Mike Meredith

When Windows Update Lies

May 172017

It seems rather strange when you discover it, but Windows Update sometimes lies about what updates have been installed. I am not sure how often this happens, but it does happen from time to time. Which with WannaCrypt rampaging around is somewhat unfortunate.

What seems to happen is that Windows Update gets confused about what patches it has installed – it’s internal database gets corrupt. One possible fix for this is to remove the database :-

net stop wuauserv
cd %systemroot%
ren SoftwareDistribution SoftwareDistribution.old
net start wuauserv
rd /s/q SoftwareDistribution.old

When using Windows 10, you may well have to start (net start wuauserv) Windows Update services before stopping them. Once you have removed the directory, the next time you run Windows Update in the gooey, it will spend some time rebuilding it’s database and hopefully will then pick up the missing updates. No promises but this worked on at least one server that had unacknowledged missing patches.

Of course without a proper vulnerability scanner it may be tricky to determine when Windows is lying about being fully patched. The best bet is to assume it is lying whenever something like WannaCrypt comes along.

The other possibility is to look into something like Autopatcher which is intended for offline updates – you can download the Microsoft updates and use the tool to patch Windows computers from the downloads.

Canute, The Tide, and The Church

History No Responses »

May 082017

Many of us know about the story of King Canute (or probably Cnut) and his attempt to hold back the tides. Although we English typically only give one king the suffix “the Great” (Alfred), Cnut himself is also known as “the Great” (perhaps more for his non-English endeavours). So it seems a touch unlikely that such a king would imagine he could control the waves by verbal command; if anything he might want to make fun of his courtiers by trying the impossible to indicate he was human.

It is a popular tale with the Church too – it’s a great example of over-weaning pride which is one of the seven deadly sins. And Cnut as a Dane, probably was not the most popular king with the church, as Danes had only recently given up going viking and pillaging churches and monasteries (in the words of a fictional viking: “they gather all their gold and silver into one building. And then so conveniently mark those buildings with crosses.¨).

But there is a far more prosaic explanation for the tale in which the Church uses a human disaster to laugh at people’s efforts to improve themselves.

Before the raw sewage pollution in the 19th century put an end to it, the South coast was home to a massive oyster fishing industry that existed in the region for at least two thousand years. Indeed, oysters were one of the staple food sources for the poor until the 19th century.

One of the ways that shallow water oyster fisheries can be improved is by building dyke-like structures that allow the high tide in, but keep some of the tide from escaping at low tide. As it happens, a place in West Sussex called Bosham happens to be ideal for this, and there is supposedly much archaeological evidence to show that these “dykes” had been built there repeatedly over the centuries.

As anyone who lives by the sea knows, to build sea structures, you have to over-build and even then, exceptional storms will cause damage, and there is also archaeological evidence to show that the “dykes” at Bosham were washed away in exceptional storms every few hundred years.

As it happens, Bosham was a royal estate in the time of Cnut (one of his daughters is supposedly buried at the pictured church), and it is all too likely that an exceptional storm would have destroyed the oyster beds whilst Cnut was holding Bosham. Thus the Church had an opportunity to use an economic disaster to poke fun at king they were probably not too fond of.

A Dummies Guide To Tactical Voting

Politics No Responses »

May 012017

With an election coming up it is time to try and persuade those who do not vote to get out there and vote. One of the main reasons people give for not voting is because none of the candidates are inspiring enough. Well it is all very well waiting for a candidate that inspires you, but you could well be waiting for a very long time.

Probably the second biggest reason for not voting is that with the first past the post system, there are places where voting for anyone other than the leading candidate is seen as a wasted vote. Nothing could be further from the truth! In almost every “safe” seat, if everyone who didn’t vote for the leading candidate all voted for an agreed alternative, then the seat could easily go to that alternative candidate. For example, the Arundel and South Downs constituency was won with 32 thousand votes in a constituency of nearly 100,000 – easily enough to overturn the Tory majority.

As to tactical voting: It can be summed up by selecting the candidate you would most like to lose (such as the Tory candidate), and picking the candidate most likely to defeat them.

Anyone can find out the last few election results (and a whole lot more) at http://www.electoralcalculus.co.uk/. Just look at the last few elections and vote for the second placed candidate (providing that’s not a Tory or a UKIP candidate of course!). And don’t keep punishing the Liberals for breaking their promises; they don’t break their promises any more than the others.

Of course this may mean you are not voting for the candidate you want, but under the present voting system it makes more sense to vote against the candidate you dislike the most. Yes this is crazy, but so is using a voting system first used in the medieval era!

Are Final Salary Pension Schemes Generous?

Politics No Responses »

Apr 302017

Short answer: NO!

One of the infuriating things I come across is the notion that final salary pension schemes are generous; it seems that a generation of Tory propaganda has persuaded people that such schemes were wildly over-generous and completely affordable. Of course many of those doing the persuading are taking advantage of those “generous” pension schemes.

What it is easy to forget is that many of those final salary pension schemes collapsed because successive governments turned a blind eye to the private sector looting pension scheme surpluses and panicking when the surpluses turned into deficits. In other words when pensions were profitable they were affordable, but whenever a company suddenly had to contribute more than it expected they were suddenly too expensive.

Now don’t get me wrong – with increasing life expectancy there are problems with funding pension schemes, and we can decide that they are too expensive, or not. But if a pension scheme was perfectly reasonable in the 1970s, it doesn’t suddenly become overly generous in the 21st century.

As it is, we have “decided” that rather than share wealth out amongst the working-class, it should be kept in the hands of the already wealthy.

Of course we could always decide to revisit that decision and spend more time thinking about it.

VirtualBox, Windows Guest Virtual Machines, and The VirtIO Network Interface

Computing, Working Notes No Responses »

Apr 302017

Despite how long I have been running Windows in virtual machines (as far back as Vmware Workstation 1.0), I have never gotten around to looking at the virtio network interface – except for naïvely turning it on once, finding it didn’t work, and turning it off – so I decided to have a look at it. I was prompted to do this by a suggestion that emulating the NIC hardware as opposed to simply using a virtual communications channel to the host would hurt network performance. Good job I chose a long weekend because I ran into a few issues :-

Getting appropriate test tools took a while because most of the tools I know of are very old; I ended up using iperf2 on both the Linux main host and the Windows 10 guest (within the “Windows
The “stable” virtio drivers (also called “NetKVM”) drivers didn’t work. Specifically they could send packets but not receive them (judging from the DORA conversation that was more of a DODO). I installed the “latest” drivers from https://fedoraproject.org/wiki/Windows_Virtio_Drivers. Note to late readers: this was as of 2017-04-30; different versions may offer different results.
Upgrading my ancient Debian Jessie kernel to 4.9 on the off-chance it was a kernel bug turned into a bit of an exercise what with ZFS disappearing after the upgrade, and sorting out the package dependencies to get it re-installed was “interesting” (for small values of course). No data loss though.

I ran two tests :-

sudo nping –tcp -p 445 –count 200 –data-len 1280 ${ip of windows guest) – to judge how reliable the network connection was.
On the Linux host: sudo iperf -p 50001
On the Windows guest (from within the Ubuntu-based environment): sudo iperf -p 50001 -c ${ip of Linux host}

Device	nping result	iperf result
Windows guest (virtual Intel Pro 1000 MT Desktop	1 lost	416 Mbits/sec
Windows guest (virtio)	0 lost	164 Mbits/sec
CuBox running ARM Linux	n/a	425 Mbits/sec

Which is not the result I was expecting. And yes I did repeat the tests a number of times (I’ve cheated and chosen the best numbers for the above table), and no I did not confuse which NIC was configured at the time of the tests nor did I get the tests mixed up. And to those who claim that the use of the Ubuntu environment screwed things up, that appears not to be the case – I repeated the test with a Windows compiled version of iperf with much the same results.

So it seems despite common sense indicating that a NIC “hardware” custom designed for a virtual environment should perform better than an emulation of a hardware NIC, the actual result in this case was the other way around. Except for the nping result which shows the loss of a single packet with the emulated hardware NIC.

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