—With the advent of x86-based Macintosh computers, Universal binaries, originally known as "fat" or multiple-architecture binaries, appeared in Mac OS X.

Universal Binaries

for one or more architectures

along with a header that describes each constituent binary.

a wrapper that contains Mach-O binaries

a "4-way fat" executable could consist of Mach-O executables for the i386 (32-bit Intel), x86_64 (64-bit Intel), ppc (32-bit PowerPC), and ppc64 (64-bit PowerPC) architectures

Mac OS X does not provide any kernel-level or user-level interfaces to extend binary format support.

we'll need to write special software

new kernel functionality

software will involve a kernel extension.

extend the kernel

and execute them through specified handler programs.

Let us call the new software that implements these features XBinary. binfmt_misc Those familiar with the Linux kernel will realize that functionality similar to what's been described here exists in Linux as the binfmt_misc kernel feature. XBinary is conceptually similar

XBinary also has some Mac OS X specific features.

download and install the XBinary package

a command-line tool (xbinary

a kernel extension (xbinary.kext)

research software at this point

choosing the best library from an extended fat library file.

for developers, researchers, and power users

take XBinary for a spin

XBinary: extended binary format support for Mac OS X Copyright (c) 2009 Amit Singh. All Rights Reserved. http://osxbook.com The XBinary software allows you to extend the Mac OS X kernel such that it can recognize arbitrary binary formats and execute them through specified handler programs. (Mac OS X natively supports executing only Mach-O binaries, Universal (fat) binaries, and interpreter scripts.) XBinary consists of a kernel extension (xbinary.kext) and this command-line tool, which lets you control the XBinary facility. This requires superuser privileges, so you should run this tool using sudo(8). The XBinary kext must be loaded for the facility to be available.

You can add and manipulate in-kernel entries that enable recognition of binary formats.

You can also specify flags that affect how a matched entry is processed. By default, the argument vector IS adjusted and setuid/setgid binaries are NOT allowed.

These examples assume that you are on an x86 (little-endian) machine.

Let us look at Java applications

then specify this wrapper script as the interpreter

and subsequently invoke the Java application launcher.

given a Java class file

a wrapper script

We don't even have to write such scripts

a Universal binary containing, say, Tiger and Leopard versions

simplify code creation and maintenance.

Consider a 2-way fat binary containing i386 and x86_64 architectures.

operating system versions in addition to processor architectures.

Now think of an "extended" fat binary mechanism that incorporates

our hypothetical extended fat binary contains eight "architectures"

the extended fat feature as implemented by XBinary is not a complete implementation

make experimentation involving new binary formats easy

XBinary requires Mac OS X 10.5.x (Leopard).

Executive Summary This document discusses XBinary, a new software that lets you add kernel-level support for executing files in arbitrary binary formats on Mac OS X.

Extending Executability

recognize arbitrary binary formats

using the xbinary tool

copious "help" output

Each entry must have as its name a unique identifier string up to 31 bytes in size. Additionally, a set of other arguments specify to the kernel how to recognize that binary format and which interpreter to invoke to handle it. XBinary can recognize a binary EITHER by matching magic bytes within the first page of the file OR by matching a file extension. OTHER_ARGS must be a valid combination of the following arguments (some are optional).

that will determine the startup class name

Bonus Feature: Extra Fat Binaries

Since XBinary is experimental, why not experiment with such a feature too?

XBinary wouldn't be able to help the dynamic linker

The XBinary software

IDLE push notifications

ACL support

supports IMAP extensions

quota limitations

vacation messages

server side email rules

Address Book Server in Snow Leopard Server

share their personal and group contacts across multiple computers

Address Book Server will make use of extensions to WebDAV

iCal Server using CalDAV

Address Book Server using the CardDAV specification

without running into the schema limitations

integrated email, contacts, and calendar

search across multiple wikis

whilst Google Calendar is selected, iCal can not create a To Do Item

Google Calendar does not support Tasks

Google Calendar To Do Items created in Apple Mail 3.5 (930.3) whilst iCal is not running are typically reverted (lost)

To Do Items in calendars other than Google Calendar can not be moved to Google Calendar

Tasks created in Google Mail are not presentable as To Do Items

Tasks created in Google Mail are not presentable as To Do Items

Google Calendar does sync calendar events with Apple Sync Services

Apple Sync Services do sync calendar events with iPod touch

visualise how the Truth Database and Sync Engine (in Apple Sync Services) relate to applications and device conduits

http://developer.apple.com/macosx/syncservices.html

http://developer.apple.com/documentation/Cocoa/Conceptual/SyncServices/Articles/SyncOverview.html#//apple_ref/doc/uid/TP40001151-139942

Tasks created in Google Mail are not presentable as To Do Items

Conflict Resolver offers its services to you — the human — for a decision to be made

use iTunes to prefer a calendar for events created on iPhone and iPod touch

The Info pane lets you configure the sync settings for your contacts, calendars, email accounts, and web browser.

For users of Mac OS X, some illustrations and background information

http://developer.apple.com/macosx/syncservices.html

http://support.apple.com/kb/HT1419

http://support.apple.com/kb/HT1957

an iPhone may use both MobileMe (wirelessly) and a computer (typically wired)

Clients of Sync Engine may be many

If you have two or more Mac OS X computers:

a Truth Database and Sync Engine on each computer

If in addition you subscribe to MobileMe:

your MobileMe account is a client of multiple Sync Engines