Solaris ZFS Pools WIth A Single Replica Are Fine!

 Computing  No Responses »
Oct 032009
 

Yesterday I went through the process of creating a ZFS storage pool with a single device :-

zpool create zt1 cXXXXX

Next adding an additional device to mirror the first :-

zpool attach zt1 cXXXXX cYYYYY

Watched it resilver, and then detached the first replica reducing the number of replicas to one :-

zpool detach zt1 cXXXXX

This is one of the nicest ways possible to migrate a large dataset from one set of devices to another (say replacing a SAN). However the documentation on Sun’s manual page for zpool is just a little vague in the relevant area and does not explicitly say that a single replica is a perfectly valid configuration.

This might all seem a little obvious, but removing a replica to reduce a storage pool to an pool without a mirror (no redundancy) is something that some volume managers don’t allow.

iPhone: What’s Missing (3): Change Red Numbers From “Unseen” To “Not Replied”

 iPhone  No Responses »
Oct 032009
 

It might be a little too much to expect, but it would be nice if there were an option to change the meaning of the little red numbers that show up on the Mail icon, the Messages icon (and other messaging apps) from “unseen” to “not replied”.

I often quickly visit a message to see if it’s something that needs dealing with straight away, and go away if it is not that important. But as soon as I do, I lose the little number that reminds me there’s a message to deal with. The whole concept of changing an icon with a little number to show how many messages there are is brilliant.

And undoubtedly for many more organised people knowing how many new messages there are is just what they need. But some of us would like to know how many messages have not been replied to or dealt with in some other way.

Alan Turing Gets An Apology At Last!

 Computing, General, History  No Responses »
Sep 112009
 

Alan Turing was a computer scientist and a homosexual at the very dawn of electronic computing, and contributed enormously to the winning of World War II by being one of those behind the code breaking efforts at Bletchley Park. When you consider his contributions to the war effort and his contributions to the new field of computer science, his sexual orientation was the least important part of him. Yet because of his sexuality, he was prosecuted, lost his security clearance (which was particularly devastating because of the lack of other places he could make his contributions), and harassed by the British security services.

Eventually he committed suicide; almost certainly because of his harassment by society that couldn’t see past his sexuality and see his vast contributions and potential.

There are those who say he shouldn’t be forgiven because he was a homosexual and that is forbidden by god. That position is contemptible and not worth commenting on.

There are those who say he shouldn’t be forgiven because he broke the law of the time. Well the law was immoral and wrong. In many ways we are obligated to break laws that are immoral.

There are those who say he shouldn’t be forgiven because there were many other men persecuted because of their sexual orientation. Perhaps 100,000 men, or even more (oddly enough homosexual women were not persecuted to quite the same extent (although I’d welcome pointers to prove me wrong … well sort of)). There is a point to that objection, but forgiving a particularly shining example of such harassment is the first step on the path of getting all those persecuted men pardoned.

And Alan Turing is a good start to that process because even those who do not like homosexuality can be brought around to believing that Alan at least deserves to be forgiven because of his immense contributions.

But most of all he should be pardoned because he didn’t really do anything wrong, and honoured because of his contributions.

Exploding Batteries – Getting More Dangerous

 Computing, General, iPhone  No Responses »
Sep 042009
 

If you are as old as I am, you will recall that batteries have always had problems – a small percentage “deteriorate” and overheat. Although this applies to any batteries, I am thinking mostly of the kind that are found in laptops, media players, phones and the like – not the old cylinder ones used in torches.

In the past, batteries did not contain as much power as they do now – it is something that is gradually increasing over time, and of course we want more power in our batteries so that our gadgets run for longer. Or do we ?

In the past battery problems would do things like melt the case of a mobile phone, but now we hear of laptops bursting into flames, and media players exploding. Seems that the effects of a problem are getting worse at the same time that batteries are holding more power.

Of course this makes sense – the more powerful the battery, the more powerful the effect when it “lets go”. So what happens when batteries become yet more powerful ? What happens when such a battery fault occurs in a large electric vehicle ?

Toilet Seats: Up or Down ?

 Humour  No Responses »
Sep 042009
 

Just for the record, I leave toilet seats in the position I found them in after I’ve used them and this is intended to be humorous.

One of the most common complaints women have about men is that we leave the toilet seats up which when you think about it is more than a little ridiculous. After all it takes perhaps 5 seconds to put the seat down, which is hardly enough work to complain about is it ?

The funny thing is when men gather in secretive enclaves to complain about women (which we have to do to avoid being accused of sexism), nobody ever complains about women leaving the toilet seat down. Why is that ? After all, men are hardly any less ridiculous than women are, and putting the toilet seat up is just as much work as putting it down.

I guess this is one of life’s great unanswerable questions.

Of course if you were to do an efficiency study of how much work in a mixed household results from moving the toilet seat, you will probably find that less work results from leaving the seat up than leaving it down. Of course then all the work will be done by women, which may be why they complain about the seat being left up.

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