ITR/SY: Center for Bits and Atoms

信息技术的规模化从其商业发展之初就一直是一个活跃的研究领域。包括[Moore， 79]和[Keyes， 87]在内的开创性研究确定了关键半导体器件参数持续指数级改进的可能性，以及保持这种速度需要克服的重大障碍。大量的智力和财政投入已经转化为整体系统性能的稳定改进，因此现在越来越多的计算机应用程序的资源限制越来越少。但在半导体行业协会（Semiconductor Industry Association）颇具影响力的路线图等预测中，通常忽略的是对整个扩展工作相关性的预测。对提高设备性能的狭隘关注忽视了计算机使用环境的重要性，这导致了非常现实的规模限制，这是进一步发展的最严重障碍之一。其中包括生产芯片和晶片厂的经济效益，以及设计和管理超大规模系统的难度。除了它们的实际意义之外，这些问题在所有信息技术中都提出了一些最深刻的研究问题，但它们是跨越传统学科界限的关键问题。最重要的是，不可能再保持硬件开发可以与软件开发完全分离的幻想。比特与原子中心是一个雄心勃勃的尝试，它汇集了同时研究信息内容及其物理特性所需的资源，从原子核到全球网络的长度尺度，试图弥合这一历史鸿沟。它的目标是开发适用于每一个描述级别的扩展信息技术的体系结构，并通过伙伴关系网络部署这些功能，以实现最大的全球影响。在此过程中，它试图从根本上重新审视什么是计算机，什么是计算的概念。CBA的计划是基于这样一种信念：在所有阻碍进步的障碍中，最重要的是将对每一个部分的调查与他们承诺实现的更大整体的调查隔离开来。研究议程按照可及性和重要性分为三个层次。第一个问题解决了系统级的问题，即如何将（相对）传统处理器的网络扩展到数十亿个交互实体之上。这种即将到来的复杂性是由无数的实际应用驱动的，但将打破现有的用于操作互联网的协议以及用于管理互联网的技术。这里采用的方法是将物理传输、逻辑连接和应用程序实现之间的划分“分层”，以便当设备连接时，它们同时创建网络、分布式数据结构和操作它的计算机。处理和路由信息的算法随着组件的组装而组装，并随着节点的来来去去而自主调整，因此随着系统的增长，可扩展性实际上是内置的。去分层还有利于将低级设备的功能暴露给高级应用程序（反之亦然），因此，诸如传感器网络之类的丰富接口可以成为常态，而不是例外。第二层是建立在这种系统级洞察力的基础上，询问能够满足将数十亿台计算机嵌入日常物品需求的技术。尽管几十年来每个晶体管的成本呈指数级下降，但每个封装部件的最低成本在整个VLSI缩放时代保持相对不变。为了使这样的大规模系统与全球GDP兼容，有必要从根本上重新思考设备制造的本质。CBA的方法将是寻求完全消除中央芯片工厂，使用桌面打印技术将计算机生产转移到需要的地方和时间。使这一切成为可能的最基本的洞察力是纳米晶体电子活性油墨的使用。这不仅有望大幅降低每个部件的成本，还提供了从大规模生产到计算机定制设计的途径，以及从2D到3D架构的发展途径。第三层（也是最具推测性的）是关于操纵信息的基本机制，这些信息将由这一议程实现。为了利用自然系统固有的计算能力，它寻求应用将发展到编程巨大的不完美的分布式系统和易于制造的纳米级结构的见解。这种方法的基础是相信，由于缺乏对适当的计算模型的洞察力，而不是缺乏实验候选，这些长期目标的进展受到了更多的限制；这项研究将建立在鼓励操纵分子系统动力学的早期工作的基础上。该计划将以两种方式为基础。首先，通过与合作伙伴合作，将结果（从预期的部署和管理超轻量级处理器网络的早期见解开始）应用到传统计算机无法实现的引人注目的计算应用程序中。第二，通过开发一个教学程序来帮助教育能够跨越传统硬件/软件边界进行推理的一代人，并能够为那些复杂行为来自许多简单元素相互作用的系统编程。

The scaling of information technology has been an active area of inquiry from the outset of its commercial development. Pioneering studies including those of [Moore, 79] and [Keyes, 87] identified the possibility of sustained exponential improvements in key semiconductor device parameters, as well as the significant obstacles that would need to be overcome to maintain such a pace. The enormous intellectual and financial investment into that effort has translated into steady improvements in overall system performance, so that now more and more computer applications are less and less resource-bound. But what's typically been missed in forecasts such as the Semiconductor Industry Association's influential roadmap is a projection of the relevance of the whole scaling effort. A narrow focus on improving device performance ignores the importance of the context in which computers are used, which is leading to very real scaling limits that are among the most serious obstacles to further progress. These include the economics of producing both chips and chip fabs, and the difficulty of designing and managing very large-scale systems. Beyond their practical significance, these issues present some of the most profound research questions in all of information technology, but they are questions that crucially cut across traditional discipline boundaries. Most importantly, it is no longer possible to maintain the fiction that developing hardware can be neatly separated from developing software. The Center for Bits and Atoms is an ambitious attempt to close this historical divide by bringing together the resources required to simultaneously study the content of information and its physical properties, on length scales from atomic nuclei to global networks. It aims to develop architectures for scaling information technology appropriate to each of these levels of description, and through a network of partnerships deploy these capabilities for the greatest global impact. Along the way, it seeks to fundamentally revisit the notion of what is a computer, and what is a computation. The CBA's program is based on the belief that the most significant of all the obstacles to progress has been the isolation of the investigation of each these pieces from that of the larger whole that they promise to enable. The research agenda is organized into three layers, in order of accessibility and importance. The first of these addresses system-level questions, asking how to extend networks of (relatively) conventional processors up to and beyond billions of interacting entities. Such coming complexity is being driven by countless practical applications, but will break the existing protocols used to operate the Internet as well as the techniques used for managing it. The approach taken here will be to "de-layer" the divisions between physical transport, logical connection, and application implementation, so that when devices are connected they simultaneously create a network, a distributed data structure, and the computer to manipulate it. The algorithms for processing and routing information are crucially assembled as the components are assembled, and autonomously adapt as nodes come and go, so that scalability is literally built in as the system grows. De-layering also beneficially exposes the capabilities of low-level devices to high-level applications (and vice versa), so that rich interfaces such as sensor networks can become the norm rather than the exception. The second layer builds on this system-level insight to ask about technologies to meet the demand for embedding billions of computers into everyday objects. Even though the cost per transistor has fallen exponentially for decades, the minimum cost per packaged part has remained relatively unchanged over the whole VLSI scaling era. For such large-scale systems to be compatible with the global GDP, it's necessary to fundamentally rethink the nature of device fabrication. The approach in the CBA will be to seek to eliminate central chip fabs entirely, using table-top printing technologies to move the production of computers to where and when they are needed. The fundamental enabling insight that makes this possible is the use of nanocrystalline electronically-active inks. Not only does this promise to dramatically reduce the cost per part, it offers a route from mass-production to the customization of the design of computers, as well as a way to grow from 2D to 3D architectures. The third (and most speculative) layer asks about the fundamental mechanisms for manipulating information that will be enabled by this agenda. It seeks to apply the insights that will be developed into programming enormous imperfect distributed systems and accessibly fabricating nanoscale structures in order to harness the intrinsic computational capabilities of natural systems. Fundamental to this approach is the conviction that progress towards these long-standing goals has been more limited by lack of insight into appropriate computational models than by a lack of experimental candidates; the research will build on encouraging early work on manipulating the dynamics of molecular systems. This program will be grounded in two ways. First, by working with partners to apply the results (starting with the expected early insights into deploying and managing networks of ultra-lightweight processors) to compelling applications of computing that have been beyond the reach of traditional computers. And second, by developing an instructional program to help educate a generation that can reason across the traditional hardware/software boundary, and can program systems whose complex behavior emerges from the interaction of many simple elements.