PDB is a container format for record 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 PRC

PRC (Palm OS)

PRC is a container format for code databases in Palm OS, Garnet OS and Access Linux Platform. Its structure is similar to PDB databases. Usually, a PRC file is a flat representation of a Palm OS application that is stored as forked database on the PDA....

 resource databases. The PalmDOC eBook format is a special version of the PDB format.

Structure of PDB file

A PDB file contains a PDB header, PDB record headers and records

Record (computer science)

In computer science, a record is an instance of a product of primitive data types called a tuple. In C it is the compound data in a struct. Records are among the simplest data structures. A record is a value that contains other values, typically in fixed number and sequence and typically indexed...

.

PDB Header

PDB Record Header

PDB Records

PDB Header

The PDB 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	file attributes	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	modification number	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

PDB Record Header

For every record, there is an eight byte record header, containing:

name	type	size	notes
offset	integer	4 bytes	Byte number in the PDB file (counting from zero), where the record is located
attributes	byte	1 byte	Attributes of the record (delete/dirty/busy/secret/category)
UniqueID	integer	3 bytes	Always 0

PDB Records

Now the records themselves follow. The usual order is AppInfoArea, SortInfoArea and records, sequentially.