Calicut University 2007 Certification TES THE PRINCETON REVIEW CET 1 - Question Paper

operating systems. Intel’s Pentium Pro, Pentium II and the new Pentium III chips contain special
hardware to give backwards compatibility with older processors while allowing for
improvements in performance. Since 1994, Apple’s Macintosh computers have contained
software to enable them to emulate older models that used a various microprocessor. And
perhaps the best-known example is Sun’s cross-platform language, Java. Called a Java virtual
machine, something that does not even physically exist, it allows software to run on any device
capable of emulating a fictitious computer.
The simplest sort of software emulator, called an interpreter, works by looking up every
instruction from the foreign program to obtain how to carry out the equivalent operation on the
host machine. This slow but reliable method allows modern PCs, for example, to emulate arcadegames
machines from the 1980s whose microprocessors ran at a fraction of the speed.
More sophisticated are just-in-time compilers, or JITs. After examining every instruction and
translating it into the native format of the system that it is running on, JITs keep the translated
code around in case it is needed again. And since most software repeats itself and small chunks
of code are typically run many times in a program, the chances are high that the translated code
will indeed be re-used. That usually makes a JIT faster than an interpreter.
The power of the modern computer means, however, that even cleverer emulators are now being
developed. Dynamic Recompiling (DR) emulators do not stop at translating instructions; they go
on to analyze how the new code works and translate the clumsiest bits all over again in order to
improve efficiency. Connectix, a company based in California, developed 1 such emulator, the
Virtual Game Station (VGS). It emulates Sony’s Play Station on a Macintosh personal computer.
Sony, which launched a new Play Station 2, is cross about this, but not because VGS might affect
the sales of consoles, which are sold at a loss, and encourage people to buy the games. It is cross,
the firm claims, because VGS might not be up to the job and customers might accordingly get an
inferior impression of Sony games. The American courts have so far, however, ruled in favour of
Connectix.
Connectix is a veteran of the emulator business. It sells also a program that enables a Macintosh
to impersonate a PC. But emulation is encouraging entrepreneurs also to begin new companies.
That is a sure sign that something significant, and possibly lucrative, is happening.

Earning:   Approval pending.