IT: Linux, ZFS and Open-Source Licenses

 Computing, Politics  No Responses »
Aug 252007
 

If you’re hoping to read about Linux finally getting ZFS (except as a FUSE module) then you are going to be disappointed … this is merely a rant about the foolishness shown by the open-source world. It seems that the reason we won’t see ZFS in the Linux kernel is not because of technical issues but because of licensing issues … the two open-source licenses (GPL and CDDL) are allegedly incompatible!

Now some may wonder why ZFS is so great given that most of the features are available in other storage/filesystem solutions. Well as an old Unix systems administrator, I have seen many different storage and filesystem solutions over time … Veritas, Solaris Volume Manager, the AIX logical volume manager, Linux software RAID, Linux LVM, …, and none come as close to perfection as ZFS. In particular ZFS is insanely simple to manage, and those who have never managed a server with hundreds of disks may not appreciate just how desireable this simplicity is.

Lets take a relatively common example from Linux; we have two disks and no RAID controller so it makes sense to use Linux software RAID to create a virtual disk that is a mirror of the two physical disks. Not a difficult task. Now we want to split that disk up into seperate virtual disks to put filesystems on; we don’t know how large the different filesystems will become so we need to have some facility to grow and shrink those virtual disks. So we use LVM and make that software RAID virtual disk into an LVM “physical volume”, add the “physical volume” to a volume group, and finally create “logical volumes” for each filesystem we want. Then of course we need to put a filesystem on each “logical volume”. None of these steps are particularly difficult, but there are 5 seperate steps, and the separate software components are isolated from each other … which imposes some limitations.

Now imagine doing the same thing with ZFS … we create a storage pool consisting of two mirrored physical disks with a single command. This storage pool is automatically mounted as a filesystem ready for immediate use. If we need separate filesystems, we can create each with a single command. Now we come to the advantages … filesystem ‘snapshots’ are almost instantaneous and do not consume additional disk space until changes are made to the original filesystem at which point the increase in size is directly proportional to the changes made. Each ZFS filesystem shares the storage pool with the size being totally dynamic (by default) so that you do not have a set size reserved for each filesystem … essentially the free space on every single filesystem is available to all filesystems.

So what is the reason for not having ZFS under Linux ? It is open-source so it is technically possible to add to the Linux kernel. It has already been added to the FreeBSD kernel (in “-CURRENT”) and will shortly be added to the released version of OSX. Allegedly because the license is incompatible. The ZFS code from Sun is licensed under the CDDL license and the Linux kernel is licensed under the GPL license. I’m not sure how they are incompatible because frankly I have better things to do with my time than read license small-print and try to determine the effects.

But Linux (reluctantly admittedly) allows binary kernel modules to be loaded into the kernel and the license on those certainly isn’t the GPL! So why is not possible to allow GPLed code and CDDLed code to co-exist peacefully ? After all it seems that if ZFS were compiled as a kernel module and released as a binary blob, it could then be used … which is insane!

The suspicion I have is that there is a certain amount of “not invented here” going on.

Bill Gates, OLPC Project, Educational Content

 Computing, Politics  No Responses »
Jul 292007
 

Just seen part of an interview with Bill Gates on News24 where Microsoft’s educational projects were being discussed, and the One Laptop Per Child project was brought up. Bill sort of avoided trying to talk about it by claiming that hardware costs will continue to come down and the real problem is about educational content.

It is true that hardware costs tend to come down … to a point where prices stay fairly static but specifications increase. He has also glossed over the fact that the OLPC laptop is semi-ruggedised with features specifically intended to help with its use as a learning tool rather than a working tool; including the special display which has a special low-power black and white mode intended for reading eBooks. Not something found in a typical laptop!

The other thing that was totally ignored is that the Sugar user interface (running on a stripped down RedHat) is designed to be easy to use for children rather than rely on some conventional approach to desktop computing. For instance there is an easy way to see your local “neighbourhood” (press F1) … the local mesh of internetworked OLPCs.

However Bill hit the nail on the head by bringing up the content issue. It is the real problem and in fact the OLPC project highlights this and has a prominent area on their Wiki to deal with content. Perhaps Bill should put his money where his mouth is and help fund the content projects … it may not help Microsoft directly (although given that the content is intended to be “open-source” there is no reason why a Microsoft operating system could not use it as well as the OLPC laptops) but it would help education.

Just How Democratic Is The UK ?

 Politics  No Responses »
Jun 292007
 

Well the answer to that question is not very … we elect representatives who make the necessary decisions on our behalf. Of course we’re a lot more democratic than some other places, and less that some others. For the record we’re probably more democratic than the ancient historical source of the idea of democracy … Athens. The Athens city state was only democratic if you were rich and male.

We happened to have had two examples of exactly how undemocratic the UK is this week … the resignation of Tony Blair and his replacement as Prime Minister by Gordon Brown, and the defection of Quentin Davies from the Conservative party to the Labour party.

The constituents of Grantham & Stamford are probably somewhat taken aback at finding themselves represented by a Labour MP; after all they were under the impression that they had voted for a Conservative MP. Well, no they hadn’t really … they really voted for Quentin Davies through thick and thin, and officially the party he belongs to is irrelevant. Of course his constituents might disagree, but their only avenue of complaint is when he tries to get re-elected.

Similarly nobody voted for Gordon Brown as Prime Minister. We all knew he was going to get into the hot seat of course … unlike Mr Grey’s (John Major) coup d’état where he replaced Margaret Thatcher. We didn’t have any say in the matter … the largest party’s leader is always (by convention) asked by the Monarch to become the Prime Minister. We may think that we are electing a Prime Minister (and the politicians encourage this), but really we ave no say in the matter except in having some influence on what party becomes the largest.

Does this need reforming ? Well perhaps, although there is always a danger in reform that we make things less stable. I think at the very least MPs who leave their party should resign their seat because we really are not living in a time where each MP acts more or less independantly.

Women or Men Are Better At Parking ?

 General, Politics  No Responses »
Jun 202007
 

There has just been an item on the morning news about how good at parking men and women are and which ones are better. It may be entertaining, but is also so inane that I can’t remember which sex was supposed to be better. Lets suppose men were worse at parking than women. Why? Perhaps because they drive more than women, or perhaps they have a tendency to drive bigger cars than women. Who knows ?

Personally I believe whatever the reason for someone being a bad parker, it is very unlikely to be because they are a man or a woman. Whilst such surveys are entertaining and provide a bit of ‘water cooler’ discussion material, all too many people jump to the obvious conclusion. All such a survey shows is that men have a statistically significantly greater chance of having an accident parking than women (or the other way around).

It does not show that men are worse at parking than women. That may be the case, but the survey doesn’t show it … because it doesn’t answer other questions :-

  • Do people who drive more than an hour a day have more or less accidents parking than those who drive less than an hour ? Repeat for other time periods.
  • Do people who drive larger cars have more accidents parking than those who drive smaller cars ?
  • Does parking in deprived areas result in more or less parking accidents ?
  • Does street parking result in more of less parking accidents than in car parks ?

The list goes on, and then you have to discover the differences between how men and women park.

We are too quick to jump on apparent evidence that shows men are better than women, or women are better than men. In reality, if you pick a woman driver and a man at random, there are probably many differences between them that could explain different driving risks, and that the difference in sex is probably the least likely explanation of differences in the risk of driving accidents.

Salman Gets A Gong, Iran Offended

 Politics  No Responses »
Jun 172007
 

So Salman Rushdie get a gong in the birthday honours list. Good for him!

And Iran gets all hot under the collar about it. Bad for them! I hope someone in the Foreign Office points out that it is none of their business and they should sulk about it in silence. After all, we’re not exactly threatening any Iranian citizens with murder are we ?

And a few days later, Pakistan also gets into the act. Again, what right do they think they have to criticise us when we honour a great writer ?

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