<architecture> A term describing a computer architecture based
around an ALU, registers and data bus which are 64
bits wide.
64-bit processors were quite common in 1996, e.g. Digital
Alpha, versions of Sun SPARC, MIPS, IBM AS/4000.
the PowerPC and Intel were expected to move to 64 bits at
their next generation - PPC 620 and Intel P7.
A 64-bit address bus allows the processor to address 18
million gigabytes as opposed to the mere 4 gigabytes allowed
with 32 bits. There were in 1996 already hard disks which
can hold over 4GB. Floating point calculations can also be
more accurate.
A 64-bit OS is needed as well to take advantage of the CPU.
In 1996 there were only a few 64-bit operating systems,
including OS/400, Digital Unix, Solaris (partialy). A
32-bit OS can run on a 64-bit CPU.
