BOOT CAMP 568 (18/03/09) – The Windows Registry, part 1
In the past few months I’ve
noticed an alarming increase in the number of emails from readers who have been
conned in to buying useless Registry Cleaner programs that purport to fix a
wide range of computer problems, improve performance and increase reliability.
I have to say these programs are mostly snake oil; they rarely make any
difference and sometimes do more harm than good. In some cases the errors
reported by the ‘free trial’ versions of these programs, and there may be
hundreds or even thousands of them, are not harmful or they are completely
fictitious, created by the cleaner program. Needless to say the software offers
to remove them, but only after you’ve purchased the full version of the
program.
Part of the problem is the widespread lack of awareness about
what the Windows Registry is and what it does. It doesn't help
that I and other PC Agony Aunts and Uncles regularly warn
of the dire consequences of tinkering with this large and
important system file. The Registry has become steeped in
mystery and endowed with almost magical powers so it's
hardly surprising that unscrupulous software companies have
recognised the gap in the market and jumped in to peddle
programs that capitalise on PC users fears.
The general advice that the
Registry is best avoided by absolute newcomers and wary novices still holds
true but it’s nowhere near as scary as it sounds. In fact I would go so far as
to encourage PC owners to have at least one quick glance at their PC’s
Registry. Not that it’s very interesting to look at, but once you’ve seen it
and understood a little about how it works I suspect that you will be less
likely to be taken in by the scare and con merchants. Later, in this short
series, if you are feeling brave, we’ll tweak a couple of settings, and look at
ways to fiddle with the Registry without getting your hands dirty or
endangering your machine and yes, if you really must, I’ll suggest a couple of
free and safe Registry Cleaners.
So let’s begin with the
basics and the somewhat dull fact that the Windows Registry is just a big
database. It is used to store settings and information about Windows, your PC’s
hardware, the programs that you use and the computer user’s preferences and
customisations. See what I mean? It’s already starting to sound less
intimidating...
Of course there’s a bit
more to it than that and the Registry is also responsible for a number of
housekeeping tasks and behind the scenes operations but the point is, it is
primarily a repository for the data that determines how your computer works,
looks and behaves, everything from how long it takes before your favourite
screensaver appears to how much memory is being used by running programs.
I said the Registry was
big, and it is, but its size varies widely from one PC to another. Depending on
the version of Windows that you are using, your software and how long you have
been using your system, it can be anywhere from 30Mb to several hundred
megabytes.
The Registry grows quickly
as you customise Windows and install new programs and this can be a problem.
Each new piece of software can create scores and sometimes hundreds of new
Registry entries. In theory they should all be removed when the program is
uninstalled. The trouble is not all programs clean up properly when they go so
the Registry swells with redundant entries. They are mostly harmless but
occasionally a new program, or a newer version of an application clashes with
an old Registry entry and up pops a worrying error message.
The size of the Registry is
also blamed for slow startup and shutdown and this definitely was the case in
earlier versions of Windows, as we’ll see in a moment. However, from Windows XP
onwards only the parts of the Registry that are actually needed are loaded
during the boot up sequence and even if the files concerned have become bloated
and unkempt it should only take a second or two to process so in most cases
Registry cleaning and pruning software makes little or no difference to boot up
time.
You may be wondering where
the Registry is stored. In Windows 95, 98, SE and ME the entire Registry was
contained in just two or three files, called System.dat, User.dat and
Classes.dat (the latter appeared in Windows ME) and they all live in the
Windows folder. Current versions of Windows (XP, 2000, Vista and Windows 7) are
built on the Windows NT platform and partly to avoid problems of a slow boot up
the Registry is split into multiple files stored in two locations. The bulk of
the Registry files can be found the Windows\System32\config\ folder. The main
files are called Default, SAM, Security, Software, System and UserDiff and they
are concerned with global or system wide settings. A second set of files are
stored in the Documents and Settings\<yourname> folder in XP
(Users\<yourname> in Vista, called Ntuser.dat, there is one of these for
every user and this stores all of the personal settings and customisations for
each user.
Next Week – The Windows Registry, part 2
JARGON FILTER
SAM
Security
Accounts Manager – encrypted database file used to store passwords
SYSTEM
RESTORE
Facility
in Windows ME, 2000, XP and Vista that stores and records changes to
key system files, which can be used in the event of a crash or serious problem
to restore Windows to a previous known good configuration
WINDOWS
NT
Windows
New Technology; family of operating systems on which XP, Vista and Windows 7 is
based, first released in 1993 and the first to use a 32-bit architecture
TOP TIP
Windows does its best to
protect the Registry and a pristine backup that is never updated is made
automatically when Windows is installed (they have the extension .sav). If
needed they could be used to reset Windows to day-one. Current Registry files
are backed up by System Restore, which on most PCs occurs every 24 hours.
Don't forget, there's a
full archive of previous Boot Camp Top Tips at www.pctoptips.co.uk
---end---
© R. Maybury 2009, 2402
Part 2 3
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