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Division of Labor
Speaking of primitive, let's hearken back to the old days of the DOS
PC. If you've worked with DOS at all, you know that about a zillion
little programs, called TSR (Terminate and Stay Resident) programs,
would jack themselves up into your PC's memory and sometimes wreak
havoc with your other programs. The same was true of the Apple
Macintosh computer, only TSRs were called CDEVs and INITs-and not all
of them would work with one another. Therefore, if you didn't have
another PC or Mac to compare with, you would have to start getting rid
of them one at a time to see if whatever you were trying to do would
start working.
Of course, most seasoned tech support operators used to recommend that
the first thing you do is to "boot vanilla"-that is, boot without all
those startup programs. Guess what they were actually telling you?
Divide and conquer! Instead of dealing with each little program, you
get rid of them all and then see if you still have problems. This is
similar to how you dealt with the previous hub problem-you split them
in half and try again until you find the offending program.
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Here's how you can "boot vanilla" from Windows 95:
o Start the computer in "safe" mode by pressing F8 right after you
turn on your computer (but before you see the blue sky design
of the Windows startup screen). You can choose Safe Mode or
Safe Mode with Network, depending upon whether you can test
whatever it is without the network.
o Press and hold down the Shift key after logging in (this
applies to Windows NT as well).
Here's how to "boot vanilla" from DOS:
o Press F8 after you turn on your computer. This will allow you to
select which TSRs and/or device drivers to load.
o Back up your startup files by copying AUTOEXEC.BAT to
AUTOEXEC.BAK and CONFIG.SYS to CONFIG.BAK; then, get rid of
drivers and TSRs manually. You can copy the respective BAK
files back to CONFIG.SYS and AUTOEXEC.BAT once you're done.
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Every single networked system you have in existence is going to
benefit from this same technique. Even though you're no longer in a
single-tasking, non-networked environment, this technique still
applies.
As I discussed in the last hour, you can find many problems in a
networked environment just by thinking about the changes that have
been made recently. However, sometimes changes aren't under your
control or you're oblivious to them. Good examples of this include
browser updates, plug-ins, and virus protection patterns. Therefore,
when the change is not obvious, you have to stop banging your head
against the wall and get back down to basics.
For example, let's say everybody in your office starts having problems
shutting down. They all get stuck at the "Please wait while your
computer shuts down" screen. It seems, at first glance, that everybody
is going to have to deal with it. Nobody has changed anything recently
that they know of, and no one is capable of wading through the guts of
what's going on.
Even though this doesn't seem like a network problem, the fact that it
just started spontaneously on a bunch of networked computers seems
very odd, so it gets dumped in your lap. Fortunately, you realize that
even if social engineering does not reveal the source of the change,
something has changed, and you can at least use the divide-and-conquer
method to figure out what it is.
Because your office runs Windows 95, many of the programs that run at
startup are in the Startup menu. You get rid of everything in the
Startup menu and reboot. All of a sudden, you can shut down again. You
return half of the programs to the Startup folder and keep restarting
until you find the source of the problem. It turns out to be your
email notification program. However, you decide to start up with just
the email notification problem, and you're able to shut down.
In this case, you've got an interaction problem, which is further
solvable via the divide-and-conquer method. You put back in half of
the programs that were in the startup file, and you manage to track
the problem down to a situation where you have both the virus
protection program and the email notification program loaded. As you
might have guessed, this troubleshooting session actually happened to
me-the virus protection program, which is automatically updated from
the Internet, had started to interfere with the email notification
program. A quick search of the vendor's Web site found a patch for the
email client (not the virus protection program) and an annoying
problem was fixed.
Obviously, the divide-and-conquer method doesn't always work to
ultimately solve your problems. In particular, it's tough to
troubleshoot intermittent problems, as well as quantitative (rather
than qualitative) problems that don't involve a black-and-white
(broken or not broken) scenario.
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You can remember the difference between qualitative and
quantitative by keeping in mind that qualitative is the analysis of
the quality of a situation (as in, "My workstation cannot print at
all"). Quantitative refers to the analysis of the quantity involved
with a situation (as in, "My workstation is slower at printing than
Sally's").
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For example, the divide-and-conquer method might lead you to believe
that a new application is causing your network slowdowns (and you
might be right). However, it's not always feasible to get rid of a new
application, and, furthermore, it might not be clear whether the
trouble is this particular application or just that the network itself
is at a saturation point in general. In this case, you might try a
different application, but can you really switch a largely deployed
application in a short period of time? You'll probably just end up
checking the application to see if it's misconfigured and taking
measurements to ensure that the application is behaving properly on
your network.
The bottom line is this: Even when the divide-and-conquer method can't
directly find your problem, it can at least point you in the right
direction.
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