Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).


Comment: PHP vs other languages, and number of frameworks (Score 1) 227

by Cato (#45277623) Attached to: Ask Slashdot: How Do You Choose Frameworks That Will Survive?

Good points about other languages such as Python, Ruby and Groovy - none of those languages is as popular as PHP, but they are harder to get started with than PHP, and perhaps as a result are generally chosen by more experienced programmers.

These smaller communities of more experienced programmers do seem more likely to create and choose a dominant framework - while Django is not the only Python framework, it is by far the most popular, with the most addon modules.

PHP isn't a completely bad language, but it does have a lot of problems that drive many experienced programmers to other languages. And the sheer number of frameworks in PHP is a huge problem.

Generally a strong framework without a single commercial backer is best - a strong core team of developers is more resilient to future decisions and competition than a single company whose strategy decisions can alter the future of a framework.

Comment: Re:Copper? (Score 5, Informative) 347

by Cato (#43893683) Attached to: Ask Slashdot: What Is the Future of Old Copper Pair Technology?

There's already terminology for this, though not 'single word'

- long = high latency
- fat = high throughput

So a satellite connection would be a 'long thin pipe' usually, while a VDSL2 or fibre connection would be 'short fat'.

See for background - as you probably know, the product of bandwidth (throughput) and delay is also the amount of data buffered in the connection.

Comment: Re:non-Oracle ZFS FTW (Score 1) 113

by Cato (#42420323) Attached to: Strong Foundations: FreeBSD, Wikimedia Raise Buckets of Development Money

For Mac, try the free Zevo ZFS from Greenbytes:

For Windows, if you are willing to use NTFS on an iSCSI volume hosted on ZFS by a FreeBSD NAS, you could still benefit from the checksumming provided by ZFS. See the comments by 3dinfluence here:

Or you could run a ZFS NAS in a FreeBSD VM on Windows, of course, and use it via SMB from Windows.

Comment: Re:Sample size too small? (Score 2, Informative) 192

by Cato (#41145715) Attached to: Exposure to Backlit Displays Reduces Melatonin Production

Yes, this is really junk science, but I believe there are other studies that show similar results - see for a list, including links to the full papers (the site is for F.Lux which I really recommend to adjust colour temperature to get more sleep, for Windows, Mac and Linux, and jailbroken iOS).

Comment: Re:Pretty Obvious + Plug for Awesomeness (Score 2) 192

by Cato (#41145709) Attached to: Exposure to Backlit Displays Reduces Melatonin Production

F.lux is great, works on Windows, Mac and (jailbroken) iOS. One of the downsides of iOS devices as e-readers is that you have to jailbreak to get f.lux installed and not change your sleep cycle.

There's also XFlux, but I use Redshift too on Linux -

[[ Now on iOS]] for jailbroken devices - see [[iPhone]] for jailbreaking.


Blue light in morning resets circadian cycle:

Tie-in to SAD and phase advance or delay associated with depression:

Comment: Re:Crashplan vs. rsnapshot (Score 1) 326

by Cato (#40955187) Attached to: Ask Slashdot: Best On-Site Backup Plan?

I have tried CrashPlan a couple of times on Windows and Linux, and had to give up. It would either fail to connect, or make very slow progress. It's not my broadband, since Mozy (Windows and Mac only) is fine. I also found that on Linux it would really hammer the system when backing up (4GB dual-core system) so it was barely usable.

Possibly CrashPlan's cloud service is the problem, but I'm not very impressed with the software.

For Linux and Mac backups, it's worth using something like rsnapshot, which is rsync-based and works very well to back up over 1 TB of data. It doesn't do block-level incremental backup, and it makes complete copies of files (rsync plus hard links) but it works incredibly well without writing shell scripts. It can do hourly, daily, weekly, monthly and yearly backups, and has automatic retention i.e. purges the oldest backups in a predictable way (say after 6 months or 5 years).

rsnapshot works well for Linux and (I believe) for Mac, as long as you don't need fully bootable backups, and it should work really well for photos as 99% of them won't change after being created.

rsnapshot is very similar in concept to Time Machine on Mac, but without the nice GUI (in fact, without any GUI). Your files end up in a big file tree and can be restored with any file-copy tool.

Comment: Re:Correction (Score 1) 691

by Cato (#39387485) Attached to: UK Plan Would Use CCTV To Stop Uninsured Drivers From Refueling

"Our motorways have cameras over every lane which track the numberplate"

Not quite true - not all motorways have these gantries with cameras over every lane, but it's true that automatic number plate recognition cameras are located alongside every motorway at least, and on major roads, in town centres, etc, and this feeds into a national database to enable the police to track any car for whatever reason (not just uninsured/banned drivers or car theft - in a few cases, demonstrators have been tracked via this system and stopped). See my other post:

These gantries do often have speed cameras as well, and in some cases there are average speed cameras.

Comment: CCTV mission creep in the UK, and ANPR (Score 1) 691

by Cato (#39387461) Attached to: UK Plan Would Use CCTV To Stop Uninsured Drivers From Refueling

Many petrol (gas) stations in the UK already have these CCTV cameras to catch people driving off without paying.

The interesting part about this story is the mission creep and data unification - once the CCTVs are in place for company reasons, the government creates another application of the data for its own reasons. Not a new story - once the data exists somewhere, the drive to get access to it is much stronger.

This all helps to turn the UK into probably the most surveilled country in the world... see for stats from 2009.

This petrol station initiative is probably tying into the nationwide UK network of automatic number plate recognition (ANPR) cameras in town centrese and virtually all major roads (not just motorways/freeways, but every "A road" too). Usually painted blue and on high poles, these capture and OCR the license plate of every vehicle that goes past. This feeds into a centralised data centre for queries, data mining, and real time alerts, for both criminal and terrorist investigations:

Comment: Re:Already won: Khan Academy (Score 1) 479

by Cato (#39326823) Attached to: X-Prize Founder Wants Ideas For Fixing Education

Khan academy is an excellent resource once kids want to learn and with some guidance from a mentor.

Sugata Mitra's self-organising learning environments are perhaps more general as they can be applied to any topic, and in fact they don't need an expert to provide the courseware or videos. Somewhat bizarrely, he just sets up small groups of children, provides an Internet connected PC per group, asks them a big question (e.g. who was Pythagoras and how did he advance geometry?) and lets them get on with researching it for 45 minutes.

See my other comment here for links and background:

Comment: Self-organising learning environments (Score 1) 479

by Cato (#39326653) Attached to: X-Prize Founder Wants Ideas For Fixing Education

Sugata Mitra has been doing practical research for 10 years that involves children learning in groups of 4 or 5 through being asked a big question such as "can trees think?", "how does a GPS work exactly", etc, then being given time with a shared computer and broadband connection to answer the question, before having to explain it to a teacher. This is called a self-organising learning environment or SOLE, and appears to work for almost any subject for children up to age 10 or so.

He started with the well-known "Hole in the Wall" experiment where he placed a computer in the wall of a building on the street, and watched what happened - the children taught themselves English as well as how to use the computer. Later experiments involved leaving a PC with English biotechnology materials in a remote village with kids who only spoke Tamil, and telling them to get on with it. Remarkably, they actually learnt a significant amount of biotech.

See - his ideas on "the granny cloud" show how this could scale enormously using Skype etc to have older mentors encourage the children, and perhaps ask or help in creating the big questions that will drive the childrens' learning.

I really hope he gets a chunk of the prize - he is a true innovator and his technique can be applied both inside and outside schools, from developing to developed world. has references - see his TED talk, he's a very engaging speaker.

Comment: Linux Mint (Score 1) 319

by Cato (#39229755) Attached to: Ask Slashdot: What Is the Best Distro For Linux Lessons?

First of all, standardise on a single distro so that the 99% of people who aren't Linux gurus can at least share solutions to problems. It's quite common to have hardware that doesn't work in some way, e.g printers, sound or graphics cards (3D performance), and it will be disastrous if everyone has different distros.

Secondly, I'd recommend Linux Mint - either the Ubuntu or Debian based version. It has a lot of simple but helpful changes for new users of Linux, but the Ubuntu/Debian base means an enormous amount of software is available. I wouldn't recommend Ubuntu these days, as it has too many regressions from release to release, and things that just don't work (had to abandon an Ubuntu 10.04 LTS installation as it froze every day or two for months, probably due to Intel drivers.)

The switch to kernel mode setting (KMS) for graphics cards in the last few distro versions is critical - in some cases this has really reduced reliability a lot, so I'd recommend you research this a lot... I ended up using an old ATI 9250 graphics card to be sure that Ubuntu (or Mint-based Ubuntu) worked properly - however doing this for a whole company would be painful. This is important given the popularity of Intel GPUs on business PCs and the crapness of Intel drivers post-KMS, but perhaps some research will show this is a non-issue with the latest kernels and X11.

The switch of most distros to GNOME 3 and/or Unity is also a big problem - these desktop UIs are very immature and simply don't work well for the sort of desktop usage many people are used to. Unity in particular is a research project that should have been left to mature for 5 years, not pushed into a long term support release - this is why a big chunk of Ubuntu users are switching to Mint or other distros.

Mint has a sane strategy for GNOME 3 which involves recreating the GNOME 2 UI on a GNOME 3 base (Cinnamon project, aka MGSE), as well as letting your retain GNOME 2 if you want (MATE, not yet mature). Most importantly, Mint as a project listens to its users a great deal, so it is less likely to take decisions that screw up the user experience (e.g. Unity.)

Thrashing is just virtual crashing.