It often confusing to distinguish between an emulator and a simulator.
Normally, an emulator is implemented in hardware, whereas a
simulator is implemented in software. For example, a router emulator
is used to test the performance or bugs in router hardware and
software. The bugs may include clock timings, software instruction
sequencing problems, and speed test. A simulator is implemented in
software only. As a result, it will not have the ability to emulate
the hardware environment such as clock timings, speed testing etc.
Simulators are relatively slow since they are implemented in
software. Emulation allows developers to see the real-time
interactions between different hardware and software modules. It is
also possible to connect real-world stimulus to peripherals and
start debugging system behavior. Normally, a simulator is used
during the initial stages of development, when the hardware is not
yet ready. An emulator is more expensive as it is implemented in
hardware and performs at the speed of real hardware or even better.
A simulator is cost effective and the utility is limited to
simulating software functional modules, often without the underlying
hardware. The roles of a simulator and an emulator usually
complement each other, thus providing a total testing environment.
The software offered by CertExams.com is a simulation software,
completely based on software. No hardware is involved. It is felt
that the performance degradation observed by using a simulator is
very marginal and worth the cost advantage offered.