It’s fairly trivial to define a decorator that doesn’t take a parameter:

from functools import wraps

def decorator(f):
    @wraps(f)
    def dec(*args, **kwargs):
        # do something useful
        return f(*args, **kwargs)
    return dec

@decorator
def hello(string):
    print string

Okay, it doesn’t do much! @wraps(f) from functools does the magic. The end effect is that the function hello ends up pointing to the decfunction that is dynamically created when the file or module is loaded. That is, @decorator runs when the file is loaded, creates a dec instance and then @wraps ‘renames’ things so that hello points to dec and the f in dec points to the original hello definition (the one with the print string)!

But, what if we want to have a decorator that takes a parameter.  i.e. we want to do this:

@pdecorator('hello')
def hello2(string, string2='optional'):
    """
    hello2 doc string.
    """
    print string, string2

So, as usual, one goes off and does some research. My answer was found here in a very useful post by Elf Sternberg. The example on the linked page has a bit more detail than I needed to understand so I simplified it as:

def pdecorator(name):
    def inner(f):
        def wrapped(*args, **kwargs):
            return f(name, *args, **kwargs)
        return wraps(f)(wrapped)
    return inner

@pdecorator('hello')
def hello2(string, string2='optional'):
    """
    My doc string.
    """
    print string, string2

So, what’s going on here? PEP-318 explains what’s going on. Essentially, the syntax of a decorator with arguments like this:

@decorator(arg1, arg2, arg3)
def func(*args):
    pass

is actually transformed into:

func = decorator(arg1, arg2, arg3)(func)

That is, decorator has to return a function that can decorate func. So in the above example, wrapped is the function we want to wrap around f. So what does

return wraps(f)(wrapped)

actually do?  For that we have to look at wraps from functools.

wraps(f) returns a functools.partial object. A partial object is sort of like a function that is partially called, i.e. it isn’t ‘finished’ yet. e.g. Take the complete function f(a,b) -> a+b. f(2,3) -> 5. However, now imagine that g(f,2) returns a function h(b) which takes a single parameter b such that h(3) -> 5. Effectively h(b) (as we designed it) has partially completed or frozen f() such that the first parameter a is now 2 in the add. In Python it looks like this:

from functools import partial
add2 = partial(lambda x,y: x+y, 2)
add2(3)
5

i.e. the 2 was captured in the in the x position in the function. Cool, huh!

Anyway, what wraps(...) returns is a partially applied functools.update_wrapper(...) function which has captured the __name__, __doc__ and __dict__ of the function passed as an argument. i.e. wraps(f) returns a partially applied update_wrapper function with f.__name__, f.__doc__ and f.__dict__ frozen into it. However, the wrap hasn’t yet been applied to a function. In our example above, wraps(f)(wrapped) thus then wraps f.__name__, f.__doc__ and f.__dict__ on to the wrapped function.

So coming back to the example (repeated again to stop you scrolling up and down!):

def pdecorator(name):
    def inner(f):
        def wrapped(*args, **kwargs):
            return f(name, *args, **kwargs)
        return wraps(f)(wrapped)
    return inner

@pdecorator('hello')
def hello2(string, string2='optional'):
    """
    My doc string.
    """
    print string, string2

inner(f) returns a function which is basically wrapped(f(…)) but has the __name__, __doc__ and __dict__ of f.

i.e. the nice equivalent of

def hello2(...): pass
hello2 = wrapped(hello2)

It happens when I open just ‘one-too-many’ tabs in Chrome. The desktop becomes unresponsive as the memory manager in Linux tries to find pages for Chrome to use for the new tab. Unfortunately, it’s so overcommitted the pages that it can’t find any. Every process wants to run and Linux essentially runs out of pages. Hence disk-thrashing starts, the desktop slows to a crawl or simply becomes unresponsive, and I try to Ctrl-Alt-F1 to get to a TTY so I can kill something (usually ‘killall chrome’).

I’d rather the box just didn’t allocate the memory if it doesn’t have it – i.e. don’t open the new tab if there isn’t memory for it.

My experiment is going to be to run for a few weeks using some sysctls of:

• vm.overcommit_memory = 2
• vm.overcommit_ratio = 120

This should give me a maximum commit of 8GB (4Gb swap and 4GB of memory). I wonder how it will go?

Useful information from:

• Linux Memory Overcommit
• How Linux handles virtual memory overcommit

Microsoft isn’t exactly known for it’s love affair with cross-platform technologies. If anything, they are the most anti-cross-platform technology provider there is. Windows and its eco-system is all that Microsoft is interested in; it’s where the bulk (nay all?) of its revenue is derived from.

Buying Skype for $8.5B is an interesting move. It’s roughly double what Google or Facebook were going to pay, if the rumours were true. Thus, Microsoft must believe that it will gain synergies (that horrible management/marketing word …) from integrating Skype technology (and brand?) into Windows in the Desktop, Server, Xbox and Windows Mobile world. It’s got a large fight on its hands with Cisco in the conferencing space and has been looking to make its Unified Communications solution really, really compelling. And maybe by adding Skype to the mix it will be compelling? But $8.5B compelling?

It’s hard to see how Microsoft is going to get its investment back. There could be some useful patents in the mix, and Microsoft is showing that it likes to throw patents around to interfere with markets and use legal tactics as competition rather that, say, just innovating and competing. However, keeping the technology away from Google et al. may also be part of there competitive strategy.

So there’s lots of interesting stuff in there. But for those of us who use Skype on Macs, Linux, Android, or anything that isn’t Windows, yesterday marks a turning point. Previous acquisitions by Microsoft that were cross-platform eventually became Windows only, with the other platforms left swinging in the breeze. What are we going to use instead? SIP, Google Voice, something else? Come on Google, sort out your Google Voice offering for the rest of the world …

However, the forums seem to attract many posts about how it is “suitable for beginner’s” or that “it’s not a beginner’s course”. Apart from being annoying, they are simply incorrect.

Fact: the course, L192, assumes no previous knowledge of French before starting on the course:

Entry

No prior knowledge of French is required to study this course.

This is a Level 1 course. Level 1 courses provide core subject knowledge and study skills needed for both higher education and distance learning. If you have any doubt about the suitability of the course, please contact our Student Registration & Enquiry Service.

The course is for beginner’s; it just isn’t easy.</rant>

The problem, of course, is that when something is hard or takes a little bit of work or time, some people instantly assume that the problem lies outside of themselves, and therefore, surely the problem is with the course/person/situation. Work harder and/or smarter; stop complaining.

However, they called me today, somewhat randomly, to inform me that the claim was proceeding normally. They called me and then asked me to provide details to ‘prove’ who I was. I said, before I do that, can you prove who you are? And they couldn’t. There’s no information they could give me over the phone to demonstrate that they were who they said they were.

Why am I so cautious? Well, why not. It’s trivially easy to spoof a phone number on ID, and this was ‘withheld’ anyway. I ended the call, looked up their number on my policy document and rang back in – it was the only way to (mostly) ensure that I was talking to who I thought I would be.

So it made me think: if we need to prove who we are when we call them, why shouldn’t they prove who they are when they call us. And the easiest way to do that is to give a piece of information that only they could know, essentially, something that you’ve given them as a password only to be given back to you – not for you to access the account.

Of course, it will never happen … (sigh).

I had the ‘pleasure’ of travelling through Heathrow T5 twice during my holiday to Thonon les Bains on Lac Leman which is reached via Geneva.  On paper, the flights look fine; catch the BA plane to Heathrow, two hours at Heathrow and then catch your onward flight to Geneva.  On the return journey, three hours are offered at Heathrow – little did I know it was to clear security.

On the way out to Geneva, the plane was delayed by nearly an hour waiting at the gate.  However, desipte a 2 hour transfer time (not including the extra delay) our bags failed to make the connection from Newcastle and didn’t travel with us.  That’s everybody who flew from Newcastle to Geneva, six in total; not one of us was joined by our bags on the flight.  The bags did eventually turn up on the next flight and were delivered to us after a 5 hour delay. The baggage company at Geneva were not surprised; it seems that bags are far more frequently delayed from T5 than any other airport in the developed world.

However, it only got worse on the way back.  First we were delayed in Geneva because there was no slot available at Heathrow.  Then, even when we were given a slot at Heathrow, when the plane arrived at the airport’s airspace we were delayed again.

Then the plane was parked away from the terminal as there were no stands available.  Normally buses await to take the passengers to the terminal.  Except there weren’t any.  For 30 minutes.   None of the ground staff seemed to have any sense of urgency.  The bus driver even seemed to wait with the bus full despite several panicked American passengers on short transfers – they didn’t stand a chance with T5.  But when we were finally delivered to the terminal the fun really began.  We didn’t get to the T5 shopping centre for another 30 minutes.

Queues seem to be the norm at T5.  Firstly, there was a ludicrous queue after getting to T5.  It transpired that at the head of this queue was a small woman asking people whether they were transferring to local or international flights.  She was completely pointless because the hall immediately behind her was full of signs directing you where to go if you were transferring to a local or international flight.  She had no purpose whatsoever.  Utterly unbelievable and the first 10 minutes of waiting.

Next we queued to have our boarding passes checked.  After that another queue to have our passports checked.  Finally, both the local and international passengers were shepherded to yet another security check.  Together.  Why we were split up into different queues is anybodies guess as both the national and international passengers had boarding card and passport checks.  The final security check is the one where you take your belt off, take your laptop out, etc.  This took another 15 to 20 minutes.  Why?  Why?  Because the staff were just slow.  Inept too, probably, but generally very, very slow at staring at the computer monitor that displays the innards of cases, jackets, purses and other assorted bags. Incredibly slow.  In Newcastle this queue usually takes about 5 minutes.  The queue for our machine was on 10 or so people long yet took nearly 20 minutes …  I dispaired.

All told from the moment of touching down to getting into T5 took over an hour; it would have been 30-40 minutes at best even if we had got to a stand.  What a disgraceful way of treating people arriving at supposedly the most advanced passenger terminal in the world.  I imagine the American passengers on short transfers missed their flights.  There bags almost certainly will have done.

However, once in T5 proper you understand that it isn’t for passengers to relax waiting for their flight.  No, it’s only purpose is to extract money; it’s simply a glorified shopping mall.  All we wanted to do was get some lunch and then find somewhere comfortable for our next flight.  Instead, there are precious few places to eat and virtually no where to actually sit.  Unless you have an executive lounge pass that is.  T5, which because of its size, should feel spacious, yet feels claustrophobic, cluttered, noisy and generally unpleasant.

Even when we boarded our flight to Newcastle the madness of Heathrow didn’t end.  We ended up staying a further hour at the stand and taxiing before we finally took off.  Because they are operating at full capacity.

That seems to be the problem.  There are simply too many passengers.  They don’t need another runway; they need less passengers.  The current ‘systems’ at T5 don’t seem to be able to cope.  Most of the staff have a ‘learned helplessness’ air around them.

Heathrow needs proper competition.  Maybe BAA needs to be broken up so that Gatwick and Stansted can offer real competition to Heathrow to force it to buck its ideas up and provide a proper service to its passengers.  The security theatre is a joke; I don’t feel more secure, just that I’m having my time wasted.  We are paying customers; yet we pay to be treated like cattle.  I’m not sure why we put up with it.  Yet another reason for competition, but perhaps in a different way.  If there was an airport that didn’t treat you like cattle and actually treated you like paying customers then I would definitely fly through there, even if it was a bit more expensive.

BAA is bad for Heathrow and bad for British Airways.  The sooner it is broken up the better.

I also arrived for the GTi breakfast event at 7.30am which I felt was quite an achievement because I didn’t go to bed until 11.30 the night before which brings me back to the first day of TDC.

Day 1 was very good with only a couple of ‘blooper’ presentations.  The highlights for me were:

Harry Drmec, Former CEO of Red Bull.  A drinks company CEO at a digital event?  Yes, and it worked very well.  The guy leaked of leadership and capability and this is of course reflected in his amazing work at Red Bull.  I particularly liked his story of how he stood up to Tesco and won.

Mike Southon, who did an inspirational talk about entrepreneurship using the Beatles (as in the Group) as a metaphor or simile.  It was great and the use of music and old b/w photos of the Beatles helped hammer his points home.

Dan Lyons (a.k.a. Fake Steve Jobs) who, after a shaky start, pulled off an amusing and informative talk.

But the outstanding session for me on Day 1 was the final session entitled “Stop Making Sense”:

Dr Michael Shermer took us on a tour of skeptism, gullableness, its biological and evolutionary roots and some techniques to combat the category errors that we all make when faced with the unknown.  Essentially, how to ensure that we address the unknown with “we don’t know” rather than attributing it to some supernatural entity or God.  Preaching to the converted for sure, but still a timely and funny reminder of how our biology and sensing systems can trick our brains into believing things that simply aren’t there.

Then, completely unexpectedly, Chandler Burr, a Perfume critic at the New York Times, gave an exhilerating tour of scent culminating in an exploration of the structure (and smells) of a boutique fragrance called “Silver Mark”.  A simply stunning perfume and a delightful speaker who is clearly massively enthusiastic about scents, the sense of smell, and the way in which they can be manipulated to produce emotional responses to, well, scent.  Who Knew, huh?

But the star of the show was an independent toy designer called Caleb Chung.  He designed the Furby which, we were told, sold 50 Billion.  That’s about 7 Furbys for every single person on the planet!  Who was buying those things.  More to the point, who bought my seven and probably your seven?

Mr Chung then went on to demonstrate his new toy which was the Pleo from Ugobe.  An amazing robotic toy which had real lifelike attributes – basically it is a very cute toy which evokes empathy.  Pleo is a learning robot and reacts to how you treat it – and it’s aimed at kids!