txt

E-books in plain text exist and are very small in size. For example, the Bible is about 4 MB. The ASCII standard allows ASCII-only text files (unlike most other file types) to be interchanged and readable on Unix, Macintosh, Microsoft Windows, DOS, and other systems. These differ in their preferred line ending convention and their interpretation of values outside the ASCII range (their character encoding).

htm; .html

HTML is the markup language used for most web pages. E-books using HTML can be read using a Web browser. The specifications to the format are available without charge from the W3C.

As markup language, HTML adds especially marked meta elements to otherwise plain text encoded using character sets like ASCII or UTF-8. As such suitably formatted files can be, and sometimes are, generated by hand using a plain text editor or programmer's editor. Many HTML generator applications exist to ease this process and often require less intricate knowledge of the format details involved.

HTML on its own is not a particularly efficient format to store information, requiring more storage space for a given work than many other formats. However, several e-Book formats including the Amazon Kindle, Open eBook, Compressed HM, Mobipocket and IDPF/EPUB use one HTML file for each book chapter and then Zip compress the files, along with images, metadata and style sheets into one file.

fb2

FictionBook is a popular XML-based e-book format, supported by free readers such as Haali Reader and FBReader. See http://haali.cs.msu.ru/pocketpc/FictionBook_description.html

chm

CHM format is a proprietary format based on HTML. Multiple pages and embedded graphics are distributed along with proprietary metadata as a single compressed file. In contrast, in HTML, a site consists of multiple HTML files and associated image files in standardized formats.

DjVu

DjVu is a format that specialises in and particularly excels at storing scanned images. It includes advanced compressors optimized for low-color images, such as text documents. Individual files may contain one or more pages.

The format has long remained in obscurity, but now that free tools to manipulate the format are available, that is starting to change.

The contained page images are divided in separate layers (such as multi-color, low-resolution, lossily-compressed background layer, and few-colors, high-resolution, tightly-compressed foreground layer), each compressed in the best available method. The format is designed to decompress very quickly, even faster than vector-based formats.

The advantage of DjVu is that it is possible to take a high-resolution scan (300-400 DPI), good enough for both on-screen reading and printing, and store it very efficiently. Several dozens of 300 DPI black-and-white scans can be stored in less than a megabyte.

pdf

A file format created by Adobe Systems, initially to provide a standard form for storing and editing printed publishable documents. The format derives from PostScript, but without language features like loops, and with added support for features like compression and passwords. Because PDF documents can easily be viewed and printed by users on a variety of computer platforms, they are very common on the World Wide Web. The specification of the format is available without charge from Adobe.

PDF files typically contain brochures, product manuals, magazine articles — up to entire books, as they can embed fonts, images, and other documents. A PDF file contains one or more zoomable page images.

Since the format is designed to reproduce page images, the text traditionally could not be re-flowed to fit the screen width or size. As a result PDF files designed for printing on standard paper sizes are less easily viewed on screens with limited size or resolution, such as those found on mobile phones and PDAs. Adobe has addressed this by adding a re-flow facility to its Acrobat Reader software, but for this to work the document must be marked for re-flowing at creation [3], which means existing PDF documents will not benefit unless they are tagged and resaved. The Windows Mobile (aka Pocket PC) version of Adobe Acrobat will automatically attempt to tag a PDF for reflow during the synchronization process using an installed plugin to Active Sync. However, this tagging process will not work on most locked or password protected PDF documents. It also doesn't work at present (2009-10) on the Windows Mobile Device Center (Active Syncs Successor) as found in Windows Vista and Windows 7. This limits automatic tagging support during synchronization to Windows XP/2000.

Multiple products support creating and tagging PDF files, such as Adobe Acrobat, PDFCreator, OpenOffice.org, and FOP, and several programming libraries. Acrobat Reader (now simply called Adobe Reader) is Adobe's product used to view PDF files, with third party viewers such as xpdf also available. Mac OS X has built-in PDF support, both for creation as part of the printing system and for display using the built-in Preview application.

Later versions of the specification add support for forms, comments, hypertext links, and even interactive elements such as buttons for forms entry and for triggering sound and video. Such features may not be supported by older or third-party viewers and some are not transferrable to print.

PDF files are supported on the following e-book readers: iRex iLiad, iRex DR1000, Sony Reader, Bookeen Cybook, Foxit eSlick, Amazon Kindle DX and Barnes & Noble nook.

epub

The .epub or OEBPS format is an open standard for eBooks created by the International Digital Publishing Forum (IDPF). It combines three IDPF open standards:

Open Publication Structure (OPS) 2.0, which describes the content markup (either XHTML or Daisy DTBook)

Open Packaging Format (OPF) 2.0, which describes the structure of an .epub in XML

OEBPS Container Format (OCF) 1.0, which bundles files together (as a renamed ZIP file)

Currently, the format can be read by the Sony Reader, BeBook, Adobe Digital Editions, Lexcycle Stanza, BookGlutton, AZARDI, Aldiko and WordPlayer on Android and the Mozilla Firefox add-on OpenBerg Lector. Several other reader software programs are currently implementing support for the format, such as dotReader, FBReader, Mobipocket, uBook and Okular. Another software .epub reader, Lucidor, is in beta. On October 20, 2009, Barnes & Noble announced their Nook Reader will support the epub format.

In 2008 BookGlutton launched a server-side HTML-to-EPUB converter.

Adobe Digital Edition uses .epub format for its e-books, with DRM protection provided through their proprietary ADEPT mechanism. The recently developed INEPT framework and scripts have been reverse-engineered to circumvent this DRM system.

prc; .mobi

The Mobipocket e-book format based on the Open eBook standard using XHTML can include JavaScript and frames. It also supports native SQL queries to be used with embedded databases. There is a corresponding e-book reader. A free e-book of the German Wikipedia has been published in Mobipocket format.

The Mobipocket Reader has a home page library. Readers can add blank pages in any part of a book and add free-hand drawings. Annotations — highlights, bookmarks, corrections, notes, and drawings — can be applied, organized, and recalled from a single location. Mobipocket Reader has electronic bookmarks, and a built-in dictionary

The reader has a full screen mode for reading and support for many PDAs, Communicators, and Smartphones. Mobipocket products support most Windows, Symbian, BlackBerry and Palm operating systems. On Linux and Macintosh applications like Okular and FBReader can be used to read non-encrypted files.

The Amazon Kindle's AZW format is basically just the Mobipocket format with a slightly different serial number scheme (it uses an asterisk instead of a Dollar sign).

Mobipocket is working on an .epub to .mobi converter called mobigen.

pdb

eReader is a freeware program for viewing Palm Digital Media electronic books. Versions are available for iPhone, PalmOS, Symbian, BlackBerry, Windows Mobile Pocket PC/Smartphone, desktop Windows, and Macintosh. The reader shows text one page at a time, as paper books do. eReader supports embedded hyperlinks and images. Additionally, the Stanza application for the iPhone and iPod Touch can read both encrypted and unencrypted eReader files.