Some research pointed me to the proliferation of the 6to4 adapters in Windows. These adapters help to route IPv6 over IPv4, and for some reason, I’ve got hundreds of these adapters in my system.

All I had to do is to remove them by disabling IPv6, and the problem got resolved. No root cause here yet, but at least there’s the fix.

So, go to http://support.microsoft.com/kb/929852 and apply Fix #50409 & #50412. Both will need a reboot each time, and then my problem was resolved.

So, what’s this about? This is about fundamental configuration of physical ethernet network connections. Something a vast majority takes for granted. This applies very much to the days of 10/100Mbps networks, which is still very prevalent in current environment, but is slowly going away.

In ethernet, when 2 devices are connected together with a regular UTP cable, they’ll need to communicated at the same speed and mode of transmission. For optimal operations, both ends have got to be operating at the same settings. For speed, there’s a choice of 10Mbps or 100Mbps, and transmission mode is full or half duplex.

If there is speed mismatch, there won’t be any communications at all, and it’s easily corrected. So once you see there’s a link, the speed is definitely a match. However, what’s not obvious at all is that the transmission mode (duplex settings) may not match. And when they don’t match, the result is horrifyingly slow throughput.

So what does full duplex and half duplex mean? It simply means when and how each device is allowed to transmit. In half duplex mode, it means only 1 of the devices is allowed to transmit at any one time. The other just listens. In full duplex mode, both devices are allowed to transmit at the same time. In the very early days of ethernet over UTP, the cores in the wire are shared, such that the transmission cables are shared, as such when more than 1 device transmits, the message on the cable  gets “noisy” and collision occurs.

Imagine, that if at one end, device A is told to communicate at half duplex, and at the other end, device B thinks full duplex is in operation. So, when A is sending out signal to B, and B needs to send something back to A, B thinks it’s ok and sends out the message. A is not expecting anything from B at all, and so is unable to handle the traffic from B. As a result collision occurs. A will keep resending it’s data thinking that it never reached B, and in the end, a whole lot of miscommunication occurs. This causes what appears to be very very slow throughput.

In this day and age, I would say all cat 5 UTP cables and devices are full duplex capable. Also, there is a 5th setting called “Autodetect”. It’s this “autodetect” setting which introduces a lot convenience as well as headache. Personally, I love “autodetect” and advocate the use of it. But by those who don’t understand it, avoids it at all cost. In fact, some IT shops will default to move away from “autodetect” at all costs.

So, why are some network people so afraid of “autodetect”? More often than not, they’ve had bad experience with poor performances due to duplex mismatch. There is some history to this…. when autodetect first showed up, there was interoperability issues between different vendors. Naturally, for that reason, it’s fair to set a standard to avoid “autodetect” as a default setting. But this is something one will observe maybe 15-20 years ago.

Soon after, the IEEE stepped in to resolve this by standardizing how “autodetect” should work. It’s a good thing, but the standardization is quite peculiar. Here’s why….

Autodetect is great with speed negotiation, if there’s no cabling issue, both devices will negotiate at the highest possible speed. Usually no issues here. Even if one end is put to a manual setting on speed, the other end on auto will still get it right.

Then, here comes the fun part… if one end is set manually on the duplex, the end which is on auto will default to half duplex. Yes, half, not full. I never understood what the reason is. But you can see that if someone sets one end to full duplex, the other end on auto will always talk in half duplex. As a result, we have a duplx mismatch, and performance will be bad.

So, if no one takes care to understand why performance tanks when network settings don’t match at both ends, you’ll get an environment without a standard. You’ll see some ports are set to autonegotiate, and some are set to manual… and some do have mismatch and some don’t.

My take is that, if you’ve got fairly recent equipment, just leave everything on default to be on “autonegotiate”. If you’ve got flaky performance, it’s more likely due to bad cabling, and have that fixed. If you are using manual or static type settings, cable issues are less likely to surface, and it’s not obvious that there may be cabling issue at all.

The website hosts a lot of popular applications, and every version of those software that have been publicly available. Most of the times, these software are no longer found on their main website, and even hard to find on the P2P network. Fret not as this site has it!

So, if there are any vintage versions of Winamp that you like, but lost due to a system rebuild. You can hop over to Old Apps and download that favorite version you like.

I’m talking about computer virtualization here. And so what the heck is it really about? To senior management, it’s a promise of lowering cost, faster ROI, better flexibility of the infrastructure, simpler management of IT infrastructure.

To the guys on the ground, it means, faster build and release to production, quick and easy back out plan for patch maintenance, fast cloning of production data for beta testing, no more hair ripping experience due to hardware refresh, and much much more.

Right, so these are some of the benefits that I just touched on. So, still what really is virtualization?

To virtualize a computer/server is simply just an extraction of the running system from a physical box, into just a bunch of files and processes. In a traditional approach of having 1 OS instance per physical box, we move into the realm of having multiple OS instances per physical box. No, this is not multiboot, this is having more than 1 OS instance running simultaneously in each physical box. Imagine, one box, be it a regular desktop or a high end server, running multiple OS at the same time. Each OS instance runs unaware of the other in the same box. They are independent of each other, they can work together, they can do anything just like how they will be as in the traditional model.

For example, you can have a Redhat Linux instance, Windows 2008,  Windows 2000 Server, all running as virtual machines (VM) in the same physical box. You can ssh into the Linux VM and do anything as you may as a regular Linux machine. You can RDP into the Windows VMs, check on running services, eventlogs ,etc… just like any other Windows servers.

To the un-initiated who logs into a VM, they will not know that it is a VM. I behaves just like any regular server.

So, since the VM does the same things as the physical counterparts… what’s the point?

Now, think about this for a moment. In nearly all data centers today, going with the 80-20 rule, we can easily find 80% of the servers running with very low utilization most of the time. Some probably only spike up once a week or month even. So, the rest of the days, it’s just there doing nothing much, and just sucking up power.

So, let’s say we take 10 of such servers, virtualized them and consolidate them all into just 1 box. If done correctly, you can expect the performance of these 10 servers to remain the same. And there you have it, 90% reduction!! Instead of buying 10 servers, you just need 1. Just 1 physical server to run, maintain and suck less power and utility. Lower up front cost, certainly less ongoing utility bills, and real estate cost. In real life examples, we can see conservative consolidations of over 20 servers into just 1 box!!

This is only the tip of the ice berg we have touched on here. Let me go on a little more before this introduction becomes too much.

One very powerful aspect of virtualization that some may take for granted, but makes all these wonderful concepts possible, is that virtualization creates a whole new hardware platform. I see it as a virtual hardware platform. The virtualization layer basically creates a whole new infrastructure, which only exists logically. What this means is that the hardware that the VM OS actually thinks it sees, are virtual. They do not exist, physically.The result is that we have essentially de-coupled VM from the real server it resides on. We can then take a copy of that VM, and allow it to run on any physical box that has the virtualization layer/engine/OS installed.

Such is not possible with OS running on physical machines. The closest thing we can probably do is pull out the harddisk from one server, transfer it to another server with the exact same hardware, CPU, RAM, NIC, HBA, etc… and then boot up. Even then, there are some differences, the NIC MAC and HBA addresses are different. If you transfer the harddisk to other boxes, but with different config. You’ll end up with some nightmare to reconfigure all the drivers, which most of the time is a very very risky maneuver.

If you are following my thoughts so far, you should now realize that virtualization transforms servers to be something portable. With the right setup, you can easily move VM from one physical box to another, even in different locations, and geography. Think server migration… you can even just copy a VM on to a 2.5″ portable harddisk, take it with you on the plane, fly half way round the planet, and load it up on to another box, and it’s up and running in minutes!!

Again, we are still only scratching the surface. The promise of what else can be done is tremendous, and I will write about them in my future posts.

For those who I’ve lost since “Avatar”, I’ll close off with a little tidbit to help you appreciate virtualization a little more. Some of you may have played old Nintento consoles, the Famicom, Super Famicom, Gameboy Advance, etc… There are emulators out there, which allows you to play these old school games on your computer, be it a Windows, Mac or even the iPhone. This in a way, is virtualization, the consoles have been virtualized so that you can play the games on other type of hardware. Though not exactly the same as server virtualization, I’m hoping it’s something more people can relate to.

What Dropbox does is that you identify a particular folder in your computer that you want to be kept in sync between computers. For me, this is my desktop, notebook & netbook. Everytime your computer is on the internet, it will keep all the files sync’d in this folder. So, no matter which machine you are on, you have access to all the files in that folder. Update the file any where, and the rest will get the updates too. To make it even more awesome, you can access these files on your iPhone or Android device.

Dropbox installs a small client on to your computer, and gives you 2GB of free space at the start. With some successful referrals, your free space goes up to 10GB!!

I use it to keep my frequently used files in sync between my computers. I’ve read other usage as to keep iTunes libraries in sync between computers, some others use it to keep emails sync’d between computers, and much more. The possibilities are endless.

So, wait no more!! give it a try and use my referral link here =)

All these years, I thought the closest thing to symbolic links in Windows will be the shortcuts. However, In Vista and Windows 7 there is actually a good support for symbolic links and hard links. The command line utility to create/manage these links are not there by default however. One will need to download a package from Microsoft.

Now, I’ve discovered that someone has actually developed a Windows explorer shell extension to create/manage symbolic/hard links. You can download the freeware here.

I’ve downloaded and installed the utility called Link Shell Extension (LSE in short), and it works nicely for me. Mind you, I strongly encourage you to read through the online manual to understand how to use it effectively. It also has a good coverage on the pitfalls in the earlier version of Windows.

For the benefits of you who do not know what are symbolic/hard links, these are references to files and directories in your computers. There are many usage for these links, and the most common scenario is this….

Imagine you have a file located in c:\users\hello\documents\download\section\blah\etc\here\thisfile.jpg

That is a very long reference to the file. To make things simple, you want the file to be available in c:\directory\thisfile.jpg but you need to keep a copy in the original location, and at the same time have c:\directory\thisfile.jpg as an exact copy. The traditional way is probably just to create a copy of the file, and anytime the original file is updated, we’ll just copy it again.

Now, imagine that we can create c:\directory\thisfile.jpg as a symbolic link to the original file. Access this symbolic link gives the exact same result as accessing the file directly. You can open, save, change the symbolic link just as if it’s a real file. And anytime the original file changes, you’ll get the update immediately. No need to copy the file over. In way, you save disk space as well, since there’s only one real copy of the file.

There’s a lot more to symbolic links and hard links, and you can easily find more information about them on the web.

Hope you’ll find this useful =)

This happens for several reasons, and one of the biggest reason is due to file fragmentation. The performance hit gets worse if your paging file (swap file) is fragmented as well.

Since nearly 2 years ago, I found a nice, free defragmentation utility on the web. Back then, it was known as JKDefrag. The idea was good and it worked by calling native Windows APIs. This means that the programmer leveraged a lot on Microsoft’s native functions to do the work. His utility just provided the brain and coordinate the whole activity.

This is a good design that the utility will not do anything out of Microsoft’s comfort zone. Meaning, all moving of the bits and pieces of the file is executed as safe as it gets. JKDefrag did not have to re-invent anything.

Now, a newer version has been released and I’ve used it. The utility has been renamed as MyDefrag (mydefrag.com) and it has a new feature. This introduces a new dimension to what JKDefrag did. MyDefrag will now optimize the files, in addition to just defragmentation.

The new optimization idea is great! It basically re-orders the files on the harddisk into zones, and depending on the type of the file, the frequency of access of the file, the files are organized into each zone. I will not go into the specifics here, so if you like to understand in greater details what is done, you may read up from the website.

I’ve installed and optimized on my desktop and 2 netbooks. The end result is phenomenal! I can actually feel that the boot up time of these computers are shorter, and general usage experience of the computers have improved.

For anyone who wants to squeeze more out of their computers, I would recommend trying this utility out.

This utility is free, and you have the freedom to make a donation to the author of the utility if you wish to. I’m in no way affiliated to this author, and I’m writing this just to share with you out there this great utility I’ve discovered.

So, if you do try out the utility, what you need to do after installation is to run “slow optimize” the very first time you use it. That basically does the initial job to re-order the entire harddisk. Be warned though, this can take a very very long time… on one of my netbooks, it took 2 days, and the other took only 3 hours. So it depends how much work needs to be done.

So, go forth and unleash some renewed performance to your computer

The messages seems somewhat realistic, and often comes with a link for you to click on…. one example I received recently is as below

huhuhahahah thats YOU?!? LOL! :D:D http://xxxxx.My-Pictures–Downloads..com/?image=DSC07819.JPG

#1 rule – Don’t Click on It!!! never click on any URL you are not sure of. If you received a message with your friend being offline, it’s a really good chance it’s not from your friend. Clicking on it will likely get you into trouble with malware.

In fact, most of the times it’s actually a malware site that’s spamming you. So the question is, how did the spammer get hold of your friend’s account? There are at least 2 possible ways.

1. your friend has a poor password used for the MSN account, a password which the spammers were able to “guess”. Most of the time this is true, not many people will have good passwords.
2. your friend has used a computer that has a malware active, so when he/she logs in to MSN, the malware captures the password and sends it to the spammer

So, how do we combat this? Just a few simple tips should make these go away

1. immediately advise your friend who’s account has been compromised to change the password to his/her MSN account
2. if you know that your password is simple, change it as well (no it’s not that it’s now compromised, it’s to avoid it being compromised in a similar fashion)
3. it’s good practice now to have passwords that mixes numbers and letters. To make it even better, throw in a punctuation. Of course the ultimate password will also contain the 3 components plus the letters are a mix of upper and lower cases, and the entire password is at least 8 characters long. So something like “BitE2mE89$” is great! and “coffeeforme” is really bad.
4. make sure your computer has an up to date antivirus/malware installed. If you don’t want to pay for one, you can get a free version from AVG. Free, only if you are using it for personal use. For a business PC, you need to buy one.
5. make sure your computer is patched (updated) regularly, if windows prompt you to update, run it. It often fix problems which antivirus/malware products cannot protect you from.
6. Patching and having an antivirus/malware product complements each other, together they cover you better.

If you use facebook or twitter, earlier in August 2009, both these websites were hit badly. As a user to these sites, you’ll probably get strange looking webpages, or perhaps slow, or nothing worked. That is the consequence of hundreds of thousands of PCs not properly maintained and have malwares running on them. These PCs were under control via the malware to attack these services. So, for a good couple of weeks, facebook was not really usable. If all computers were properly maintained with the few simple steps above, we wouldn’t have any problem. It’ll be good for facebook and the rest of us.

If you have friends and family who you feel may not know these few basic and hugely important tips, do share these tips with them.

If you have any queries or comments, just drop in a message below or email me