The Main File Formats for eBook

As many reading devices settle on a sub-list of formats the ePUB, PDF have emerged as the leading list, with Adobe DRM support on both. Amazon does not support ePUB and insists on

A writer or publisher has many options when it comes to choosing a format for publication. While the average end-user might arguably simply want to read books, every format has its proponents. The myriad e-book formats are sometimes collectively referred to as the "Tower of eBabel". The following is a comparison of e-book formats used to create and publish e-books.

AZW which is the same as MOBI but the DRM is different. You often see TXT with TXT no formatting and HTML with eBook readers often ignores any complicated formatting. More general purpose portable devices will have loadable applications for other formats.

ePub is an open format defined by the Open eBook Forum of the International Digital Publishing Forum. It is based on XHTML and XML along with optional CSS style sheets. Its predecessor was the OEB standard. Specifications are found at the IDPF web site. Some epub files have drm protection on eBook if you need to remove drm from epub first before reading.

MOBI is the format used by the MobiPocket Reader. It may have a .mobi extension or it may have a .prc extension. The extension can be changed by the user to either of the accepted forms. In either case it may be DRM protected or non-DRM. The .prc extension is used because the PalmOS doesn't support any file extensions except .prc or .pdb. Note that Mobipocket prohibits their DRM format to be used on dedicated eBook readers that support other DRM formats.

PRC stands for Palm Resource Compiler. It is one of two extensions (the second is PDB used to identify files intended for use on PalmOS devices. All files synced to RAM on a PalmOS device must be in Palm Database Format, PDB. PRC files were intended to identify a Palm Database containing "resources". In actual fact files synced in RAM are not files at all as there is no file system in RAM on a PalmOS system thus no need for extensions or other file designators. These extensions are placed on the files when they are residing on a PC.

PDF - Portable Document Format created by Adobe for their Acrobat products. It is the defacto standard for document interchange. Software support exists for almost every computer platform and handheld device. Some devices have problems with PDF since most content available is scaled for either A4 or letter format, both of which are not easily readable when reduced to fit on small screens. Some Readers can reflow some PDF documents, including the Sony PRS505, to accommodate the small screen. Some eBook readers, including the iRex iLiad, have a pan-and-zoom feature that aids readability, but extracts a price in ergonomics. Some PDF files have drm protection on eBook if you need to remove drm from pdf first with pdf drm removal before reading it on other devices.