Information Technology Reference
In-Depth Information
Web
Page
Web
Page
Good Web
Site
Evil Web
Site
Script
Script
Browser
Plug-in
OS
Figure1.6: Web browser
site. The user in most cases doesn't notice the dierence, even when
updating a shopping cart or web form. How does the browser mask
server changes transparently to the user?
{ Glue. How does the browser achieve a portable execution environ-
ment for scripts that works consistently across operating systems and
hardware platforms?
Media players, such as Flash and Silverlight, are often packaged as browser
plug-ins, but they themselves provide an execution environment for script-
ing programs. Thus, these systems face many of the same issues as both
the browsers and the operating systems on which they run: isolation of
buggy or malicious code, concurrent background and foreground tasks,
and plug-in architectures.
Multi-user database systems (Figure 1.7) such as Oracle and Microsoft's
SQL Server provide the ability for large organizations to store, query,
and update large data sets, such as detailed records of every purchase
ever made at Walmart. Large scale data analysis provides a huge benefit
to optimizing business operations, but a consequence is that databases
face many of the same challenges as operating systems.
Databases are
