Direct Access Archive, or DAA, is a proprietary file format developed by PowerISO Computing

PowerISO

PowerISO is an application used to create, open, mount / emulate, compress, encrypt, and otherwise manipulate CD / DVD image files. It is most commonly known for its proprietary DAA disc image format. Other supported formats include ISO, BIN, NRG, and CDI. PowerISO is able to modify all supported...

 for disk image

Disk image

A disk image is a single file or storage device containing the complete contents and structure representing a data storage medium or device, such as a hard drive, tape drive, floppy disk, CD/DVD/BD, or USB flash drive, although an image of an optical disc may be referred to as an optical disc image...

 files. The format supports features such as compression, password protection, and splitting to multiple volumes. Popular disk image mounting

Mount (computing)

Mounting takes place before a computer can use any kind of storage device . The user or their operating system must make it accessible through the computer's file system. A user can access only files on mounted media.- Mount point :A mount point is a physical location in the partition used as a...

 programs such as Alcohol 120% and Daemon Tools

Daemon Tools

Daemon Tools is a disk image emulator and optical disc authoring program for Microsoft Windows. Daemon Tools was originally a furtherance in the development of another program, Generic SafeDisc emulator, and incorporated all of its features. The program claims to be able to defeat most copy...

 currently do not support the mounting of DAA images.

Currently there is no published information about the format. Among mainstream applications, it can be opened or converted with PowerISO

PowerISO

PowerISO is an application used to create, open, mount / emulate, compress, encrypt, and otherwise manipulate CD / DVD image files. It is most commonly known for its proprietary DAA disc image format. Other supported formats include ISO, BIN, NRG, and CDI. PowerISO is able to modify all supported...

, MagicISO

MagicISO

MagicISO is a CD/DVD image shareware utility that can extract, edit, create, and burn disc image files. It offers the possibility of converting between ISO and CUE/BIN and their proprietary Universal Image Format disc image format.In addition to being able to edit the contents of the disc images...

, AnyToISO and UltraISO

UltraISO

UltraISO is an application for Microsoft Windows for creating, modifying and converting ISO image files used for optical disc authoring.Since the first release of UltraISO on 20 April 2002, its author EZB Systems has maintained and kept the product shareware.UltraISO is currently produced by EZB...

. Various free open source packages are also available to convert DAA to ISO images.

File Structure

Although lacking official documentation, DAA image files are zlib-

Zlib

zlib is a software library used for data compression. zlib was written by Jean-Loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. Zlib is also a crucial component of many software platforms including Linux, Mac OS X,...

 or lzma-

LZMA

The Lempel–Ziv–Markov chain algorithm is an algorithm used to perform data compression. It has been under development since 1998 and was first used in the 7z format of the 7-Zip archiver...

compressed ISO image

ISO image

An ISO image is an archive file of an optical disc, composed of the data contents of every written sector of an optical disc, including the optical disc file system...

s chunk by chunk.

Conversion

PowerISO provides free command-line tools for Linux

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 and Mac OS X

Mac OS X

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

 which allow the user to extract DAA files or convert them into ISO format, however these tools haven't been updated to support the newest version of the DAA format. The PowerISO Windows

Microsoft Windows

Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 trial version only supports converting images from DAA files up to 300MB, less than half of the capacity of a standard CD.

AcetoneISO

AcetoneISO

AcetoneISO is a free software program to mount and manage image files. Its goals are to be simple, intuitive and stable. Written in Qt 4, this software is meant for all those people looking for a "Daemon Tools for Linux"...

is a free CD/DVD management application for Linux that can convert DAA to ISO with the help of the external PowerISO command-line tool for Linux.

daa2iso is an open source command line application has been developed to convert DAA files to ISO files. The program comes with a Windows binary and source code which compiles under Unix-like operating systems. daa2iso allows users to select the .daa file, and the location for the .iso output via standard windows open and save dialogs.

For Mac OS X, DAA Converter is a GUI application which wraps the daa2iso command-line tool (GNU license).

Features

Due to using freely available compression algorithms, DAA includes the following features that are absent in ISO (but can be obtained by manually compressing ISO files):

• Ability to compress images, thus saving space and allowing smaller downloads
• Can be password protected
• Can be split into multiple smaller files

ISO conversion utilities

• daa2iso application for Windows (source code included, and may be compiled for *nix / MacOSX without modification)
• DAA Converter for Mac OS X, graphical Mac interface for daa2iso