OpenDoc - Problems

Problems

OpenDoc's flexibility came at a cost. OpenDoc components were invariably large and slow. For instance, opening a simple text editor part would often require 2 megabytes of RAM or more, whereas the same editor written as a standalone application could be as small as 32 KB. This initial overhead became less important as the number of documents open increased, since the basic cost was for shared libraries which implemented the system, but it was large compared to entry level machines of the day. Many developers felt that the extra overhead was too large, and since the operating system did not include OpenDoc capability, the memory footprint of their OpenDoc based applications appeared unacceptably large. In absolute terms, the one-time library overhead was approximately 1 megabyte of RAM, at the time half of a low-end desktop computer's entire RAM complement.

Another issue was that OpenDoc had little in common with most "real world" document formats, and so OpenDoc documents could really only be used by other OpenDoc machines. Although one would expect some effort to allow the system to export to other formats, this was often impractical because each component held its own data. For instance, it took significant effort for the system to be able to turn a text file with some pictures into a Microsoft Word document, both because the text editor had no idea what was in the embedded objects, and because the proprietary Microsoft format was undocumented and required reverse engineering.

Another problem was the fact that each part saved its data within Bento (the former name of an OpenDoc compound document file format) in its own internal binary format, and it was very common to find one component could not open a document created by another, even though the internal data represented similar objects (spreadsheet data for instance). OpenDoc attempted to solve this problem by allowing developers to store multiple formats to represent the same document object. For instance, it was both possible and encouraged to store a common format like JPEG along with editable binary format, but in practice few developers followed this recommendation. This problem was not unique to OpenDoc, and in fact was also experienced by the Microsoft equivalent, Object Linking and Embedding (OLE). Indeed, many years later, XML documents which attempt to perform embedding of other XML formats also encounter similar issues.

It also appears that OpenDoc was a victim of an oversold concept, that of compound documents. A few specific examples are common, for instance most word processors and page layout programs include the ability to include graphics, and spreadsheets are expected to handle charts. Yet beyond that it seems there aren't all that many other examples.

But certainly the biggest problem with the project was that it was part of a very acrimonious competition between OpenDoc consortium members and Microsoft. The members of the OpenDoc alliance were all trying to obtain traction in a market rapidly being dominated by Microsoft Office. As the various partners all piled in their own pet technologies in hopes of making it an industry standard, OpenDoc grew increasingly unwieldy. At the same time, Microsoft used the synergy between the OS and applications divisions of the company to make it effectively mandatory that developers adopt the competing OLE technology. In order to obtain a Windows 95 compliance logo from Microsoft, one had to meet certain interoperability tests which were quite difficult to meet without adoption of OLE technology, even though the technology was largely only useful in integrating with Microsoft Office. OpenDoc was forced to create an interoperability layer in order to allow developers to even consider adoption, and this added a great technical burden to the project.