computer science

History of PDF

History of PDF is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand History of PDF rather than just read about it. In short: The Portable Document Format (PDF) was created by Adobe Systems, introduced at the Windows and OS/2 Conference in January 1993 and remained a proprietary format until it was released as an open standard in 2008. Since then, it has been under the control of an International Organization for Standardization (ISO) committee of industry experts.

Key takeaways

History of PDF belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect History of PDF to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of History of PDF from memory before moving on to harder problems.

Reference excerpt

The Portable Document Format (PDF) was created by Adobe Systems, introduced at the Windows and OS/2 Conference in January 1993 and remained a proprietary format until it was released as an open standard in 2008. Since then, it has been under the control of an International Organization for Standardization (ISO) committee of industry experts. Development of PDF began in 1991 when Adobe's co-founder John Warnock wrote a paper for a project then code-named Camelot, in which he proposed the creation of a simplified version of Adobe's PostScript format called Interchange PostScript (IPS). Unlike traditional PostScript, which was tightly focused on rendering print jobs to output devices, IPS would be optimized for displaying pages to any screen and any platform. PDF was developed to share documents, including text formatting and inline images, among computer users of disparate platforms who may not have access to mutually-compatible application software. It was created by a research and development team called Camelot, which was personally led by Warnock himself. PDF was one of a number of competing electronic document formats in that era such as DjVu, Envoy, Common Ground Digital Paper, Farallon Replica and traditional PostScript itself. In those early years before the rise of the World Wide Web and HTML documents, PDF was popular mainly in desktop publishing workflows. PDF's adoption in the early days of the format's history was slow. Indeed, the Adobe Board of Directors attempted to cancel the development of the format, as they could see little demand for it. Adobe Acrobat, Adobe's suite for reading and creating PDF files, was not freely available; early versions of PDF had no support for external hyperlinks, reducing its usefulness on the Internet; the larger size of a PDF document compared to plain text required longer download times over the slower modems common at the time; and rendering PDF files was slow on the less powerful machines of the day. Adobe distributed its Adobe Reader (now Acrobat Reader) program free of charge from version 2.0 onwards, and continued supporting the original PDF, which eventually became the de facto standard for fixed-format electronic documents. In 2008 Adobe Systems' PDF Reference 1.7 became ISO 32000:1:2008. Thereafter, further development of PDF (including PDF 2.0) is conducted by ISO's TC 171 SC 2 WG 8 with the participation of Adobe Systems and other subject matter experts.

Adobe specifications From 1993 to 2006 Adobe Systems changed the PDF specification several times to add new features. Various aspects of Adobe's Extension Levels published after 2006 were accepted into working drafts of ISO 32000-2 (PDF 2.0), but developers are cautioned that Adobe's Extensions are not part of the PDF standard.

Adobe declared that it is not producing a PDF 1.8 Reference. Future versions of the PDF Specification will be produced by ISO technical committees. However, Adobe published documents specifying what proprietary extended features for PDF, beyond ISO 32000-1 (PDF 1.7), are supported in its newly released products. This makes use of the extensibility features of PDF as documented in ISO 32000–1 in Annex E. The specifications for PDF are backward inclusive. The PDF 1.7 specification includes all of the functionality previously documented in the Adobe PDF Specifications for versions 1.0 through 1.6. Where Adobe removed certain features of PDF from their standard, they are not contained in ISO 32000-1 either. Some features are marked as deprecated.

ISO standardization On January 29, 2007, Adobe announced that it would release the full Portable Document Format 1.7 specification to the American National Standards Institute (ANSI) and the Enterprise Content Management Association (AIIM), for the purpose of publication by the International Organization for Standardization (ISO). By virtue of this change, ISO produces versions of the PDF specification beyond 1.7, and Adobe will be only one of the ISO technical committee members. ISO standards for "full function PDF" are published under the formal number ISO 32000. Full function PDF specification means that it is not only a subset of Adobe PDF specification; in the case of ISO 32000-1 the full function PDF includes everything defined in Adobe's PDF 1.7 specification. However, Adobe later published extensions that are not part of the ISO standard. There are also proprietary functions in the PDF specification, that are only referenced as external specifications. These were eliminated in PDF 2.0, which includes no proprietary technology.

PDF documents conforming to ISO 32000-1 carry the PDF version number 1.7. Documents containing Adobe extended features still carry the PDF base version number 1.7 but also contain an indication of which extension was followed during document creation. PDF documents conforming to ISO 32000-2 carry the PDF version number 2.0, and are known to developers as "PDF 2.0 documents".

ISO 32000-1:2008 (PDF 1.7) The final revised documentation for PDF 1.7 was approved by ISO Technical Committee 171 in January 2008 and published as ISO 32000-1:2008 on July 1, 2008, and titled Document management – Portable document format – Part 1: PDF 1.7. ISO 32000-1:2008 is the first ISO standard for full function PDF. The previous ISO PDF standards (PDF/A, PDF/X, etc.) are subsets intended for more specialized uses. ISO 32000-1 includes all of the functionality previously documented in the Adobe PDF Specifications for versions 1.0 through 1.7. Adobe removed certain features of PDF from previous versions; these features are not contained in PDF 1.7 either. The ISO 32000-1 document was prepared by Adobe Systems Incorporated based upon PDF Reference, sixth edition, Adobe Portable Document Format version 1.7, November 2006. It was reviewed, edited and adopted under a special fast-track procedure, by ISO Technical Committee 171 (ISO/TC 171), Document management application, Subcommittee SC 2, Application issues, in parallel with its approval by the ISO member bodies. According to the ISO PDF standard abstract:

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with History of PDF

Start with the simplest possible case. Write down what History of PDF claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to History of PDF before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about History of PDF ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of History of PDF

In research: History of PDF appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses History of PDF in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: History of PDF is common in secondary-school and first-year university syllabi. It links to neighbouring topics Adobe Inc., History of software, so understanding it makes those chapters shorter.
In everyday life: Look for History of PDF outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study History of PDF in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what History of PDF means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain History of PDF out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is History of PDF in simple terms?

Why does History of PDF matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study History of PDF?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on History of PDF.