A few weeks ago I bought a pair of Devolo 500AV Ethernet over mains units
to replace/extend a pair of 200AV units I already had. Someone asked if could
iperf to see how much faster they were.
To baseline what I had I ran the test from my desktop to my server over a 1 Gig switch and the most I could get was a feeble 333 GBit/s. I then tried from my laptop to the server on the same switch and that got a much better 740 GBit/s. The Marvell Yukon card on my desktop is a PCI device and the JMC250 in the laptop is a PCI-e so that may partially explain the differences.
Trying my laptop to the server via a 200AV/500AV/Gig-E switch gave a throughput of 56 GBit/s - about what you would expect. I then tried the laptop through a combination of 500AV/500AV/Gig-E but that wouldn't work as the JMC250 refuses to detect the 500AV. I then tried the laptop with different switches, it refuses to talk to my second Gig-E switch or my old Ethernet hub.
After some Goggling it turns out that the JMC NIC is a bit fussy and often fails
to auto-negotiate with some "green" Gig switches, such as in the 500AV or my newest
GBit switch, but is happy with older switches and plain Fast Ethernet. If you
manually set the speed with
ethtool then it's okay. I downloaded
the latest driver from JMC and that is a bit better but while it will connect
to my 500AV and my newer Gig-E switch automatically, it won't negotiate the correct
GBit speed, falling to the older 100 MBit setting.
Footnote: The JMC250 is a 1 Gig Ethernet NIC from JMicron Technology Corporation, not something from the Jupiter Mining Corporation...
Looking up French figures you can convert European Energy ratings to an annual kWh·m-2:
|Rating||French kWh·m-2||UK SAP|
|A||< 50||92 - 100|
|B||50 - 90||81 - 91|
|C||91 - 150||69 - 80|
|D||151 - 230||55 - 68|
|E||231 - 330||39 - 54|
|F||331 - 450||21 - 38|
|G||> 451||1 - 20|
Our house basted on last year at 104 kWh·m-2 for a 1936 house is doing very well in band C and not the band E that the idiot surveyers put it in.
Last week someone in the village was asking about installing PV panels on their south facing roof. From 01 April 2013 the government will only allow the full feed in tariff if you have already fully insulated your house - it is obviously pointless generating electricity if your house leaks heat like a sieve.
I checked the EPC chart for our house that came with the HIP when we bought the house. It's quite pathetic, it reports loft insulation of 250 mm when in fact there was only 100 mm when we moved in. It does however note the old boiler with primitive controller and lack of efficient light bulbs. It then gives some bland advice and ranks the house at grade "E" with a SAP score of 48. The best the house could be is apparently grade "D" with a SAP score of 55. That corresponds to an annual energy use of 314 kWh·m-2 falling to a minimum possible of 275 kWh·m-2. Annoyingly there is no explanation of how a SAP rating relates to a energy use per unit area.
This is all utter rubbish! We changed all the old bulbs to mostly CFL, plus some LED and some halogen the day we moved in. Last autumn we put in a modern boiler and controller and started to insulated under the floors. We added 200 mm of loft insulation taking it up to a minimum of 300 mm over the whole loft with the spare in the centre to >400 mm. We have yet to replace the windows and doors (A rated) and complete the under-floor insulation.
For the first full year we were in the house we used 137 kWh·m-2 (a cold year too and with the old central heating boiler & controller), which is better than half the potential minimum energy use and last year we used only 104 kWh·m-2 (mild year plus new boiler for the last 2 cold months).
I am in favour of improving things, but if the official schemes and assessments are so rubbish how are people who don't know ever going to figure out what to do...
This month I'm in the middle of a thermal imaging survey in the village. I potter around to people's houses in the evening and look for energy leaks. Everyone has been really nice and I hope I've been able to help them save a few quid and some CO2.
At the same time I'm looking to replace our old Everest double glazing units. Overall the glazing is sound, they are well spaced units and most of them have not blown. I'm not sure of their exact age but they are probably over 20 years old, as they are aluminium frames. So while the glazing is still sound the frames conduct heat like it's going out of fashion... We probably have some of the worst window (frames) in the village.
I've started the process of getting quotes for higher performance modern triple glazed windows with proper engineered frames that result in an overall "A rated" unit. Suffice as to say the prices are many thousands, the current highest quote for all new British made, top end windows is £25k.
If you believe the glass and glazing Federation, replacing our old windows with modern BFRC "A rated" ones and assuming 4% fuel inflation they calculate over 25 years a saving of £8k and just under 7 tonnes of CO2,
Based on my own figures, running a 12.3 MWh annual gas usage and using the same 4% inflation I calculate a similar saving if you assume that windows account for over 35% of all heat loss in the house. The house was built in 1936, so it's a bit leaky, so I'm not convinced that the windows are as much as 35% of the total loss. The loft is well insulated to about 40 cm of insulation, but the cavity walls were filled several years ago and I'm not convinced it was done that well.
If you assume more gas inflation then the savings come in quicker or require the glazing to be less of a source of heat loss. To get my money back on £25k, I would need to wait 30 years, at gas inflation of 8% and assume that withe windows contributed to 45% of all heat loss.
As much as I would like to buy British made, "A" rated windows, and assuming gas prices rise faster than general inflation, it just doesn't make economic sense to buy top of the range. Imported windows of similar quality cost considerably less and I will break even with them - eventually!
Power company EDF wants to build some wind turbines on a small hill in the village next door. While I would like electricity to come out of the socket magically with no consequences I know that this isn't possible. I am opposed to nuclear, coal and gas power generation but accept that in the UK they will probably form the bulk of our generating capacity for the next 30 years. I am in favour of various renewable solutions and accept that they are not going to be as cheap as coal and will only be viable if we reduce national demand.
The proposal is to build fourteen 2 MW turbines for a total capacity of about 28 MW which is two and a bit Eurostar trains worth of electricity. I am not qualified to say if this is or is not a sensible place to put a wind turbines but from a subjective view point I don't think they are ugly and most of the arguments against them are pure FUD.
A good read is the www.yes2wind.com web site.
One of the disk on my home server is reporting issues through SMART,
it's still healthy but it will have to be replaced... The disks are
in a mirrored pair using Linux
mdadm so I won't lose
any data if the drive actually dies, but it's a pain as they are
not hot-swappable and it will take a bit of effort.
It's annoying but I suppose I bought the computer with a pair of
disks for just this reason.
While disk drives have got larger since I bought this server and marginally faster they haven't got any cheaper because the recent flooding screwed up the supply chain. SSD disk are just not cheap and reliable enough for a home server yet - though they are a good idea on a laptop or even desktop system.
I'm naturally cautious and careful. I don't like to make rash decisions, I like to carefully weigh my options and do the right thing. I'm very keen to get the very best value for my money, doesn't matter if I'm buying something cheap or expensive I like to get the best value.
Nearly 7 years ago I bought a pair of DNUK desktop computers running Debian. They have been very good and with upgrades have kept going very well over the years. The moving bits on them are now coming to the end of their natural lives, I've lost one PSU and a DVD player already and the CPU cooling fan is a bit noisy now. Their old AGP graphics cards are clearly not up to modern standards and while the single core AMD64 processor was fast when new - they aren't that fast anymore. A new quad core system, with four times as much RAM and faster RAM at that (DDR to DDR3), new graphics and larger faster disks isn't that expensive. I will replace them with the next 18 months - the dilemma is how long to wait to get the most out them and the best new versus a sudden failure and the fact they do feel slow now...
In the same token I have a more expensive dilemma. We bought our house 2 years ago. We knew that the boiler would need replacing. The solar water heater is home made and not to modern standards nor is it linked to the current gas system. The solar system isn't performing well so the current dilemma is when to rip all the antique junk out and replacing it with a modern high efficacy condensing boiler, versus carrying on as we are - again accepting that there may be a sudden failure.
The annoying this is that I know in some respects the £3000 we spend on a boiler would be paid off by the reduced gas costs over 10 years. Just as I know the increased productivity from a faster computer would help (well only a little),
The only change I made to my normal method is to freeze and defrost the lemon as Mr Miot suggests as it does get you a lot more juice and pectin out of the lemon. I made 2 kg of rhubarb up and it made 11 assorted jars as expected.
Last year I bought a new DSLR camera. As part of the deal, I agreed to use it and not let it gather dust in a corner. One of the things I've been doing is trying to take regular pictures and upload them to a daily photo blog.
For most of last year I was managing to load one or two pictures or "blips" per week at best. Since Christmas I've been able to maintain a daily stream, and while only a third are actually DSLR images - I don't take it to work - I think it has been useful forcing me to think creatively and my DSLR has been used more than it would have been otherwise.
If you have been following this blog you will have noticed a fall off of postings here over the past year. This is partially a result of more tweeting and Google+ use, but increasingly because of my blipfoto efforts. This blog isn't dead it's just resting a bit more of the time than it use to.
You should find at the top right a link to my current blipfoto entry, which should contain a picture, which if you follow the link will reveal some trivial diary entry and a larger image.
On Sunday night my 7 year old DNUK desktop would not turn off but was clearly not actually on. On Monday I took the PSU out, on Wednesday a friend lent me a spare and the rest of the computer is okay.
Today I've ordered a cheap silent PSU to replace the noisy and now dead one that was originally in there.
I got a new camera just before our summer holiday and have been doing my best to take lots of pictures, forcing myself to post a regular photo blog. I've not quite managed a photo per day, but I've managed to get a fairly regular steam of pictures loaded up.
As I said at the end of 2010 Gordon managed to flood the economy with cheap money which brought the economy skipping out artificially early of recession, only to start sliding back in as I suggested. We are not quite in the full blown state of recession, but it's clear to all that the UK isn't in a good place and until the debt has been wiped out we aren't going anywhere fast.
On the IT front, 2012 will be very much as 2011:
Bye bye 2011, Happy New 2012!
After a very long delay I have upgraded this server from Debian Lenny to Squeeze. It has taken about an hour and has gone pretty well, just a few hand edits required. The key services of email and web are still working properly and I've not locked myself out or anything silly yet!
On a server you don't get lots of new toys to play with in the way you do on a desktop system, and it's more important that it works than it's shiny, so the only reason I've done the upgrade now is so that it's before Lenny comes to the end of security upgrades - which is important.
This autumn has been very strange. We had a cool/snowy winter which is apparently bad for shops, we then had a very mild spring - which is bad for shops, then a cool damp summer - which is bad for shops and now we have a mild dry autumn - which is bad for shops. I wish people would stop their drivel - we're in the middle of a bloody recession what the hell do they expect?
Anyway back to colour, last weekend we went for a walk and I took lots of pictures. I've started to upload them to my Picasa account in the Overton album - the autumn ones are at the end of the album. It was a very pretty day and I will have to share are few more pictures - once I've processed them.
This year we have been busy at work, with two big successful project deployments this autumn. As a reward we decided to take a day off work and go and watch the steam engines go by at the Mid Hants Railway "Watercress Line". They had a three day special this October so we went down on the Friday, hoping to avoid the weekend rush.
We didn't quite arrive as early as I would have liked but no matter we took the train from Ropley Station to New Alresford on a A4 hauled train. At each station the trains sit about so we took some pictures before going to get fish and chips in town. After lunch we took a "Lord Nelson" hauled train back to Ropley where there is a bit more space to take pictures from.
It was a lovely day, very unseasonably warm sunshine and we found a nice spot on the path just outside Ropley station to take lots of pictures from.
I took over 200 photos, though only a handful are any good once you have removed the rejects and duplicates. Digital may not have the same charm that Kodachrome did, but it's a lot cheaper if you aren't a great photographer!
It's taken a while to sort out, but the pictures are now on the web in my Google Picasa album: Watercress Line. As I finish off going through them I will probably add a few more pictures of the next few months.
We had a fantastic holiday this summer and with two digital cameras with us we took over 500 photographs. It's fair to say that the vast majority were pants and will be deleted as we process them. The ones that have come out okay are being uploaded to my Google/Picasaweb account and can be viewed now. I've also been going through our previous year's holiday snaps and uploading them too!
Some of the albums are private/invite only. Public albums only contain places and have no identifiable people in them.