These are the useful pages that UK_Nick wrote for us on the forum.

• Manual results upload information
• Result & intermediate data upload information
• Quick Pause & Resume of the CPDN service under WinXP
• Creating & restoring from a backup
• Hardware specific tests & checks
• File errors at phase change
• Basic hardware maintenance

NB: Manual results upload is only appropriate if either;

1. The client window stalls at "connecting" with a line containing "can't open xxxxx file" near the end of "\execs\client_log.txt". or
2. You see an error message during results upload that will neither clear by using the [Try another file] button in the uploading window nor by rebooting. or
3. CPDN stalls during results upload for no apparent reason and it will neither clear by using the [Try another file] button in the uploading window nor by rebooting. (This sometimes happens when results upload appears to have completed succesfully.) or
4. You have a 'smallexecs' or other 'model corruption' error message that isn't cleared by rebooting. (These are sometimes cleared by installing the latest version as an 'upgrade', even if you're already running that same version - it depends which file has been corrupted.)

NB: Please don't use 'manual upload' at other times without checking here first - it will stop your model run at that point for no good reason..!

To upload results files manually from a completed full run (or a completed short run) use the "Manual Upload" option on your user stats page.

Upload the Config.cpdc file from the C:\Program Files\Climate Prediction\Execs folder together with all the .gz files that failed to upload from the C:\Program Files\Climate Prediction\Return folder - this may take quite a long time if there were a lot of files that failed to upload.

Note1: If your 'return' directory is empty then simply upload the '\execs\config.cpdc' file on it's own.

Note2: Files in \return have names like "39oqaa.pg.gmts.x1.nc.gz" - if you have Windows Explorer / Folder Options / View / "Hide extensions for known file types" checked then the '.gz' will be missing off the end when you 'browse' there. ("Hide extensions for known file types" checked is the default for a new Windows installation.)

You will then be given a URL to download a new Config.cpdc file which needs to go in the C:\Program Files\Climate Prediction\Execs folder.

Simply restart the client and presto, back to crunching on a new model.

Note3: If you move all the .gz files from \return to the appropriate \archive\experiment_x folder then your archive will be complete. ie. exactly the same as if the machine had uploaded automatically. NB: Do this before restarting CPDN or they will simply disappear when you start the new model..!

Note4: To avoid interference with subsequent automatic uploads;

1. Delete anything else in \return if present - \return should be empty at the start of a new model.
2. Delete "\execs\upload_*.txt" if present.
3. Delete "\execs\ufl.txt" if present.
4. Manually truncate "\execs\client_log.txt" keeping all lines including and beyond the last;

"DELIMITER,Beginning of experiment cycle.,00000,01924,010,Client Interface".

Note5: Prior to v2.2.28 the files in \return had an .lzp extension - v2.2.28 onward they have a .gz extension - the manual upload page will accept either type or a mixture of both for folks who upgraded in the middle of a model.

No stats 'trickle' updates after a manual results upload.

carl wrote:
Manual uploading bypasses the normal "clearing" of a run when it loops around to a new run - so the "trickle" entry in the registry never gets reset - so until you hit the same phase/timestep the new model won't trickle. The solution is to remove the key in your registry for:
HKEY_LOCAL_MACHINE\SOFTWARE\Climateprediction\lsts
If you are not handy with "regedit" we have made a simple 20KB Windows EXE that will take this key out which you can run from:
http://cpdn.comlab.ox.ac.uk/trklreset.exe
After running this and restarting CPDN you should trickle right away.

Note: The official release version is now v2.2.29 on all the download mirrors off the main CPDN website. (Minor cosmetic changes from v2.2.28 for OU students et al - you lose access to the 'decorations' and gain a pressure visualisation instead.)

v2.2.29 release version

Stats 'trickle updates': At intervals around 10,802 timesteps (circa 4.2% of each phase) CPDN will attempt to upload a small 'trickle' of statistics data to the CPDN Stats server. CPDN first checks with Windows whether you are online - if you are online then CPDN will upload the 'trickle' data and you should be able to see the change in your personal stats accessible via Settings / "View My Currently Registered Profile" in the CPDN user interface. If you are not online at the time then CPDN will query Windows whether you are online at 144 timestep intervals - about 10 minutes on a medium speed machine. Thus when you next go online, at the next 144 timestep interval, CPDN will upload an aggregate of any stats it could not upload whilst you were offline and your personal stats page will be updated.

Note1: A newly registered computer will not show up on your personal stats web page until the first trickle has been received by the stats server.

Note2: If you connect via a LAN or have 'always on' broadband then these 'trickle updates' will also occur whilst you're away from your computer at any time of day or night.

Note3: 'Trickle' updates use https port 443 the same as computer registration and the first model parameters download - connection via this port can be verified using CPDN GUI / Settings / "Check Central Server Connection".

Big Trickles: At the end of all three phases, CPDN compresses a segment of the data and sends it to the CPDN team at Oxford in addition to the final results for the third phase.

Note: v2.2.23B & v2.2.24 only uploaded 'big trickles' at the end of phases 2 & 3, not phase 1. Original release version 2.2.23 uploaded no 'big trickles' at all

Temperature & precipitation data graphs plotted from 'big trickle' data may be viewed via the Xs at the bottom righthand side of your personal stat's page after you have completed at least the first phase of your first model - you will eventually be able to compare how doubling CO2 and the other parameters specific to your model affected your model's world. (Also, see - this - for information on the new Advanced Visualisation Package Beta test.)

After you have completed the first phase of your model you should see something like the following at the bottom of your personal stats page;

-------------------- Run Information Received ------------------

RunID# -- Date Started ------------ Date Completed -- Model Name ---------------------------- Phase 1 Temps -- Phase 1 Precip -- Etc.
115215 -- 21-Nov-2003 11:14:02 ----------------------- UK Met Office HADSM3 (Slab Model) -- X ------------------- X -------

Eg. From one of my completed full runs; Temperature comparison by phase - Precipitation comparison by phase

Main Results Upload: At the end of the third phase, CPDN processes and compresses all of the data from the whole model into a number of files that total approximately 4MB. These files are uploaded to the CPDN results server when you are next online. CPDN will then download a new set of initial parameters for your next model and resume number crunching without any intervention from you.

Note: Subsequent data downloads and all result uploads to the Oxford servers use http port 80.

Unstable Model: If your model becomes unstable for any reason then it will crash. Model crashes like this are expected to happen reasonably frequently during the current Experiment 1. The model crash will be captured by the CPDN model controller software "Client Interface.exe" and the model will be rewound by resuming processing at an intermediate 'save point' dated some time before the instability crash. If the same crash happens again after three 'rewinds' then CPDN gives up on that model. The partial data is then processed and compressed into a number of files and uploaded to the CPDN results server. CPDN will then download a new set of parameters for your next model and resume number crunching.

Note1: A model crash isn't a bad thing if it was caused by the physics parameters used for your model. Experiment 1 is testing the boundaries with some 'way out' parameters to ensure no possibile scenario is missed. These crashed models are just as useful to the project's scientists for fine tuning later CPDN experiments as the models that complete succesfully.

Note2: If your computer is having difficulty running CPDN then this model instability may happen at very frequent intervals, usually soon after commencing the first phase of each new model - you should cease running CPDN and run the hardware stability checks detailed - here - to determine what is wrong with your machine before resuming CPDN. (Many slower machines have problems like this and there is no easy fix unfortunately, except a hardware upgrade. )

THC Slowdown version 3.0.01 BETA All much the same as v2.2.28 with regard to trickles & 'big trickles' - main change is that there are now four fifteen year phases, 60 model years altogether;'Spinup' phase 1, 'Control' Phase 2, 'Double CO2' phase 3 & 'Atlantic Thermo Haline Circulation Slowdown' phase 4.

Final results are all uploaded after phase 4 completes - v3.0.01 final results upload is circa 4.5MB which is ~0.7MB more than v2.2.28.

After you have completed phase four of your v3.0.01 model, 4s that link to phase 4 graphs will appear in the 'phase 3' columns at the bottom of your personal stats page and the '.....comparison by phase' graphs will also have an additional plot on them for phase 4.

Eg. From one of my completed v3.0.01 full runs;
Phase 4 temperatures - Phase 4 precipitation.
Temperature comparison by phase - Precipitation comparison by phase .

Note: Trickle intervals for v3.0.01 are currently more erratic than v2.2.28. They tend to stabilise after a few trickles at 10,804 timesteps per trickle but that will most probably change again if/when you reboot or restart CPDN.

Absolutely the easiest 'minimum click' way to stop / start the CPDN service under WinXP is;

1. Open Notepad then copy & paste the following
   net stop CPDNservice
   echo off
   cls
   echo . CPDNservice paused.
   echo .
   echo . Click anywhere outside this box before using your keyboard.
   echo .
   echo . To restart the CPDNservice, click on the title bar then.....
   echo .
   pause
   echo on
   cls
   net start CPDNservice
   
   Save as "CPDNpause.bat" wherever you want - I used C:\Windows\Program Files\Climate Prediction
   


2. Navigate to the CPDNpause.bat batch file using Windows Explorer - Right click on CPDNpause.bat and 'Send to...' Desktop (as shortcut)
   
3. Grab the new icon on your desktop and dump it on your 'Quick Start' bar then trash the extra icon that will remain on your desktop.

Anytime you want the CPDN service halted whilst doing something especially I/O or CPU intensive on your computer then simply click the Quickstart icon titled "CPDNpause". This way you'll have a reminder that the CPDNservice is effectively paused from the Commandline box on your desktop or in your taskbar if you minimise it - only problem with that is CPDN won't resume if another user kills the Commandline box before it completes running CPDNpause.bat but that's not my endaba. If the main user clicks the "CPDNpause" Quickstart icon again and follows the instructions onscreen then it will restart anyway.

One click pause & click + key tap resume, beat that if you can.

Ratopher wrote:
I have a short question concerning the THC-upgrade. I want to save my current experiment, because I want to be able to restore it if the upload of the data fails at the end of the experiment (since you and others have described this problem, and it is not solved yet, as I understand).

It is always a good idea to backup the \climate prediction folder before applying any upgrade just in case the install process screws things up completely - it does happen occasionally.

Quote:
So, which subfolders of the CPDN-folder do I have to save? Is that all of them in the main folder except the archive data of the old experiment, or can I exclude some of them?

I store the contents of each \climate prediction\archive\experiment_x folder elsewhere - that reduces the maximum size of the whole \climate prediction folder to a more maneagable size for speedy & easy regular backups. If I were you, I would do exactly the same rather than trying to 'slice up' the \climate prediction folder's contents - ie.:

1. Edit / select all / cut & paste the whole contents of each \archive\experiment_x folder eleswhere, eg. I use x:\CPDN Archive\experiment_x - run ID#xxxxxx
2. Create a backup folder, eg. I use x:\CPDN Backup
3. Copy the complete \climate prediction folder into the backup folder.

Note: I also do (1) & (3) at the same time whenever I create a new backup copy, so that my separate archive always matches the state of my most recent backup copy. The current archive only changes at phase transition - so there's nothing to do mid-phase when you make a backup.

To restore from a backup, all you would have to do is:

4. Delete the original \climate prediction folder eg. c:\program files\climate prediction
5. Copy x:\CPDN Backup\climate prediction back into the same place as in (4) & restart it - there's no need to do anything else.

If your computer is having difficulty running CPDN then model instability may happen at very frequent intervals, usually soon after commencing the first phase of each new model - you should cease running CPDN and run some of the hardware stability checks detailed below to determine what is wrong with your machine and fix it before resuming CPDN.

From personal experience. (I have no solid figures);

1. short run is entirely possible.
2. consecutive short runs would be too much of a coincidence - the proportion of short runs caused by 'bad parameters' is most likely less than 1 in 25. eg. I had a series of 25 consecutive completed full runs in a row that was eventually broken by two short runs which were almost certainly due to machine errors - I then had another long series of 32 consecutive completed full runs that was eventually broken when I upgraded to v3.0.0 Beta (THC Slowdown) due to a bug in the first version.
3. short runs in 5 runs would be beyond suspicious and I would have long since started running tests to find out what was wrong.

Note: If you didn't assemble the machine yourself and it is still inside guarantee then calling the manufacturer is your first option if it fails any of the following tests. Any computer sold should be capable of passing all of these tests entirely free of errors over a reasonable period of time; Eg. 24 hours of Prime95's 'Torture Test'.

Memory sub-system: Memtest86+ - download - is a really good standalone check for your memory sub-system.
(Select "Download - Pre-Compiled package for Floppy (DOS - Win)")

Note: Memtest86 runs outside Windows, directly off a floppy disk, so you cannot use your machine for anything else whilst it is running.

From Memtest86's 'Readme.txt';
To install Memtest86:

• Extract the files from the zip archive
• Open the directory where the files were extracted and click on "install.bat".
• The install program will prompt you for the floppy drive letter (usually 'a') and also prompt you to insert a blank floppy.
• To run Memtest86 leave the floppy in the drive and reboot.

When Memtest86 has loaded, Hit [c], [2], [3] & [Enter] for the full 11 test suite. This will take quite some time on an older machine but you cannot be sure your memory sub-system is error free until Memtest86 has run at least one clean pass of the full 11 test suite.

Memtest86 will loop continuously until you hit [Esc] to exit - remove the floppy disk and Windows will boot as normal.

If you see errors then you can try;

1. Slowing down memory timings in BIOS.
2. Increase memory Voltage a notch or two - I have a lot of DDR memory that has run at 2.7V (0.2V above spec.) for years without problems - some PC3200 will not even run error free at spec' timings unless it is overVolted slightly.
3. Re-seating memory, perhaps in different slots.
4. Fitting better quality memory.

Note: Check your motherboard handbook and hardware specific websites or Usenet newsgroups for information relating to your particular hardware. Eg. The alt.comp.periphs.mainboard.abit Usenet newsgroup has many folks who can help with any problem regarding Abit motherboards.

CPU: Even an off-the-shelf 'whitebox' may be unstable at specification speed due to manufacturing errors (Eg. an incorrectly seated CPU heatsink) [3] but instability is more often due to enthusiasts pushing their overclock just a little tooooo far. [2]

Tests:
SuperPI - download - is a good initial check for CPU and memory sub-system stability. The full 32M test may take some hours but, if it runs clean, then the CPU is at least reasonably stable. Any errors at all then you need to back off on the overclock [2] or do some basic maintenance. [3]

Note: The full 32M test may not run under Win98OE/SE/ME due to memory limitations but the 16M test is adequate.

Prime95 - download from here - has a good CPU & memory sub-system stability check embedded in it. Prime95 / Options / Torture Test. If you see any error at all whilst running Prime95's 'Torture Test' overnight then there is something wrong with either the memory sub-system or CPU, most often the CPU is being pushed a little too hard for either your cooling system or the CPU's own architectural limitations. [2] or [3]

Using CPDN itself to test a system after either a number of fast 'short runs' or tweaking BIOS or a hardware upgrade - I test my own systems thus;

1. Disconnect the machine from the internet so that it cannot send in dud results. [1]
2. Backup the complete C:\Program Files\Climate Prediction CPDN folder so that I can revert to the backup if I see any errors at all - Eg. If the world turns to an iceball very quickly & tries to upload results then I would back off the overclock [2] to where it was, revert to the CPDN backup & check to see if it still turns to an iceball.
3. Run self-checking software like Prime95 & SuperPI at the same time as CPDN.
4. un the CPDN '3D' visualisation for some time to see if it causes a lockup. (3D applications are prone to causing stability problems, as any 'gamer' knows all to well, but these are more usually driver related - update to the latest drivers is the primary 'fix' if you have problems here.)

Prime95's execution thread priority can be changed using the password found in the Readme file - I run Prime95, SuperPI 32M & CPDN's Model.exe all at the same time with 33% of the CPU going to each - when SuperPI 32M completes a clean run, I then balance Prime95 & Model.exe at roughly 50% CPU each overnight. If Prime95 has run clean overnight then I reduce Prime95's priority a notch so that it takes under 10% of the CPU and leave it running for a few days, occasionally allowing CPDN to connect (if Prime95 is still running clean) & taking a new backup of CPDN immediately afterward.

Hard Disk Drives:(HDD)
I always test a new HDD by running Windows XP's Checkdisk 'Scan for and attempt recovery of bad sectors' or Windows 98xx's Scandisk 'Thorough' full surface scan.

WinXP: Running 'checkdisk' - double click 'my computer' / rightclick your hard drive (C: ) / properties / tools tab / error-checking [check now] / check off 'automaticaly fix file system errors' & 'Scan and attempt recovery of bad sectors' [Start] - since it's your 'system disk' a box will come up telling you that a check can't be run now and asking if you want to schedule a check for the next reboot, click [yes] and then reboot - during boot the program 'chkdsk' will run and the machine will automaticaly reboot itself again when it finishes.

Win98xx: Running 'scandisk' - double click 'my computer' / rightclick your hard drive (C: ) / properties / tools tab / "error-checking staus" [check now] / select 'Thorough' & also check 'Automaticaly fix file system errors' [Start].

Warning: WinXP and Win98xx - this test can take a loooong time with the huge size of recent HDDs.

If the HDD passes this test then it should be good for some years of continuous use as long as it remains reasonably cool in operation, preferably under 40C. HDD errors will show up in a number of ways; Eg. A warning from Windows that XXX file is missing or corrupt during bootup - WinXP can recover by itself from a lot of errors like this but not all.

If your machine has passed that lot then it should be good-to-go - have fun.

[1] Disconnect a machine from the internet by either;

1. Pull the plug, ie. Remove the telephone cable from the modem or the Ethernet cable from your router / hub.
2. Win98OE/SE/ME - Rightclick on 'My Computer' / Properties / Device Manager tab / select 'Network adapters' and 'Dialup Adapter' if you connect via a modem or ''XXXX Ethernet Adapter' if you connect via Local Area Network (LAN) - check 'Diasble in this hardware profile' & [Okay] back to the desktop. (Some setups may require a reboot.)
3. WinXP - Rightclick 'My Network Places' / Properties / Rightclick 'Dialup adapter' or 'Local Area Connection' and select 'Disable' - I then leave this window active whilst testing for stability so that I remember I have the connection disabled.
4. It may be possible to block CPDN from accessing the internet by changing some settings in your firewall software.

Reverse the above to re-connect - Win98 systems may require a reboot. (Check the connection is good using CPDN GUI / Settings / 'Check Central Server Connection'.)

[2] For Overclockers: Backing off only 2~3MHz on the FSB & memory bus can make a surprising difference to longer term overall stability. You lose less than 100MHz raw CPU speed but you get to see a model complete a full run, so that little loss will be well worthwhile.

Note: There are literaly thousands of overclocking resources on the internet - try a search for 'overclocking' at Google..! Thus I've made no attempt at helping beginners to overclocking here, you'll have to do some work on that one yourselves. One good resource that I used a lot in the past, & fed back into as my experience widened, is the Usenet Newsgroup alt.comp.hardware.overclocking - lots of very knowledgeable folks there but do read through the FAQ first if you desire a polite reply.

[3] Perhaps the CPU heatsink, other fans &/or filters simply need a good cleanup - see the "Basic Hardware Maintenance" article in this page.

Quick fix (maybe) for CPDN File Errors at Phase Change.

WinXP:
One thing you could easily try is running 'checkdisk' - double click 'my computer' / rightclick your hard drive (C: ) / properties / tools tab / error-checking [check now] / check off 'automaticaly fix file system errors' [Start] - since it's your 'system disk' a box will come up telling you that a check can't be run now and asking if you want to schedule a check for the next reboot, click [yes] and then reboot - during boot the program 'chkdsk' will run and maybe fix your errors - the machine will automaticaly reboot itself again when it finishes &, hopefully, your CPDN model may get started again but it's only a hope, not a guaranteed fix.

NB: Don't check 'Scan and attempt recovery of bad sectors', that will deny you access to your computer for a loooooong time, the 'fix errors' scan will only take a few minutes.

Win98xx:
Note:I'm reading out of WinME for this thus Win98OE/SE will probably be slightly different but not by much - WinME is Win98 Third Edition.

One thing you could easily try is running 'scandisk' - exit CPDN then double click 'my computer' / rightclick your hard drive (C: ) / properties / tools tab / "error-checking staus" [check now] / select 'Standard' & also check 'automaticaly fix file system errors' [Start] When scandisk has completed it's run then close it and try re-running CPDN - hopefully, your CPDN model may get started again but it's only a hope, not a guaranteed fix.

NB: Don't check 'Thorough', that will deny you use of your computer for a loooooong time, ('Scandisk' quits & starts again every time you access the hard disk drive it is checking.) the 'fix errors' scan will only take a few minutes.

Note: If the CPDN file system has been completely screwed up by some form of hardware glitch during the many file accesses by CPDN then there is currently no way back from it but do please check with Carl direct before wiping week's of hard crunching and starting again with a new model. If this happens repeatedly then you really need to run some very thorough checks on your I/O system or have your local computer handyman take a look at it.

It can happen to anyone: I had an older hard disk crash bigtime at ~10% through Phase 1 - a 13Gb ATA/66 Fujitsu 1998 'vintage' HDD on 'Dilly': I made zero attempt at recovery, I simply replaced the HDD, re-installed WinME from scratch & ran Scandisk's 'full surface scan' from Windows prior to re-registering the machine with CPDN. Bit drastic if you're any further through a model but, IMNSHO, the only 'safe computing' way forward in the circumstances.

(A regular 'rolling backup' to off machine media will avoid data loss from hard disk failure but it's a bit of a pain to keep up-to-date with the current size of my harem. )

PS: Please do post in this thread if you have to start again with a new model because of file corruption..!

If you're running CPDN, or any other distributed computing application, your machine will quite likely be running 24x365. Recent CPUs use quite a lot of power (60~80Watts) when compared to older desktop machine's CPUs (20~30Watts). Many components in a recent machine are operating at speeds faster than the CPU in that old desktop box, so all those other components combined require significant power too. That power has to be dissipated as heat thus many individual components require quite sizeable heatsinks & fans along with a good draft of relatively cool air through the whole machine for stable operation. All that air carries dust with it thus a lot of dust will end up lodged in heatsinks and fans as 'dust bunnies' - or in inlet fan dust filters, if the assembler fitted them.

Soooo, one of the first things to check if your machine starts having problems is if the heatsinks or inlet filter(s) are choked with dust. Switch off at the wall and unplug first - modern ATX format computers do not have dangerous Voltages outside their power supplies (PSU) but older AT format machines have full A/C Voltage at the computer's main switch. Beyond that, I can't give you specific advice for your particular machine because they vary so widely but it is usually quite easy to remove one side panel of a 'tower' or the top of a small desktop box to check for dust accumulation.

Warning1 - electrostatic shock: Be careful to touch an earth point (Eg. a metal sink or bare metal on a central heating radiator.) before touching any electronics inside your machine. It is also a good idea to avoid working on a machine whilst standing on carpeting - if you've ever walked around a department store wearing shoes with plastic soles then you will already know why. (Touch a metal handrail & wonder what bit you. ) Electrostatic shocks can destroy many integrated circuits instantly with no visible sign of damage.

Warning2 - working inside a power supply: If you decide to open & clean out your PSU then be very careful what you touch inside it - those big capacitors in there can carry one heck of a charge. Left for some hours before opening, the capacitors should have discharged through other circuitry but - you have been warned..! The PSU exhausts a lot of heat from most machines, it is the only exhaust fan in many 'white boxes', thus it may get choked with dust bunnies after a while - a plastic or wooden handled stiffish brush is your safest bet for this particular cleanup job.

Any filter will be on inlet fan(s), sometimes behind the plastic front bezel - easy enough to remove too but, if you're unsure, get your local computer handyman to do it for you. Dust bunnies can be blown off heatsinks and fans using compressed air - don't switch back on too quickly after using compressed air because water is likely to condense out on the cold areas where you've used it. (No problem once it has dried off.) You can also use a 1/2" to 1" paint brush to remove dust from heatsinks but do hold the heatsink firmly so that you don't disturb it's contact with CPU, graphics processor (GPU) or chipset.

If you smoke (as I do) then heatsinks may need removal and washing to get them completely clean - the amount of sticky tar that condenses out on them is truly amazing..! If you remove a CPU heatsink that was fitted using a thermal pad (most recent white-box computers.) then you will need to clean the residue off the heatsink & the CPU with something like Cellulose thinners or some other form of degreasant before refitting the heatsink using a thermal paste. Eg. Arctic Alumina. Take great care refitting any heatsink to FCPGA chips like PIII Coppermines or Athlons - the silicon wafer is directly exposed to the heatsink and it is quite delicate.

Warning: Faster PIIIs and all Athons will self-destruct in seconds if switched on without a heatsink in situ..! If the CPU fan is disconnected, or has simply quit, then the motherboard may refuse to boot - if it does boot then you should soon hear a two tone 'siren' warning of overheating & recent motherboards will shut themselves down. Intel's P4 will slow itself down rather than self destructing but it won't be much use at the speed it will slow to without a heatsink in place.

Sleeve bearing fans will often become a little noisy then slow down or stop completely after a period of continuous operation - usually measured in years but some GPU & chipset fans don't last that long. Standard size 12V DC fans, ie. 120mm, 92mm, 80mm, 60mm & 40mm measured across the fan case, are easy enough to replace with inexpensive similar units - twin ball bearing fans are a little more expensive but will usually outlast the service life of a computer. Many difficult to replace chipset & GPU fan 'specials' can be revitalised; Remove the fan, lift the label & put a single drip of light oil in the bearing, (too much oil will act as a dust bunny attractor.) stick the label back down & work the fan back and forth until it spins freely then refit it.

Monitoring your machine's temperatures, Voltages & fans is a good idea for preventative maintenance before you start having problems: Many motherboard manufacturer's supply hardware monitoring software on their drivers CD. Motherboard Monitor is the best hardware monitoring tool that I know of but MBM5 setup is a little 'geeky'.

Any computer component will last longer if it runs cooler, especially modern hot-running high-speed HDDs. The coolest place in almost any room is the lower part of it. Dust gets kicked up from carpeting, so standing a computer directly on floor carpets isn't a great idea but a few inches off the floor is usually the best place temperature wise. Good air circulation around a modern machine is also a 'must'; Eg. Standing a computer inside a cupboard is not a good idea unless the cupboard has very good ventilation.

"HDD Health" HDD monitoring freeware is available from Pantera Soft. It will monitor many aspects of your HDD, give a loose prediction of the time to failure and a good idea if funny things are starting to happen with the HD.