PRC is a container format for code database

Database

A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

s in Palm OS

Palm OS

Palm OS is a mobile operating system initially developed by Palm, Inc., for personal digital assistants in 1996. Palm OS is designed for ease of use with a touchscreen-based graphical user interface. It is provided with a suite of basic applications for personal information management...

, Garnet OS and Access Linux Platform

Access Linux Platform

The Access Linux Platform , once referred to as a "next-generation version of the Palm OS" is an open source-based operating system for mobile devices developed and marketed by Access Co., of Tokyo, Japan. The platform includes execution environments for Java, classic Palm OS, and GTK+-based native...

. Its structure is similar to PDB

PDB (Palm OS)

PDB is a container format for record databases in Palm OS, Garnet OS and Access Linux Platform. Its structure is similar to PRC resource databases...

 databases. Usually, a PRC file is a flat representation of a Palm OS application that is stored as forked database on the PDA.

PRC files are also used by the Mobipocket

Mobipocket

Mobipocket SA is a French company incorporated in March 2000 which produces Mobipocket Reader software, an E-Book reader for some PDAs, phones and desktop operating systems....

 e-book

E-book

An electronic book is a book-length publication in digital form, consisting of text, images, or both, and produced on, published through, and readable on computers or other electronic devices. Sometimes the equivalent of a conventional printed book, e-books can also be born digital...

-reader (here sometimes referred to as MOBI format). The AZW format of Amazon's Kindle

Amazon Kindle

The Amazon Kindle is an e-book reader developed by Amazon.com subsidiary Lab126 which uses wireless connectivity to enable users to shop for, download, browse, and read e-books, newspapers, magazines, blogs, and other digital media...

 reading device is in turn a DRM

Digital rights management

Digital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...

-restricted form of the Mobipocket format.

On Palm OS, PRC files are used for applications, localized resources (overlays) and shared libraries.

Structure of PRC file

In its essence, a PRC file is similar to a classical Mac OS

Mac OS

Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...

application. It contains a PRC header, PRC resource headers and PRC resources.

PRC Header

PRC Resource Header

PRC Resources

PRC Header

The PRC header is located at the beginning of the file and contains meta-information on the file:

Offset	Name	Type	Size
0x00	name	char	32 Bytes
0x20	flags	integer	2 Bytes
0x22	version	integer	2 Bytes
0x24	creation time	Macintosh time	4 Bytes
0x28	modification time	Macintosh time	4 Bytes
0x2c	backup time	Macintosh time	4 Bytes
0x30	mod_num	integer	4 Bytes
0x34	app_info	integer	4 Bytes
0x38	sort_info	integer	4 Bytes
0x3c	type	integer	4 Bytes
0x40	creator	integer	4 Bytes
0x44	unique_id_seed	integer	4 Bytes
0x48	next_record_list	integer	4 Bytes
0x4c	num_records	integer	2 Bytes

PRC Resource Header

For every resource (specified by num_records), there is a resource header containing:

name	type	notes	size
name	char	Name of the resource	4 bytes
ID	integer	ID number of the resource	2 bytes
offset	integer	Pointer to resource data	4 bytes

PRC Resources

Every application contains al least a Code #0 resource with size information and jump tables, a Code #1 resource with executable code and data resources containing pre-initialized values of global variables in compressed form. Other resources that may be contained are forms, form objects, alerts and multimedia data, e. g. images and sounds.