1990年，东湾市政公用事业区在其主机上使用计算机辅助设计（CAD），但在个人电脑上使用其他应用程序，但与主机没有任何链接。这导致了严重的设计碎片、不可传输的数据、工作重复和硬件外围池分裂。需要设计一个计划，将个人计算机与现有的CAD环境集成。一个功能强大的PC网络，包括PC机、Macintoshes和大型机工作站，成为主要关注点。这种网络的开发需要使用OSI（开放系统互连）模型来促进跨平台连接。OSI模型可以简化，以演示开发PC网络所涉及的决策过程以及各种选项的选择。 本文自下而上讨论了个人计算机互连模型，包括以下几层:物理层、数据链路层、网络软件层。还分析了决策过程。特别注意复制大型机环境、Macintosh支持，以及允许和促进网络增长。问题包括PC发送的打印作业损坏、地板到地板的网络连接速度慢，以及由于布线问题导致的零星连接性能。

In 1990 the East Bay Municipal Utility District was using computer assisted design (CAD) on its mainframe, but other applications on personal computers without any link to the mainframe. This led to severe design fragmentation, nontransferable data, work duplication, and split hardware peripheral pools. A plan needed to be devised to integrate personal computers with the existing CAD environment. A very powerful PC network incorporating PCs, Macintoshes, and the mainframe workstations became the primary focus. The development of such a network required the use of the OSI (Open Systems Interconnection) Model to facilitate cross platform connectivity. The OSI model can be simplified to demonstrate the decision making process involved in developing a PC network and the selection of various options. The Personal Computer Interconnectivity model is discussed in this paper from the bottom up, including the following layers: physical, data link, network software. The decision making process is also analyzed. Special attention is paid to duplicating the mainframe environment, Macintosh support, and allowing and promoting network growth. Problems have included corruption of print jobs sent by PCs, slow floor-to- floor network links, and sporadic connection performance due to cabling problems.