Andy Millar

Configuring a DRAC (Dell Remote Access Card) behind NAT is surprisingly simple, yet Google fails to yield any useful results.

All that needs doing is to forward the following ports (TCP Only) to the DRAC card:

• 80
• 443
• 5900
• 5901
• 5902

If you find that ports 80 and 443 are already mapped to an existing server, you can forward different ports (i.e. 81 and 444) however the DRAC card must be configured with these ports. You cannot forward an external port 444 to an internal port 443! The HTTP(s) ports can be changed from the Services section in the DRAC configuration menu. (Read as: System->Remote Access->Configuration->Services). I have not yet found a way of changing the last 3 ports.
It is worth noting that the last 3 ports are only required for the DRAC console. The web interface (without remote console access) is fine with just ports 80 and 443 forwarded.

NO!

I will not add your stupid application.

O2 did an oopsie!

They accidentally made some of their customers’ MMS pictures available online, and indexable by Google!

You can view them using the Google cached versions!

Anyway, here’s one of them (with the mobile number attached):

Anyway, apart from her, it appears that all the other O2 users are mothers with young children. Boring really.

Enjoy!

You may have noticed that it’s been a little quiet around here.

This would be because I am working on my patch to provide Cache Cohereny Event Profiling for Cachegrind, a Valgrind tool.

This is a university project for Imperial College London and is due in on Wednesday 18th June.

Further updates, including code and a pretty report will be available online once this is over.

PANIC will be over soon :-)

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?

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!

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!