server in the form of a 3 × 3 × 3 array of bricks, capable of storing 26 TB, is operational at the IBM Almaden Research Center. It successfully demonstrates the concepts of the Intelligent Bricks architecture. The paper describes this implementation of brick architectures based on newly developed communication and cooling technologies, the software developed, and techniques for building very reliable systems from low-cost bricks, and it discusses the performance and the future of intellegent brick systems.

Improved cycle efficiency of lithium metal electrodes in Li–O2 batteries by a two-dimensionally ordered nanoporous separator

We demonstrate a facile but very effective approach to improve the cycling efficiency of metallic lithium electrodes by controlling the pore morphology of separators. We employed anodized porous alumina as the model nanoporous separator and demonstrated the improvement of cycle efficiency of lithium electrodes in lithium–oxygen cells.

Reliability of modular mesh-connected intelligent storage brick systems

A key objective of the IBM Intelligent Bricks project is to create a highly reliable system from commodity components. We envision such systems to be architected for a service model called fail-in-place or deferred maintenance. By delaying service actions, possibly for the entire lifetime of the system, management of the system is simplified. This paper examines the hardware reliability and deferred maintenance of intelligent storage brick (ISB) systems assuming a mesh-connected collection of bricks in which each brick includes processing power, memory, networking, and storage. On the basis of Monte Carlo simulations, we quantify the fraction of bricks that become unusable by a distributed data redundancy scheme due to degrading internal bandwidth and loss of external host connectivity. We derive a system hardware reliability expression and predict the length of time ISB systems can operate without replacement of failed bricks. We also show via a Markov analysis the level of fault tolerance that is required by the data redundancy scheme to achieve a goal of less than two data loss events per exabyte-year due to multiple failures.

Percolation in dense storage arrays

As computers and their accessories become smaller, cheaper, and faster the providers of news, retail sales, and other services we now take for granted on the Internet have met their increasing computing needs by putting more and more computers, hard disks, power supplies, and the data communications linking them to each other and to the rest of the wired world into ever smaller spaces. This has created a new and quite interesting percolation problem. It is no longer desirable to fix computers, storage or switchgear which fail in such a dense array. Attempts to repair things are all too likely to make problems worse. The alternative approach, letting units “fail in place”, be removed from service and routed around, means that a data communications environment will evolve with an underlying regular structure but a very high density of missing pieces. Some of the properties of this kind of network can be described within the existing paradigm of site or bond percolation on lattices, but other important questions have not been explored. I will discuss 3D arrays of hundreds to thousands of storage servers (something which it is quite feasible to build in the next few years), and show that bandwidth, but not percolation fraction or shortest path lengths, is the critical factor affected by the “fail in place” disorder. Redundancy strategies traditionally employed in storage systems may have to be revised. Novel approaches to routing information among the servers have been developed to minimize the impact.

Toward Human-Scale Brain Computing Using 3D Wafer Scale Integration

The Von Neumann architecture, defined by strict and hierarchical separation of memory and processor, has been a hallmark of conventional computer design since the 1940s. It is becoming increasingly unsuitable for cognitive applications, which require massive parallel processing of highly interdependent data. Inspired by the brain, we propose a significantly different architecture characterized by a large number of highly interconnected simple processors intertwined with very large amounts of low-latency memory. We contend that this memory-centric architecture can be realized using 3D wafer scale integration for which the technology is nearing readiness, combined with current CMOS device technologies. The natural fault tolerance and lower power requirements of neuromorphic processing make 3D wafer stacking particularly attractive. In order to assess the performance of this architecture, we propose a specific embodiment of a neuronal system using 3D wafer scale integration; formulate a simple model of brain connectivity including short- and long-range connections; and estimate the memory, bandwidth, latency, and power requirements of the system using the connectivity model. We find that 3D wafer scale integration, combined with technologies nearing readiness, offers the potential for scaleup to a primate-scale brain, while further scaleup to a human-scale brain would require significant additional innovations.

The 800-km battery lithium-ion batteries are played out. Next up: lithium-air

Proposition: Electric cars will remain mostly niche products until they have a range of 800 kilometers, or roughly 500 miles, with an affordable battery. Thats as far as most people would want to drive in a day, and then they have all night to recharge. Thats how we came up with a figure of 800 km-or a nice round 500 miles-as the goal for our R&D project, Battery 500. It began in 2009 at the IBM Almaden Research Center, in San Jose, Calif., and has grown since then into a multinational partnership with commercial and academic participants in Europe, Asia, and the United States. It is based on metal-air technology, which packs far more energy into a battery of a given mass than todays state-of-the-art technology, the lithium-ion battery. We are still years away from commercialization, but we have made enough progress to predict that these batteries could be used in cars in the foreseeable future. Why are we so confident? Read on.