Older blog entries for etbe (starting at number 1028)

Samsung Galaxy Camera – a Quick Review

I recently had a chance to briefly play with the new Samsung Galaxy Camera [1]. The Galaxy Camera is an Android device with a 4.8″ display (the same size as the Samsung Galaxy S3) that has a fairly capable camera (IE nothing like a typical phone camera). It runs Android 4.1 (Jelly Bean) and the camera has 21* zoom with a 16 megapixel sensor.

Camera Features

It seems that professional photographers are often annoyed when they see someone with a DSLR set in auto mode. It’s widely regarded that auto mode is a waste of a good camera, although the better lenses used with DSLRs will usually give a better result than any compact camera even when it’s in auto mode. The problem is that photography is quite complex, in an earlier post about digital cameras I summarised some of the technical issues related to cameras and even without any great detail it became a complex issue [2]. The Galaxy Camera has a reasonably friendly GUI for changing camera settings which even includes help on some of the terms, I expect that most people who use it will end up using most of the features which could make it a good training camera for someone who is going to move to a DSLR. A DSLR version of the Galaxy Camera could also be an interesting product. The camera also has modes such as “Waterfall” and “Panorama”, hopefully the settings for those would be exposed to the user so they could devise their own similar groups of settings.

I’ve seen the phone criticised for the lack of physical controls as the expert mode in software is inherently slower than manually turning dials on a DSLR. But it seems obvious to me that anyone who knows how to use the controls manually should be using a DSLR or bridge camera and anyone who doesn’t already know how to do such things will be better suited by the software controls.

It supports 120fps video at 720*480 resolution (with a file format stating that it’s 30fps to give 1/4 speed) which could be useful. I used to have a LG Viewty smart-phone that did 120fps video but the resolution was too low to be useful. 720*480 is enough resolution to see some detail and has the potential for some interesting video, one use that I’ve heard of is filming athletes to allow them to analyse their performance in slow motion. It also does 60fps video at 720p (1280*720) resolution.

One down-side to the device is that the lens cover doesn’t seem particularly sturdy. It’s quite OK for a device that will be stored in a camera case but not so good for a device that will be used as a tablet. I didn’t get to poke at the lens cover (people don’t like it if you mess with their Christmas presents) but it’s design is a couple of thin flaps that automatically retract when the camera is enabled which looks quite weak. I’d like to see something solid which doesn’t look like it will slide back if the device is treated as roughly as a phone.

I think that the lack of a solid lens cover could be the one factor that prevents it from being used as a replacement for a smart phone. Apart from that a Galaxy Camera and a cheap GSM phone could perform all the functions of a high end phone such as the Galaxy S3 while also producing great pictures. It would probably make sense for retailers to bundle a cheap phone with a Galaxy Camera for this purpose.

Tablet Features

The device boasts WiFi Direct to allow multiple cameras and phones to talk to each other without a regular WiFi access point [3]. I didn’t test this and I don’t think it would be particularly useful to me, but it seems like a handy feature for less technical users.

It can connect to the Internet via Wifi or 3G, supports automatic upload of pictures (it comes with Dropbox support by default like the Galaxy S3), and has a suite of photo and video editing software. I don’t expect that any photo editing software that runs on an Android device would be much good (I think that you really need fine cursor control with a mouse and a high resolution screen), but it would probably be handy for sending out a first draft of photos.

Most Android apps should just work, the exceptions being apps that rely on a camera that faces the user or full phone functionality. So the Galaxy Camera can do almost anything that an Android phone or tablet can do.


The RRP for the Galaxy Camera is $599, that puts it in the same price range as a DSLR with a single lens. While that’s not a bad price when compared to smart-phones (it’s cheaper than the LTE version of the Galaxy S3 phone) it’s still quite expensive for a camera that’s not a DSLR.

Fortunately Kogan is selling it for $469 and has free shipping at the moment [4]. This still makes it more expensive than some of Bridge Cameras which probably have significantly better optical features, but in terms of what the typical user can do with a camera the Galaxy Camera will probably give a much better result.

The sensor in the Galaxy Camera is smaller than that in the Nokia 808 PureView [5] (1/2.3″ vs 1/1.2″) so the Nokia PureView should be able to take better pictures in some situations. Unfortunately the Nokia 808 doesn’t run Android, I’d probably own one if it did.

Some of the reviews are rather harsh, the Verge has a harsh but fair review by Aaron Souppouris which makes a number of negative comparisons to cheaper cameras [6]. I really recommend reading Aaron’s review as there’s a lot of good information there. But I think that Aaron is missing some things, for example he criticises the inclusion of ebook software by saying that he wouldn’t read a book on a camera. But the device is a small tablet computer which also has a compact camera included. I can easily imagine someone reading a book or playing Angry Birds on their camera/tablet while in transit to where they are will photograph something. I can also imagine a Galaxy Camera being a valuable tool for a journalist who wants to be able to write short articles and upload pictures and video when out of the office.

Aaron concludes by suggesting that the Galaxy Camera is a $200 camera with $300 of editing features. I think of it as $200 in camera hardware with software that allows less skilled users to take full advantage of the hardware and the ability to do all the software/Internet things that you would do on a $450+ smart-phone.

Would I Buy One?


The Galaxy Camera is among other things a great toy, I’d love to have one to play with but I can’t spare $469 on one. Part of the reason for this is that my wife just bought a DSLR and is getting lessons from a professional photographer, so I really won’t get better pictures from a Galaxy Camera. The DSLR on auto mode will allow me to take pictures that will usually be better than a Galaxy Camera can achieve (sometimes you just can’t beat a good lens). For more demanding pictures my wife can tweak the DSLR. The 120fps video is a really nice feature, I don’t know if my wife’s DSLR can do that, but it’s a toy feature not something I really need.

I’ve just bought a Galaxy S3 which is a great little tablet computer (most of the time it won’t be used for phone calls). I don’t need another 4.8″ tablet so a significant part of the use of the Galaxy Camera doesn’t apply to me.

I recommend the Galaxy Camera to anyone who wants to take good photos but can’t get a DSLR and lessons on how to use it properly. But if you would rather get a 35mm camera with interchangeable lenses that runs Android then it might be worth waiting. I expect that the Galaxy Camera will be a great success in the market (it’s something you will love when you see it). That will drive the development of similar products, if Samsung doesn’t release a 35mm Android camera soon then someone else will (for example Sony develops both high end cameras and Android phones).

If my wife didn’t have a DSLR then I’d probably have bought a Galaxy Camera already. I will recommend it to my parents and many other people I know who want an OK camera and can benefit from a tablet, but don’t know how to use a DSLR properly (or don’t want to carry a bulky camera).

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Syndicated 2012-12-29 14:35:14 from etbe - Russell Coker

SIM Annoyances

My new Samsung Galaxy S3 phone takes a micro-SIM (see the Wikipedia page about Subscriber Identity Modules for details [1]). All my other mobile devices take a mini-SIM so I can’t just put the SIM from my old phone in my new phone. I’ve just made my second application to Virgin Mobile for a new micro-SIM, the first time they sent me a nano-SIM by mistake. Also if my new phone breaks I will have difficulty in getting a micro-SIM to run in a mini-SIM device (it should be possible, but will be difficult at least). I may even have to ask my Telco to send me a new mini-SIM to allow the use of an older phone if my Galaxy S3 breaks.

The difference between micro and mini SIMs is 25*15mm vs 15*12mm. For a phone with a 4.8″ display this doesn’t seem to be a great benefit. It doesn’t seem that the phone would be much bigger if they had designed it for a mini-SIM. If they had used a nano-SIM which is 0.09mm thinner that might have allowed them to make the entire phone thinner, I think that such thin phones are a bad idea but the reviewers seem to like thin phones with small batteries. I think that any device which is large enough to have a speaker somewhere near my ear and a microphone somewhere near my mouth will be big enough to fit a 25mm long SIM card.

It seems to have been a trend in Australia in the last few years towards only selling unlocked phones on contracts (relying on the contract terms to lock the customer in) and only use locked phones for discount sales for pre-paid use. Also the “free” phones in Australia are considerably more expensive than buying a phone outright [2]. So I’m sure that most people have a collection of older phones which in future can’t be easily interchanged with new phones due to SIM card size differences.

This is more of a problem due to the fact that modern phones seem to have a low quality of hardware production, the majority of Android phones owned by my relatives have failed in some substantial way well within the two year replacement period. I don’t believe that I can rely on my Galaxy S3 working until I want to buy something better, I expect that my old Galaxy S (which has a hardware fault that makes it crash regularly but is mostly usable) will be pressed into service again.

In terms of phone purchases, buying a phone that takes a micro-SIM seems like a bad strategy as there is an even smaller nano-SIM available. For all I know Samsung will release a Galaxy S4 or Note3 that uses a nano-SIM and give me the same upgrade problem in a couple of years time.

I wish that the people who reviewed phones would pay more attention to the real world use cases than to slightly better specifications. The micro and nano SIMs seem to provide no real benefit for users. Saving a fraction of a gram in device mass or a fraction of a millimeter in one dimension might seem nice when aggregated with other small savings, but for the user it’s no real benefit. Being able to interchange a bunch of random phones is a real benefit. It’s also a real benefit to be able to buy a phone and expect it to just work immediately. With the current state of the market one can’t buy a phone and make any assumptions about the SIM size that it will accept, at best this requires some extra research before buying and at worst this could involve some time without phone service.

I think that a major feature for a review of an important device like a modern smart phone should be how quickly and easily it can be deployed for full use. When SIM size issues prevent a new device from being used properly for over a week (as has happened for me) then it seems like a design failure.

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Syndicated 2012-12-28 02:11:53 from etbe - Russell Coker

Finding an ATM Skimmer

A member of SAGE-AU [1] found two ATM skimmers [2] and gave me permission to publish his description and analysis of the situation. I’ve lightly edited this from a mailing list post to a blog format with permission from the author. This Courier-Mail article refers to the skimmers in question [3].

People were wondering what gave the skimmers away so here goes, NB this is only about the 2 I discovered.

  1. The actual atms in question were the free standing type (but even this doesn’t matter in the scheme of things because they can be on those in a bank of the things).
  2. I’d actually conducted transaction and was waiting for my card to come out of the machine – these things looked that good. The colours matched – especially in the 3/4 or less light that you typically have on the fascia’s of such machine. The backing plate grey matched atm fascia as did the green “bubble” where the card goes.
  3. WHAT REALLY CAUSED SUSPICION – my card was having difficulty coming out of the atm at end of transaction i.e. card coming out extra slow – then only the end couple of mm, I had to physically grab my card with fingertips to get it out and there was barely perceptible movement of skimmer due to my fingers using the green “bubble” as purchase point, THAT was what made me suspect. I then really had close look and found that I could move the “bubble” with its backing plate – I pulled it off the machine and then looked at the atm next to it and found it to look exactly the same. These things are held on by double sided tape.
  4. Grabbed the cleaning lady wandering past showed her the device and asked her to get security. Security and centre operations manager subsequently showed up, while waiting for them I had to stop people from using either machine (everyone amazed at how good these things looked). Centre ops guy went and checked other machines in the centre, I left my details and they called the cops… I went straight to my credit union and reported what had happened and they cancelled my card are rdered a new one on the spot for me.
  5. Coincidently (or not) the centre ops and security lady told me that the machines had been serviced (refilled) not too much earlier that day – i.e. I wondered if the bad guys did the “service” or were tracking armaguard servicing types.

Quick side notes:

  1. 3 more skimmers have been found since then.
  2. Subsequently, I found out these were the type that needed to be picked up for the bad guys to retrieve the data i.e. these weren’t the type that transmitted to some-one sitting near by via Bluetooth/wireless i.e. in this instance I need not have cancelled my card and gotten a new one from my credit union.
    HOWEVER, it is best practice if you discover one and you’ve used that machine to immediately have your financial institution cancel your card and issue you a new one – though getting the new one can take up to a week.
  3. As I understand it, These 2 devices (i.e. others could be different) have 2 usb ports one for the reader and the other to a pinhole camera (commercially available type removed from it’s original housing). The magnetic stripe data is held on the audio track associated with the video and there was an 8GB storage card to hold it all i.e. it makes things easier for the bad guys to match PINs to card details.
  4. If you do find a skimmer DO NOT touch the insides (non public facing parts) of it – this is where the cops can really try lift dna and prints from; gathering prints from externally is far more fraught as everyone and their dog has probably touched the exterior of the skimmer.
  5. In the lead up to Xmas these things or similar are highly likely to become more prevalent as we all go about parting with dosh while gift shopping – SO BE AWARE AND CAREFUL.

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Syndicated 2012-12-23 01:08:49 from etbe - Russell Coker

Everyone Needs a Tablet

Care2 has an interesting article about people being offended by a picture of a poor Afro-American boy using an iPad [1]. It seems that people object to poor people having what is in many ways the greatest educational tool available because it can also be seen as a status symbol. I wonder if one of the cheaper Android tablets (at 1/3 the price of an iPad or less) would get the same response.

Dvice has an inspiring article by Evan Ackerman about an experiment where a large quantity of Motorolla Xoom tablets were delivered to Ethiopian kids who couldn’t read and didn’t know English [2]. The kids learned printed English and learned to hack the devices to enable all the hardware features! I don’t expect that kids in first-world countries would get the same benefits as kids in countries such as the US and Australia are distracted by TV, games consoles, and other forms of entertainment that aren’t readily available in Ethiopian villages. But the potential benefits for widespread deployment of tablets in the poorer parts of first-world countries seems significant.

I think that the government of every first-world country should give a voucher to every resident who is more than two years old for a $100 discount off the list price of a tablet. If someone is happy with a cheap Android tablet then $100 will cover the prices. If they want something better then they can pay more. I’m happy for wealthy people to get a $100 discount on the price of one of the more expensive tablets, it seems that “means testing” such government subsidies just causes political issues without saving much money.

Apart from the obvious educational benefits for people who own tablets (which means adults as well as children) there are also benefits in having everyone own a tablet. If everyone owned a tablet then the resale price of a low-end tablet would approach zero and the resale price of even more desirable tablets such as the iPad would drop a lot. This would reduce the incentive to steal tablets and allow people to use them in situations where there is less safety. If most people felt safe to use a tablet computer on public transport and started doing educational things instead of reading newspapers then it would improve the overall education of the population. Newspapers generally aren’t educational and in the case of News Corp publications and other tabloids you can become less well informed by reading them – I believe that on average newspapers have a negative educational value in Australia.

The cost of giving a $100 tablet voucher to every resident of Australia would be about $2,200,000,000 (plus administrative costs) which seems like a lot of money. But when compared to the costs of building infrastructure it’s not significant. I’ve just read some government announcements regarding transport budget which includes items such as $6,500,000 to determine the best route for a new rail line. So if we were to get 350 new rail lines (and we need more than this) then merely determining the routes would cost as much as getting a tablet for everyone in the country!

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Syndicated 2012-12-22 06:20:10 from etbe - Russell Coker

Samsung Galaxy S3 First Review with Power Case

My new Samsung Galaxy S3 arrived a couple of days ago. Kogan added to the weirdness in their shipping that I documented in a previous post [1] by shipping the two phones on consecutive days with separate invoices for $789 each (as opposed to the $449 that I paid). This means that if customs were to track this down they could bust me for import duties (which apply whenever you order more than $1000 of electronics from another country) as multiple shipments in a small period of time are aggregated for tax purposes. It also means that it would be easy to defraud the tax office or an employer about the cost of the devices if I didn’t blog about it…

Phone and Case Review

back of power case with S3 installed next to back plastic of S3 S3 and case next to each other

To install the Samsung Galaxy S3 in the power case I bought from Kogan the back of the S3 has to be removed. One annoying implication of this is that when using the phone in it’s case I will either have to carry the back of the phone with me or have no option of removing the case during the day. The phone has to slide in to the case from a small angle and if it’s removed carelessly there seems to be a risk of breaking the power connector on the case.

S3 on power case stand edge view of S3 in power case stand

The above photos show the kick-stand on the power case in use, I haven’t yet had an opportunity to use the stand for anything other than photography and as it’s made of thin plastic there’s a reasonable chance that it will break off before I ever use it properly.

One major deficiency of the power case is that it has no protection for the screen. The typical gel case will extend by about 2mm above the screen which means that you can place the phone screen-down on a table without a risk of scratching the screen. Also if a phone in a gel case is dropped on a hard surface it seems likely that the chance of the screen hitting a bump and cracking will be lower although I’m not aware of any research regarding how well this theory works in practice. This combined with the fact that the power case is smooth and difficult to grip makes it quite unsuitable for regular use. I am concerned that the added mass of the power case would increase the risk of serious phone damage if it’s dropped screen-down.

I plan to buy a gel case ASAP which I will use most of the time. I will swap the gel case for the power case on the occasions when I expect to spend an extended period of time away from home or an office where I can charge my phone. The power case really should have been designed with a flange that extends above the level of the screen on all sites. It also shouldn’t be smooth on the outside.

Phone Review

The Galaxy S3 equals the Galaxy S for the title of the most slippery phone I’ve ever owned. This combined with the fact that the Galaxy S3 is slightly thinner and also 10% wider and longer makes it a more difficult phone to hold. It’s a phone that really needs a case with a lot of grip.

The camera is reasonable given the fact that any device that is 8.6mm thick will have a very small focal length and also a very small CCD for receiving light. The laws of physics just don’t allow something the size of the Galaxy S3 to have a half-decent camera. My ideal mobile phone would be about the size of the Galaxy S3 with the power case, it would use the extra thickness for a big battery as well as a much longer focal length for the camera. I’d like a phone to be about 16mm thick over most of it’s area with a section that’s 20mm for the camera. The burst shot mode (which allows you to take 20 pictures rapidly) is good for capturing certain types of relatively slow movement (EG someone’s mouth moving when they talk). But it’s no good at all if you try to pan the camera while doing burst mode.

When I first started using the phone it gave me lots of hints about using various functions. This wasn’t particularly useful for me as most things are obvious to anyone who has much experience with computers and the non-obvious things are probably going to be forgotten if you are doing something else when the help system prompts you. It will be useful for my sister in law who’s getting the other phone, but the down-side of this is that I can’t configure her phone before delivering it. She needs to use it first to see all the tips.

The Galaxy S3 has a screen that’s 4.8″ diagonally which is slightly larger than the 4.0″ screens of my previous Android phones (Sony Ericsson Xperia X10 and Samsung Galaxy S). That gives 44% more screen area which is a good thing. Unfortunately many apps seem to display the same amount of data, I had hoped that 44% more area and 140% more pixels would result in most apps displaying more data by default. Fortunately ConnectBot (my SSH client of choice) gives me 60 rows and 120 columns on the Galaxy S3 as opposed to the mere 31 rows and 80 columns on the Xperia X10. I don’t use ConnectBot that often (a phone is a really bad ssh client no matter how you do it), but when I do it’s really important and the extra space matters.

The down-side of the larger screen for me is that the distance from the center of the palm of my hand to the end of my thumb is slightly less than 4.8″. This means that I can’t hold the Galaxy S3 with one corner in the palm of my hand and still reach the far corner of the screen. So I am forced to hold the sides of the phone for one-handed use which means that it would be easier for it to slip out of my hand. A further complication is that the settings and back buttons are very close to the edge of the phone and can be hit by accident very easily. Hopefully a gel case will alleviate that. But I have never owned a hand-held device which was so difficult to hold in a stock configuration.

According to AndroSensor (one of my favorite demo programs for showing useless things that a phone can do) the Galaxy S3 lacks support for measuring humidity and external temperature but it has all the other sensors. I think I can survive without knowing how hot and humid my pockets are, but it would still be nice to have every possible feature.

The default partitioning of the phone storage is to have all internal storage used for applications and none used for a VFAT filesystem accessible over USB. It’s nice that I won’t run out of application storage space (a problem I’ve had with every other Android device) but it does mean that I’ll have to buy a micro SD card before I can use the phone properly. Micro SD storage costs about $1.50 per gig in the size range from 8G to 32G, it’s not particularly expensive but it’s annoying to have the phone not be fully usable right from the start. Without using a SD card I have to use gphoto2 to download pictures from the phone so it’s fully usable in every way. But the cost of the power case, the gel case I’m about to buy, and an SD card make the phone less of a bargain.

The phone has more RAM, a faster CPU, and Android 4.1. These are all really good things, but nothing worth writing about in a review.


The power case is very poorly designed, I probably wouldn’t buy it if I knew then what I know now.

For one-handed phone use by someone like me with longer than average fingers a 4.0″ phone is about the largest possible. This doesn’t mean that phones should stay small, but it does mean that Apple weren’t being entirely silly when they released all the 3.5″ iPhones. Presumably a large portion of the population would find a 3.5″ phone to be as usable as a 4.0″ phone is for me. It now seems to me that as a 4.8″ screen is going to be impractical for one-hand use by almost everyone the phone designers should concentrate more on larger phones similar to the Samsung Galaxy Note. I think that the 4.8″ screen size may be ideal for some young children who could use it the way an adult might use a 7″ tablet – an Android phone seems to be a relatively common present for children in the 6-12 age range.

Generally I think that no-one should ever buy a new phone or tablet without trying one of the same size. While I am happy with the S3 it really doesn’t work in the way I expected.

Having 2.9* as many characters on screen for ConnectBot is a massive benefit. If I ever write another magazine article on a hand-held device the extra size and resolution will really help if I found a suitable editor (please make suggestions in the comments). For the WordPress client to write long blog posts on it then the screen could potentially be reasonably useful, but so far it seems that it’s more suited to reviewing posts and comments than to writing posts.

Generally the Samsung Galaxy S3 is a good phone and I think it’s great value for money when it’s less than $500.

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Syndicated 2012-12-20 14:43:10 from etbe - Russell Coker


I’ve just installed BTRFS on some systems that matter to me. It is still regarded as experimental but Oracle supports it with their kernel so it can’t be too bad – and it’s almost guaranteed that anything other than BTRFS or ZFS will lose data if you run as many systems as I do and I run lots of systems that don’t have enough RAM for ZFS (4G isn’t enough in my tests). So I have to use BTRFS.

BTRFS and Virtual Machines

I’m running BTRFS for the DomUs on a virtual server which has 4G of RAM (and thus can’t run ZFS). The way I have done this is to use ext4 on Linux software RAID-1 for the root filesystem on the Dom0 and use BTRFS for the rest. For BTRFS and virtual machines there seem to be two good options given that I want BTRFS to use it’s own RAID-1 so that it can correct errors from a corrupted disk. One is to use a single BTRFS filesystem with RAID-1 for all the storage and then have each VM use a file on that big BTRFS filesystem for all it’s storage. The other option is to have each virtual machine run BTRFS RAID-1.

I’ve created two LVM Volume Groups (VGs) named diska and diskb, each DomU has a Logical Volume (LV) from each VG and runs BTRFS. So if a disk becomes corrupt the DomU will have to figure out what the problem is and fix it.

for n in $(xm list|cut -f1 -d\ |egrep -v ^Name\|^Domain-0) ; do
  echo $n
  ssh $n "btrfs scrub start -B -d /"

I use the above script in a cron job from the Dom0 to scrub the BTRFS filesystems in the DomUs. I use the -B option so that I will receive email about any errors and so that there won’t be multiple DomUs scrubbing at the same time (which would be really bad for performance).

BTRFS and Workstations

The first workstation installs of BTRFS that I did were similar to installations of Ext3/4 in that I had multiple filesystems on LVM block devices. This caused all the usual problems of filesystem sizes and also significantly hurt performance (sync seems to perform very badly on a BTRFS filesystem and it gets really bad with lots of BTRFS filesystems). BTRFS allows using subvolumes for snapshots and it’s designed to handle large filesystems so there’s no reason to have more than one filesystem IMHO.

It seems to me that the only benefit in using multiple BTRFS filesystems on a system is if you want to use different RAID options. I presume that eventually the BTRFS developers will support different RAID options on a per-subvolume basis (they seem to want to copy all ZFS features). I would like to be able to configure /home to use 3 copies of all data and metadata on a workstation that only has a single disk.

Currently I have some workstations using BTRFS with a BTRFS RAID-1 configuration for /home and a regular non-RAID configuration for everything else. But now it seems that this is a bad idea, I would be better off just using a single copy of all data on workstations (as I did for everything on workstations for the previous 15 years of running Linux desktop systems) and make backups that are frequent enough to not have a great risk.

BTRFS and Servers

One server that I run is primarily used as an NFS server and as a workstation. I have a pair of 3TB SATA disks in a BTRFS RAID-1 configuration mounted as /big and with subvolumes under /big for the various NFS exports. The system also has a 120G Intel SSD for /boot (Ext4) and the root filesystem which is BTRFS and also includes /home. The SSD gives really good read performance which is largely independent of what is done with the disks so booting and workstation use are very fast even when cron jobs are hitting the file server hard.

The system has used a RAID-1 array of 1TB SATA disks for all it’s storage ever since 1TB disks were big. So moving to a single storage device for /home is a decrease in theoretical reliability (in addition to the fact that a SSD might be less reliable than a traditional disk). The next thing that I am going to do is to install cron jobs that backup the root filesystem to something under /big. The server in question isn’t used for anything that requires high uptime, so if the SSD dies entirely and I need to replace it with another boot device then it will be really annoying but it won’t be a great problem.

Snapshot Backups

One of the most important uses of backups is to recover from basic user mistakes such as deleting the wrong file. To deal with this I wrote some scripts to create backups from a cron job. I put the snapshots of a subvolume under a subvolume named “backup“. A common use is to have everything on the root filesystem, /home as a subvolume, /home/backup as another subvolume, and then subvolumes for backups such as /home/backup/2012-12-17, /home/backup/2012-12-17:00:15, and /home/backup/2012-12-17:00:30. I make /home/backup world readable so every user can access their own backups without involving me, of course this means that if they make a mistake related to security then I would have to help them correct it – but I don’t expect my users to deal with security issues, if they accidentally grant inappropriate access to their files then I will be the one to notice and correct it.

Here is a script I name btrfs-make-snapshot which has an optional first parameter “-d” to cause it do just display the btrfs commands it would run and not actually do anything. The second parameter is either “minutes” or “days” depending on whether you want to create a snapshot on a short interval (I use 15 minutes) or a daily snapshot. All other parameters are paths for subvolumes that are to be backed up:

set -e

# usage:
# btrfs-make-snapshot [-d] minutes|days paths
# example:
# btrfs-make-snapshot minutes /home /mail

if [ "$1" == "-d" ]; then
  BTRFS="echo btrfs"

if [ "$1" == "minutes" ]; then
  DATE=$(date +%Y-%m-%d:%H:%M)
  DATE=$(date +%Y-%m-%d)

for n in $* ; do
  $BTRFS subvol snapshot -r $n $n/backup/$DATE

Here is a script I name btrfs-remove-snapshots which removes old snapshots to free space. It has an optional first parameter “-d” to cause it do just display the btrfs commands it would run and not actually do anything. The next parameters are the number of minute based and day based snapshots to keep (I am currently experimenting with 100 100 for /home to keep 15 minute snapshots for 25 hours and daily snapshots for 100 days). After that is a list of filesystems to remove snapshots from. The removal will be from under the backup subvolume of the path in question.

set -e

# usage:
# btrfs-remove-snapshots [-d] MINSNAPS DAYSNAPS paths
# example:
# btrfs-remove-snapshots 100 100 /home /mail

if [ "$1" == "-d" ]; then
  BTRFS="echo btrfs"


for DIR in $* ; do
  BASE=$(echo $DIR | cut -c 2-200)
  for n in $(btrfs subvol list $DIR|grep $BASE/backup/.*:|head -n -$MINSNAPS|sed -e "s/^.* //"); do
    $BTRFS subvol delete /$n
  for n in $(btrfs subvol list $DIR|grep $BASE/backup/|grep -v :|head -n -$MINSNAPS|sed -e "s/^.* //"); do
    $BTRFS subvol delete /$n

A Warning

The Debian/Wheezy kernel (based on the upstream kernel 3.2.32) doesn’t seem to cope well when you run out of space by making snapshots. I have a filesystem that I am still trying to recover after doing that.

I’ve just been buying larger storage devices for systems while migrating them to BTRFS, so I should be able to avoid running out of disk space again until I can upgrade to a kernel that fixes such bugs.

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Syndicated 2012-12-17 00:39:42 from etbe - Russell Coker

Globalisation and Phone Calls

I just watched an interesting TED talk by Pankaj Ghemawat (of which the most important points are summarised in a TED blog post) about the world not being as globalised as people expect [1]. One point is that only 2% of traditional voice phone calling minutes (and ~6% when you include VOIP) are for international calls which is less than most people expect.

After reading that it occurred to me that most of the “included value” in my mobile phone contract goes unused, I pay for extra data transfer and it includes voice calling credit that I don’t use. So out of $450 of included calls I typically use much less than $50. $400 of calls to even the most expensive countries is about 100 minutes of talking. So the logical thing to do is to find people in other countries to call.

If you are involved in the FOSS community and would like to speak to me then send me an email with your phone number, time zone, and a range of times that are convenient. I won’t make any promises about calling you soon (I could use up my monthly credit on a single call), but I will call you eventually.

I will also send email to some people I know by email and suggest a chat. Some years ago I did this with people who were involved in SE Linux development and it seemed to help the development of the SE Linux community.

Also if anyone in Australia wants to speak to me then that’s OK too. While Pankaj’s talk inspired me to call people I’m not dedicated to calling other countries.

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Syndicated 2012-12-14 13:17:08 from etbe - Russell Coker

Dependencies in Online Ordering

I have just ordered two Samsung Galaxy S3 phones and matching cases from Kogan. The price was good and Kogan gave me 30 cents discount as part of a verification process. Instead of billing the full amount for a large order (for which the cutoff is somewhere between $25 and $1014) Kogan will deduct a random number of cents and demand that you confirm the amount of money on your credit card statement, if you don’t know the amount that was billed then it’s a fraudulent transaction.

But now Kogan have decided that my phones and cases are separate things, they have dispatched the cases but not the phones. This is really annoying, I will have to arrange to receive two separate parcels and the first of which won’t be of any immediate use to me. I can use a phone without a case, but a case without a phone isn’t useful.

If I had wanted to receive two parcels then I would have gone through the checkout process twice! It should have been really obvious to Kogan that I didn’t want two parcels, they suggested that I buy cases after I selected the phones, so while it’s theoretically possible that I might want to buy two new phones at the same time as buying two cases for entirely unrelated phones I don’t think that the people who programmed the Kogan web server expected that to be the case.

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Syndicated 2012-12-11 10:45:56 from etbe - Russell Coker

Links December 2012

Steven Johnson gave an interesting TED talk about where good ideas come from [1]. He starts by attributing coffee replacing alcohol as a standard drink for some good ideas and then moves on to how ideas develop.

Erez Lieberman Aiden and Jean-Baptiste Michel gave an interesting and amusing TED talk about the ngram analysis of books that Google scanned [2]. Here is the link for the Google Books ngram search [3].

Clay Shirky gave an insightful TED talk about how the Internet is changing the world [4]. He cites Open Source programmers as the modern day equivalent to the Invisible College based on our supposed great ability to get along with other people on the Internet. If we really are so much better than the rest of the Internet then things must be bad out there. He ends with ways of using Git to draft legislation.

Hans Rosling gave an interesting TED talk about religion and the number of babies that women have [5]. His conclusion is that it’s more about income and social stability and that the world’s population can stabilise at 10 billion if we provide family planning to everyone.

Alexis C. Madrigal wrote an interesting interview with Genevieve Bell about her work at Intel and the way people use technology [6].

Indigogo is raising funds for the “Cuddle Mattress”, it’s a mattress with foam slats and a special fitted sheet to allow your arm to slide between the slats [7]. So you could have your arm underneath your SO for an extended period of time without risking nerve damage. They also show that when sleeping on your side your shoulder can go between the slats to avoid back problems.

Nate Silver (who is famous for predicting US elections gave an interesting TED talk about racism and politics [8]. One of his main points is to show the correlation between racism and lack of contact of members of other races.

Sociological Images has an interesting article by Lisa Wade about whether marriage is a universal human value [9]. In regard to historical marriage she says “women were human property, equivalent to children, slaves, servants, and employees”. The general trend in the comments seems to be that there are so many types of marriage that it’s difficult to make any specific claims to traditional marriage unless you count a tradition of a short period in a single geographic region.

Plurality is an excellent sci-fi short movie on youtube [10].

TED has an interesting interview with Hakeem Oluseyi about his research about astrophysics and how he achieved a successful career after being a gangster as a teenager [11]. He has some good ideas about helping other children from disadvantaged environments become successful.

Paul Dwerryhouse wrote an interesting blog post about his work in designing and implementing a filesystem based on a Cassandra data store with FUSE [12]. Paul also wrote a post about using Apache Zookeeper to lock metadata to permit atomic operations [13].

The documentary “Monumental Myths” provides an interesting and insightful analysis of the processes of creating, maintaining, and explaining monuments [14]. It focusses on some significant monuments in the US and explains both sides to each story. Howard Zinn makes the insightful point that “when people present a certain point of view of history it’s not controversial, as soon as you present the other side they call it controversial“. That happens even in debates about current issues. Howard also says “to criticise whatever the government does is not anti-America, it’s anti-government, it’s pro-America, it’s pro the people, it’s pro the country“. The song that plays during the closing credits is interesting too.

The music video “Same Love” is one of the best presentations of the argument for marriage equality [15].

Chris Samuel wrote an interesting post about systems locked down for Windows 8 and options for purchasing PCs for running Linux [16]. His solution is to buy from ZaReason. I saw his laptop in action at the last LUV meeting and it looks really nice. Unfortunately a byproduct of the extremely thin form factor is the fact that it lacks a VGA port, this meant that Chris had to use my Thinkpad T61 (which is rather clunky by comparison) for his presentation.

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Syndicated 2012-12-11 06:10:29 from etbe - Russell Coker

Returning the Aldi Tablet

I have decided to return the 7″ Android tablet I bought from Aldi last week [1]. I still think that the tablet isn’t all bad, but the main problem I had is the short battery life. The battery can be entirely exhausted in less than an hour’s use. Another problem is the fact that most of the Angry Birds games just abort on startup, as my plans for the tablet involved some recreational use this is a significant problem.

The final factor that made me decide to return it is the fact that Kogan offered a special deal on a Samsung Galaxy S3 [2] for $449. That ended up as $507 per phone for two phones that have PowerCases (which more than double the battery life as well as protecting the phone from being dropped). So a Galaxy S3 increments my Android device count and with a 4.8″ 720*1280 display will compete well with a low-end 7″ tablet that only has a 800*480 display (the Galaxy S3 has 2.4* as many pixels).

Aldi offers 60 days money back, so I’ll return the tablet when my Galaxy S3 arrives.

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Syndicated 2012-12-10 05:45:41 from etbe - Russell Coker

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