Apple currently has computers that use both a 32-bit and 64-bit architectures. One of the big the differences between the two architectures is how large a block of memory an application can use at any one time, and how large any particular piece of data can be processed at once.
The differences between 32-bit and 64-bit computing architectures can be just as confusing to a programmer as it might to a layman. What if you were tasked with creating an application that uses the 32-bit architecture of the legacy Mac OS X, yet can take advantage of the 64-bit architecture available on Macs using the G5 processor and Appleis upcoming OS X update, codename: Tiger?
Not to worry: Apple has posted an informative overview of how to develop 64-bit applications aptly called "Developing 64-bit Applications" at the Apple Developer Connection, the companyis network for Mac developers.
"By definition, the difference between 32-bit computing, the gold standard for the last 20 years of desktop computing," the article explained, "and 64-bit computing is the size of the memory space an application can use. In a 32-bit world, an application can address 4GB of memory. For many of the applications that we use everyday, such as word processors and spreadsheets, this is more than enough memory. However, if you work with large datasets, such as the human genome or geospatial data, 4GB suddenly becomes very limiting.
"64-bit computing shatters the 4GB limit giving a virtual address space in excess of 16 exabytes. Thatis 16 billion billion bytes. You canit even begin to put that much RAM in a Power Mac-yet-but Tiger sets the stage for some truly incredible system capabilities."
The article goes on to give in fairly digestible terms an overview of how one might create applications that can take advantage of both the 32 and 64-bit capabilities available in G5 processors, and in OS X Tiger. You can read the full article at the Apple Developer Connection Web site.