A directory service
manages information about users and resources, such as
printers and servers. It can manage this information for anything
from a single machine to an entire corporate network. The Directory
Service architecture in Mac OS X is called Open Directory. Open
Directory encompasses flat files (such as
/etc/hosts), NetInfo (the legacy directory
service brought over from earlier versions of Mac OS X and NeXTSTEP),
LDAPv3, and other services through third-party plug-ins.
This chapter describes how to perform common configuration tasks,
such as adding a user or host on Mac OS X with the default
configuration. If your system administrator has configured your
Macintosh to consult an external directory server, some of these
instructions may not work. If thats the case, you
should ask your system administrator to make these kinds of changes
In Mac OS X 10.1.x and earlier, the system was
configured to consult the
NetInfo database for
all directory information. If you needed to do something simple, such
as adding a host, you couldnt just add it to
/etc/hosts and be done with it. Instead, you had
to use the NetInfo Manager (or
NetInfos command-line utilities) to add the host.
Linux on ordinary commodity hardware can handle small to medium routing needs just
fine. The low- to mid-range commercial routers use hardware comparable
to ordinary PC hardware. The main difference is form factor and
firmware. Routers that use a real-time operating system, like the Cisco
IOS, perform a bit better under heavy loads than Linux-based routers.
Big companies with large, complex routing tables and ISPs need the
heavy-duty gear. The rest of us can get by on the cheap just fine. You
don't want poor-quality hardware; that's always a bad idea. You just
don't need to spend the moon for simple routing like this chapter
The highest-end routers use specialized hardware that is designed
to move the maximum number of packets per second. They come with
multiple fat data buses, multiple CPUs, and Ternary Content Addressable
Memory (TCAM) memory. TCAM is several times faster than the
fastest system RAM, and many times more expensive. TCAM is not used in
lower-cost devices, and no software can shovel packets as fast as
Most sponsors regard business impact data as the most important data type because of its connection to business success. For many projects, poor performance in business measures (the business need) is what would have initiated the project. Impact evaluation data close the loop by showing a project’s success in meeting the business needs. This chapter examines a variety of business impact measures and the speciﬁc processes needed to collect the measures within a project, but ﬁrst it addresses the reasons why impact data are measured.
Why Measure Business Impact?
Several rationales support the collection of business impact data related to a project.
Following the assumption that higher-level data create more value for key stakeholders, business impact measures offer more valuable data. Impact data are the consequence of the application and implementation of a project. They represent the bottom-line measures positively influenced when a project is successful. For some stakeholders, these are the most valuable data.