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Updated: 1 hour 16 min ago

Chris Lamb: Estimating Training Stress Score (TSS) for running on Strava

Tue, 18/02/2014 - 21:17

In cycling, a ride's Training Stress Score is a function of that ride's duration, average power and the intensity of the ride relative to the rider's capability. This Slowtwitch article provides a good overview on how intensity and TSS is calculated on a bike.

However, having TSS values for other sports allows a multisport athelete to take into consideration the physiological cost of activities in different sports. This is achieved by ensuring, say, 50 TSS on the bike "counts" the same as a 50 TSS run.

This can be used to simply determine the length, intensity and scheduling of an athletes next workout (to ensure adequate recovery) regardless of the combination of sports, or to identify the athlete's long-term tolerance to—and targets for—training load using metrics such as Chronic Training Load.

To make this possible when using Strava, I wrote a Chrome extension that estimates the TSS score of a run from its Grade Adjusted Pace distribution:

The "TSS (estimated)" value is calculated by the extension.

Source code is available. If you found this Strava extension useful, you might like my extensions to quickly switch between metric and imperial units or to change the default comparison filter.

Categories: LUG Community Blogs

Chris Lamb: The effect of pedestaling on TT bike position

Tue, 18/02/2014 - 00:19

To "pedestal" an aerobar means to elevate the bars above the basebar using risers instead of using headset spacers:

David Millar, 2010 Giro d'Italia.

You might do this for a few reasons:

  • The rider is in a more aerodynamic position when cornering or descending on the basebars.
  • Lowers the rider's centre of gravity, improving cornering confidence.
  • Less flex when climbing or accelerating under high wattage.
  • Teardrop-shaped risers are more aerodynamic than a cylindrical steerer tube:

So, assuming you currently have a bike that uses headset spacers, what would be the effect on your position if you were to replace, say, a 10mm headset spacer with a 10mm armrest riser?

First, let us consider the effect of removing the headset spacer. The crucial insight is that removing a 10mm spacer will not lower the stack height—ie. the vertical distance relative to the bottom bracket—by 10mm.

This is because spacers are not oriented perpendicular to the ground; they are stacked along the steerer tube at the head tube angle of the frame. We will assume a head tube angle of 72.5° degrees.

We can calculate that removing a 10mm spacer will reduce the stack height by:

sin(72.5°) × 10mm = 9.54mm

... and by the same argument it will also increase the effective reach—ie. the horizontal distance relative to the bottom bracket—by:

cos(72.5°) × 10mm = 3.01mm

Next, let us consider the impact of adding the riser. These are oriented perpendicular to the ground, so its addition makes no further change to the reach. However, we can now calculate the overall change in stack height:

Δ stack = -(sin(72.5°) × 10mm) + 10mm = 0.46mm

We can then repeat the calculation for any length of replacement:

Replacement (mm) Δ stack (mm) Δ reach (mm) 10 +0.46 +3.01 20 +0.93 +6.01 30 +1.39 +9.02 40 +1.85 +12.0 50 +2.31 +15.0 60 +2.78 +18.0

From this table, I can discover that if I were to replace 30mm of headset spacers with 30mm of risers it would:

  1. Increase my effective stack height by 1.39mm (likely neglible).
  2. Increase my reach by 9.02mm. This might require me to use a shorter stem to get the same position. If that was undesirable—for example, if was already using an extremely short stem—I might be forced to abandon the idea altogether.

Three further considerations must be noted:

  1. The resultant low height of the base bar could be quite drastic and prevent you breathing properly whilst climbing.
  2. Having the steerer tube cut down after to removing headset spacers will reduce the resale value of your bike.
  3. You might need to re-cable your brakes as you may have changed the distance the cables must span.

(It may seem odd to provide results for up to 60mm of headset spacers when such a large number of spacers would—at the very least—void one's warranty. However, I suspect such setups are transiently common within the confines of a fitting studio.)

Categories: LUG Community Blogs

Wayne Stallwood (DrJeep): Dancing Ferrofluid first test

Sun, 16/02/2014 - 19:03
First attempt, This is using a coil scavenged from an old hard drive. The real project I am working on isn't really about driving it with audio but I just wanted to see how it worked out.

Fed with half wave rectified audio. The coil impedance measured at approximately 6 ohms which was convenient as it's not that far from a loudspeaker coil.

Running it with a 60W amp meant that I only had about 30 seconds before the coil started to overheat. Quite fun though I might try a bigger coil or an array of more small coils.

Categories: LUG Community Blogs

Mick Morgan: checking client-side ssl/tls

Wed, 12/02/2014 - 21:06

At the tail end of last year I mentioned a couple of tools I had used in my testing of SSL/TLS certificates used for trivia itself and my mail server. However, that post concentrated on the server side certificates and ignored the security, or otherwise, offered by the browser’s configuration. It is important to know the client side capability because without proper support there for the more secure ciphers it is pointless the server offering them in the handshake – the client-server interaction will simply negotiate downwards until both sides reach agreement on a capability. That capability may be sub-optimal.

A recent post to the Tor stackexchange site posed a question about the client side security offered by the TorBrowser Bundle v. 3.5 (which uses Firefox). The questioner had used the “howsmyssl” site to check the cipher suites which would be used by firefox in a TLS/SSL exchange and been disturbed to discover that it reportedly offered an insecure cipher (SSL_RSA_FIPS_WITH_3DES_EDE_CBC_SHA). Sam Whited responded with a pointer to his blog post about improving FF’s use of TLS.

From that post, it appears that TLS 1.1 and 1.2 were off by default in FF versions prior to 27. Hence they would have been off in the TorBrowser Bundle as well.

Categories: LUG Community Blogs

Mick Morgan: policy update

Wed, 12/02/2014 - 18:39

An exchange of emails with Mark over at a day or so ago made me realise that my privacy policy needed updating. Not, I hasten to add, for any fundamental reason, but simply because a couple of the references in that policy were out of date. I have therefore amended it and version 0.2.0 is now in place. As promised in the policy, this post draws attention to the changes.

The amendments I have made are as follows:

I have amended my reference to geo-locating IP addresses because I stopped using the off-site “clustrmaps” tool some time ago. I now point out that I collect aggregate IP address geo-location data incidentally through my use of Counterize. However, as I note in the policy, I may drop Counterize shortly because it is becoming a drain on the site. Unlike static web log analysis tools, Counterize runs a script in real time to update its database. That database is now getting too large for my liking and some of the (automatic) queries it runs are not well optimised. I haven’t spent any long time investigating this, largely because my MySQL DB skills are woefully inadequate, but it looks to me as if some of the fields are not properly indexed to allow fast queries.

As an aside, readers may care to note that Counterize reports that I get between 30,000 and 40,000 hits on trivia each month and the top visiting countries are: the US at 57.8%, China at 13.6%, the EU at 6.8% and the Russian Federation at 4.5%. The dear old UK is eighth at 2.4% just ahead of Canada and the Ukraine. Those stats might look odd until you realise that I have allowed Counterize to include known webcrawlers. The biggest of these of course are based in the US, but Baidu in China is not far behind in its activity.

I have changed my references to the captcha and contact forms I use on trivia because I have stopped using Mike Challis’s plugins. I did this because Mike seems to like to update his plugins every other week or so and, much as that is to be applauded if there are real gains to be made, I found the maintenance overhead to be too high for what I was getting. Stability is good too.

Incidentally, for anyone interested in FreeBSD, particularly in its use on a server running Tor, or a website it is well worth paying a visit to Mark’s blog. He writes well and it is always worth looking at alternatives to Linux.

Categories: LUG Community Blogs

Jonathan McDowell: Choosing a new laptop

Tue, 11/02/2014 - 23:31

Recently I've been thinking about getting a new laptop. I have this rule that a laptop should last me at least 3 years (ideally more) and my old laptop was bought in September 2010. So for the past few months I've been trying to work out if there's something suitable on the market that is a good replacement (last time I didn't manage to find something that ticked all the boxes, but did pretty well for the price I paid).

To start with I decided to track my laptops over time - largely because one of my concerns was about the size of a replacement, because I have a significant leaning towards subnotebooks. In the end the reason I decided to upgrade was for some extra CPU grunt; my old machine had a tendency to get pretty hot under any sort of load.

DateModelCPUScreenRAMStorageW (mm)H (mm)D (mm)WeightCost 1991Amstrad PPC 640DNEC V30 8MHz9" 640x200 non-backlit green LCD640k2 x 3.5" FDD45023010010kg??? August 1997Compaq Aero 4/33c486sx337.8" 640x480 CSTN LCD4MB80MB260190431.6kg??? July 2002Compaq Evo N200P-III 700MHz10.4" 1024x768 TFT192MB20GB251198201.1kg£939.99 August 2005Toshiba Portege R200Pentium M 753 1.2GHz12.1" 1024x768 TFT1280MB60GB286229201.29kg£1313.58 September 2008Asus EEE 901Atom N270 1.6GHz8.9" 1024x600 TFT2GB4GB + 16GB SSD248175231.1kg£299.99 September 2010Acer Aspire 1830TCore-i5 470UM 1.33GHz11.6" 1366x768 TFT8GB500GB284203281.4kg$699.99 (~ £480)

The EEE didn't actually replace the Toshiba, but I mention it for completeness. It was actually the only machine I moved to the US with, but after about a month of it as my primary machine I realized it wasn't an option for day to day use - though it was fantastic as a machine to throw in an overnight bag, especially when coupled with a 3G dongle.

I wasn't keen on significantly increasing the size of my laptop. There are a number of decent 13" Ultrabook options out there, and I looked at a few of them, but nothing grabbed me as being worth the increase in size. Also I wanted something better than the Acer - one of the major problems was finding something smaller than 13" that had 8G RAM, let alone more. There's a significant trend towards everything soldered in for the smaller/slimmer notebooks, which makes some sense but means that the base spec had better be right.

Much to my surprise the Microsoft Surface Pro 2 looked like an option. It comes with an i5-4300U processor (at least since around Christmas 2013), and the 256/512G SSD models have 8G RAM. Screen resolution is an attractive true HD (1920x1080) and the 10" display means it's smaller than the Aspire. Unfortunately the keyboard lets it down. It's fine given a flat surface, but not great if you want to support the whole thing on your lap. Which is something I tend to do with my laptop, whether that's on the sofa, or in bed, or on a bus/train.

Another option was the Sony Vaio Pro 11. This is a pretty sweet laptop (I managed to get to play with one at a Sony store in the US). Super slim and light. 8GB RAM. True HD screen. However I have bad memories of the build quality of the older Vaios and the fact that there was /no/ user replaceable parts put me off - it's a safe bet that a laptop battery is going to need replaced in a 3 year lifespan.

What I managed to find, and purchase, was a Dell Latitude E7240. I admit that the Dell brand made me wary - while I've not had any issue with their desktops I didn't associated their laptops as being particularly high quality. Mind you, I could say the same for Acer and I've been very pleased with the Aspire (if they'd had a more up to date model I'd have bought it). I bought the E7240 with the Core-i5 4300U (so the same as the Surface Pro 2) and True HD touch screen. It has a replaceable battery, expandable RAM (up to 16G) and the storage is an mSATA SSD. It also came with a built in 3G card. At 12.5" it's a little bigger than my old machine, but I decided that was a reasonable idea given the higher resolution. I'm typing this article on it now, having finally completed the setup and migration of the data from the old laptop to it this evening. More details once I've been using it for a little bit I think.

Categories: LUG Community Blogs

Wayne Stallwood (DrJeep): AWS EC2 Tricks

Tue, 11/02/2014 - 22:14

PIOS are expensive but EBS optimisation isn't. If your application is storage bound then setting the “EBS optimised” flag should always be your first step to improving performance.

The benefit is actually two-fold, setting this option essentially adds a dedicated network link for the EBS volumes. So as well as improving data throughput for your storage it also stops it competing with regular network traffic so your overall network performance improves as well.

Instance sizing

Firstly, if you are on first generation instance types such as M1 and C1 then you need to check out the newer generation machines now. In almost all cases the M1 and C1 instances have a direct replacement in M3 or C3 which will almost certainly be better value in terms of price


ECU's I used to assume had a bit of marketing adjustment. The truth is that in my testing and on CPU bound workloads I find they are pretty spot on (twice the ECU's really does tend to give you twice the performance)

As with hardware sizing generally, look at your workload and choose appropriate instance classes. Don't just default to the general purpose classes.

Reserved Instances

I'd recommend against 3 year reservations. You can't take advantage of new instance classes unless you manage to sell your old reservations (not so easy on the older generations) also discounts on reservations when AWS drop EC2 prices are entirely at Amazon's discretion. 3 years is way too long to be contracted in to a current instance class at current pricing.

I'd also think very carefully before reserving at Heavy Utilisation. It's not that much cheaper than Medium, the upfront cost is higher and you are billed the hourly rate whether you are using it or not. If you lose funding for your environment then you can't escape the costs until your reservation contract is up.


Volumes are thin provisioned. So new writes to previously unused space tend to be very slow. If you have the time, pre-fill your volumes for maximum performance in production.

Snapshots may be inconsistent if there are writes to the volume in the the initial pending phase. Avoid writes for the first 10 minutes of requesting a snap. Snapshots of Raided volumes however will most likely be inconsistent unless the instance is stopped for the duration of the snap.

PIOPS (Provisioned IO) can “currently” only be changed when provisioning the volume.

Work hard to optimise IO in your application and then use cloudwatch or on OS tools to determine what you really need before reserving IO. Tricks such as aligning block sizes to access (MS-SQL) can pay dividends, though be aware that PIOPS count for block sizes not larger than 16KB. So optimising above that has limited benefit because accessing a 64KB block will occupy 4 PIOPS.

Categories: LUG Community Blogs

Mick Morgan: privacy matters

Tue, 11/02/2014 - 17:54

The Open Rights Group here in the UK has been campaigning against mass, umwarranted surveillance by GCHQ since the Snowden revelations first emerged in summer of last year. Two of its current campaigns are: “don’t spy on us” and “the day we fight back“.

I have signed both of them.

I have also written to my MP in the following terms:

I have today signed the on-line petition for the “don’t spy on us” campaign. That campaign calls for an inquiry into the mass, unwarranted, surveillance of the UK population by GCHQ.

I call upon you, as my elected representative, to support my rights under Article 8 and 10 of the European Convention on Human Rights to a private life with full, unfettered freedom of expression.

I ask that you support the campaign both on-line, and in Parliament. Parliament has been completely ineffective in its oversight of GCHQ. That must end. You, along with all other Parliamentarians must do a much better job of holding them to account.

Yours sincerely

Mick Morgan

I’ll let you know what he says (though I can guess the reply. In fact I could probably write it myself.)

Categories: LUG Community Blogs

Mick Morgan: compare and contrast

Sat, 08/02/2014 - 17:34

Foreign Secretary William Hague is apparently concerned about press restrictions in Egypt. He has reportedly urged the interim Egyptian government to demonstrate commitment to free expression.

The press release on the website says:

Speaking today about increasing restrictions placed upon journalists and the media in Egypt, Foreign Secretary William Hague said:

  • “I am very concerned by restrictions on freedom of the press in Egypt, including reports of the recent charging of Al Jazeera journalists, two of whom are British, Sue Turton and Dominic Kane.
  • “We have raised our concerns about these cases and freedom of expression at a senior level with the Egyptian government in recent days. I will discuss these concerns with other European Foreign Ministers at the European Foreign Affairs Council on Monday, and we will continue to monitor the situation of the journalists very closely, and raise them with the Egyptian authorities.
  • “The UK believes a free and robust press is the bedrock of democracy. I urge the Egyptian interim government to demonstrate its commitment to an inclusive political process which allows for full freedom of expression and for journalists to operate without the fear of persecution.”

So, the UK Government believes that a “free and robust press is the bedrock of democracy”.

I agree.

Last weekend’s Guardian newspaper reported on the visits they had from and the conversations they had with Cabinet Secretary, Sir Jeremy Heywood and colleagues back in June and July of last year when the Snowden revelations were just starting to cause some ripples.

That article says:

In two tense meetings last June and July the cabinet secretary, Jeremy Heywood, explicitly warned the Guardian’s editor, Alan Rusbridger, to return the Snowden documents.

Heywood, sent personally by David Cameron, told the editor to stop publishing articles based on leaked material from American’s National Security Agency and GCHQ. At one point Heywood said: “We can do this nicely or we can go to law”. He added: “A lot of people in government think you should be closed down.”

It goes on:

Days later Oliver Robbins, the prime minister’s deputy national security adviser, renewed the threat of legal action. “If you won’t return it [the Snowden material] we will have to talk to ‘other people’ this evening.” Asked if Downing Street really intended to close down the Guardian if it did not comply, Robbins confirmed: “I’m saying this.”

Perhaps Hague should have a word with Cameron. They really need to be more consistent. If freedom of expression is vital in Egypt, I submit it is equally vital in the UK.

Categories: LUG Community Blogs

Adam Bower (quinophex): I finally managed to beat my nemesis!

Thu, 06/02/2014 - 23:40
I purchased this book (Linked, by Barabasi) on the 24th of December 2002, I had managed to make 6 or 7 aborted attempts at reading it to completion where life had suddenly got busy and just took over. This meant that I put the book down and didn't pick it up again until things were less hectic some time later and I started again.

Anyhow, I finally beat the book a few nights ago, my comprehension of it was pretty low anyhow but at least it is done. Just shows I need to read lots more given how little went in.

Categories: LUG Community Blogs

Andrew Savory: Login problems on Mac OS X Snow Leopard

Thu, 06/02/2014 - 13:05

These are notes from a tech support call with my parents last night, saved here for the next time stuff breaks.

If you’re running Mac OS X Snow Leopard (and possibly other versions), you may find you can’t log in. Symptoms are:

  • You click on your username and enter your password
  • The login screen is replaced by a blue screen for a short time
  • You are returned to the login screen.

After searching the interwebs I found Fixing a Mac OSX Leopard Login Loop Caused by Launch Services. It seems the problem is caused by corrupted cache files (which could be caused by the computer shutting down abruptly, or may just be “one of those things” that happens from time to time). This gave me enough information to come up with these “easy” steps to resolve it:

  1. Log in to the Mac as a different user*
  2. Press cmd-space to open Spotlight, type “Terminal”, and click on the Terminal application.
  3. Work out the broken user’s username by typing: ls /Users and look for the appropriate broken account name e.g. franksmith or janedoe.
  4. Find out the user ID of the user from the previous step by typing: id -u janedoe which will print a number something like 501
  5. Delete the user’s broken cache files. In the following command, be sure to substitute the correct username (in place of janedoe) and the correct user ID after the 023 (in place of the 501): su -l janedoe -c ‘rm /Library/Caches/*’ (be very careful with this, you don’t want to delete the wrong things).
    • If you’re super-confident in figuring out backticks you could of course skip step 4 and instead of step 5 do: su -l janedoe -c ‘rm /Library/Caches/`id -u janedoe`.*’
  6. Test by logging in to the troublesome user account.
Note that if you had any apps configured to launch at login, you may need to re-add these.

* This makes me think it’s good practice when setting up a Mac to always set up an extra user account, just in case stuff breaks.

Categories: LUG Community Blogs

Wayne Stallwood (DrJeep): IPv6

Mon, 03/02/2014 - 00:22
This site is now IPv6 enabled, it turns out that my co-lo provider already offers IPv6 addresses. So all I had to do was enable the ipv6 kernel module on the RPi, fiddle some iptables rules and the Apache config so it listened on the IPv6 address. Then head over to my DNS provider and drop the appropriate AAAA records onto my zone.

If you are running a dual stack from where you are browsing you may already already be using it but to force the issue try visiting

Categories: LUG Community Blogs

Chris Lamb: Defaulting to comparing against yourself on Strava

Sun, 02/02/2014 - 13:30

Strava's brand positioning is based around challenging and comparing yourself to others through virtual competitions and leaderboards.

I am not against the competitive spirit in principle, but my personal experience is that most psychologically and physiologically rewarding training comes from comparing your own past performances to today or from setting long term goals. I accordingly use the service as a glorified training diary, with the public leaderboards serving only as curiosa or as an occasional check on hubris.

(Zen-like introspection aside, using public data as a guide in a metropolis such as London is problematic as rankings are distorted by professional racers, KOM hunters, drafting, fraud and—obviously—traffic conditions.)

To make this easier, I wrote a Chrome extension that changes the default leaderboard to "My Results" instead of "Overall" when viewing a segment effort:

The other leaderboards can still be viewed via the usual selector:

I've found it curious—but not altogether surprising—how this mere change of default dramatically affects one's mindset.

Source code is available. If you found this extension useful, you might like my extension to quickly switch between metric and imperial units.

Categories: LUG Community Blogs

Adam Bower (quinophex): Why buying a Mio Cyclo 305 HC cycling computer was actually a great idea.

Sat, 01/02/2014 - 15:11
I finally made it back out onto the bike today for the first time since September last year. I'd spent some time ill in October and November which meant I had to stop exercising and as a result I've gained loads of weight over the winter and it turns out also become very unfit which can be verified by looking at the Strava ride from today:

Anyhow, a nice thing about this ride is that I can record it on Strava and get this data about how unfit I have become, this is because last year I bought a Mio Cyclo 305 HC cycle computer from Halfords reduced to £144.50 (using a British Cycling discount). I was originally going to get a Garmin 500 but Amazon put the price up from £149.99 the day I was going to buy it to £199.99.

I knew when I got the Mio that it had a few issues surrounding usability and features but it was cheap enough at under £150 that I figured that even if I didn't get on with it I'd at least have a cadence sensor and heart rate monitor so I could just buy a Garmin 510 when they sorted out the firmware bugs with that and the price came down a bit which is still my longer term intention.

So it turns out a couple of weeks ago I plugged my Mio into a Windows VM when I was testing USB support and carried out a check for new firmware. I was rather surprised to see a new firmware update and new set of map data was available for download. So I installed it think I wasn't going to get any new features from it as Mio had released some new models but it turns out that the new firmware actually enables a single feature (amongst other things, they also tidied up the UI and sorted a few other bugs along with some other features) that makes the device massively more useful as it now also creates files in .fit format which can be uploaded directly to Strava.

This is massively useful for me as although the Mio always worked in Linux as the device is essentially just a USB mass storage device but you would have to do an intermediate step of having to use to convert the files from the Mio-centric GPX format to something Strava would recognise. Now I can just browse to the folder and upload the file directly which is very handy.

All in it turns out that buying a Mio which reading reviews and forums were full of doom and gloom means I can wait even longer before considering replacement with a garmin.

Categories: LUG Community Blogs

Steve Engledow (stilvoid): btw

Fri, 31/01/2014 - 10:30

I discovered my new favourite fact about my new favourite language recently. I suppose it should be obvious but I hadn't though about it in explicitly these terms.


char* myStringArray[] = {"Hello", "Goodbye", "Tomatoes"}; int index = 2;

then the following will print Tomatoes:

printf("%s ", myStringArray[index]);

and so (this is the bit I hadn't fully realised) will this:

printf("%s ", index[myStringArray]);

Good times :)

Categories: LUG Community Blogs

Steve Engledow (stilvoid): btw

Fri, 31/01/2014 - 10:30

I discovered my new favourite fact about my new favourite language recently. I suppose it should be obvious but I hadn't though about it in explicitly these terms.


char* myStringArray[] = {"Hello", "Goodbye", "Tomatoes"}; int index = 2;

then the following will print Tomatoes:

printf("%s\n", myStringArray[index]);

and so (this is the bit I hadn't fully realised) will this:

printf("%s\n", index[myStringArray]);

Good times :)

Categories: LUG Community Blogs

Steve Engledow (stilvoid): Stuff what I done

Thu, 30/01/2014 - 22:18

The diet is still going fairly well apart from a lapse yesterday owing to work-sponsored lunchtime pizza for a workshop session with JG and an evening meal out for Dad's birthday.

Roasted broccoli is the best thing ever.

I finally switched over to using mutt for my primary mail client after pondering doing so for ages. With some pretty minimal setup, I've already got more featureful (and considerably less annoying) than any other client. I honestly (actually) don't understand why people are so put off by terminal applications.

Roasted carrots are the second best thing ever.

I've learned a lot about C. For reasons I don't fully understand, I've been reading about C and coding things in my spare time. It's definitely my new favourite language.

Lamb chops are a close third.

Categories: LUG Community Blogs

Steve Engledow (stilvoid): Diet?

Sun, 26/01/2014 - 13:34

One of my new year's resolutions is to lose a stone. After some consideration of how I might do that, I decided some sort of diet would be in order. Fairly obvious, I suppose, but I did toy with the idea of seeing if I could do it just by exercising more; I don't think it would even be possible to practically exercise enough to burn off half of what I like to eat.

Before Christmas, I had been thinking about reducing my carbohydrate intake as it seemed that every meal I was eating centred around bread or potatoes. Curry, for example, was all about mopping up the sauce with the naan bread :)

I decided, in the interests of science or summat, to go the whole hog and drop my carbs completely. Well, almost completely. I've been on this very-low-carb diet for about three weeks now and I've already lost half a stone. It's probably not sustainable but here's why I think I've lost weight already when previous attempts at eating less have failed:

  1. The general advice on the intertubes seems to be that, when eating low carbs, one should eat more fat to feel sated. That seems to bear out so far; I've been having things like omelette cooked with butter for breakfast and I don't get hungry until lunch time easily.

  2. Having a very simple rule to stick to has made it easier to stick to. Simply telling myself "try to eat a bit less" or "eat more healthily" may have been a little too wishy-washy for my probably-slightly-autistic brain to deal with. "Has it got a carbohydrate content of greater than 5%? Then no, you can't have it." is a hard and fast - and therefore simple - rule to adhere to.

  3. Carbs seem easier to gorge on than other foods. I can devour a massive portion of chips without pausing for breath but I simply can't do the same with steak or vegetables.

  4. Every meal feels like a treat. When I can bust out home-made salads with various exciting meats and "naughty" cheeses for lunch, it feels like I'm having something special every time I eat. Dinners consisting of some sort of meat plus some nicely cooked (this likely means with butter) vegetables are fantastic.

  5. There is almost no way to eat any kind of snack food, so I don't. Fruit is quite high in carbs so I don't eat too much of it. Crisps, biscuits, and sweets are right out and I'm not even tempted any more.

  6. I don't need to count anything or keep a tally in my head.

All of which makes me sound a right wanker.

This morning, I just proved to myself the main reason this diet is working for me. I have forbidden myself carbs and I have just about enough willpower to follow that rule because it is just one, unambiguous rule. I haven't been following it completely strictly; I allow myself a beer every now and then. Today, I decided to have a cheat breakfast and included some home-made chips. Without even thinking about it, I ate an absolute ton of them and now I feel slightly sad and very, very full.

Lesson learnt; back to the diet. With any luck, I'm looking forward to being 13 stone by my birthday.

What a wanker.

Categories: LUG Community Blogs

Andrew Savory: Super markets

Sat, 25/01/2014 - 11:11

I’ve been using our local Lidl recently, because their policy of regularly baking throughout the day means I can pick up fresh croissants and pains au chocolat whenever I go, whereas the local Tesco, Sainsburys, and Waitrose have usually run out by mid-morning. Are the so-called discount supermarkets really cheaper than the mainstream supermarkets? Here’s the result of one unscientific survey.

This morning I checked my till receipt against Tesco online. There are some items that cost the same regardless of which supermarket (fabric softener, fresh orange juice). There are some items that don’t have direct equivalents across stores, so price comparisons aren’t possible. And there are some items where the price is not significantly different (fresh milk, toilet paper). On today’s basket of comparable items, Lidl was £10.62 cheaper (costing £18.46 instead of £29.08). There are some real eye-openers. Eggs are 1.5x more expensive at Tesco. Fresh vegetables were often almost twice the price at Tesco. And what about my fresh croissants and pains au chocolat? £0.29 and £0.39 at Lidl, vs £0.80 each at Tesco. Over twice the price — on today’s shop, buying just these alone saved me £4.70. And they were fresh from the oven, still warm when I got them home.
Categories: LUG Community Blogs

Mick Morgan: dis-unity

Wed, 22/01/2014 - 21:13

The “cloud” is achingly trendy at the moment and new companies offering some-bollocks-as-a-service (SBaaS) keep popping up all over the ‘net. Personally I am extremely unlikely to use any of the services I have seen, I just don’t trust that particular business model.

I checked out the website for one of these companies today following an article I read on El Reg. The company’s website says, in answer to its own question, “what can you do with younity?” that you can:

Spontaneously access any file, from any device, without planning ahead.

Browse all your devices at once.

It further says:

share any file.

(I love that “privately to facebook” bit.)

However, further down it says “Step 1, download younity for Windows or Mac, Step 2, install on iOS”. So, the “any file stored on any computer” claim is just not true if, like me you have a mixture of Linux machines, Android tablet and CyanogenMod ‘phone. I’m pretty sure that claim must breach some advertising standard and I’d complain if I cared about using the product. Fortunately I don’t.

Another “cloud” company making some interesting claims is Backblaze, the company whose blog commentary on consumer grade disks I referenced below. They supposedly offer a service with “unlimited storage”, which “automatically finds files” on your computer and then stores them in the Backblaze cloud with “military-grade encryption”. The website says that “everything except OS files” is backed up, so the system must have the freedom (and permissions) to ferret about on your local disk and then pass the files it finds out to Backblaze’s pods. Forgive me if I don’t like that idea.

The section about encryption is intriguing because it claims:

When you use Backblaze, data encryption is built in. Files scheduled for backup are encrypted on your machine. These encrypted files are then transferred over a secure SSL (https) connection to a Backblaze datacenter where they are stored encrypted on disk. We use a combination of proven industry standard public/private and symmetric encryption methods to accomplish this task. To a Backblaze customer all of this is invisible and automatic. For example, when you create your Backblaze account, we automatically generate your private key that is used to uniquely protect your data throughout our system.

They go on to say:

Upon arriving at a Backblaze datacenter, your data is assigned to one or more Storage Pods where it is stored encrypted. Access to your data is secured by your Backblaze account login information (your email address and password). When you provide these credentials, your private key is used to decrypt your data. At this point you can view your file/folder list and request a restore as desired.

A blog posting by Backblaze’s Tim Nufire gives some detail about how the company encrypts your data. On the face of it, the use of a 2048 RSA public/private key pair in conjunction with ephemeral 128 bit AES symmetric keys (to actually encrypt the data) looks impressive – particularly when the company claims that the private key can be further protected by encryption with a user provided passphrase. But given that the company is US based, that claim bothers me. I am particularly sceptical about any claims that the company is unable to decrypt private data because /they/ generate the public/private key pair and they admit (in the blog post) that they store the private key on their servers. Sorry, but if my data is private enough for me to wish to protect it with strong encryption, then I want to use keys I have generated myself, on a system which I control.

Backblaze’s description of the file restoration process does not give me any warm feeling either. Here is what they say:

When you request a data restore, we do what is known as a cloud restore. This simplifies the data restoration process. For example, let’s assume your hard drive crashes and you get a new hard drive or even a new computer. To restore your data you first log in to Backblaze using a web browser by providing your Backblaze account information (email address and password). Once you have logged in to the Backblaze secure web interface you can request a restore of your data. You do not have to install Backblaze to get your data back. To make this work, we decrypt your data on our secure restore servers and we then zip it and send it over an encrypted SSL connection to your computer. Once it arrives on your computer, you can unzip it and you have your data back.

So if I want my data back, they get a clear text copy of it all before sending it to me. Worse, they even offer to send it to me through the post on a USB disk.

I don’t call that a private recovery system.

Categories: LUG Community Blogs