Workshop on Electronic Texts · Library of Congress
SESSION V. APPROACHES TO PREPARING ELECTRONIC TEXTS
HOCKEY urged the need to look at ways of using markup to facilitate retrieval, not just for referencing or to help locate an item that is retrieved, but also to put markup tags in a text to help retrieve the thing sought either with linguistic tagging or interpretation. HOCKEY also argued that little advancement had occurred in the software tools currently available for retrieving and searching text. She pressed the desideratum of going beyond Boolean searches and performing more sophisticated searching, which the insertion of more markup in the text would facilitate. Thinking about electronic texts as opposed to images means considering material that will never appear in print form, or print will not be its primary form, that is, material which only appears in electronic form. HOCKEY alluded to the history and the need for markup and tagging and electronic text, which was developed through the use of computers in the humanities; as MICHELSON had observed, Father Busa had started in 1949 to prepare the first-ever text on the computer. HOCKEY remarked several large projects, particularly in Europe, for the compilation of dictionaries, language studies, and language analysis, in which people have built up archives of text and have begun to recognize the need for an encoding format that will be reusable and multifunctional, that can be used not just to print the text, which may be assumed to be a byproduct of what one wants to do, but to structure it inside the computer so that it can be searched, built into a Hypertext system, etc.
Project ADAPT, then, which OCLC completed a couple of years ago and in fact is about to resume, is a model in which one takes page images either in paper or microfilm and converts them automatically to a searchable electronic database, either on-line or local. The operating assumption is that accepting some blemishes in the data, especially for retroconversion of materials, will make it possible to accomplish more. Not enough money is available to support perfect conversion. WEIBEL related several steps taken to perform image preprocessing (processing on the image before performing optical character recognition), as well as image postprocessing. He denied the existence of intelligent character recognition and asserted that what is wanted is page recognition, which is a long way off. OCLC has experimented with merging of multiple optical character recognition systems that will reduce errors from an unacceptable rate of 5 characters out of every l,000 to an unacceptable rate of 2 characters out of every l,000, but it is not good enough. It will never be perfect. Concerning the CORE Project, WEIBEL observed that Bellcore is taking the topography files, extracting the page images, and converting those topography files to SGML markup. LESK hands that data off to OCLC, which builds that data into a Newton database, the same system that underlies the on-line system in virtually all of the reference products at OCLC. The long-term goal is to make the systems interoperable so that not just Bellcore's system and OCLC's system can access this data, but other systems can as well, and the key to that is the Z39.50 common command language and the full-text extension. Z39.50 is fine for MARC records, but is not enough to do it for full text (that is, make full texts interoperable).
WEIBEL next outlined the critical role of SGML for a variety of purposes, for example, as noted by HOCKEY, in the world of extremely large databases, using highly structured data to perform field searches. WEIBEL argued that by building the structure of the data in (i.e., the structure of the data originally on a printed page), it becomes easy to look at a journal article even if one cannot read the characters and know where the title or author is, or what the sections of that document would be. OCLC wants to make that structure explicit in the database, because it will be important for retrieval purposes. The second big advantage of SGML is that it gives one the ability to build structure into the database that can be used for display purposes without contaminating the data with instructions about how to format things. The distinction lies between procedural markup, which tells one where to put dots on the page, and descriptive markup, which describes the elements of a document.
WEIBEL believes that there should be no procedural markup in the data at all, that the data should be completely unsullied by information about italics or boldness. That should be left up to the display device, whether that display device is a page printer or a screen display device. By keeping one's database free of that kind of contamination, one can make decisions down the road, for example, reorganize the data in ways that are not cramped by built-in notions of what should be italic and what should be bold. WEIBEL strongly advocated descriptive markup. As an example, he illustrated the index structure in the CORE data. With subsequent illustrated examples of markup, WEIBEL acknowledged the common complaint that SGML is hard to read in its native form, although markup decreases considerably once one gets into the body. Without the markup, however, one would not have the structure in the data. One can pass markup through a LaTeX processor and convert it relatively easily to a printed version of the document. WEIBEL next illustrated an extremely cluttered screen dump of OCLC's system, in order to show as much as possible the inherent capability on the screen. (He noted parenthetically that he had become a supporter of X-Windows as a result of the progress of the CORE Project.) WEIBEL also illustrated the two major parts of the interface: l) a control box that allows one to generate lists of items, which resembles a small table of contents based on key words one wishes to search, and 2) a document viewer, which is a separate process in and of itself. He demonstrated how to follow links through the electronic database simply by selecting the appropriate button and bringing them up. He also noted problems that remain to be accommodated in the interface (e.g., as pointed out by LESK, what happens when users do not click on the icon for the figure).
Given the constraints of time, WEIBEL omitted a large number of ancillary items in order to say a few words concerning storage requirements and what will be required to put a lot of things on line. Since it is extremely expensive to reconvert all of this data, especially if it is just in paper form (and even if it is in electronic form in typesetting tapes), he advocated building journals electronically from the start. In that case, if one only has text graphics and indexing (which is all that one needs with de novo electronic publishing, because there is no need to go back and look at bit-maps of pages), one can get 10,000 journals of full text, or almost 6 million pages per year. These pages can be put in approximately 135 gigabytes of storage, which is not all that much, WEIBEL said. For twenty years, something less than three terabytes would be required. WEIBEL calculated the costs of storing this information as follows: If a gigabyte costs approximately $1,000, then a terabyte costs approximately $1 million to buy in terms of hardware. One also needs a building to put it in and a staff like OCLC to handle that information. So, to support a terabyte, multiply by five, which gives $5 million per year for a supported terabyte of data.
The recognition that all representation is encoding, SPERBERG-McQUEEN argued, leads to the recognition of two things: 1) The topic description for this session is slightly misleading, because there can be no discussion of pros and cons of text-coding unless what one means is pros and cons of working with text with computers. 2) No text can be represented in a computer without some sort of encoding; images are one way of encoding text, ASCII is another, SGML yet another. There is no encoding without some information loss, that is, there is no perfect reproduction of a text that allows one to do away with the original. Thus, the question becomes, What is the most useful representation of text for a serious work? This depends on what kind of serious work one is talking about. The projects demonstrated the previous day all involved highly complex information and fairly complex manipulation of the textual material. In order to use that complicated information, one has to calculate it slowly or manually and store the result. It needs to be stored, therefore, as part of one's representation of the text. Thus, one needs to store the structure in the text. To deal with complicated representations of text, one needs somehow to control the complexity of the representation of a text; that means one needs a way of finding out whether a document and an electronic representation of a document is legal or not; and that means one needs a grammar of documents.
SPERBERG-McQUEEN discussed the variety of forms of formal grammars, implicit and explicit, as applied to text, and their capabilities. He argued that these grammars correspond to different models of text that different developers have. For example, one implicit model of the text is that there is no internal structure, but just one thing after another, a few characters and then perhaps a start-title command, and then a few more characters and an end-title command. SPERBERG-McQUEEN also distinguished several kinds of text that have a sort of hierarchical structure that is not very well defined, which, typically, corresponds to grammars that are not very well defined, as well as hierarchies that are very well defined (e.g., the Thesaurus Linguae Graecae) and extremely complicated things such as SGML, which handle strictly hierarchical data very nicely. SPERBERG-McQUEEN conceded that one other model not illustrated on his two displays was the model of text as a bit-mapped image, an image of a page, and confessed to having been converted to a limited extent by the Workshop to the view that electronic images constitute a promising, probably superior alternative to microfilming. But he was not convinced that electronic images represent a serious attempt to represent text in electronic form. Many of their problems stem from the fact that they are not direct attempts to represent the text but attempts to represent the page, thus making them representations of representations.
In this situation of increasingly complicated textual information and the need to control that complexity in a useful way (which begs the question of the need for good textual grammars), one has the introduction of SGML. With SGML, one can develop specific document-type declarations for specific text types or, as with the TEI, attempts to generate general document-type declarations that can handle all sorts of text. The TEI is an attempt to develop formats for text representation that will ensure the kind of reusability and longevity of data discussed earlier. It offers a way to stay alive in the state of permanent technological revolution. It has been a continuing challenge in the TEI to create document grammars that do some work in controlling the complexity of the textual object but also allowing one to represent the real text that one will find. Fundamental to the notion of the TEI is that TEI conformance allows one the ability to extend or modify the TEI tag set so that it fits the text that one is attempting to represent. SPERBERG-McQUEEN next outlined the administrative background of the TEI. The TEI is an international project to develop and disseminate guidelines for the encoding and interchange of machine-readable text. It is sponsored by the Association for Computers in the Humanities, the Association for Computational Linguistics, and the Association for Literary and Linguistic Computing. Representatives of numerous other professional societies sit on its advisory board. The TEI has a number of affiliated projects that have provided assistance by testing drafts of the guidelines.
Among the design goals for the TEI tag set, the scheme first of all must meet the needs of research, because the TEI came out of the research community, which did not feel adequately served by existing tag sets. The tag set must be extensive as well as compatible with existing and emerging standards. In 1990, version 1.0 of the Guidelines was released (SPERBERG-McQUEEN illustrated their contents). SPERBERG-McQUEEN noted that one problem besetting electronic text has been the lack of adequate internal or external documentation for many existing electronic texts. The TEI guidelines as currently formulated contain few fixed requirements, but one of them is this: There must always be a document header, an in-file SGML tag that provides 1) a bibliographic description of the electronic object one is talking about (that is, who included it, when, what for, and under which title); and 2) the copy text from which it was derived, if any. If there was no copy text or if the copy text is unknown, then one states as much. Version 2.0 of the Guidelines was scheduled to be completed in fall 1992 and a revised third version is to be presented to the TEI advisory board for its endorsement this coming winter. The TEI itself exists to provide a markup language, not a marked-up text. Among the challenges the TEI has attempted to face is the need for a markup language that will work for existing projects, that is, handle the level of markup that people are using now to tag only chapter, section, and paragraph divisions and not much else. At the same time, such a language also will be able to scale up gracefully to handle the highly detailed markup which many people foresee as the future destination of much electronic text, and which is not the future destination but the present home of numerous electronic texts in specialized areas.
SPERBERG-McQUEEN dismissed the lowest-common-denominator approach as unable to support the kind of applications that draw people who have never been in the public library regularly before, and make them come back. He advocated more interesting text and more intelligent text. Asserting that it is not beyond economic feasibility to have good texts, SPERBERG-McQUEEN noted that the TEI Guidelines listing 200-odd tags contains tags that one is expected to enter every time the relevant textual feature occurs. It contains all the tags that people need now, and it is not expected that everyone will tag things in the same way. The question of how people will tag the text is in large part a function of their reaction to what SPERBERG-McQUEEN termed the issue of reproducibility. What one needs to be able to reproduce are the things one wants to work with. Perhaps a more useful concept than that of reproducibility or recoverability is that of processability, that is, what can one get from an electronic text without reading it again in the original. He illustrated this contention with a page from Jan Comenius's bilingual Introduction to Latin.
SPERBERG-McQUEEN returned at length to the issue of images as simulacra for the text, in order to reiterate his belief that in the long run more than images of pages of particular editions of the text are needed, because just as second-generation photocopies and second-generation microfilm degenerate, so second-generation representations tend to degenerate, and one tends to overstress some relatively trivial aspects of the text such as its layout on the page, which is not always significant, despite what the text critics might say, and slight other pieces of information such as the very important lexical ties between the English and Latin versions of Comenius's bilingual text, for example. Moreover, in many crucial respects it is easy to fool oneself concerning what a scanned image of the text will accomplish. For example, in order to study the transmission of texts, information concerning the text carrier is necessary, which scanned images simply do not always handle. Further, even the high-quality materials being produced at Cornell use much of the information that one would need if studying those books as physical objects. It is a choice that has been made. It is an arguably justifiable choice, but one does not know what color those pen strokes in the margin are or whether there was a stain on the page, because it has been filtered out. One does not know whether there were rips in the page because they do not show up, and on a couple of the marginal marks one loses half of the mark because the pen is very light and the scanner failed to pick it up, and so what is clearly a checkmark in the margin of the original becomes a little scoop in the margin of the facsimile. Standard problems for facsimile editions, not new to electronics, but also true of light-lens photography, and are remarked here because it is important that we not fool ourselves that even if we produce a very nice image of this page with good contrast, we are not replacing the manuscript any more than microfilm has replaced the manuscript.
The TEI comes from the research community, where its first allegiance lies, but it is not just an academic exercise. It has relevance far beyond those who spend all of their time studying text, because one's model of text determines what one's software can do with a text. Good models lead to good software. Bad models lead to bad software. That has economic consequences, and it is these economic consequences that have led the European Community to help support the TEI, and that will lead, SPERBERG-McQUEEN hoped, some software vendors to realize that if they provide software with a better model of the text they can make a killing. ****** +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ DISCUSSION * Implications of different DTDs and tag sets * ODA versus SGML * +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ During the discussion that followed, several additional points were made. Neither AAP (i.e., Association of American Publishers) nor CALS (i.e., Computer-aided Acquisition and Logistics Support) has a document-type definition for ancient Greek drama, although the TEI will be able to handle that. Given this state of affairs and assuming that the technical-journal producers and the commercial vendors decide to use the other two types, then an institution like the Library of Congress, which might receive all of their publications, would have to be able to handle three different types of document definitions and tag sets and be able to distinguish among them.
Office Document Architecture (ODA) has some advantages that flow from its tight focus on office documents and clear directions for implementation. Much of the ODA standard is easier to read and clearer at first reading than the SGML standard, which is extremely general. What that means is that if one wants to use graphics in TIFF and ODA, one is stuck, because ODA defines graphics formats while TIFF does not, whereas SGML says the world is not waiting for this work group to create another graphics format. What is needed is an ability to use whatever graphics format one wants. The TEI provides a socket that allows one to connect the SGML document to the graphics. The notation that the graphics are in is clearly a choice that one needs to make based on her or his environment, and that is one advantage. SGML is less megalomaniacal in attempting to define formats for all kinds of information, though more megalomaniacal in attempting to cover all sorts of documents. The other advantage is that the model of text represented by SGML is simply an order of magnitude richer and more flexible than the model of text offered by ODA. Both offer hierarchical structures, but SGML recognizes that the hierarchical model of the text that one is looking at may not have been in the minds of the designers, whereas ODA does not.
ODA is not really aiming for the kind of document that the TEI wants to encompass. The TEI can handle the kind of material ODA has, as well as a significantly broader range of material. ODA seems to be very much focused on office documents, which is what it started out being called-- office document architecture. ****** +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ CALALUCA * Text-encoding from a publisher's perspective * Responsibilities of a publisher * Reproduction of Migne's Latin series whole and complete with SGML tags based on perceived need and expected use * Particular decisions arising from the general decision to produce and publish PLD * +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ The final speaker in this session, Eric CALALUCA, vice president, Chadwyck-Healey, Inc., spoke from the perspective of a publisher re text-encoding, rather than as one qualified to discuss methods of encoding data, and observed that the presenters sitting in the room, whether they had chosen to or not, were acting as publishers: making choices, gathering data, gathering information, and making assessments. CALALUCA offered the hard-won conviction that in publishing very large text files (such as PLD), one cannot avoid making personal judgments of appropriateness and structure. In CALALUCA's view, encoding decisions stem from prior judgments. Two notions have become axioms for him in the consideration of future sources for electronic publication: 1) electronic text publishing is as personal as any other kind of publishing, and questions of if and how to encode the data are simply a consequence of that prior decision; 2) all personal decisions are open to criticism, which is unavoidable.
CALALUCA rehearsed his role as a publisher or, better, as an intermediary between what is viewed as a sound idea and the people who would make use of it. Finding the specialist to advise in this process is the core of that function. The publisher must monitor and hug the fine line between giving users what they want and suggesting what they might need. One responsibility of a publisher is to represent the desires of scholars and research librarians as opposed to bullheadedly forcing them into areas they would not choose to enter. CALALUCA likened the questions being raised today about data structure and standards to the decisions faced by the Abbe Migne himself during production of the Patrologia series in the mid-nineteenth century. Chadwyck-Healey's decision to reproduce Migne's Latin series whole and complete with SGML tags was also based upon a perceived need and an expected use. In the same way that Migne's work came to be far more than a simple handbook for clerics, PLD is already far more than a database for theologians. It is a bedrock source for the study of Western civilization, CALALUCA asserted.
In regard to the decision to produce and publish PLD, the editorial board offered direct judgments on the question of appropriateness of these texts for conversion, their encoding and their distribution, and concluded that the best possible project was one that avoided overt intrusions or exclusions in so important a resource. Thus, the general decision to transmit the original collection as clearly as possible with the widest possible avenues for use led to other decisions: 1) To encode the data or not, SGML or not, TEI or not. Again, the expected user community asserted the need for normative tagging structures of important humanities texts, and the TEI seemed the most appropriate structure for that purpose. Research librarians, who are trained to view the larger impact of electronic text sources on 80 or 90 or 100 doctoral disciplines, loudly approved the decision to include tagging. They see what is coming better than the specialist who is completely focused on one edition of Ambrose's De Anima, and they also understand that the potential uses exceed present expectations. 2) What will be tagged and what will not. Once again, the board realized that one must tag the obvious. But in no way should one attempt to identify through encoding schemes every single discrete area of a text that might someday be searched.
That was another decision. Searching by a column number, an author, a word, a volume, permitting combination searches, and tagging notations seemed logical choices as core elements. 3) How does one make the data available? Tieing it to a CD-ROM edition creates limitations, but a magnetic tape file that is very large, is accompanied by the encoding specifications, and that allows one to make local modifications also allows one to incorporate any changes one may desire within the bounds of private research, though exporting tag files from a CD-ROM could serve just as well. Since no one on the board could possibly anticipate each and every way in which a scholar might choose to mine this data bank, it was decided to satisfy the basics and make some provisions for what might come. 4) Not to encode the database would rob it of the interchangeability and portability these important texts should accommodate. For CALALUCA, the extensive options presented by full-text searching require care in text selection and strongly support encoding of data to facilitate the widest possible search strategies. Better software can always be created, but summoning the resources, the people, and the energy to reconvert the text is another matter. PLD is being encoded, captured, and distributed, because to Chadwyck-Healey and the board it offers the widest possible array of future research applications that can be seen today. CALALUCA concluded by urging the encoding of all important text sources in whatever way seems most appropriate and durable at the time, without blanching at the thought that one's work may require emendation in the future. (Thus, Chadwyck-Healey produced a very large humanities text database before the final release of the TEI Guidelines.)
Ideas discussed in this chapter
Text from Project Gutenberg, public domain in the United States.