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Universal Time (UTC)

Coordinated Universal Time (UTC) was adopted as an international standard in 1967 when it became apparent that the world needed to know what time it was to a greater degree of exactitude than ever before.

UTC was developed as a means of measuring time independent of the Earth’s rotation and the sun and the stars.

Yet UTC is one of the least understood measurements of time.

That’s because unlike, for example, Greenwich Mean Time (GMT) in London or Eastern Standard Time (EST) on the east coast of the United States, UTC is not the time measured in a specific place.

Rather, it is the same time all over the world because it is the time measured by the vibration of caesium atoms in atomic clocks.

That said, caesium clocks had to be set by reference to time somewhere, and Greenwich Mean Time (sometimes called ‘London Time’) was chosen.

What is Greenwich Mean Time?

Greenwich Mean Time was adopted as the time standard around the world at the Washington Meridian Conference of 1884.

It is the time calculated by the Greenwich Observatory in London by reference to the Earth’s rotation and by the position of the sun in the heavens.

The signatories to the Washington Conference were happy to adopt Greenwich as the meridian or ‘zero’ line because of what was on the other side of the world.

You see, if you are a few feet to one side of the meridian line at Greenwich in London on a particular day of the year then it is still the same day of the year as it is a few feet to the other side of the meridian line at Greenwich.

However, the Earth is divided in Time Zones, with the time in Paris being one hour ahead of the time in London, the time in New York being five hours behind the time in London, and so on around the world.

But there comes a point on the other side of the world that when you are standing on one side of the Date Line you are a whole day ahead of the date on the other side of the Date Line.

You can imagine how inconvenient that could be if there were a lot of messages flying back and forth across the Date Line. The reply could be sent before the original message was sent.

The thing is that if you draw the meridian line of longitude around the world, the line on the other side of the world from Greenwich in London lies mostly over the open water of the Pacific Ocean.

And everyone at the 1884 Washington Meridian Conference agreed that the open water of the Pacific Ocean was a convenient place for the Date Line. Therefore Greenwich Mean Time was an equally convenient place to use as a reference for UTC.

Atomic Clocks

The first successful caesium atomic clock was built in the Teddington laboratory in England in 1955. It works by measuring the vibrations of caesium atoms.

Once the reliability of these clocks was proven and established, the time measured by them was adopted internationally, and now there are many caesium clocks in various parts of the world. Today, there are approximately 70 caesium clocks in the United States alone.

Why UTC Was Developed

For all practical purposes, UTC is the same as Greenwich Mean Time, but they are not exactly the same because the Earth is slowing down in its rotation. As it slows, it puts everything out of synchronisation.

Of course in 1884 when Greenwich Mean Time was adopted as the international standard for the Meridian, a few fractions of a second difference between the actual time and the time measured by reference to the sun and the stars was insignificant.

Since the first observation of the vibration of caesium in 1958, the Earth has only moved 33 seconds out of synchronization, so the discrepancy is small.

To correct the discrepancy leap-seconds are introduced every few years. For example, a leap-second was added to Greenwich Mean Time at the end of 2008 to coordinate it with UTC.

In the latter part of the 20th century, those fractions of a second started to become important for electronic communications. Now that the measurement of time for very practical uses is measured in milliseconds, measuring time as exactly as possible is all the more critical.

For example, some stock trading networks have moved their servers nearer to the point of origin of the stock trading prices so that they can shave milliseconds off the time it takes them to gather and act on the information.

You can check times throughout the world at Time And Date.

Intel Chip Vulnerabilities Affecting Web Hosts

It seems like not a month goes by without another code vulnerability being discovered. One only hopes that the people who find the vulnerabilities are good guys. This time it is an L1 Terminal Fault (L1TF) in the Intel chip that it used by web hosts running virtual machines. That includes Digital Ocean, the web host that we use.

The vulnerability exposes data to anyone running on the same processor core as another domain’s data. It’s like one tenant in an apartment block being able to look in on the next apartment.

Thankfully, Intel has learned from its earlier mistake of keep its problems to itself. Instead, it shared information about the problem with web hosts and that means that Digital Ocean has already started working on a fix.

They say that it’s going to take a few weeks to complete the work, but they do not anticipate any downtime for their users (Quillcards, in our case) as a result of their efforts to fix the problem.

What I do expect is that they will share any information about anyone who actually has used the vulnerability to look where they shouldn’t.

Quillcards Is Being Temporarily Affected By Our Web Host Rebooting Its System

This is a follow-up to our last newsletter about Quillcards being affecting by our web host working to patch vulnerabilities in Intel chips.

Our hosting company, Digital Ocean, which hosts thousand of websites, began a server reboot at 2pm UK time today.

Our site went down at 2:02pm, and it has not come back up automatically. Therefore we are going to have to manually restart it, which will not be until tonight.

Then we will also need to do some work on our setup, and we will do that after the site is running again.

As we said before, Digital Ocean is doing the reboot because of the industry-wide security vulnerabilities known as Meltdown and Spectre that affect Intel chips that are deep at the heart of many web host servers.

Update Tuesday Evening

The site is now running normally.

Quillcards May Be Affected By Our Web Host Patching Vulnerabilities in Intel Chips

You may have read in the news that there are industry-wide security vulnerabilities, known as Meltdown and Spectre, in the Intel chips used in literally millions of systems and thousands of web hosts.

Because of these vulnerabilities in the chips, web hosts need to patch and reboot their systems.

This is not a problem in Quillcards itself. It is a problem with the Intel chips used by web hosts all over the world, including the chips used by our web host.

We have been expecting to hear from our web host about this and we have now received an email from them telling us when they are going to start work to patch their system to mitigate the vulnerabilities.

Our web host is beginning the work now and will start with data centers in the USA. Then they will move to deal with data centers elsewhere.

When Will We Be Affected

Our data center is located in London in the United Kingdom, so it will be affected at some point later this week or next week.

This is an unknown. Rebooting their system and our system may be easy and you may not notice it, or it could take us down and we don’t know how quickly we will be able to restart the site.

Our web host has promised us at least 24 hours ahead of scheduled maintenance windows for our data center.

We can’t do anything about the maintenance schedule but we will make every effort to keep you updated.

We will add updates here and on the Server Updates page on this site.

We suggest you bookmark this page so that you can reach it easily.

Packet Loss And Denial Of Service Attacks

We track Quillcards and get an email alert if it goes down for any reason. It went down for about 15 minutes less than an hour ago.

Our web host posted a notice immediately and I signed up to be alerted with updates to the notices.

The first notice said:

We are seeing some heavy packet loss at our Dallas datacenter right now. We are investigating.

I signed in to a chatroom at the web host and was told that the packet loss (loss of data) was at the Dallas data center where our site is hosted.

So I knew that the problem affected our web host and was not Quillcards itself that was having a problem internally.

The next notice said:

It looks like the loss has subsided now, this affected our entire Dallas network, and appears to have been something from upstream. Working with the datacenter NOC team to find out what occurred.

The thing is that the Dallas data center handles data for various web hosts, and this was the final notice:

We have been advised another customer at the datacenter was subject to a very large DOS attack. That has been blocked and the network has returned to normal.

So what is a DOS attack?

It’s a malicious attack by outsiders who send a query with forged credentials to the website they are attacking. The web server responds and the attacker asks the same question again. Except the attacker doesn’t just ask once or twice: It asks many, many times a second and eventually overwhelms the service.

The way to stop the attacks varies with the kind of attack, but one way is to query the credentials and get the attacker to prove it is who it claims to be. When it fails to do so, the attack is blocked.