Older blog entries for etbe (starting at number 1030)

Links January 2013

AreWomenHuman has an interesting article about ViolentAcrez and the wide support for trolling (including by media corporations) [1].

Chrys Stevenson wrote an important article for the ABC about the fundamentalist Christians who are trying to take over the Australian education system [2].

Tavi Gevinson gave an interesting TED talk titled “A teen just trying to figure it out” about her work starting Rookie magazine and her ideas about feminism [3].

Burt Rutan gave an interesting and inspiring TED talk about the future of space expploration [4]. One of his interesting points is that “fun really is defendable” in regard to tourism paying for the development of other space industries.

Stephen Petranek gave an interesting TED talk about how to prepare for some disasters that could kill a significant portion of the world’s population [5]. Some of these are risks of human extinction, we really need to spend some money on it.

John Wilbanks gave an intresting TED talk about the way that current informed consent laws prevent large-scale medical research [6]. He says “I live in a web world where when you share things beautiful stuff happens, not bad stuff“.

Joey Hess was interviewed for The Setup and the interview sparked a very interesting Hacker News discussion about workflow for software development [7]. Like most developers I prefer large screens with high resolution, I have an EeePC 701 which works reasonably well for an ultra-portable system but I largely don’t use it now I have an Android phone (extremely portable and totally awful input usually beats moderately portable and mostly awful input for me). But Joey’s methods are interesting and it seems that for some people different systems give the best result.

Jeff Masters gave an insightful TED talk about the weather disasters that may seriously impact the US in the next 30 years [8]. Governments really need to start preparing for such things, some of them are really cheap to mitigate if work is started early.

Bryan Stevenson gave an inspiring TED talk about the lack of justice in the US justice system [9].

Wouter Verhelst wrote an insightful article about some of the criticisms of Linux from Windows users [10]. He references a slightly satirical post he previously wrote about why Windows isn’t ready for desktop use.

Paul Carr wrote an interesting article comparing “disruptive” business practices of dot-com companies to the more extreme aspects of Ayn Rand’s doctrine [11]. In reading some of the links from that article I discovered that Ayn Rand was even more of a sociopath than I had previously realised.

Lindy West gave an amazing Back Fence PDX talk about dealing with nasty blog comments from the PUA/MRA communities [12]. After investigating them she just feels sorry for the trolls who’s lives suck.

Hang from the Vlogbrothers explains gender, sex, sexual orientation, etc [13].

Rick Falkvinge wrote an interesting article about recent political news from Brazil, they had a proposed law that was very positive for liberty on the Internet but it was sabotaged by the media and telcos [14]. We should try to avoid paying any money to the media industry so that they can go away sooner.

Amy Cuddy gave an interesting TED talk about body language, power, and the imposter syndrome [15].

Caleb Chung gave an interesting TED talk about toy design which focussed on Pleo a robotic dinosaur with a SD card and USB socket to allow easy reprogramming by the user [16].

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Syndicated 2013-01-04 11:47:41 from etbe - Russell Coker

Modern Swap Use

A while ago I wrote a blog post debunking the idea that swap should be twice as large as RAM [1]. The issue of swap size has come up for discussion in a mailing list so it seems that it’s worth another blog post.

Swap Size

In my previous post I suggested making swap space equal to RAM size for systems with less than 1G of RAM and half RAM size for systems with 2-4G of RAM with a maximum of 2G for any system. Generally it’s better to have the kernel Oom handler kill a memory hungry process than to have the entire system go so slow that a hardware reset is needed. I wrote memlockd to lock the important system programs and the shared objects and data files they use into RAM to make it easier to recover from some bad paging situations [2], but even that won’t always make it possible to login to a thrashing system in a reasonable amount of time.

But it’s not always good to reduce swap size. Sometimes if you don’t have enough swap then performance sucks in situations where it would be OK if there was more swap. One factor in this regard is that pages mapped read-only from files are discarded when there is great memory pressure and no swap space to page-out the read-write pages. This can mean that you get thrashing among memory for executables and shared objects while there’s lots of unused data pages in RAM that can’t be paged out. One noteworthy corner case in this regard is Chromium which seems to take a lot of RAM if you have many tabs open for a long time.

Another factor is that there is a reasonable amount of memory allocated which will almost never get used (EG all the X based workstations which have 6 gettys running on virtual consoles which will almost never be used). So a system which has a large amount of RAM relative to it’s use (EG a single-user workstation with 8G of RAM) can still benefit from having a small amount of swap to allow larger caches. One workstation I run has 8G of RAM for a single user and typically has about 200M of the 1G swap space in use. It doesn’t have enough swap to make much difference if really memory hungry programs are run, but having 4G of memory for cache instead of 3.8G might make a difference to system performance. So even systems which can run without using any swap can still be expected to give better performance if there is some swap space for programs that are very inactive.

I have some systems with as much 4G of swap, but they are for corner cases where swap is allocated but there isn’t a lot of paging going on. For example I have a workstation with 3G of RAM and 4G of swap for the benefit of Chromium.

Hardware Developments

Disk IO performance hasn’t increased much when compared to increases in RAM size over the last ~15 years. A low-end 1988 era hard drive could sustain 512KB/s contiguous transfer rates and had random access times of about 28ms. A modern SATA disk will have contiguous transfer rates getting close to 200MB/s and random access times less than 4ms. So we are looking at about 400* the contiguous performance and about 10* the random access since 1988. In 1988 2MB was a lot of RAM for a PC, now no-one would buy a new PC with less than 4G – so we are looking at something like 2000* the RAM size in the same period.

When comparing with 1993 (when I first ran a Linux server 24*7) it was 4M of RAM, maybe 15ms random access, and maybe 1MB/s contiguous IO – approximately double everything I had in 1988. But I’ll use the numbers from 1988 because I’m more certain of them even though I never ran an OS capable of proper memory management on the 1988 PC.

In the most unrealistically ideal situation paging IO will be a factor of 5* more expensive now relatively than it was in 1988 (RAM size increase by a factor of 2000 divided by contiguous IO performance increase by a factor of 400). But in a more realistic situation (random IO) it will be 200* more expensive relatively than it was. In the early 90s a Linux system with swap use equal or greater than RAM could perform well (my recollection is that a system with 4M of RAM and 4M of active swap performed well and the same system with 8M of active swap was usable). But nowadays there’s no chance of a system that has 4G of RAM and 4G of swap in active use being usable in any way unless you have some corner case of an application allocating RAM and not using it much.

Note that 4G of RAM doesn’t make a big system by today’s standards, so it might be reasonable to compare 2M in 1988 to 8G or 16G today. But I think that assuming 4G of RAM for the purpose of comparison makes my point.

Using Lots of Swap

It is probably possible to have some background Chromium tabs using 4G of paged out RAM with good system performance. I’ve had a system use 2G of swap for Chromium and perform well overall. There are surely many other ways that a user can launch processes that use a lot of memory and not use them actively. But this will probably require that the user know how the system works and alter their usage patterns. If you have a lot of swap in use and one application starts to run slowly you really don’t want to flip to another application which would only make things worse.

If you use tmpfs for /tmp then you need enough swap to store everything that is written to /tmp. There is no real upper limit to how much data that could be apart from the fact that applications and users generally don’t want to write big data files that disappear on reboot. I generally only use a tmpfs for /tmp on servers. Programs that run on servers tend not to store a large amount of data in /tmp and that data is usually very temporary, unlike workstation users who store large video files in /tmp and leave them there until the next reboot.

Are there any other common corner cases that allow using a lot of swap space without serious performance problems?

My Swap Space Allocation

When I setup Linux workstations for other people I generally use 1G of swap. For a system that often has multiple users (via the user-switch feature) I use 2G of swap if it only has 3G of RAM (I run many systems which are limited to 3G of RAM by their chipset).

For systems that I personally use I generally allocate 4G of swap, this is to cater to excessive RAM use by Chromium and also because I test out random memory hungry programs and can’t easily predict how much swap space will be needed – a typical end-user desktop system is a lot more predictable than a workstation used for software development.

For servers I generally allocate 512M of swap space. That’s enough to page out things that aren’t used and make space for cache memory. If that turns out to be inadequate then it’s probably best to just let the watchdog daemon reboot the system.

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Syndicated 2012-12-31 00:07:47 from etbe - Russell Coker

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

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