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Newsletter 2 (22nd September 2014)

Computing Pool Newsletter 2

Note: You can view a print copy of this newsletter at http://www.pool.phy.cam.ac.uk/newsletters/02.pdf.

Welcome to this second edition of the Computing Pool’s newsletter. We aim to inform you about what we’ve been working on and our future plans, along with providing hints and tips to help your computing go more smoothly.

— Dr Andrew Alderwick (editor)

Updates

Pool Management

by Dr Crispin Barnes

The previous newsletter has turned out to be a great success and has encouraged many of you to engage with us on the improvement of IT provision. Following these discussions, Pool team members have attended some research group technical meetings where IT has been an issue in the past, and this has led to further valuable exchanges of feedback both from the research groups and from the Pool. If your research group holds technical meetings and the presence of Pool staff would be useful then please contact us. We are also happy to give brief group talks, particularly if this helps introduce new students to IT in the lab at the beginning of the new academic year.

The surgery hours announced in the previous newsletter have proved popular. Please do feel free to drop in and ask about IT matters any day between 1400 and 1500.

Finally, I’d like to congratulate the pool team on their recent response times. One request was even dealt with before I could make it from my office to the pool office to ask what we could do about it.

New Pool GNU/Linux Version

by Dr Andrew Alderwick

Pool GNU/Linux is a custom version of Ubuntu installed on around 35 computers in SP since 2010, and continues the tradition of Ubuntu-based installs from SP’s computing staff. It badly needs an update, and next Thursday, the 25th of September, the Computing Pool will be proud to release the next version of Pool GNU/Linux. The renewed security support of this new version is important, but not necessarily that exciting. More things to come include:

  • improved reliability, being based on Debian GNU/Linux instead of Ubuntu Linux;
  • a move to the freshly-released MATE desktop environment, featured later on in this newsletter;
  • remote desktop functionality courtesy of x2go, so you can use Pool GNU/Linux computers in other parts of the lab, or from home; and
  • new versions of popular proprietary software suites MATLAB and Mathematica.

Those familiar with Debian will know that their main repositories feature only Free Software, according to their guidelines at http://www.debian.org/social_contract, so we will provide our own repository for MATLAB and Mathematica. During October, we’ll be delighted to update SMF’s Linux workstations with the new Pool GNU/Linux.

In time, we aim to provide installations on any lab-owned or personal computers for research groups subscribing to the Computing Pool. There is a wide range of flexibility required on all these installations; for a personal machine we don’t have any right to restrict what you are able to do on it, while a collection of workstations owned by a research group would be expected to behave consistently. My configuration system provides that flexibility, along with a range of useful tweaks and settings. While you can certainly install your own Debian, Ubuntu, Fedora etc., our goal is that you’ll get working more quickly, on a more reliable and stable platform, with Pool GNU/Linux.

AutoCAD on the Terminal Servers

by Cormac O’Connell

The license for the install of AutoCAD on the Terminal Servers run by the Pool for members in SP has expired. With most bits of software, it is a simple task to redo or update the license and away everything goes. This has turned out to be everything but the case with this package on these machines.

Following recommendations from AutoDesk’s own pages, I started trying to uninstall them from the servers to give a clean install and new license. Simple no? No. This also went wrong at the first hurdle, and I’ve ended up having to remove the entire thing by hand.

If you’ve ever seen the inside of the Windows Registry, you will know that it is a place to tread lightly and that most of it is a pile of garbage looking entries like “{F78DCF7C-043D-45FC-9D21-676FC307BA3F}” rather than something vaguely helpful.

So, as you can probably guess it has been a rather slow and headache-inducing job so far and I still haven’t been able to get it to the point of getting the software back on again.

So, this would lead on to what? Well, firstly an apology. Not many people have been pestering me about this so far (which I appreciate, thank you for your patience!), but I am aware that this service is something that a number of you rely on. So I do apologise for the inordinately long downtime for this piece of software. Secondly, I am looking at a better solution for this software, and also a newer version of the Terminal Servers. When I commissioned them a while ago, there were issues that some pieces of software would not run on the latest operating system from Microsoft (this is why we are running on 2003 Server at the moment). It is hoped that they fixed the issues preventing us from running AutoCAD on 2008 Server as we don’t particularly want to run unsupported operating systems.

Hopefully one or other solution will get us (you) back in business. And soon!

File Space

by Dr Andrew Alderwick

Storing files on the Pool servers instead of workstations or laptops protects your data from loss in all sorts of situations, but the lengths we go to keep your data safe makes our storage more expensive than what you may be used to at home. Right now, you can buy a 3TB desktop hard drive from PC World for £70, and of course, if that hard drive fails with your only copy of your experimental data or your thesis on it, you are stuck.

On the Pool servers,

  • we use proper enterprise-grade hard drives, which are more reliable and perform better than desktop-grade drives;
  • we arrange groups of these drives to carry redundant information, so that any single drive can fail without losing unique data;
  • we then duplicate whole servers between two physical locations, so a fire that destroys one building won’t affect the complete copy of data in another; and
  • we take regular tape backups and hold them offsite.

With all this extra protection, it’s no surprise that storage per byte is much more expensive than the single PC World desktop drive. It’s therefore important that we keep the storage of unnecessary data to a minimum on the servers. Experimental data, theses, papers, anything academically related is an obvious yes, while several copies of the install DVDs for software like MATLAB and Mathematica is much less desirable.

At the end of the academic year, Colin has identified where files have been duplicated on the Windows servers in NOM and have sent group members a detailed report of these duplicates as well as their general file usage. After archiving some files to appropriate areas, elimination of the duplicates and with the careful attention of group members to their own files, we were able to recover almost 1TB of storage. This saving is significant compared to the total space we have on the servers, and it pushes back the day when we’ll need to make another large investment on the next set of hard drive arrays for NOM, so you have our heartfelt thanks for your time on this task.

We’d also like to give thanks to Colin Edwards for suggesting this article’s topic and providing information.

Owncloud: a Dropbox Alternative

by Cormac O’Connell

Alongside the Microsoft Windows and GNU/Linux servers run by the Pool, we are aware that some group members make use of Dropbox and other similar cloud-based file storage. These services do have benefits over the Pool servers in terms of accessibility: they often provide apps for tablets and phones for you to access the same data that you manipulate using your laptop or desktop machine.

Storing your data in the cloud provides several challenges, mainly due to the fact that data is being stored outside the University: see the table for a quick summary. It’s clear that being able to keep files within the University but also having the same convenience as Dropbox and friends presents the best of both worlds.

To that end, Colin has installed ownCloud on one of NOM’s test servers. The ownCloud software provides clients to access data via a web browser, on tablets, phones and more, and has been favourably reviewed by The Register at http://bit.ly/1rTAOvM. We are considering whether this might be something we can offer, even in a limited way, to our groups.

Colin has also found that we can use our existing user database to authenticate users of such a service, which eliminates the need to create additional usernames and passwords.

Interested? We would welcome some feedback.

Challenges posed by storing files online
Vulnerability to attack Popular file sharing services are regularly attacked by criminals, either to disrupt regular service or steal data. Naturally, the University is also under regular attack, but because University systems are highly heterogenous any breaches are limited in scope. [http://cnet.co/XSndrF]
Third party T&Cs University IT personnel have a duty of care to ensure the security and privacy of your data. File sharing services can change their Terms and Conditions at any time, allowing themselves to get out of trouble. [http://bit.ly/1phjyyK]
Data ownership Many services allocate ownership of data to themselves in order to avoid inconvenient parts of copyright law from affecting their operations.
Data Protection Act Transmitting other people’s personal data outside the University can become a legal minefield, especially if that data leaves the UK. [http://bit.ly/1tV6Owg]

MG4 Refurbishment

by Dr Andrew Alderwick

MG4, the server rack just outside the Pool office, has been given a new purpose. When the Computing Pool was created, several groups’ primary file servers were in this rack, and over time it gained other servers and our tape drive as well. MG4 has a big problem, however; its problem is dust. Huge amounts of it. We’ve had years of server chassis caked with dust, and more on the internal components. Even the tapes inside the tape drive were covered with it.

Things changed for the better when a new server room in the Rutherford building, R11, became available. The new location is a perfect example of server rooms done well, with air conditioning, plenty of power and network connectivity, so naturally we jumped at the chance to move anything we cared about from MG4 to R11.

But where does this leave MG4? As grotty as it is, it does have some charms. It has plenty of network connections and power, thanks to a recent refurbish by Maintenance. It has a KVM switch linked to the one in the Pool office so we can control the computers held within. And it has the quick overview display of how the Pool servers and networks are doing, provided by our extensive monitoring system. The final piece of the puzzle is the fact that computers that aren’t intended to spend a long time in there will do fine.

While on a quick tour of the SP offices, I spotted two Linux workstations that weren’t plugged in. Both weren’t booting, and neither had been reported to the Pool as being broken. There is demand for working Linux workstations in SP, so I’ve taken them (along with a testing workstation and one with a hardware fault) and placed them in MG4. The rack now contains the four workstations and I’ll be using them for testing the builds of the new Pool GNU/Linux. Once they’re ready, they can be released to SP and TFM members and there’ll be extra space in MG4 for the next group of broken machines.

What on Earth?

MATE

by Dr Andrew Alderwick

Here we introduce MATE, the desktop environment that will be used in the upcoming release of Pool GNU/Linux. This release is designed to replace SP’s and SMF’s Linux desktops, but any research group is eligible to use Pool GNU/Linux.

What is a desktop environment? This question has become a lot easier to answer now that we have the likes of Android and Windows 8. It’s what you see when you log in and shapes how you go about your work. When you launch applications, resize windows and move them about, see icons in a tray for connecting to wireless networks and so on, the desktop environment determines how you actually do these things.

Is that all? Not quite—certainly on GNU/Linux, the desktop environment also comes with a suite of basic applications, such as text editors, document viewers and file managers.

Okay. So what is MATE? Back in 2010, Pool GNU/Linux shipped with GNOME 2 as its main desktop environment. When the GNOME Project released GNOME 3 it completely threw away the look and feel of GNOME 2 and aimed to provide a single interface for desktop computers, tablets and smartphones. The MATE (pronounced ma-tay) project took the code that made up GNOME 2 and continues to maintain and improve it.

Why not just use GNOME 3? It’s not simply a case of “just using the next version”. GNOME 3 is so different to GNOME 2 that it’s not a stretch to say that the only thing they still share is the name. When choosing a desktop environment, there are many popular options such as KDE, XFCE and LXDE as well as GNOME 3 and MATE, and without a simple continuity from GNOME 2 to GNOME 3, there’s no automatic election of GNOME 3 for Pool GNU/Linux.

So why choose MATE? In SP, Pool GNU/Linux users still use GNOME 2, so moving to MATE allows them to keep a familiar environment. While change is exciting in a new mobile phone or tablet, these computers are used for serious productivity and forcing users to interact with a new interface when they’re in the middle of writing their thesis is no good for anyone. MATE is also much snappier than heavyweight desktops like KDE and GNOME 3. It’s difficult to justify attractive interfaces when it takes ages for older computers to catch up with what you’re doing. Finally, the next version of Pool GNU/Linux will feature remote desktop functionality as standard, and MATE’s lack of reliance on a 3D graphics card makes it play very nicely with the remote desktop software we’re using.

Any downsides? Unfortunately, yes. The names of applications we’re used to with GNOME 2 still largely live on in GNOME 3, and so the MATE developers have renamed them to avoid conflicts. I’ve listed the old and new names in the table below.

Old and new program names
Program GNOME 2 name Icon MATE name
File manager Nautilus caja Caja
Text editor Gedit pluma Pluma
Image viewer Eye of GNOME eom Eye of MATE
Document viewer Evince atril Atril
Archive manager File Roller engrampa Engrampa
Terminal emulator GNOME Terminal terminal MATE Terminal

“Pluma”? “Engrampa”?!? Are you serious? I guess it’s worth pointing out that a lot of the former names didn’t make an awful lot of sense, either, but we got used to it. It’s better to have a silly name like Caja than to have something completely ambiguous, such as Files in GNOME 3. At least the icons should be familiar.

Can we choose another desktop environment? Actually, that’s something we’re removing! The old Pool GNU/Linux allows you to choose the desktop environment on login. KDE, GNOME 2 and XFCE are fully supported. But while the choice is nice, it crowds the application menus with reams of duplicate applications to do the same things.

For example, in the world of text editors you are meant to use KEdit or Kate on KDE, Gedit on GNOME 2 and Mousepad on XFCE, but you currently have the choice of all four no matter what desktop environment you’re in. Multiply that by several different types of applications and it’s a right mess. So in the next Pool GNU/Linux version you’ll only have the MATE suite to play with.

But I use, say, KDE. Can’t I keep it? Yes. If you have a strong preference for any desktop environment, our software management is flexible enough to let us get it installed for you. Just let us know. It’s still a far cry from having everything present from day one!

One last thing: when will the next Pool GNU/Linux be released? It will be released on Thursday, September the 25th, in time for the next academic year.

About the Pool

We’re responsible for meeting the computing needs of the following research groups:

  • Atomic, Mesoscopic & Optical Physics;
  • Microelectronics;
  • NanoPhotonics;
  • Optoelectronics;
  • Quantum Matter;
  • Structure and Dynamics;
  • Surfaces, Microstructure & Fracture;
  • Semiconductor Physics and
  • Thin Film Magnetism

plus limited support for Hitachi and TCM.

Contact

If you’d like any computing assistance, there are two main ways to receive our help:

This email address contacts all of us simultaneously, so we can quickly get the right person on the task for you. We have a mix of expertise and cover for each other during busy times or leave, so using this address rather than the address of the CO who helped you last time is best.

The surgery hours are a new addition to our support. Please feel free to visit the Pool office between 1400 and 1500 every workday if you prefer to get help face-to-face. The Pool office is on the ground floor of the Mott building, room 328a.

If, instead, you’d like to contact the Pool on more general matters, our manager, Dr Crispin Barnes, will be delighted to hear from you. His email address is chwb101@cam.ac.uk, and will reply directly to you.

Feedback

Finally, we’d be really pleased to receive feedback on this very newsletter. If you have any comments, or would like to see coverage of a particular topic in a future newsletter, please let us know at the usual support@pool.phy.cam.ac.uk email address.