Information Technology Reference
In-Depth Information
Parallel App
Runtime System
OS
Processors
Figure1.8: Parallel Application
HTTP ... SKYPE
TCP UDP
IP
DSL CABLE
ETHERNET WIFI PHONE
Figure1.9: Internet
vided by the underlying operating system, others need more careful con-
trol of the assignment of work to processors to achieve good performance.
These systems interpose a runtime system on top of the operating system
to manage user-level parallelism, essentially building a mini-operating sys-
tem on top of the operating system.
On the Internet (Figure 1.9), multiple users share the underlying physical
network, posing the challenge of how the system should handle resource
contention. The Internet is rife with malicious behavior, such as denial-of-
service attacks that flood trac on certain links to prevent legitimate users
from communicating. Various attempts are underway to design solutions
to allow the Internet to continue to function despite such attacks.
{ Referee. Should the Internet treat all users identically (e.g., network
neutrality) or should ISPs have the ability to favor some uses over
