Lulzbot TAZ 6 vs Makerbot Replicator 2

For a long time the Makerbot Replicator 2 has been seen as the plug and play workhorse for 3D printing. I was disappointed with their next generation after the Makerbot Replicator 2, as I have blogged before. I think they lost the plot, personally.

We (A&A) have now got a Lulzbot TAZ 6. It has some differences, and I hope to explain them here. However, overall, I think the TAZ 6 from Lulzbot is actually a good choice and value for money.


A good starting point in any comparison is price, and Makerbot Replicator 2 seems to be listed for around £1500 at the moment. The TAZ 6 I got was a little under £2000, but oddly they are often listed nearer £2500 (inc VAT). The price I paid seemed quite good, and I got it from Amazon. DPD screwed delivery so a working day late.

Unpacking and getting ready

The Makerbot pretty much was complete (though later versions needed some assembly), but the TAZ 6 is not far off. The bed+carriage needed fitting, which was 4 thumb screws, and the extruder needed fitting which was one screw with a (provided) Allen key. It came with a tool kit even. Very simple and easy and very clear instructions. A few connectors needed plugging in along the way, but all simple and obvious. I was originally concerned that the TAZ 6 was more "hobby" style than the "plug and play" style of the Makerbot, but I really cannot fault the packaging and installation instructions much. It really was simple and took maybe 10 minutes from opening the box, if that.

Print area

The Makerbot 2 is a closed frame, and has a print area of 280 x 153 x 155. The TAZ 6 is an open frame and has print area of 280 x 280 x 250, so way more. This is pretty major in terms of features - being over 2.6 times the volume!

Print bed

The print bed on the Makerbot is acrylic but on the TAZ 6 it is glass (with PEI surface?), and importantly on the TAZ 6 it is heated. This is important as it can ensure large prints do not curl up - this happens a lot on the Makerbot. So far not needed to print any sort of raft on the TAZ 6, unlike the Makerbot. Getting prints off the bed has been easy on the TAZ 6 - not so much on the Makerbot.


Checking the Internet the layer resolution of the Makerbot can be as good as 50µm, but the software appears to only go down to 100µm. Even at 100µm we found the prints to be "stringy" (fine threads between parts of the print). The TAZ 6 can go down to 50µm but the quality is much the same as 100µm, and very good. My practical tests suggest the quality of the TAZ 6 is at least as good as the Makerbot Replicator 2. As usual it is simply a trade off between quality and speed.


The Makerbot uses 1.75mm PLA, but the TAZ 6 uses 2.85mm PLA, or ABS. The fact it can print ABS is a definite plus point for stronger prints.


The TAZ 6 manages 200mm/s. I am struggling to find the Makerbot spec. It seems similar. We may have to do a race between the two some time soon!

Bed levelling

The Makerbot Replicator 2 has a zero Z axis only, bed levelling is a manual process to go through with turning thumb screws. The TAZ 6 has built in levelling. Unlike the Makerbot which means making the bed level, the TAZ 6 measures the bed and builds that in to the X/Y/Z plotting on every print - never a bad print that way. Nice feature.

Moving bed

I was not really that happy with a moving bed - seems to be asking for trouble somehow, but to be honest the TAZ 6 seems fine. Yes the bed and the whole of the print so far moves, but it seems to not break anything, so fair enough. It has the side effect, along with an open frame, of making video of the print process a lot easier.

Dual extruder

There is a dual extruder for both of these, not tried either, but that is a key feature for dissolvable supports. More on that when I eventually try that. The open frame of the TAZ 6 could mean no loss of print size though, to be tested.


The Makerbot app is very good, and easy to use, but to be honest the open source Cura used by the TAZ 6 is at least as easy to use! There is nothing really to tell them apart here.

Any criticisms?

The TAZ 6 lacks maybe on thing. The on device menu should have load and unload filament for totally off line operation. I think it may be possible with movement command. Could be clearer. At present that works well via USB from the Cura app. That is pretty much my only criticism of the TAZ 6 so far!

The only other issue on the TAZ 6 was that when it arrived, probably down to vibration in transit, the two Z axis screws were not aligned meaning I could not do the auto bed levelling. My left/right Z axis was skewed! It was a simple matter of turning one screw a few turns, but the manual did not seem to cover this simple flaw. They could easily improve that.


I prefer the TAZ 6, not much more in price but a lot more in features, and just as easy to use as the Makerbot Replicator 2. Well done Lulzbot.

I am also quite impressed with how much of the TAZ 6 is in fact 3D printed parts!


"Alternative" Dispute Resolution

We have ADR in the telecoms industry and it is creeping in to other areas from what I can see.

My issue here is simple, why "alternative"? Surely that simply means the "original" is not fit for purpose? If that is so, why not fix the "original" rather than making an "alternative".

So what is the "original"

Well, to for most civil low level disputes that ADR may cover it is the county courts system under the small claims track.

I have used the courts may times. I have seen them work, and (in my opinion) go wrong. I have been the one making the case, and the defender. I have learned a lot of lessons. In some ways, the fact that I have had to learn lessons is an issue. It should be a process the novice can handle without learning lessons from the past.

The process, and I mean the "small claims process" here,  has some really good features.
  • Fixed costs, starting very low, in the tens of pounds
  • Loser pays (up front if making the claim, so costs known and spent in advance)
  • Lawyers can get involved but their costs are not claimable (and they are looked down on)
  • Judgement is binding (either way)
There are however issues. It is normally a court hearing, in a location where one of the parties may have to travel at some cost (what with so many contracts over the Internet and not face to face). This itself is a problem, and daunting.

There are some things to help - the county court at Reading, and I assume many others, have a system of free (once you have made a claim) arbitration. This is a one hour phone call (so no travelling) alternating the parties, to try and resolve the issue.

This is huge - it removes the travel and the scary court appearance. It will not always work, but I bet it works a lot - anyone got stats on that?

But if that fails the process is not hard. It may seem scary, it is just you, the other side, and a judge, in a room (an office), and discussion. That is all. Not really a problem (apart from travel).

Can we make it better?

The arbitration is good, but we could do more. How about a remote (email) based arbitration as next step. Each party emails arguments and evidence to the judge to consider. If the parties accept that ruling then all done, if not then a court appearance.

I would be in favour of this, even if it has a small additional fee over the telephone arbitration.

Why is ADR bad?

The only ADR we have had was a fucking nightmare. We were not even allowed to see the details of the case against us - what the hell? That is mental and would never be allowed in a court. The judgement was made with no discussion and no appeal. It was final.

Also ADR for ISPs, and others, is cost one-sided, only the ISP pays either way. It allows customers to threaten ADR with no risk even when they know they are wrong. The cost is way more than the county court, by a factor of around 10. How is "alternative" justice so much more expensive than "real" justice? ADR only makes sense if it is cheaper.

My proposal?

Well, the emailed resolution to add to the phone call arbitration for a start.

In some cases we could err on the side of the consumer, maybe having some limits on cost that are more skewed towards ADR. My suggestion is end user must have a risk and up front cost of maybe £5 or £10, so as to remove the frivolous claims. Then maybe up to a certain level for large claims that is all their cost, with company paying the rest (tens of pounds).

Even so, I think cases need to allow counter claims. If ISP says "they have not paid bill", that should be valid. ISP pays fee to counter claim, and adds that to claim if they win. At present ADR is one-sided and cannot act against end user. Why have any one-sided system?


We could make the "real" dispute resolution better and remove the need for "alternative" dispute resolution in so many areas. Let's do that!


Aliens killing the network?

Just sharing a story from long long ago...

We had racks in a data centre, as you do, and we had a load of new supermicro servers all set up and ready to be deployed to do useful things (like spam filtering).

And we lost power - killing the whole service for some minutes until power was restored and everything booted.

The reason - aliens!

Well, actually, more a question of load testing the new servers running the SETI stuff. I think we managed a passable ranking at one point with that.

I remember running the SETI command on the last box, and oddly not getting any response to my command, or, well, anything.

Moral of story - always make sure you put kit in well within the current limit of the supply and the circuit breakers, FFS. A lesson to learn early on.

These days we have racks full of FireBricks which are hard pushed to use 0.1 amps even on dual supply when running flat out and shifting 2Gb/s of traffic, so not such an issue.


Calling all small ISPs: Fixing broadband faults

There is a big problem in the industry with broadband faults and getting them fixed. Some of this has leaked out to end users who get charged to fix broadband faults, but mostly it is the smaller ISPs buying from wholesale back-haul providers that are suffering and have been for years.

This video below explains it in terms of BT Wholesale, as of today. But this is just the current ploy with BTW. The issues exists with other carriers, and we even see moves to actually try and formally charge to fix faults for which the carrier is responsible (is that even legal?).

It has been going on for years, and has changed over time - with some crazy inventive logic like "engineer charge applies if he visually inspects the end user equipment" (i.e. looks at the router) and charge applies even if router is actually hidden away in a cupboard - that is how crazy it has been. You'll see from the video how bad it is getting now. Next year it will be some new stupidity, I am sure.

This needs sorting, and it may have to be sorted in a court to finally fix it. Like many smaller ISPs we challenge these invalid charges, and we always win. But if it went to court properly then every ISP ever charged incorrectly to fix faults going back at least 6 years (maybe more) could reclaim what they paid. I'm not after back dating the solution (as we have always been successful in every dispute of charges to fix faults, eventually) but it would be a blow if any case went to court. What I would like is this whole issue knocked on the head and sorted once and for all - each party in the the whole broadband Internet Access supply chain taking responsibility (including financial responsibility) for the part of the service they provide, simple as that. Not unfair or unreasonable - simple.

We have created a Facebook group called "Wholesale Broadband Buyers Forum". If you are an ISP buying from a wholesale provider, please apply to join. We want to encourage an open and frank discussion with you [Chatham House rule]. We want to solve the issue of paying to fix faults. We are happy to share arguments and techniques to get disputes resolved. We want to make working with back-haul carriers work for us, you, and them. We want to save everyone the hassle of these disputes. Some of this will mean wholesale carriers changing their ways and taking proper responsibility. Some will mean Openreach taking some responsibility. Some may even mean OFCOM and political public policy issues if that is what it takes. But it needs fixing or else broadband in the UK is doomed.

We are after people happy to engage in debate, and I cannot rule out meetings in pubs even...

Watch the video, and if you are a UK small ISP using carriers like BT Wholesale, Talk Talk Business, Vodafone, or others, please do apply to join the Facebook group.

P.S. we did try this before, with an actual (mutual) company and web site, but to be honest Facebook works well as a forum and means to discuss such things, so we are trying again. Thank you for your support.

DE Bill - phone blocking orders

One of the more recent amendments to the Digital Economy Bill proposed the possibility of orders to block use of a device or phone number or something else that may be used with a device if it is, or likely to be used for drug dealing.

There are some problems with this!

Does it make any sense?

This appears to be based on an NCA report that talks of basically telephone ordered drugs. The report talks of people call a long standing and well known (mobile) phone number, and order drugs, then someone gets sent to deliver them. Lots of exploitation involved in various levels, dealers trying to keep at arms length, nasty business.

The proposal seems aimed at disrupting the supply by blocking these numbers. It is not clear that this is an NCA proposal though, so not clear why it had been put forward.

To me that makes no sense. I am not in law enforcement, and do not know how these things work, but surely if you have evidence of drug dealing, arrest someone. If you know the number is used to order drugs, get an intercept, record calls for evidence, physically locate the phone and arrest someone? One comment I got to this is that when you take one person out the number just moves to someone else - well that sounds perfect as you can just repeat the process until the number becomes a poison chalice that no dealer would touch - the same result as blocking the number but also arresting several people along the way.

But assuming I don't know what I am talking about, and the seemingly lazy approach of just blocking the number is sensible somehow, surely all you are doing is driving the dealers to use more covert and secure communications? Phone numbers are so last millennium! For a start the dealer could get a non UK mobile, which is just as easy to use but harder to get blocked. They could use a non UK number that forwards to a UK mobile, the non UK number then not even being on a roaming phone, and the final target being changeable as needed - again hard to block as has to be blocked at all calling telcos, not just the receiving telco.

But forget "phone numbers" for a moment, what of "iMessage moredrugs@example.com" as the instruction you give. Now you have communications that are end to end encrypted, and even the fact of the communication is in the hands of a foreign company. The dealers have just dropped under the radar massively if they do that, and there are many other common platforms for such communication.

So it seems nonsensical and very short sighted to even consider this as a means to tackle the problems, even a lazy means.

What about due process?

Another big concern I have here is that such action, which is clearly harming or punishing someone (the phone user), is done without any actual evidence or conviction of a crime. Indeed, the amendment covers cases where no crime is even committed but the conduct by someone is likely to mean a device is could be used to commit a (drug) crime.

This is a worrying trend that bypasses a proper due process. We seem to have too many of these. It could also be abused - if someone put our business number on some toilet walls saying call for drugs, then we could be blocked, even though no crime committed?

Wide scope?

The other problem I see is this does not just cover devices (how quaint) and telephone numbers (almost as quaint) but anything else used with the device. This means such orders could block domain names. If someone emailed me offering drugs then could I find my domain name blocked? Would there be notice? Would there be an appeal?

Now this would involve a judge, but even so, this is punishment without charge or conviction, and has much wider scope than simple mobile phones.

What should we do?

We need to stop trying to find short term shortcuts and actually catch the criminals. We also need to fix the social issues that create the environment for such criminals to thrive in the first place. But all of that is a lot more work than just making phone blocking orders...


ADR (Otello) from the other side (EE)

Having dealt with Otello, or whatever they are called now, from the ISP side, and it ending very badly with them breaching their own terms and basically screwing us, I have now seen ADR with them from the customer side.

It is not me personally but my son, who had mobile service with EE. He had a SIM for him and his girlfriend and ceased the later, and paid all on Direct Debit. He is young, and he does not pay attention, which is fair enough - Direct Debit is perfect for him.

However, after a couple of years when he should have only been paying one mobile contract he finally clocked that he was paying two - a couple of weeks out of phase, both similar amounts. Direct Debits a couple of weeks out of phase. And no, surprisingly, not the SIM for his girlfriend but a third SIM that started when he first got a contract.

The problem is, every time he saw a bill or DD, it looked a reasonable amount, and it did not click it was twice a month not once a month. He is known for not even opening post. I remember when I was young and I don't hold it against him. I think he is learning - the world is there to screw you if you let it!

So he got on to EE who decided to handle it via their Fraud department, took ages, did not tell him anything, and got nowhere. I serious doubt any fraud. I suspect a simple cock up by EE sales droids. Eventually he got around to complaining again, and again they did the same. This was getting silly, so I suggested ADR.

Now, EE have no evidence that he asked for an extra SIM. They have no proof of delivery. They have no record of the SIM ever being used in a phone or making or receiving any calls. Nothing to say he has a contract with them apart from the fact he has paid (by Direct Debit).

ADR conclusion - even though EE have no evidence of any contract? They decide in EE's favour?!?! They say it is odd he did not notice earlier or claw back the Direct Debits.

I suggested he write back and say that if "clawing back the Direct Debits" would swing the case in his favour, he can do that, for all payments right now if they like. (DD rules allow that if no physical signed DD mandate). He did not write that, and sort of gave up.

If he did not have to worry over credit rating then simply clawing back all DDs would force EE's hand and they would have to take him to court with no evidence. He has to worry about credit ratings. A sad sate of affairs really for all of us.

Anyway, ADR is clearly a waste of space, so next steps:

  1. Data Protection Act Subject Access Request to EE for all evidence of any contracts formed with him (call recording, web logs, signed contract) or any usage of the SIM or even proof of delivery.
  2. Assuming none exist, letter before action for county court.

At the end of the day if they cannot prove a contract exists, even by implicit "use of the service provided" I think they are going to lose. Well worth a try and trains him on the ways of DPA and county courts, and not a lot to lose in trying.

I'll try and post an update once we make progress. This is around £1000 so worth his time, even if he loses, to learn the processes.


UBNT/Ubiquiti and iPhone and roaming not working

I have posted a few times on this - the issue is plain...

If I go to the toilet my iPhone stops working. Obviously everyone takes their phone to the toilet, don't they. It is not just me. Tell me it is not just me?

If I sit in the bath in the morning trying to catch up on twitter and FaceBook my iPhone stops working.

This is all about roaming between Access Points on the WiFi, when I roam between APs (I have 3 in the house) I lose connectivity. It is annoying.

This has varied from occasionally to damned annoying, depending on s/w versions. The latest code on the iPhone and Ubiquiti led me to turn off WiFi and read Twitter in the bath on 3G as I kept having to reset the WiFi. That really is the last straw.

Ubiquiti are now talking to me and working on it. Thank you.

We have tried many things, but the last few days I tried turning off the IPv6 on my LAN. Yes, that was strange. Most of what I do uses IPv6. Most of it will fall back to IPv4 (but not all). I have machines (e.g. my main Mac) with fixed IPv6 addresses but router set via RA, so that caused delays on access to all sorts of things. Turning off IPv6 is strange. It is, after all, the current version of IP. I'd be happier turning off IPv4. I have turned it back on now. Phew!

Initially it did not fix anything, but the iPhone still had IPv6 addresses even though RA was off. Looks like my RA code sent "infinite" life on prefixes on removing IPv6 RAs rather than zero - oops. Fixed. But proved RA itself is not the issue, it is the iPhone having IPv6 addresses.

Once it had only IPv4 addresses it worked, and roamed between APs seamlessly with no problems for 2 days! Turned IPv6 back on and the problem came back immediately.

So, is it an iPhone issue or a Ubiquiti issue? Hard to say. I do not know if "roaming between APs" has any "is this IP OK still" logic? Or what? I don't know enough of the protocols.

Many people have said they use Ubiquiti and see no issues. Ubiquiti have said a few people have issues, and they don't understand why. This could be it.

The good news is Ubiquiti are working on it - trying to reproduce the issue. I have offered a FireBrick that will send RAs for them to test. Let us hope this is close to the end of the issue. If it is iPhone, I hope they will raise with Apple.

If we can only solve this, the Ubiquiti are excellent APs at a sensible price.


Barcode reader apps (iPhone)

Yes, OK barcodes are a hobby, but I have been looking at the different apps you can get on an iPhone. I imagine many are available for Android as well.

Firstly, I have to say this: Why the hell is reading barcodes not STANDARD in the camera function in the phone?

After all, it has face recognition - why not put a box around barcodes it sees and you poke the box and it reads the barcode and does something with it if it knows what it is. Why on earth does a phone like an iPhone need an "app" to read barcodes in the first place. Crazy. I can see merit in apps being able to hook in to that, registering URL schemes and so on to handle the barcodes you scan and do specific things, but why an app to read the barcodes in the first place. And then there are a million (exaggeration) different apps to choose - how does a user know which app to use?


i-nigma is an app that has been around for a long time, it is free, and it will read IEC16022 and IEC18004 (data matrix and QR) 2D codes as well as 1D barcodes of various sorts. If the content looks like a URL it opens that in a browser, or will link to things that register a URL scheme like otpauth for one time passwords, etc. It is quick and seems to work well. However, it seems to use a low resolution on the camera meaning it cannot read high density codes, and has its own decode logic which means it cannot handle some high end UTF-8 QR codes (e.g. pile of poo).

QR Reader for iPhone

This is quite a find! It is free (pay to remove small adverts), uses high resolution on the camera so can scan very large codes easily, is fast, reads 2D and 1D barcodes quickly. Like most apps it tries to make sense of the barcode, and will look up UPC/EAN product codes, and interpret WiFi setting barcodes and so on. It will use front and rear facing camera, zoom, and even scan images from photos you have taken. It even has a QR code generator!

However, the biggest feature of this is that you can tell it to feed the codes it reads in to a web site of your choice as an argument and display the page it gets. This means it can work as a front end for your own web based applications directly.

Seriously - that is awesome - I don't need to make a mobile app to do stuff with barcodes, I can just do something on my own web site. I am now thinking of all the things we can do with this, and we'll never have to buy a bar code reader again. At work we scan serial number of routers, for example, but we can do way more than just type in to the keyboard now, and we can handle 2D barcodes as well (we only have 1D scanners at present).

Most other readers

I have tried several others. Some are not free (ha!). Some will not read IEC16022 codes (Datamatrix). Some only do 1D barcodes. Some are packed with adverts. Most do try to link in to selling you the thing you have scanned in some way. But so far I have not found one as good as the QR Reader app.

If anyone knows any that are better, let me know...


On the TV again

Thanks to RT... Very brief inclusion in this clip, but it all helps get the message across.


The Queen's cold

Gotta love iPhone suggested location
Obviously there is no way to know if it is the same virus from which the Queen has been suffering, but I, like so many people I know, have suffered from a particularly bad cold over the last few months. It is telling that she was publicly so ill as to not attend Christmas events.

I really am sick of it, and it has now been a month.

More than once (like today) I started to think it may be over now. It is mostly a cough, sometimes dry, sometimes coughing something up, but seems to have lots more in store than just a cough. I was tired, feverish, aching all over, to various degrees for the whole month.

I am not one to stop working for something like a cold, though I was trying to work from home even more than usual as no need to infect the office. Most of the time I was able to do some work, but quite a few days I could not even do that. I know some will cry "man flu", and I understand that, but this has been a real bugger.

A few times I have had to go to the office - two TV interviews in the last week. Thankfully recorded so they can edit out the coughing. As often is the case with a cough, if I stay still, don't talk to anyone, and work at home, I feel like things are going well. Go outside and change temperature, or start talking, and shit hits the fan.

I'd love to know how/why a virus can be so much more resilient than others. Clearly we win the battle - everyone I know who has had this, whether 3 weeks or 6 weeks or whatever, has "survived" it. So what makes one virus take so long to be defeated I wonder?

Even so, this really long bout of being ill is depressing. I have been taking paracetamol and sudafed regularly (at a bit below max dosage, as I do worry) for weeks now.

This week was extra special, on Tuesday I went to the office to meet a TV crew for Euronews. I had a coughing fit, and coughed so hard I pulled a muscle. I do not recall agony like this ever before, I was thinking I must have cracked a rib or something, I could not move, I could hardly breath, let alone talk. My staff were great, especially Andrew and Jimi, an ambulance was called. They got me on gas and air which helped. They concluded I had pulled something! After a couple of hours I was able to struggle though a TV interview thanks to a very patient TV crew before getting codeine and valium, which I then spent two days solid on. I could not lay down properly, ended up sort of propped up on my sofa to sort of sleep. To be honest, neither codeine nor valium seem to do much for me. Thankfully over the two days the pain has gradually reduced.

So, once again, I find myself hoping that this is close to the end. The muscle pain is mostly gone, or at least manageable. I have to be "careful" coughing, which is, in itself, strange.

Good luck to anyone else that has this - I know some that have had it as "an annoying cough" for many weeks and little more - well done for fighting it so well. Personally, I have been suffering. I suspect there are those way worse off than I, and you have my sympathies. Get well soon.

P.S. I discovered the ambulance crew were self employed working for a company that subcontracts the work from NHS, and so we like Uber drivers, even fined if they have too long a break. That is going to be the next uproar, I am sure. They were very good though.


Teaching us to suck eggs? BT?

We have a customer on a fibre to the cabinet (FTTC) service which has packet loss.

The red is loss, as measured by one second LCP echoes over the PPP link, and is often over 5%. Levels of random packet like this are severely impacting his ability to make use of the service.

The loss started at the exact moment BT did work on the circuit due to a major outage, so is clearly related.

This is the line before the outage, and you do not get much clearer than that - no loss. Same as every day before :-

This is the day the line came back after their major outage (which lasted two days) :-

And this is the next day, which looks much like every day since :-

It does not take a rocket scientist to see there is a problem there - periods of around 5% loss, sometimes more, most of the day, every day, since the outage.

And yes, that is start of OCTOBER 2016! BT have failed to fix the fault for that long!

Today we got this, and I am almost at a loss for words! Talk about teaching us to suck eggs!

Is the customer using a VPN? Data is transmitted in discrete units known as packets. When a network server is overloaded, these can get discarded. 
This is known as packet loss and results in slow loading game dynamics and graphics, or the unsatisfactory performance of a VPN connection.
In such circumstances, there isn't much which can be done to improve matters, as the cause is not associated with your PC or broadband service.

I'm really not happy about this, but the "there isn't much which can be done to improve matters" is just shocking. We have asked BT to confirm if they are stating, officially, that 5% loss on an idle line is considered "acceptable" for a GEA/FTTC service - we await the response.

They even go on to say :-

In the meantime can you ask the customer to run some traceroute and provide and this hopefully will aid us in seeing where in the network  the packet loss is occurring.
SPs engineers can use a "wire shark" which can detect packet loss at points in network.

This is after explaining that we can see the loss at the LCP level on the PPP link and providing access to and copies of graphs showing the loss over and over again! It is like dealing with Dory to find a fault called Nemo. We keep having to repeat ourselves.

There is one other small snag.

We are all used to the notion of "fibre" broadband not actually being "fibre" which is why this is "Fibre to the cabinet". BT sell this to us as "Fibre to the cabinet" and call it FTTC. It turns out this line is in fact "Microwave to the cabinet". A good idea, normally, but not as described, and clearly beyond BT to actually understand and fix.

This just highlights the problem with a clear definition of the service: We need a clear specification of levels of idle/random packet loss, idle latency and jitter, reliability/resyncs, min sync speeds up and down, and even throughout before loss/latency starts. Without these you can literally spend months bashing your head against a brick wall and having engineer after engineer sent (each potentially costing around £200).

P.S. Today we get "Openreach have completed the engineering checks on the Radio back-haul and discovered some issues with the Link.". Well, yes, we have said this from day one (113 days ago). How bloody annoying. Maybe we finally get it fixed now.

P.P.S. After 120 days they finally fix the microwave link and the line is clean. So annoying.


Traffic management in A&A

A&A do not do much in the way of "traffic management"!

This was somewhat brought home recently when someone tried to sell Alex some DPI / traffic management system over linked-in seeming to think A&A would need some.

What he was selling was DPI (Deep Packet Inspection) systems that can "manage" various types of traffic. As he explained, this could "throttle" peer to peer traffic.

What was amusing is Alex tried to explain that we don't need that - one would only need such things to manage a congested link. We aim not to be the bottleneck and so not have congested links. This is hard work and there are always occasional exceptions from time to time, but the plan is that we have enough back-haul to carriers, core network, and links to peers and transit that normally we are not the bottleneck. Basically, we should not slow down at peak times.

Alex's tweet (here) showed the exchange, where the salesman did not quite understand how we work. I am pleased at the number of comments and retweets appreciating our stance on this.

From the discussion it is worth mentioning a couple of exceptions to the rule.

1. Denial of service attacks are where so much data is sent to a customer they have an unusable Internet link anyway. We take action in such cases not only to help the end user in question but everyone else on our network that could be affected. Such traffic is far from "normal" usage and not something our customer has asked for. We always reserve the right to protect the network as a whole. Thankfully this is rare.

2. Where the link to the customer is congested because of the capacity of that link to their line - here we do do some extremely "light" traffic management in that larger packets are dropped before smaller ones. We have to drop packets if the link is full! This is a very simple metric and needs no DPI. Large packets are a feature of bulk data transfer like TCP, which can adapt and slow down, but smaller packets are more likely interactive or VoIP or DNS which cannot adapt. This level of management, which we allow customers to control, allows VoIP to work in the face of large downloads. We offer customer options to manage this, so you have control.

Basically, that is it.

We have no need for Deep Packet Inspection traffic management. If someone wants to P2P filling links, then they can. Our tariffs all have some level of usage cap, even if in the terabytes, so if someone is "taking the piss" they will hit limits. Even so, with 1TB and 2TB monthly usage packages now, we are pretty accomodating even with non stop streaming video.

At the end of the day we should not care what you are doing and do not need DPI based traffic management systems! Well done Alex for explaining this.



I have been messing with barcodes most of my life - and I don't say that lightly! My first ever commercial software was when I was 15 or 16 and I did some bar code reading software for an RML 380-Z. It involved reading some simple character barcodes, and also EAN/UPC barcodes. All the timing was done in the processor based on a one bit input from a light pen / reader.

I learned about barcodes back then and have been messing about ever since in various ways.

There are two main types of barcodes, though, to be fair, only one has "bars". The two types are 1D or linear barcodes, and 2D barcodes. It is really misleading to call the 2D codes "barcodes" to be honest.

Linear barcodes

There are many types of linear, or 1D, barcodes. They are designed to be read by a wand or laser or reader which looks at a line across the barcode seeing black and white in specific timing or spacing.

Normally these need a quiet zone (usually white) before and after the code, and then have bars and spaces (bars being black and spaces being white) which are certain sizes. Some standards have simply thick and thin for these and thick could be different to simply twice the width of thin. In practice, using thick as 2 "units" and thin as 1 "unit" usually works even in such cases. Some systems have several thicknesses of bar and space, each a multiple of a basic unit size. This maps well on on to simple pixel graphics images.

One of the least efficient and most annoying of these is "code 39". This uses 5 (black) bars with 4 (white) spaces making a total of 9, of which (mostly) 3 are thick and the rest are thin. Thick can simply be twice the width of thin. Code39 allows 40 combinations of 3 from 9 being thick, which codes letters, numbers and a few symbols. The space between each character could be one thin space, or more. There are a set of special codes that are thin bars and thin spaces with one of the spaces thick giving 4 extra characters.

The beauty of such a system is that each character is a self contained sequence, and you can in fact make a font out of it. There are no inherent check digits. Each normal character is the same size. The codes start and end with "*" character. So it is very easy to construct, though very inefficient.

Another simple code that only uses thick and thin bars and spaces is ITF (Interleaved 2 of 5) which only codes numbers, and then only even number of digits. It is much more compact for numeric sequences. A common checksum is the LUHN checksum as used on credit card numbers. Each pair of digits is 5 bars and 5 spaces (interleaved) where 2 of the 5 are thick. This makes 10 combinations for digits 0-9.

We then get a tad more complex where we do not simply have thick and thin, but 1, 2, 3 or even 4 unit widths. The system used for retail product code marking UPC (Universal Product Code) and EAN (European Article Number) allows coding for products using a numeric value.

By using more different widths, this allows more code density. The format has specific additional control fields such as the two thin bars with thin space at start and end and in the middle. There is a standard checksum coding as well. This is coding specific 13 or 12 or 8 digit sequences only.

Another common linear code is codabar 128 - this uses multiple width bars and spaces (up to 4 units wide). It has special coding for pairs of digits to be efficient for numeric sequences, but allows for letters and numbers and symbols. It is probably the most dense and flexible 1D coding that you can use.

Like most systems for linear coding the barcodes all have consistent width (apart from special characters in code 39). This helps allow formatting of a specific number of digits or characters in a specific space.

Two dimensional codes

There are two main standards for 2D codes. These are not "barcodes" as they do not use "bars", instead they use patterns of pixels which are black or white. Both of these include forward error correction using Reed/Solomon coding. This means that defects errors printing and reading and can for many errors. Obviously the technology to read these is different - based on cameras rather than linear pens or laser scanners.

One standard is IEC16022 "DataMatrix". It is quite nice technically. It allows a number of different methods for encoding data optimised for numeric or alpha numeric and so on. It is used on postal systems in the UK quite a lot.

The other common 2D code is QR codes (IEC18004). These are, in my opinion, not as nice technically, and not as compact, but look "cooler" so are kind of winning the popular vote on such things. They have target squares within them that sort of look better. They do have different coding formats for numeric, alphanumeric, etc.


There are many 1D and 2D coding systems and some clever new colour systems even, and picking the right on is a good idea. You want something compact and with good error corrections and detection. It is a shame so many systems opt for the worst of 1D coding using code 39 fonts though, especially when the data is purely numeric and could be much better coded as ITF or codabar128.

P.S. My card ordering system allows you to create cards with any of the above bar coding systems. The Odeon card is an example.


URL shorter for barcodes

Some time ago I made a URL shortener site specially aimed at use with barcodes.

The site is http://4.gg/

Today I just changed it to use QR codes rather than DataMatrix codes (IEC 18004 rather than IEC 16022), which meant the codes are now using 16 rather than 13 characters of unique data in them. I prefer IEC16022, but I have to recognise that IEC18004 (QR) codes are more popular.

The idea is the URL it makes is short, but no shorter than needed to fit in a sensible small barcode. Hence in data matrix it is a different size to QR codes.

Using a URL shortener site like this allows for a smaller and easier to read barcode.

We use it internally for all sorts of things, including on ID cards, and invoices, and so on.

The site holds very little data - it has the code to URL mapping, a hit count, and the IP from which the URL/code was created.

I don't think I have advertised it much, well, at all even!

So I had a look today, whilst changing to QR code basis.

To my surprise it has been used to create URL/codes from over 59,000 different IPs. A lot are ours, a few IPs cover hundreds of thousands of URL, and we have over 1.4 million URLs in total, but still, I am quite surprised.

Thousands are youtube links, lots are links to other short URLs.

So I looked at the usage (hits) and the top one has over 500,000 hits and is a 404 not found? After that are the ones on the main 4.gg web site (e.g. BBC) and then a few specific web sites with different URLs, most of which now fail.

Even so, over 3 million hits, not bad for something I never published!


Happy New Year

I sort of felt that I should post something but now I come to, I am not sure what to say.

My new year's resolution is the same as last year, 5120x2880, which is the resolution of the nice 5k Mac I use :-) I don't really make traditional "resolutions", never have done. If I set my mind to something there is no reason to wait for a new year. Like anyone else getting older, I hope to stay reasonably healthy - but that has been slightly thwarted by nearly two weeks of rotten cold / cough. I really think I am getting over that now, I hope so, so the year should start on a good footing.

I have a great family, and that moves on whether the year is ending or not. Another grandchild on the way - which is great news, but makes me feel even older.

The company (A&A) is doing well - the upgrades we have done over the last year have helped make sure we keep up with ever increasing usage and manage to offer what I really feel are good value packages. Yet more to invest in the coming year with a lot more 10Gb/s stuff happening but happy we can afford to make that investment - I do feel we have the balance right. The company is 20 later this year so we should do something for that!

Politics in in the UK is nearly as mental as the US. OK UK politics is a tad less likely to be world wide armageddon, but still crazy. Our illustrious leader, May, is still suggesting radical moves, like abandoning Human Rights, which is just plain scary. We have DE Bill to contend with, which is also scary. And the IP Act, with all its secret orders, should be challenging.

I did one fun thing last year - I learned a new skill and was tested and approved - drone flying. Not actually done any commercially yet, but it was actually quite interesting just learning something completely new and different at my age. Even so, law on that is probably changing soon as well.

I do plan to try and come up with some sort of holiday plan this year. Oddly things are getting a tad strange for holidays - it used to be like one family holiday a year, but with the kids having their own family now things get more complex. A holiday with my with darling wife, obviously, but probably also a holiday with some of my mates which I did for first time last year (LA and Vegas). We'll see how that goes and what I can afford.

It should go without saying, but always seems necessary for so many people to say, so I wish everyone a Happy New Year. Wishing does not really do anything (much like praying) but saying it does make people feel I am a nice person (which I am, obviously). Maybe that is the cold and/or alcohol talking. Even so, I do hope everyone has a good year...

My latest clever trick is that hard pressing the "send" on iMessage means you can send with bubbles and screens, like "fireworks" (saying "Happy New Year" sends with fireworks automatically). Yes, by so much, I am not the first to know that. But that is what the image is.

I have a busy week ahead, change freeze over, we have a new FireBrick release, and upgrades for that, and loads of other things now that I am allowed to tinker. Still hoping, after this cold, I have my mojo back. Right now I have a temperature, I think, and have had to turn on air-con in the man-cave. Wish me luck (as if wishing worked), ta.

ISO8601 is wasted

Why did we even bother? Why create ISO8601? A new API, new this year, as an industry standard, has JSON fields like this "nextAccessTim...