.BOM File Extension

Mac OS X Bill of Materials File

Developer	Apple
Popularity	Average rating 3 / 5. Vote count: 9
Category	System Files
Format	.BOM
Cross Platform	Update Soon

What is an BOM file?

The .BOM file, also known as the Bill of Materials file, is a crucial part of the macOS package management system. It is created by the Installer application in macOS and is used to keep track of the files installed by a software package. Specifically, it lists the files within a package, including their locations, file permissions, and checksums, ensuring the installation process is accurate and complete.

More Information.

The initial purpose of the .BOM file was to provide a robust method for managing the installation of software packages in NeXTSTEP and later macOS. By keeping a record of all files in a package, it ensured that the correct files were installed, with the proper permissions and without overwriting existing files that shouldn’t be modified. It also enabled the system to verify file integrity through checksums and facilitated clean uninstallation by tracking which files were added during installation.

Origin Of This File.

The .BOM file format originated with NeXTSTEP, an operating system developed by NeXT, which later evolved into macOS after Apple acquired NeXT in 1997. The BOM file format was retained in macOS to handle package installations and has been a part of macOS since its inception.

File Structure Technical Specification.

Header: Contains metadata about the BOM file, such as the version and the number of entries.
Index: A list of file paths and directories included in the package.
File Attributes: For each file or directory, attributes such as permissions, ownership, and checksums are recorded.
Size and Checksums: To verify file integrity, the size and checksum (typically CRC-32) of each file are stored.BOM files use a binary format that is not human-readable. To interact with these files, Apple provides command-line utilities such as lsbom and mkbom.

How to Convert the File?

Windows

On Windows, converting .BOM files to another format is not straightforward, as the BOM format is native to macOS.

However, you can try the following approaches:

Use a Mac Virtual Machine or Hackintosh: Install a macOS virtual machine or a Hackintosh setup on your Windows system, then use macOS utilities like lsbom to extract and convert the .BOM file contents.
Cygwin or WSL: You can install Cygwin or Windows Subsystem for Linux (WSL) to emulate a Unix-like environment on Windows. After setting up, you may try compiling macOS tools like lsbom to work with BOM files.
Hex Editor: If you need specific data from the BOM file and you are familiar with its binary structure, you can use a hex editor like HxD to manually interpret and convert the data.

Linux

Similar to Windows, Linux does not have native support for .BOM files.

You can attempt conversion through the following methods:

Compile macOS Tools: Download and compile macOS utilities such as lsbom on your Linux machine. This requires access to the source code and may involve manual modifications.
Use a macOS Virtual Machine: Run macOS in a virtual machine on your Linux system, and then use macOS tools to convert the BOM file.
Hex Editor: For experienced users, using a hex editor to manually extract and convert information from a BOM file is an option.

macOS

On macOS, you have the most straightforward options to convert .BOM files:

Use the lsbom Command: You can extract the BOM file contents to a plain text format using the lsbom command.
Custom Scripting: If you need a more specialized conversion, you can create scripts in languages like Python or shell scripting to parse the BOM file and output the information in your desired format.

Android

Direct conversion of BOM files on Android is difficult, but here are some potential approaches:

Termux App: Install the Termux app to access a Linux-like terminal on Android. If you are technically proficient, you could try compiling macOS tools or use scripting to convert the BOM file.
Transfer to macOS: Transfer the BOM file to a macOS device, perform the conversion there, and transfer the converted file back to your Android device.

iOS

Conversion of BOM files on iOS is generally impractical due to the platform’s restrictions.

However:

Transfer to macOS: Similar to Android, the best approach is to transfer the file to a macOS system where you can perform the conversion using native tools like lsbom, and then transfer the converted file back to your iOS device.

Other Platforms

For other platforms like Chrome OS, non-mainstream Linux distributions, or BSD systems:

Use a macOS Virtual Machine: If possible, run a macOS virtual machine on these platforms and use macOS tools to convert the BOM file.
Hex Editor: As with Windows and Linux, using a hex editor is a last resort for manual conversion if you have knowledge of the BOM file format.

Advantages And Disadvantages.

Advantages:

Integrity Checking: BOM files help ensure that files are correctly installed and have not been tampered with.
Package Management: Facilitates clean installation and uninstallation by tracking which files belong to a package.
Efficient Installations: Speeds up the installation process by using pre-calculated file paths and attributes.

Disadvantages:

Limited Usage: Primarily used in macOS, limiting cross-platform compatibility.
Binary Format: Not human-readable, making manual inspection difficult.
Complexity: May complicate troubleshooting when something goes wrong with the installation process.

How to Open BOM?

Open In Windows

BOM files are not natively supported on Windows. However, you can use third-party tools such as Cygwin or WSL (Windows Subsystem for Linux) to access macOS utilities and work with BOM files. Alternatively, open and analyze them using a hex editor, though this requires detailed knowledge of the BOM file structure.

Open In Linux

Like Windows, BOM files are not natively supported on Linux. You would need to manually compile macOS tools such as lsbom if available. Alternatively, you can open and inspect them using a hex editor.

Open In MAC

BOM files are natively supported in macOS. You can use the lsbom command in the Terminal to view the contents of the BOM file and the mkbom command to create BOM files.

Open In Android

BOM files cannot be directly opened on Android devices. However, you could use terminal emulators like Termux and compile necessary tools to extract BOM contents, though this process is complex and not typically practical.

Open In IOS

BOM files are not directly accessible or viewable on iOS devices. iOS is a closed system, and access to such low-level file details is not typically available without jailbreaking, which is not recommended.

Open in Others

BOM files are tightly integrated with macOS systems, and as such, other operating systems (e.g., Chrome OS, non-mainstream Linux distros) do not have native support for this file format. If necessary, you could use a macOS virtual machine to interact with BOM files on these platforms.