Major Features

The major features of the 64-bit environment include support for:

• Large virtual address space

• Large files

• 64-bit arithmetic

• Removal of certain system limitations

Large Virtual Address Space

In the 64-bit environment, a process can have up to 64-bits of virtual address space, that is, 18 exabytes. This is approximately 4 billion times the current maximum of a 32-bit process.

Because of hardware restrictions, some platforms might not support the full 64-bits of address space.

Large Files

If an application requires only support for large files, then it can remain 32-bit and use the Large Files interface. However, if portability is not a primary concern, it might be useful to convert the application to a 64-bit program to take full advantage of 64-bit capabilities with a coherent set of interfaces.

64-bit Arithmetic

Though 64-bit arithmetic has long been available in previous 32-bit Solaris releases, the 64-bit implementation now uses the full 64-bit machine registers for integer operations and parameter passing. This allows an application to take full advantage of the capabilities of the 64-bit CPU hardware.

System Limitations Removed

The 64-bit system interfaces are inherently more capable than some of their 32-bit equivalents. Application programmers concerned about year 2038 problems (when 32-bit time_t runs out of time) can use the 64-bit time_t. While 2038 seems like a long way off, applications that do computations concerning future events, such as mortgages, might require the expanded time capability.