text: **7.2 Getting started with PDF indexing**
  
  PDF is a standard that is specified by Adobe Systems, Incorporated, for the electronic 
  distribution of documents. PDF files are compact. They can be distributed globally through 
  email, the web, intranets, or CD-ROM, and viewed with Adobe Reader. 
  
  PDF is a data type or file format that is platform (hardware, operating system)-independent. A 
  PDF file contains a complete PDF document that is composed of text, graphics, and the 
  resources that are referenced by that document. 
  
  Two PDF file layouts are possible: 
  
  (cid:2) Non-Linear (not “optimized”) 
  
  This file layout is optimized for space savings. Storing a PDF file by using a Non-Linear 
  layout consumes less disk space than storing the same PDF file linearly. It is slower to 
  access or display this type of layout because portions of the data that is required to 
  assemble pages of the document are scattered throughout the PDF file, so the whole PDF 
  file must be downloaded and accessed before the file can be displayed. 
  
  (cid:2) Linear (“optimized” or “web optimized”) 
  
  In this file format, the PDF file is created in a linear (in page order) fashion. This file format 
  allows the PDF viewer to start displaying the PDF document pages when they are 
  downloading without waiting for the whole PDF file to be downloaded. 