Friday, November 28, 2008

Modern Cryptography

AES, RSA, and Rijndael - if these mean nothing to you then you're clearly not interested in cryptography. If that's the case why are you reading this blog?!
Anyhow - if your an engineer of any kind in this modern world then there are certain things you should have at least a passing familiarity with - how TCP/IP works is another one.
The best primer I've ever come across is episode 31-37 of Steve Gibson's Security Now podcast go from symmetric stream ciphers (the Enigma Machine being a prime example) through to current state-of-the-art methods. It's very listenable and so if you have a spare eight hours (ideal on the commute) you should check out those podcasts from a couple of years ago - link in the title.

Thursday, November 27, 2008

The Shield, end of season

Episode 13 of Season 7 was one of the best and most dramatic hours of television I've ever seen. I've been following it since the first year and it is the only cop show that has never lost it's dramatic tension and has never indulged in 'character development' episodes. Compared to the various CSI variants (which I like for different reasons) it shines.

Wednesday, November 26, 2008


I am so far behind what the kids are listening to but after hearing this blaring out of my eldest two's bedrooms and iPods I thought I'd check it out.
I'd had a vague interest in some of the more intelligent hip-hop from the early nineties - Jungle Brother, Tribe called Quest, De La Soul etc. but most modern hip-hop leaves me cold. It seems like all the things I ranted about as a teenager - materialism, violence, mysogyny, and hatred are all required elements for the modern rapper. I found this in a paper by Darren Rhym of The Department of English of The University of Georgia;

In the end, this whole argument boils down to the fact that misogyny is ingrained into our culture and we allow it. We buy CDs and go to concerts where gangsta rappers call black women "bitches" and "hos." It is not just black women who are victimized. Since gangsta rappers disrespect our mothers, sisters, and daughters, every black man is a victim.

Excuses -- "I like the beat," "I don't listen to the words," and "They are only referring to certain types of women" -- are not acceptable. When gangsta rappers disrespect men and women and preach violence and hate to us, we must reject their messages. We cannot buy their CDs, albums, or tapes, or attend their concerts, or appear in their videos, or even support record labels or radio or television stations that advocate gangsta rap in any way. Malcolm X used to preach about the ills of airing "dirty laundry," and that is what gangsta rappers do when they disrespect black women in rap songs.

Rap is not just music; it is our African-American culture. It is the way we blacks perceive ourselves, and the way we are perceived by the world. The content of gangsta rap music in its current form is unacceptable. It cannot and should not be tolerated by anyone.

He should check out Flobots album - not only is it intelligent non-hate-filled lyrics but they are musically an order of magnitude more interesting that Dr Dre et al. Real drums with guitars and even jazz-influenced arrangements. Currently what's on my MP3 player.

Tuesday, November 25, 2008

Jailbreaking / unlocking iPhone for v2.2 f/ware

If you have a first gen iPhone and it's at v2.02 (at least) you can proceed to doing an iTunes upgrade without fear - the radio firmware isn't changed but apparently battery life and stability are improved (so Joe, my fifteen year-old tells me!)

Friday, November 21, 2008

Friday thoughts

I was out at Pinewood Studios on Wednesday doing some final work in a grading theater - Brian kindly brought me a good cup of brewed coffee (it was around 11:30am and it was my fifth cup of brewed coffee) and it left me feeling very jittery! Consequently I've decided to cut down on the coffee and I only drank tea yesterday - I felt a lot better by the end of the day and I have a feeling I slept better. The problem is I like coffee so much!

Parallels version four is out and I installed it yesterday - very good, a bit faster on the screen handling and startup/close-down of the virtual machine (XP SP3 on Leopard) was a lot faster. Simon didn't find it so good though on his MacBook. It tried to convert the v.3 VM but it failed - however, re-creating a BootCamp VM is trivial.

Good TV - There seems to be a load of good tele at the moment - Lead Balloon (Jack Dee's sitcom) - currently BBC2 are showing season 3 (it used to be a BBC4 show). Outnumbered - BBC1's (again, from BBC4) is hilarious. Little Dorrit - the BBC does a superb job of Dickens again. Star Wars:Clone Wars the animated series - Cartoon Network are showing the latest itteration of that franchise. Mythbusters - fantastic family tele. The Shield - series 7 on FX is the best yet and very exciting.

10mBit broadband - I recently got upgraded and although Virgin Media are hopeless when things go wrong I'm loving being able to torrent an episode of something that aired in the US last night at 3 minutes per half-hour of TV!

Monday, November 17, 2008

I wish I had the nerve...!

Wednesday, November 12, 2008

Inductive loads and power correction

The power factor of an AC electric power system is defined as the ratio of the real power to the apparent power, and is a number between 0 and 1 (frequently expressed as a percentage, e.g. 0.5 pf = 50% pf). Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current and voltage of the circuit. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power can be greater than the real power.
In an electric power system, a load with low power factor draws more current than a load with a high power factor, for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment. Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor.

Thinking about power-factors all came from various discussions with the wiremen and engineers whilst working on site over the last couple of weeks - In the case of the kind of builds we do we always ask customers to provide a power supply with inductive rated breakers. This is from our standard Scope Of Works document;

The equipment cabinets will be wired with 14-way IEC mains distribution units. Every circuit is fuse-protected and the mains input is terminated in a 16A C-Form connector (AKA a ‘Commando’ plug) – Root6 requirement is that the client’s electrician provides a separate spur connection for each bay and all feeds are provided via a D-rated 16A MCB. We recommend the area is protected by an Earth Leakage Breaker. We will test all mains installs in accordance with edition 4 of the 16th ed. IEE regulations using a standard suite of PAT tests.

We've fallen foul of a customer who didn't pass this on to their electrician and we've been battling with B-Rated (i.e. resistive-load) breakers not being able to hold an 16A circuit to a bay full of switch-mode power-supplies (i.e. all modern broadcast equipment!). When a strongly inductive load such as a switch-mode/resonant-mode power supply is switched on input surge current which may be several times larger than the steady current flows. It's also why the mains in Soho is nearly a square-wave - all those odd-order harmonics being dumped back out onto the incoming supply.

Tuesday, November 11, 2008

The idiots have won!

Charlie Brooker's Nathan Barley is still one of the funniest things ever on TV - I know 'cause I deal with a lot of those people - Meeja Fools!

Once the idiots were just the fools gaping in through the windows, now they have entered the building. You can hear them everywhere, they use the word cool, it is their favourite word, the idiot doesn't think about what he is saying, thinking is rubbish and rubbish isn't cool...... Stuff and shit is cool. The idiots are self regarding, consumer slaves. Oblivious to the paradox of their uniform individuality, they sculpt their hair to casual perfection, they wear their waist bands below their balls, and they babble in to handheld twit machines about that cool email of a woman being bummed by a wolf.... their cool friend made it, he’s an idiot too. Welcome to the age of stupidity, hail the rise of the idiot.

Those two fine examples of humanity - Jonathon Ross and the other guy are in trouble for reverting to type on Radio 2. But, imagine my suprise when I was in the newsagents to buy a bag of crisps and I saw this cover of a lads mag - the young woman in the centre of the whole debacle with her kit off - the idiots have won!

Thursday, November 06, 2008

Fridge-freezer mains earth defrosting connundrum!

I have an upright fridge-freezer in my kitchen and about a year ago I moved it to clean underneath. Since then every month I've had to defrost it (despite it being a frost-free model) and was getting ready to maybe replace it. However, three months ago I noticed that the extension cable that powers it (from a socket in the lader) had been tugged (I assume when I moved it out to clean) and on further inspection the mains earth had come out in the trailing MK13 socket on the end of the extension. I re-wired it and since then the thing hasn't frosted up once!
I'm at a loss - how does the presence (or not) of a mains safety earth cause this behavior? What about those countries that don't have an earth?

If you've got a thought then I love to hear it - have a party in the comments!

Monday, November 03, 2008

Trying to get enthused!

Despite my first weekend since August when I did no work between Friday tea time and Monday I don't feel very enthusiastic about broadcast engineering - I hoped I'd be refreshed and full of beans but I'm a bit flat. Hopefully the following lecture at the IET will perk me up!
The Beijing games were the biggest and best ever. Paul Mason of BBC Television will describe the technical challenges of delivering multi-media coverage from dozens of venues from the other side of the world. He will cover the planning and technical operation of the Games, including both the Host Broadcaster and BBC operations

I can take guests so if you want to go let me know.