Supporting broad internet access to TACOMA
Supporting broad internet access to TACOMA
复制标题
支持对 TACOMA 的广泛互联网访问
DOI：
10.1145/504450.504461
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
F. Schneider
中科院分区：
文献类型：
--
作者：
D. Johansen;R. V. Renesse;F. Schneider
塔科马系统[JRS 95]为移动的进程或代理提供操作系统支持，这些进程或代理在完成某些任务时穿越网络主机。在一台主机上执行的塔科马代理通过使用TCP与目标主机上的塔科马软件通信而移动到另一台主机。假设塔科马软件已安装在任何可能启动或被代理访问的主机上。这种假设是值得怀疑的：·系统管理员不愿意安装允许任意导入软件（如代理）在其主机上执行的软件。而且，这种不情愿是有充分理由的。·他们是自治的。因此，即使不考虑安全问题，在大型网络中的大部分主机上安装一个非关键软件也是不切实际的。网络软件安装问题并不是代理或塔科马所独有的。如果软件必须安装在大型网络的自治站点上，则任何软件提供商都将面临这个问题。WWW软件通过因特网传播的速度是一个例外;分布式应用支持软件的设计师不应该计划以这种方式传播他们的系统。但是，这些架构师最好有一些计划，传播他们的系统，因为效用和成功的大型网络将取决于提供新的服务，在及时的方式。本文报告的经验，在解决网络软件安装问题的塔科马。然而，我们认为，所采用的技术在其他情况下也有用处。下一节概述塔科马及其当前支持的应用程序。第3节描述了一个基于WWW的计划，以避免在所有可能启动塔科马代理的站点安装软件;第4节讨论了一个基于电子邮件的计划。第5节最后提出了一个总结和一些意见。
The TACOMA system [JRS95] provides operating-system support for mobile processes, or agents, that traverse the hosts of a network in accomplishing some task. A TACOMA agent executing on one host moves to another host by using TCP to communicate with TACOMA software at the destination host. The presumption is that TACOMA software has been installed at any host that might launch or be visited by an agent. This presumption is questionable:• System managers are reluctant to install software that allows arbitrary imported software, like agents, to be executed on their hosts. And, there is good reason for this reluctance.• Hosts are autonomous. So, even were security not a concern, arranging for installation of a piece of non-critical software on a significant fraction of the hosts in a large network is impractical.The network-software installation-problem is not unique to agents or to TACOMA. Any provider of software will be faced with this problem if that software must be installed on autonomous sites of a large network. The speed with which WWW software spread through the Internet was an exception; architects of distributed-application support-software should not plan on having their systems disseminated in such a fashion. But, these architects better have some plan for disseminating their systems, since the utility and success of large networks will depend on offering new services in a timely way.This paper reports experiences in addressing the network-software installation-problem for TACOMA. However, we believe that the techniques employed have utility in other situations as well. The next section gives an overview of TACOMA and the applications it currently supports. Section 3 describes a WWW-based scheme for avoiding software installation at all sites that might launch TACOMA agents; section 4 discusses an email-based scheme. Section 5 concludes with a summary and some observations.