Datasheet

LOGGING ON AND LOGGING OFF
5
How Logging On and Off Worked in Windows 95, 98, Me, and Windows 2000
Logging on and off in Windows Vista works in much the same way as in Windows XP. But in versions of
Windows before Windows XP, only one user at a time could be logged on to a computer running Win-
dows. For a second user to log on, the first user needed to log off. Logging off involved closing all the open
programs and files: Either the user could close the programs and files manually before logging off, or
Windows would close them automatically when the user issued the Log Off command and confirmed
that they wanted to log off.
Once all the programs and files were closed, and all network and Internet connections were closed as
well, Windows displayed the Log On to Windows dialog box or the Enter Network Password dialog box,
depending on whether the computer was attached to a network. Another user could then log on to Win-
dows, run programs, open files, establish network and Internet connections, and so on.
You May Want to Avoid Using Fast User Switching to Improve Performance
Having multiple users logged on to Windows at the same time affects performance because each user
who’s logged on takes up some of the computer’s memory. Having a user logged on itself takes up a fair
amount of memory, and each program that the user has running, and each file that they have open, adds
to the amount being used.
Windows Vista needs a minimum of 512MB of RAM to run at all and runs much better with 1GB
(1,024MB) or more. For each light user, figure in another 128MB of RAM; for each moderate user,
256MB; and for each heavy user, 512MB. If your computer has 1GB of RAM or more, you should be able
to have two or three users logged on and running several programs each without running short of
memory.
Another issue is what the programs in a disconnected session are actually doing . A program that’s run-
ning but waiting for user input consumes very few processor cycles, but one that’s actively engaged in
a task consumes many—sometimes as many as Windows can give it. For example, if you leave
Microsoft Word open with a document that you’re composing displayed, Word waits for user input, and
if you disconnect your session, it just sits there waiting until you come back. But if you’re performing a
processor-intensive task such as video rendering in a disconnected session, performance in the active
session is poor.
Some programs pretty much suspend themselves when Windows disconnects their session and so do
not affect the performance of the active session. Experiment with the programs you and the people with
whom you share your computer use and establish which programs you can’t reasonably leave running
in a disconnected session.
If your computer has only 512MB RAM, avoid using Fast User Switching to reduce the amount of mem-
ory needed. Instead of switching user, close your programs and log off.
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