#X86 ARCHITECTURE PROS AND CONS SOFTWARE#
#X86 ARCHITECTURE PROS AND CONS PC#

#X86 ARCHITECTURE PROS AND CONS SOFTWARE#

Rather than performing a one off translation, the software could profile and optimise code as it ran.

In an attempt to make its Alpha architecture more attractive, Digital Equipment developed software that could translate Intel binaries into native Alpha machine code.

#X86 ARCHITECTURE PROS AND CONS PC#

Intel's dominance of the PC market and an increasing stranglehold on servers led competing manufacturers to try to find ways to run Intel compatible code on their own processors. In the 1990s, a different motivation for translating instruction sets took hold. Computers would simply target these stripped down instruction sets directly. The rise of RISC architectures, led by the realisation that compiler writers rarely took advantage of specialised high level instructions, removed much of the motivation for developing other computers that could remap instructions. Because programmers never dealt with the memory address map directly – everything on the AS/400 is handled through object references – even the change in addressing range was transparent to applications. The design let IBM swap out the custom 48bit CISC processor and replace it with 64bit PowerPC-architecture processors when the time came to expand the machine's memory address space with no change to the actual programs.

Software never 'sees' the actual instruction set of the core processor. Every single instruction generated by the OS/400 compiler is actually a piece of microcode. The microcode was designed to provide compilers with access to instructions that could support language features, such as allocating memory to objects, directly.Īlthough the B1000 had limited success and was discontinued in the mid 1980s, IBM found success with a similar approach, albeit designed for a single instruction set, when it launched the AS/400 minicomputer. Instead, Burroughs' aim was to close the gap between high level languages and machine code. The idea behind the B1000 series was not to create a chameleon machine able emulate the behaviour of other machines, such as the IBM System/370 – that was an idea that came later. Later versions used a combination of early field programmable gate arrays – mainly for the instruction decoder – and SRAM. In the mid 1970s, Burroughs introduced the first of its B1000 mainframes that included the idea of a 'writeable control store' that could be reprogrammed on the fly to emulate different machines.īecause hardware was so expensive, the earliest mainframes implemented many of their software visible instructions as short 'microcode' routines that were translated at execution time into short sequences of low level machine operations.

X86 architecture pros and cons