BOOT CAMP 559 (14/01/09)

Startup and Shutdown Problems, part 1

I am often amazed by readers writing in with tales of PCs that take 30 minutes or more to start up or shut down. I know it’s easy to let things slip a bit but anyone who can wait half an hour for a PC to boot up must have the patience of a Saint…

From switch-on a Windows XP or Vista PC should be ready to use in a minute or so and shut down in under 30 seconds. Back in the real world very few well-used PCs manage that – except in the first few days of use -- but the alarm bells should start ringing loudly when boot up takes much more than two or three minutes and the shutdown process lasts longer than a minute or two.

Over the next few episodes of Boot Camp we’ll look at some of the most common causes of a lethargic boot up and sluggish shut down and hopefully we’ll be able to claw back some of those wasted minutes with a few simple and safe procedures but first let’s run through what happens when you press the On button or click the Turn Off icon.

Booting up a PC is a fantastically complex business involving tens of thousands of operations. Each one has to be the correct order and timed to perfection or the whole thing grinds to a halt. It’s awe inspiring and once again it brings to mind Dr Johnson’s famous observation on performing dogs: the wonder is not that they do it so well, but they do it at all!

It's mind-boggling but it can be boiled down to a small number of digestible chunks. The first thing that happens when you press the On button is the power supply and motherboard wake up and the disc drive(s) spin up to speed. Within a few milliseconds a small program stored in an EEPROM memory chip on the motherboard leaps into action. This is called the BIOS or Basic Input Output System and its first task is to carry out a series of diagnostic checks on the computer's hardware bits and bobs (CPU, memory, drives, system busses, ports etc.). This is the POST or Power On Self Test and on many PCs a successful test is heralded by a single beep. If you hear more than one beep, or a sequence of beeps and the computer won't boot you have a hardware problem - it can't be Windows for the simple reason that it hasn't started loading at this point. You'll find an explanation of the most common BIOS 'beep codes' at: http://tinyurl.com/tc5y

If the POST is okay the BIOS sets about initialising and configuring the hardware components. When everything is working to its satisfaction it begins searching the disc drives and any memory devices one by one (the boot order), looking for the Master Boot Record (MBR). This is a set of instructions and a program, called the Boot Loader that tells the CPU how to start loading the computer's operating system (i.e. Windows). Normally the MBR is stored in the first sector of the first active partition (the boot sector) of the hard disc drive. If the primary hard drive is faulty or the MBR is missing or corrupt then it checks the next drive in the boot order sequence and this how you can get a dead PC to start using the 'bootable' Windows, DOS or Linux disc.

Windows PCs use a bootloader program called NTLDR and its first job is to read the Boot.ini file. This selects the operating system (if there is more than one) and begins to load two core Windows files called the 'kernel' and HAL (Hardware Abstraction Layer), into the PC's RAM chips. Next, the bootloader loads Registry System files and some key system and device drivers that are needed to continue the booting process. A Windows program called the Session Manager now takes over and this is responsible for setting up Windows graphics, loading any remaining drivers and configuring the PC's memory components.

Up to this point everything is pretty much on autopilot and it should only take a few seconds but the next stage is crucial, and where things usually start to slow down. The Windows Logon Manager takes over at this point and this handles user logon, setting up personal preferences, starting the Windows Services, and finally loading user-installed services and programs that are set to launch with Windows. This is the part of the boot up process we'll be concentrating on next week.

Thankfully shutting down a Windows computer is a lot simple. After you've closed all open programs and clicked the 'Turn Off' icon a utility called Services Control Manager (SCM) attempts to close any remaining Services that are still running and if they don't respond in 20 seconds they are terminated. However, some of the programs you've been using may have background components that won't shut down and some Services simply refuse to go away and this is what delays or halts the shutdown sequence so take a look at this week's Top Tip, or stay tuned for the Boot Camp shutdown Troubleshooter.

Next Week – Startup and Shutdown Problems, part 2

JARGON FILTER

EEPROM

Electrically Erasable Programmable Read Only Memory – memory chip that retains data when power is removed and can be updated or reprogrammed many times

NTLDR

Windows New Technology (NT) Loader – bootloader program used by Windows

SYSTEM BUS

Data connections within a computer

TOP TIP

Here’s a nifty way to shut down a disobedient Windows XP PC in just 5 seconds, and it almost always works. Press Ctrl + Alt + Delete to bring up the Task Manager, select Shut Down then press the Ctrl key and click Turn Off and watch Windows vanish in record time. Used occasionally it shouldn’t do any harm but it’s not an alternative to a proper shutdown so only use it as a last resort.

Don't forget, there's a full archive of previous Boot Camp Top Tips at www.pctoptips.co.uk

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© R. Maybury 2008, 2412

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