Archive for May, 2008

How long do you spend on the loo every day?

Friday, May 30th, 2008

This rather strange thought came to me whilst on the loo today!

I worked out that I must spend somewhere between 30 and 45 mins per day on the loo!

Is this a long time?

How long do you spend on the loo every day?

RAID1 increases chances of disk failure

Friday, May 23rd, 2008

fact

When I was first told this, my initial response was “rubbish“, there was no way that using RAID1 (mirroring) could increase the chance of disk failure, was there?

Then I actually thought about the statement again, and I was wrong!

Consider 2 hard disks A and B. The make/model/manufacturer is irrelevant for this proof.

Given that P(e) is the probability of event e occurring, we can state that:

P(disk A fails) = a

P(disk B fails) = b

Trivially, in a single disk system using either disk A or disk B, the probability of disk failure will be a or b, or for ease of demonstration we shall pick the average of the two.

Therefore, the average chance of a single disk machine suffering disk failure is (a+b)/2.

Now, consider the RAID1 system containing disks A and B.

The chance of a disk failing is the probability of disk A failing or the probability of disk B failing; so:

P(disk A fails or disk B fails) = P(disk A fails) + P(disk B fails) = a + b.

In fact, the chance of disk failure in a RAID1 system doubles. Hardly surprising if you stop and think about it.

Now, the statement I initially inferred actually was: RAID1 increases chances of data loss, which is obviously rubbish, as can be easily shown.

We know the chance of disk failure (and in this case data loss) with a single disk, (a+b)/2.

Now, using RAID1, the chance of data loss is defined as:

The probability of both disk A and disk B failing.

This is defined as:

P(disk A failing and disk B failing) = P(disk A failing) * P(disk B failing) = a * b.

It can be stated that any probability must be in the range 0 <= P(e) <= 1.

For any two numbers i,j; if both i and j satisfy 0 <= i <= 1; 0 <= j <= 1 then:

i * j < i; i * j < j

Therefore, the probability of data loss is lower when using RAID1, however the chance of disk failure doubles!

Current Location is Disabled

Sunday, May 18th, 2008

My “current location” is currently disabled.

This is because I now have a new phone and have yet to get the GPS working properly.

Apart from the GPS not being easy to get working, the Samsung i780 is a pretty nice phone!

More details on the i780 to follow later!

How to cook couscous

Sunday, May 11th, 2008

Since the internet sucks for finding out…

Cover with one to one and a half times its volume of hot water and leave to soak for 10 minutes.

Simple, now why can’t every site say this? :-)

Facebook Applications

Sunday, May 11th, 2008

Facebook Stupid Requests

Why, just why?

Do people really add these stupid facebook applications just because someone they may or may not know has added them and then sent them the request?

Sorry, but I don’t think I’ll ever want to play “Have I Ever…”.

Exchange 2003 pop3svc stuck starting

Sunday, May 11th, 2008

I recently experienced a problem with an Exchange 2003 deployment where pop3svc was stuck starting.

To resolve it, try killing inetinfo.exe using Task Manager.

You should then be able to restart the pop3 and imp services via MMC.

Make sure you start the pop3/imap services via the Exchange System Manager as well as via MMC.

Byethost mentioned on StopBadware.org

Wednesday, May 7th, 2008

Byethost has been mentioned on the StopBadware.org blog – Taking a Byet Out of Badware!

Maxim’s comments are very positive – hopefully there is scope for some form of partnership to help the eradication of badware from the Byethost servers.

Fighting badware is challenging as, as a host, you are always one step behind the spammers and phishers. Proper support from organisations like StopBadware will really help reduce the time between a new badware site being created and the host being notified.

Only cooperation between the hosts and enforcement groups will see an end to badware!