It's all falling apart – bad data

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This topic contains 10 replies, has 6 voices, and was last updated by  iguiyichm 7 years ago.

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  • #74708

    timjwatts
    Participant

    Just wasted an hour this morning. Left William IV St as usual, but later than normal, at 9:40.

    The iPhone app said 8 spaces at Drury Lane. I got to Drury Lane 5 mins later and it was full. iPhone app now showing 8 spaces.

    So I followed the iPhone app to Kingsway. There were spaces, but the some joker of a scaffolder has put support bars over the tops of the central section preventing docking – they could easily have moved their support frame 4″ towards the road and left the docks clear.

    Sardinia St next – showing as some spaces. Nope, full

    Next – Carey St – full.

    Last stop, Breams Blds, Holborn. Full. This time I clicked the pillar terminal for nearest stations with empty spaces. It showed several surrouding stations with spaces – some of which were those above (ie full)

    So, now very very pissed off I rang the support number. Bloke said Stonecutter had spaces but that is even further away in the wrong direction.

    So I asked him to tell me how many spaces were at Breams: “4″ he said. So I pointed out I was right next to the bike docks and they were all full, so their computer was talking crap.

    I asked to escalate the call to a manger. After about 20 minutes on hold, I got someone called “Kabir”. He did admit they had “issues” with the central IT systems and were trying to fix it. I pointed out that the data had been noticeably flaky for a while. I asked for a refund of any excess charges and also to be emailed when they thunk they have fixed it. I confirmed he was working for SERCO.

    I went to great pains to point out that the scheme is a good idea, while they cannot be expected to guarantee availability, people rightfully *expect* accurate and timely data.

    I’m a systems programmer – it’s not a hard problem if it is approached as a “real time” design problem even allowing for the weak cellular links from the docks to the database. First rul would be to keep a fast state database in RAM – there are only some 7000 docking points, this is not a great deal of data.

    Ditto for the subscriber data (which bike is booked out on a key, if any)

    The accounting data can be spooled off to a proper RDBMS, and it matters a little less if that is slow and non real time.

    I’m going to email a rehash of this message to TFL and SERCO, but I am becoming so unimpressed with the pathetic unreliability of the real time data, I’m tempted to write something to the Metro or the Standard. What do you folk think?

    Cheers

    Tim

    #83861

    radii8
    Participant

    And my key doesn’t work any more And neither does the new one they sent out. :cry:

    #83862

    7209
    Participant

    I sympathise with the problem (and pretty much agree with your proposed solution), but it has got to be remembered that Serco aren’t starting from scratch – they’re bastardising the Bixi software which was designed for a much smaller scheme.

    Whilst it would probably be a good thing if they threw away the software & designed something bespoke, that’s not going to happen (the costs involved would be prohibitive). So what happens? They’ll no doubt continually try to tweak the software so it can cope with the volume of data that’s being thrown at it…and hopefully throw some new hardware at it.

    I was at a conference/sales event last week where a server was mentioned with 10-core Intel CPUs and 5 Terrabytes of RAM that was dealing with something stupid like 7 Petabytes(sp?) of data in ridiculously small amounts of time. I’m sure one of these would help! :D

    #83863

    timjwatts
    Participant

    This rather implies that the original software was not competently designed.

    It has to be remembered that the size of the “current state” data is not big (7-8k docks, 6k bikes, few 100k subscribers) – this is not big, if you remember that the real-time part of the system does not need to know the subscriber’s name and address and so forth.

    You’ve basically got a list of live keys;

    List of docks, grouped by location

    List bikes

    bike is either linked to a dock, or it is linked to a key. Bike may be broken. Dock may be broken.

    That’s really all the real time stuff you need – it is very small, even with a million subscribers and 100k bikes/docks

    The state-changes (key takes bike out) need to be streamed to an accounting database, but all you need for the operational system is the live “now” state (which would fit in less than a gig of RAM)

    and the ability to query it quickly.

    Sadly, you are probably right – they won’t chuck it in the bin and start again (although a lot ought to be rescuable from teh existing system – eg terminal UI software).

    But I wonder how much money they’ll waste hacking on it and what effective “waste” they’ll be from a system that does not have the confidence of the user.

    #83864

    jacob123
    Participant

    The IT system is also so poor it doesn’t track your usage any more – I just called on a different issue and happened to ask the lady to tell me what my last usage was – her most recent info was for February! Yes folks – February

    #83865

    Timmmm
    Participant
    Quote:
    Whilst it would probably be a good thing if they threw away the software & designed something bespoke, that’s not going to happen (the costs involved would be prohibitive)

    This is bullshit. Tracking bikes is possibly one of the simplest real-world pieces of software you could write. I could re-write it in a week, and it would actually work.

    It is worth noting that when you use your oyster card it doesn’t have to contact a central database. There’s no reason why boris bikes couldn’t work the same way.

    #83866

    7209
    Participant

    Replying to @Timmmm‘s post:

    If you’ll accept a further piece of “bullshit” from me: If you can do it – get in touch with Serco & tell them! I’m sure they’ll take you up on your amazing offer if you can promise to re-write their whole system in a week.

    Oyster is a completely different system – it works in a completely different way and wasn’t designed for small-scale operation for 8 months per year, bastardised & then asked to deal with a far bigger scheme.

    #83867

    Timmmm
    Participant

    The boris bikes are *not* a big scheme in computer terms. There are only 100k members and less than 30k journeys per day. We’re talking about volumes of data that could fit on a floppy disk and be processed by a mobile phone.

    And this system has the same challenges as oyster – namely deciding whether a person has permission to travel in a short time. Oyster gates can’t talk to a central database because it would take too long (probably ½ a second is the limit). Bixi systems *do* talk to a central database, but it’s clear that they shouldn’t because the 3G connection is obviously totally unreliable.

    The solution is the same in both cases: store the critical data on the oyster card/bike key, and consolidate that data with the central database when time allows.

    As for the problems with the dock status… well there’s no reason for that. I’m pretty sure it used to work, and 3G isn’t so bad that you can’t send a couple of bytes every few minutes. Hell you could use SMS for that.

    #83868

    7209
    Participant

    Replying to @Timmmm‘s post:

    What’s at risk if Oyster fails and someone gets through a barrier without their card being recognised? £5?

    What’s at risk if a bike is released without a key being recognised? £300

    As I said – if you can do better, contact Serco & tell them.

    #83869

    jacob123
    Participant

    I think the over-riding issue, when you look back at posts over the recent months, is that loyal users and supporters have seen a significant deterioration in the service. Whether it’s a system that has already reached its capacity, is developing faults, was built to be obsolete within a short period of time (IT companies do this to keep the money coming in) – it doesn’t really matter. Perhaps additional investment is needed. To talk about extending the scheme when the existing one is now unreliable is silly.

    #83870

    iguiyichm
    Participant

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