The Last Remnant of 1993

Reading Time: 2 minutes
Computer Connection Mousemat
From the depths of history…

This is my mousemat. It’s about the same age as many of our students and it’s pretty much the only piece of computing technology from 1993 that’s still relevant today.

  • The 3.5 inch floppy was the standard way of supplying data and even software. Windows came on 6 to 8 of them depending on the edition.
  • Mice used to use a ball and rollers to track movement. They’re now optical.
  • Only cheap keyboards used membranes. Good ones were mechanical (switch) keyboards. These are now almost impossible to get hold of.
  • USB was unheard of. Peripherals either had to connect via an existing serial or parallel port or use their own interface card.
  • The Compact Disc was common, but the CD-ROM had not yet entered the world of computing (let alone DVD or recordable technology).
  • Monitors used Cathode Ray Tubes. This made anything bigger than 19″ heavy, awkward and expensive. If the office heating failed though they were good for that.
  • A myriad of interfaces have come and gone. ISA bus, VESA local bus, DIN style keyboard connections, PS/2, IDE, etc. etc.

There are a few things that haven’at changed that much.

  • Hard disks – the mechanical type – still use much the same physical technology. The data capacity now though is astounding. A “big” HDD in 1992 was 20Mb. It’s now 50,000 times that.
  • VGA was the latest and greatest in 1992. We still use it today, mainly for projectors although even this is fading in favour of DVI / HDMI.
  • Cases are still made of cheap steel and PSUs are still cheap switch-mode devices that fail every  more often than any other component.

Having said all this it’s not so long ago I lifted the lid on a piece of equipment that had just been decommissioned from a fire service. I recognised the CPU instantly, it was a Zilog Z80 in a DIL40 package, placing its vintage firmly in the 1980s and possibly as early as 1976. 

Small Scale Disaster Recovery Planning

Reading Time: 2 minutes

Or why to but a top efficiency freezer.

An A Rated Fridge-Freezer

So the power company decided to schedule a 9 hour outage for today and not bother telling us. At 09:15 the power went off and we were suddenly in the dark. No power, no network and even the cordless house phone was off. Sure we have mobiles but we live in a dip and have minimal signal.

We’re screwed, right?

Not at all, because when I became a remote worker I spent some time working out exactly what I’d do if this happened. Dress this up in fancy clothes and a consultant will call it “disaster recovery planning” and relieve you of the contents of your wallet. The reality is that it’s just a bit of common sense, but it is important that any small business actually does it.

There’s an old phone I keep in the spare bedroom that doesn’t need external power so within a couple of minutes we have some form of communication. All the utility company phone numbers are on a board by the fridge so within 10 minutes I want someone’s head on a plate. At least I know the score though and it means we’re out of the office for the day. We both use (docked) laptops as our primary machines so we grab them, an external HDD and a bunch of other goodies and decamp to a nearby relative’s. All sorted.

If you are a small business, a remote / home worker or a contractor you need to think about what you’d do if something goes wrong. There are four things to look at.

  • What can go wrong?
  • How likely is it?
  • How severe it it?
  • What are you going to do about it?

There are 2 parts to the last one. One part is obvious, what you do when it happens but you should also consider how you can mitigate it – how you can make it less likely or its effect less serious if it does happen.

Oh, and a small piece of advice, always get the most efficient freezer you can. 9 hours of no power and not a hint of defrosting!

Beating the Winter Blues.

Reading Time: 2 minutes
Woodbridge Harbour

It’s depressing – the end of September has gone and the nights are drawing in. Soon we will be getting up in the dark. I think most of us find it a little harder to get motivated in the winter, perhaps not to the stage where we would say we were actually depressed or suffering from SAD, just a bit “meh”.

Thankfully there are things we can do to alleviate that somewhat. Here are 2 that I do…

1 – Get a “Dawn Simulator” Alarm.

I’ve got a Lumie Bodyclock Starter 3o (there are much cheaper alternatives). Half an hour before the alarm goes off it starts to turn the light on. It steadily increases the brightness so that when the alarm finally does go off it’s actually quite light in the room.

The effect is relatively subtle – I don’t wake up full of the joys of spring as the marketing material for these things implies. What I find is that I’m alert when I wake up instead of half asleep and that actually makes a big difference to the start of the day, which in turn makes a big difference to the rest of the day.

2 – Use Daylight Coloured Lights

It may be a stereotype that programmers like to sit in the dark but not all of us are like that. I’m lucky – my office environment is under my control. I’ve replaced all the lights with daylight coloured LED units. This makes a big difference too – the office is bright and cheerful even on a grey winter day. It just makes putting in a day’s work that little bit easier.

If you’re not as lucky as me you can always put a request in to your building manager to get the light colour changed. Often “daylight” units are the similar prices to other colours so  you can usually get them swapped out, if not immediately then when the units fail.

You can also try getting a daylight desk light – be aware though that when using a desk light you have to make sure that you look away from your desk a lot. It’s rather easy to get zoned in for hours and that won’t do your eyesight any good at all.

These are 2 really simple and easy things that can make a big difference in the middle of December when you start and finish work in the dark.

2 Paris Con Tricks

Reading Time: 2 minutes

2 people tried on tricks on me when I was recently in Paris – the first was blindingly obvious but the second was a little more subtle. Neither were particularly offensive or likely to cost a lot of money however.

1 – The Fake Charity

A chap approached me speaking bad English – this was immediately odd as most people in France spoke French to me. He asked for “Just a signature – to support the children – it’s for UNICEF” and showed me a page on a clipboard (the sort of thing that looks like a sponsor form). Part of the clipboard was carefully covered by his hand.

The page was badly photocopied, didn’t mention UNICEF and the chap had nothing that looked even vaguely like proper charity apparel. More out of curiosity than anything else I took the clipboard and pen and of course, under the part that he had been covering it said “Donation” and, apparently, several people had donated €5 or €10.

I pondered for a second whether I should throw the clipboard a good distance, deface the page entirely, tear it off or simply hand it back on the grounds that he might get a bit stabby if I did any such thing. In this moment he grabbed it back and ran as a security guard was rapidly approaching.

2 – Is This Your Ring?

This one is much better – I was walking along the Seine when a chap bent down a couple of metres in front of me and apparently picked up a ring. “Is this yours?” he asked (in French). “No”, I replied (in French, with a Gallic shrug) and carried on walking but he walked with me. “It looks expensive” he said (in English) and was suspiciously insistent about it being mine and expensive. I figured it was a distraction trick and wondered what the distraction was from. He went away though and I still had wallet, phone, keys, rings etc.

Later I saw the same guy chatting to some girls – he was asking for a small contribution – a “finder’s fee” to let them keep the ring that he had apparently just found on the floor near them.

I didn’t get a good look at the ring – so I couldn’t tell whether it was extremely cheap or stolen. I like this trick because it plays or your own dishonesty and greed which is something we all have whether we like it or not.


Food Feedback – The Better You Eat the Better You Want to Eat

Reading Time: 2 minutes
America Thinks This is a “Light Lunch”

I’m not on a diet. Historically I’ve been more than averagely careful about what I eat anyway. However I have noticed that of late I have become a little lazy about it and that’s had an effect on my body. So I did a bit of an audit and came to a few simple conclusions.

  • Most of the food I eat is pretty healthy but I have a bit of a psychological problem with eating everything on my plate. I was therefore eating too much.
  • There were a few horrors – a couple of common evening meals provided enough calories for the entire day.
  • Alcohol has calories in it. Who knew?

So I’ve addressed those three things in easy simple ways.

  • I put less on my plate. If I’ve cooked too much (common) I put the remainder in the fridge and eat it for lunch the next day. I just had a lovely bean curry burrito with last night’s left-overs.
  • Some of the recipes were easily modified, others taken out of regular rotation so they’re now occasional treats.
  • I’ve stopped drinking midweek.

One recipe particularly surprised me – a smoked salmon tagliatelle. By reducing the amount of pasta slightly, switching from double cream to single + cornflour and using a “low calorie” garlic bread I could all but halve its calorie count.

The really surprising element is that I prefer the lower calorie version of the recipe, the full fat version was always a bit sickly. It goes further than that though, I’ve fallen back in love with food. When I was a kid – in fact right up until I moved to Hull and became a sedentary office worker I used to get hungry about half an hour before a meal, then I used to really enjoy the meal. The tastes and textures were really vibrant. That’s happening again now, I’m appreciating what’s on my plate which feeds back into the care and attention I’m paying to putting it there.


3 Easy Ways Not To Pick a Crap Password

Reading Time: 3 minutes

Most people are rubbish at picking secure passwords – “pr0gn0s1s” for instance is a crap password. Taking an English word or a name and then changing a few of the letters just doesn’t cut it. Why? Well, the complex explanation is given in XKCD Comic but for normal mortals it works like this.

Most hacking attempts aren’t a done by a smart but misguided geek, they’re done by other computers and they’re dictionary based. That doesn’t always mean an English dictionary, rather a list of words that are commonly used in passwords. A computer program works through the dictionary trying each phrase in turn. Unsurprisingly hackers are well aware that people change O to zero etc. so all those combinations are tried too. Thus using the password “pr0gn0s1s” will take maybe a millisecond more to crack than  simply “prognosis”. Changing letters to numbers is almost no help in making a password more secure[1].

So how do we avoid this?

1. Use Multiple Unrelated Words

XKCD makes a good point, you can just use multiple unrelated words, spelt entirely normally. By unrelated I mean that “DavidBeckham” is 2 words but would be a monumentally terrible password. “hollowpoolbutton” is much better and much easier to remember. “The Hollow Crown” is a series of Shakespeare plays on BBC TV, “Crown Pools” is a swimming pool in Ipswich, “Poole” is the town where Jenson Button (a racing driver) wasn’t born (but I thought he was until I just Googled him). So this is an easy password for me to remember.

This might not sound like it’s better than “pr0gn0s1s” but it is, massively so. There are more than 200,000 words that could follow “hollow” and another 200,000 that could follow “pool”. That’s more than 40 billion possibilities. A bit better than the handful of different substitutions that can be made in “prognosis”.

2. Insert Something Foreign Into a Word

Another way that sounds rather counter-intuitive but is surprisingly effective is to add something into the middle of a word rather than replacing a letter. So instead of “pr0gn0s1s” you could use “progn9osis”. Now it’s not an English word any more and it’s not an obvious change. Personally I’m not happy with a single insertion, but dump an entire other word in and it makes a big difference. It is massively improbable that “prognmintosis” would ever be tried by a hacker.

3. Use The First Letters of a Passage of Text

The last simple method I’ll mention is to find a phrase, a bit of poetry, prose or song fragment and take the first letter of each word. So if you’re a big Samuel Taylor Coleridge fan you might select;

“The naked hulk alongside came,
And the twain were casting dice;”

from the most excellent (but rather scary) Rime of the Ancient Mariner. This would make a password of “tnhacattwcd” which scores well on all levels. It feels like a secure password, it actually is a secure password and it’s easy to remember.

[1] So why do a lot of systems insist that we use password which contain letters, numbers, punctuation or conform to even more strange rules? Well some people really are unbelievably crap at passwords. They’ll use their own names, pet names or other information that a lot of people would know and could easily guess. At least if they’ve got a number or some punctuation in the password they stand some chance of their new credit card not being immediately hacked by their 5 year old son.

Tom Recommends

Reading Time: < 1 minute

Occasionally, in all the stuff I use, I find something that I really like. So why not tell people about it?

Polycell Crack Free Ceilings is great. It’s thick, gloopy paint that hides a multitude of sins and not just on ceilings. It’s expensive, but combined with a little lightweight filler the time it saves is well worth it. As an aside though, this doesn’t mean that I recommend all the Polycell miracle solutions, some of which I’ve found not to work for me.

Dawn Simulator Alarm Clocks – any of them really – I happen to have the Lumie Bodyclock Starter 30. I’m not a SAD sufferer, but nonetheless I find that not being suddenly jolted awake makes me far more alert and puts me in a far better mood in the morning.

Ultrafire WF-606a – a pocket size LED torch, runs on 2 AA size batteries. It’s very bright and very rugged. A thoroughly sound piece of kit, far better in my opinion than the equivalent MagLite and much cheaper, too.

Taoism and Trees

Reading Time: 2 minutes
Not an oak

We change. We move on. It’s part of being human.
There’s a lot of change going on with me at the moment and it’s at times like this when a little wisdom can make a big difference.

One of the most effective pieces of advice I’ve ever been given was from a Kung-Fu instructor. She asked me which tree was stronger, the willow or the oak.
The oak is a potent symbol of power, it stands strong against the wind, assenting only to the gentlest of sways whereas the willow flops around all over the place in the merest breeze. The oak will still stand strong in a storm while the willow is battered into the ground.
When the wind gets too strong though, the oak will snap. When the wind subsides the oak will lie broken on the ground and the willow will return to its original form, swaying gently in the breeze.

The skill is knowing when to be the oak and when the forces against you are all too strong. I naturally tend toward the oakish, so I have to keep asking myself if I’m trying to be too strong, if perhaps I should stop pushing and just weather the storm. An ability to recognise when a something is beyond my control, to accept it rather than exhaust myself fighting against it (and probably lose anyway) has saved my bacon many, many times.

This goes hand in hand with another important skill – the ability to seek advantage even in adverse circumstances. When something bad happens it’s all too easy to concentrate on the bad, on what will be lost. A little bit of objective thinking often reveals that whilst some doors are closing others are opening. Sometimes an apparently bad change, on proper analysis, works out to be positive overall.

Lastly, and leading directly from the above, it’s easier to influence something that you’re on board with. If you diametrically oppose something you are likely to find that you become marginalised and are ignored. If you align yourself with it but suggest changes, you are more likely to be listened to.

Take these three together and you can remove a great deal of hassle from your life.

Diving Headfirst into Worcester Bosch 240 Repair

Reading Time: 7 minutes


Worcestor Bosch 240

In December 2005 it all went horribly wrong and I feared a huge repair bill when my boiler went weird. Could I save a small fortune and fix it myself? Yes, replacing the Pressure Release Value turned out to be pretty easy.


I’m not a gas fitter or plumber. I don’t know very much about boilers myself, but I am generally good with mechanical things. Some of this advice could be very, very bad. All I know is that it worked for me. I accept no responsibility for any consequences of anyone following any advice on this page!

The Pressure Release Valve

The Problem

If you’re just interested in how to replace the valve, skip forward to “Opening up the Boiler”.

We had a sealed radiator system that always dropped pressure. I needed to top it up about once a month, but in December 2005 it was getting serious. Over the Xmas period I had to top it up once per day. There aren’t that many reasons for this in a central heating system, so I availed myself of the Sealed Central Heating System FAQ. Read it. Now!

Sealed CH systems have to have a pressure release valve somewhere. Usually this is actually in the boiler, there certainly is one in the WB240. The pipe from this goes straight through my wall and down to the drain, so I put a bowl over the drain to catch any water, turned the heating on and went to do other things for 1/4 of an hour or so. When I came back the pressure in the system was just under 2 bar, but there was nearly 3/8 of a pint of water in the bowl! No wonder I was having to top it up a lot!

There are two reasons this can happen.

  1. The pressure release valve is leaking.
  2. The system is genuinely over-pressure.

The latter can happen if the expansion vessel is malfunctioning. The Sealed Central Heating System FAQ which you read earlier explains this. To test whether it’s the expansion vessel or not you will need to find it. This isn’t difficult. It’s a large red thing. Follow the instructions below about Opening the boiler up.

In my case the pressure in the system was nowhere near 3 bar and there was plenty of charge in the expansion vessel. Ergo leaking PRV. Flushing it through wasn’t working so it had to be replaced.

Getting a replacement PRV

There’s nowhere local I know that’s likely to stock WB spares, so I got a replacement valve from Keep The Heat On. They’re not the cheapest on the web, but their delivery is good and they’re not too far away so a visit isn’t out of the question. The valve in question is order code 108151. WB Part 8-716-142-416-0. It arrived the next day despite me picking the 2-3 day delivery.

Opening the boiler up.

Firstly, make sure that the boiler isn’t on and hasn’t been for some time. Then isolate it electrically. Somewhere you should have some means of actually turning the boiler’s electricity supply off. This may be near the boiler or near your main electrical distribution board. It could even have its own RCD (switch) in your mains electrical distribution board. When the boiler is powered down there should be no lights on.

Isolate the gas

The rightmost pipe going into the boiler needs to be isolated, just as a precaution.
This is the gas pipe. Turn the screw so that the slot faces across the pipe.

Now take the white front panel off the boiler. If you can’t figure out how to do this yourself then you’re in trouble. Call a Registered Gas Installer!

[picture of screw]
At the top of the grey control panel are two screws. Not the ones facing you, the ones holding the grey control panel to the flanges at the side of the boiler. Supporting the grey control panel from the bottom, undo these screws. The whole control panel unit will then pull forward and hinge down. Note that the actions of pulling it forward and dropping it down are somewhat simultaneous.

The large red thing is the expansion vessel.

Testing the expansion vessel.

The valve for the gas charge is located on the right hand side of the expansion vessel just above the white thing with the 4 pipes going in on the left and the drain tap on the right (I must try to work out what this is). The Sealed Central Heating System FAQ details how to test it. Mine had plenty of pressure in it.

Finding and testing the PRV

The 5th pipe from the left (2nd from the right) connects directly to the PRV.
It’s right up the back of the boiler. How convenient.

The tap is on the right hand side and is red. With the control panel dropped, I managed to get my left hand in under the “white thing” and over the top of the PRV so that I could operate the valve.

Highlighted in the image below is the pipe that enters the bottom on the PRV.

Now if you’ve not tested a PRV before this might take you by surprise :- they don’t turn back, only forward. Turn the top towards you, you will hear water escaping. Keep turning it the same way! Eventually it will snap back to the closed position.

If your leak doesn’t magically go away then you’re likely to need a new PRV.

Replacing the PRV: Isolating the CH and draining the boiler

I’m assuming here you have opened the boiler and dropped down the control panel (instructions for this are above).

isolating the CH

OK, now we need to isolate the central heating circuit. Hopefully some clever spark has installed a pair of isolators other than the boiler’s own ones. If there is another pair, use them. If not, the two leftmost pipes on the boiler will have isolators on them at the bottom of the boiler. Turn them so that the screw slots face across the pipes not along them. They may leak a bit, so beware.

If you haven’t isolated the gas then do this now (instructions above).

You now have an isolated boiler, but it’s still full of water. Unless you plan on getting very wet whilst you’re working, draining the boiler is a good idea. To do this, just tweak the PRV so that water is flowing down the release pipe and leave it until it sounds like it’s empty.

Replacing the PRV: Spannering

Worcester Bosch have been quite cunning here. If you look just to the left of where the water pipe enters the PRV, there is a slot cut in the panel. This exposes the nut that connects the PRV to the pipe that extends leftward.

With the control panel pulled forward but pushed up, there is just enough room to get a spanner in here and work it to loosen the nut on the PRV. Don’t do that quite yet though! First, undo the nut that connects the PRV to the waste pipe.

OK, now undo the nut on the left of the PRV. If you’ve ever worked on a Citroen, this will be small beer to you. If not, just persevere. There’s very little room to work the spanner and you have to be very patient!

So the PRV is free! Almost. Don’t go yanking it around. It’s still connected via a thick piece of copper wire to the pressure gauge at the front of the control

Carefully ease the PRV downwards until you can get a spanner on the connector at the top. Undo this, then the PRV is really free! If you’re feeling brave you can test it once and for all :- I turned it to make sure it was shut, covered the pressure gauge socket with my thumb and then blew through it. The problem being that I did in fact blow through it. These gauges are supposed to open at 3 bar and there is no way I can provide 3 bar of pressure with my lungs!

Now, in the style of a Haynes manual, reassembly is the reverse of disassembly, only with the new PRV, of course. I added a bit of PTFE tape to the threads. It’s probably not required and may make matters worse, although I can’t think why.

Recommissioning the boiler

DO NOT THINK YOU CAN JUST TURN THE BOILER BACK ON! The boiler will still be full of air!

It is worth mentioning here that I don’t have the official Worcester Bosch instructions for recommissioning and I don’t know what they are. This is what I did and it worked.

Ensure that the CH circuit is no longer isolated. You will hear the boiler gurgle a bit as (some) water flows back in.

Ensure that the gas still is isolated.

Turn the electricity back on. Then cause demand from the CH system (select Heating and Hot water and then tweak the controller until the boiler attempts to fire up). Clearly the burner will not work, but everything else will. It will attempt to pump water round the system. If the pump makes a horrible noise, check its temperate.
If it becomes uncomfortable to touch, turn it off and wait until it has cooled down, then give it another few minutes.
Eventually the boiler should sound pretty much like it did before, but without the burner running, obviously.

Now turn it back off, turn the gas back on and fire it up!

If there’s still air in the heat exchanger it may well trip the overheat protector. This is the strange little button on the top of the control panel. It should be pressed in. If it pops out the boiler will stop. If this happens, turn off the gas and run it for a few more minutes without the gas on, then give it another go (you will need to press the reset switch in again).

Apparently there are other, better ways of getting the air out of the boiler. There is a bleed nipple on the pump, there may be one on the heat exchanger, too. Unfortunately I don’t know anything about this! If you do (or manage to find out) then please let me know!