Gmail hit by mass outage

Gmail suffered an outage of more than one hour some time ago.
First impressions are to point out potential problems with Gmail. However, it’s actually a fine testament to the power of cloud.

The alternative to the cloud is to rely on a mail system created that relies on a good many more steps in the mail delivery process.

Typically, you have a mail client such as Outlook which connects to a mail server such as a Qmail or Outlook server. Outlook typically runs on a PC that is running Windows.

If any of these links fail, and almost everyone seems to have a tale of a Windows crash to tell, then so does the entire mail chain. Downtimes can be many hours especially if a technician has to be brought in. If you’re lucky it will be an expensive technician and you will have your email back up with just an expensive bill. At worst, you may end up with a junior web designer.

And this is the beauty of Gmail. You can sit back assured that a veritable army of some of the finest technical engineers on the planet are working relentlessly to get your problem fixed.

Sender Signatures – DKIM and SPF

Sender Signatures are used to avoid spam.

If you’re using a service like Outlook or Gmail you won’t even be aware of this.

However, if you send an email programmatically then you need to say who the Sender is. You usually do that using a Reply-To header. Unfortunately spammers have being doing this forever so, to avoid an email being labelled as spam, you’ll need to sign your email.

There are two main methods of creating Sender Signatures: DKIM and SPF.

DKIM (DomainKeys Identified Mail) has emerged from IETF (one of the Internet governing bodies) specifications and uses a signer’s public key which is published in the DNS. More here:

SPF (Sender Policy Framework) adds the list of authorized sending hosts for a domain in a TXT record. More here:

For other methods see:

window.onload != user perception

window.onload used to be pretty accurate.

But now we’re lazily loading stuff, using responsive images, dynamic elements rendered with JS and CSS. So, it’s not an accurate guide to user perception. E.g. take Gmail.

This isn’t ready till after window.onload. But there’s nothing that can tell us it’s ready.

Or, it’s usable (i.e. we can see products and prices) after around 2.0 seconds but the window.onload doesn’t fire till 5.8 seconds.

Which is the reasoning behind Speed Index at Web Page Test.

See also:

Automatic Post Tagger

Not quite as awesome as an automatic post categoriser but still pretty handy: