Rob – Page 92 – Rob Pomeroy

29 January 2014

Review: Giotto’s Rocket-air Super Blower AA 1900

Anyone who’s pulled a computer apart will know how much dust, crud and miniature wildlife can take up residence within your machine’s delicate circuitry. This build-up is bad for your computer. In particular, it makes fans and heat sinks less efficient and causes everything to warm up.

At best, this is a nuisance. Many power-regulating computers will simply slow down to allow the system to cool off. At worst, though, the excess heat in a power supply for example can set your computer – and your house or office – on fire. Clearly this is not A Good Thing.

Periodically then, it’s a good idea to take an “air duster” to your computer’s innards. Air dusters usually consist of cans of compressed air, with a straw-like nozzle to direct the air flow. They’re designed to create enough pressure to remove dirt but not so much as to cause damage.

Where I work, we used to get through a ton of these cans of air. The problem was, just when you really needed the air duster, you’d look on the shelf and there’d just be an empty can. Harrumph. How inconsiderate.

Giotto’s Rocket-air Super Blower AA 1900

So looking around for a better solution to the problem, I came across this fellow, the “Rocket-air Super Blower” by the Chinese/Taiwanese Company, Giotto’s Industrial Inc. (Beware of the annoying noisy Flash animation that plays whenever you visit the site.)

The Rocket-air has a thick flexible rubber body and a solid plastic nozzle. Squeeze firmly and you get a blast of air not dissimilar to that from a can of compressed air. It’s not hard work to operate and of course the best part is that you have an unlimited supply of air at your disposal (at least until some thieving, envious toe-rag runs off with it).

It’s theoretically available in a few different colours. I’ve only seen it in the UK in the red/black regalia, not that it matters: I didn’t buy it for its looks. Mind you, as looks go, it’s a fairly funky tool and was surprisingly quite a conversation piece when it first arrived.

Speaking of design, you have to love the attention to detail here. Giotto’s makes camera equipment, so the Rocket-air’s primary function is to blow dust from delicate camera lenses (the fact that we can bend it to other uses is a big bonus). On the opposite side to the nozzle, there’s a fast air inlet valve. This means that when you release the blower, rather than sucking dust back in through its nozzle, it pulls in (hopefully) clean air from the other side.

Oh, and the “rocket fins” on the base of the blower enable it to stand up stably. Not massively important, just a nice bit of design. On two of these fins there are holes punched so that you can thread a lanyard through. Great for hanging it from your neck should you be so inclined. People will give you funny looks though.

So it’s well made, durable, moderately attractive, great at its job – there’s got to be a catch, right? The price. Amazon has it on sale for £8.99 at the moment. I don’t know about you, but my first thought was, “That’s a bit expensive for a glorified executive stress toy.” But then if you think about it, you can’t really buy a can of compressed air for less than £3 or £4. So the Rocket-air pays for itself pretty quickly – I would expect it to last as long as a hundred cans of compressed air. When you put it that way, it’s a bit of a bargain.

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[easyreview title=”Geek rating” icon=”geek” cat1title=”Ease of use” cat1detail=”Short of poking it in your own eye, I’m not sure you can get this wrong.” cat1rating=”5″ cat2title=”Features” cat2detail=”Does everything you expect of it. I suspect it could be made slightly more powerful, but otherwise, there’s little to criticise.” cat2rating=”4.5″ cat3title=”Value for money” cat3detail=”When you compare it with the alternatives, it’s pretty near the cheapest solution to our dusty problems.” cat3rating=”4.5″ cat4title=”Build Quality” cat4detail=”Great attention to detail. Some slightly annoying slivers of rubber haven’t quite been removed after it came out of its mould. But otherwise, really well made. Feels like it will last forever – or at least until I retire (which is much the same thing).” cat4rating=”4.5″ summary=”Great solution to the problem of safely cleaning dust and dirt out of computers and fans. As a bonus, you can use it on your camera too. Can’t really recommend it any more highly.”]

28 January 2014

16GB Class 10 MicroSD card head-to-head shootout: SanDisk vs Kingston vs Transcend vs Samsung vs Toshiba

There’s a lot of information and misinformation concerning SD technology, on the Internet. I’ve read a few conflicting theories about how many different companies actually manufacture SD cards and how many re-badge other companies’ kit. For your average consumer (and by this, I mean Dummy) though, this is all a bit of a red herring. Dummy wants to know (a) which card is fastest and (b) which card is best value for money. End of.

In order to separate the wheat from the chaff, we’ve picked 16GB Class 10 MicroSD cards (with full size adapters) from the top five brands out there: SanDisk, Transcend, Kingston, Toshiba and Samsung. We’re not too concerned with who made ’em; we just want to see which is the best package overall. To that end, we’ve benchmarked the cards in two different environments: firstly using a MicroSD card USB reader on a Windows PC and secondly on an Android mobile device. This gives us a really good idea of how these five cards perform in real-world scenarios.

MicroSD cards - the contenders — MicroSD cards – the contenders

If you can’t be bothered with all the stats and just want the summary (and we can’t blame you!), click here.

Test rig

eSecure All-in-1 USB card reader connected to HP Probook

Our Windows 7-based test rig consisted of an eSecure All-in-1 card reader connected to an excellent HP ProBook 6560b. The 6560b isn’t available any more by the way, but the 6570b is a worthy successor. Our test software was the venerable and well-respected CrystalDiskMark.

Our mobile device test rig consisted of the brilliant Samsung Galaxy Note 2 (replaced by the even more incredible Note 3). Using this phone we ran the handy app A1 SD Bench. It’s less comprehensive than CrystalDiskMark, but gives you a good feel for how the card performs in one of its most likely use cases – plugged into a smartphone or tablet.

The Tests

For our tests, we ran five passes of the benchmarks on each card. When a test run contained anomalous results (which could be down to processor blips or other irrelevant causes), we discarded the test and ran again. We then averaged the scores from the five clean passes. We think this gives us a pretty bulletproof set of scores.

We ran three distinct batteries of tests:

5 passes of CrystalDiskMark with the file size set to 1000MB
5 passes of CrystalDiskMark with the file size set to 50MB
5 passes of A1 SD Bench

The results are summarised in this image (click to enlarge):

This is worthy of some explanation! The bottom row of the table shows the “standard deviation”. You don’t need to understand statistics to get the point: if there’s not a lot of difference between the cards, you’ll see a small figure on this row. So for example in the sequential read tests, there’s very little difference between the cards (standard deviations of 0.12 and 0.18). In the case of a 50MB file written randomly in 512k chunks, there’s a huge variation – 5.97. If you look more closely at the column, you’ll see that the Samsung card clocked in at 15.2MB/s in this test, which is very good, while the Toshiba managed a paltry 1.3MB/s.

The bar chart overlays are fairly easy to follow, we hope. For each column, the card that has the biggest bar achieved the best speeds. This is most noticeable on columns with the largest deviation (512K random writes).

The price column is colour-coded going from red to green; expensive to cheap. “Expensive” is a relative term – there’s only £3.50 difference between the most expensive and least expensive cards here. Mind you, that means that the pricy SanDisk is over 40% more expensive than the modest Toshiba.

SanDisk MicroSD card - overpriced and over here — SanDisk MicroSD card – overpriced and over here

Let’s look at the SanDisk card for a moment. It’s considerably more expensive than the cheaper cards on test, so what do you get for your money? Well it actually performs worst on one of the tests (1000MB sequential write). If you’re working with video, that is going to be noticeable. The story’s better with random writes, but that seems to us to be a fairly “edge” scenario. It also does worst when being written to in an Android environment. All in all, not good. It certainly hasn’t justified its high price ticket. We were expecting a lot better from such a well known and respected manufacturer.

With generally narrow deviations, it’s hard to pick out an outstanding card, but if you can managed to stare at the figures a bit without your eyes glazing over, we do think a hero emerges.

Look at that Samsung card. Best at the 1000M sequential read. Best at the 1000MB sequential write. Second best at the 1000MB/512K random write and leading the pack for the 50MB/512K random write. In almost every test, it achieves consistently good results. It’s top dog when it comes to writing data and no slouch at reading it. All this and it’s the second cheapest.

Conclusion

Samsung MicroSD card - the winner — Samsung MicroSD card – the winner

If you’d like to mine the data we collected, you can download it here as a zipped Excel spreadsheet – this contains the raw data from all our tests – no less than 450 data points! Whatever you do, we think you’ll agree with us that in this class, the best value MicroSD card by far is the Samsung 16GB Class 10 MicroSD. There isn’t even a runner up in this contest; the remaining contenders are either too slow or too expensive.

21 January 2014

How-to: Using WhatsApp on a Windows PC

UPDATE 2: WhatsApp has finally bowed to pressure and created a web interface for desktop usage.

UPDATE: We’ve been blown away recently by new-instant-messenger-on-the-block, Telegram. Unlike WhatsApp, it’s free forever. It’s more secure than WhatsApp, it has desktop apps, chats are synchronised across all devices (at least the normal chats not marked as “secret” anyway) and best of all, it’s not owned by Facebook. Find out more here.

Wow, so this is a popular search on Google! And sadly, most of the results you find are riddled with either viruses, bad advice or broken English.

As you almost certainly know if you’ve found this page, WhatsApp is a massively popular (over 7 million downloads on Android alone) app for instant messaging. Its distinguishing feature is that it relies on a user’s mobile phone number, rather than any dedicated username/password combination. The idea is that you use it as a drop-in replacement for SMS and MMS messaging. You can also use it instead of your favourite instant messaging client, on the basis that almost everyone has a mobile phone number these days.

Linking the product to a mobile phone number is also one of this product’s weaknesses – you may want to use WhatsApp from your desktop PC or laptop, but WhatsApp doesn’t provide PC (or Mac) software. The good news is that it can be done! The bad news is this process depends on you having a Google account – sorry, Apple/iOS users. The REALLY bad news is that you can’t link a single mobile phone number on two different devices. Because WhatsApp associates to a mobile phone number, this means that you can’t synchronise your chats across more than one device. If you try to link two different devices to the same mobile number, one of the devices will disconnect and you’ll be greeted with the following message:

I don't want to reverify! — I don’t want to reverify!

So this piece of information can’t be stressed enough: you can’t run WhatsApp in two places simultaneously using the same mobile phone number. If you want the convenience of being able to input messages via your computer, you need to look at some form of remote control program for your mobile device (VNC, for example). That’s beyond the scope of this How-to.

The remainder of this guide assumes you’re going to be associating your mobile phone number to WhatsApp and using it only on your PC. If that’s what you want to do – good news! It’s entirely possible.

BlueStacks Android Emulator

The easiest way to get started is to install the BlueStacks Android emulator. BlueStacks is in beta at the moment and free to use. We imagine this will change at some point in the future. There will still be other possibilities, but one of the beauties of BlueStacks is its simplicity.

It’s worth mentioning at this point that whenever you’re going to emulate one operating system on another, you’re well advised to ensure your computer is up to the job. I’m using an Acer Veriton M6610G which is more than up to the job. (It has since been replaced with the M6630G series – very competent and expandable PCs.)

Visit the BlueStacks web site and download and install the emulator. We’re doing this on a Windows PC, but I suspect it would also work on a Mac. (Any Mac users out there that have an Android phone? I suppose it could happen…)

During the installation, you’ll be presented with a set of three options – App store access, App Notifications, and Spotlight. I’d suggest you only select the first of these. The installation can take a fair few minutes.

If you’re prompted to update your graphics drivers, you’ll need to allow this, for BlueStacks to run. As always, make sure System Restore is working, in case something goes wrong when installing the drivers.

Set up BlueStacks

When you first load BlueStacks, you’ll be taken though a setup wizard. Click “Continue”:

You need to connect BlueStacks to a Google Account for two reasons: first, to download the app from the Google Play Store. Secondly, so you have access to your address book. It’s best to link BlueStacks to an existing Google account, so you have the benefit of your Google address book. Choose “Existing”:

Enter your Google credentials and click “Sign in”:

If, like me, you use Google’s two-factor authentication, you’ll now be taken through a web-based login process (still within the BlueStacks emulator). Click “Next”:

Re-enter your credentials and click “Sign in”:

Again, this is only if you’ve enabled two-factor authentication (which you should, by the way). A code will be sent to your mobile phone number. Enter it here and click “Verify”:

The “Back up and restore” section – what you choose here is up to you. Click “Next”:

You’ll be taken back to the BlueStacks wizard. Click “Continue”:

Re-enter your Google account details (yawn):

Do you want your password to be remembered? Your choice:

Again, leap through the two-step verification hoop if it applies to you:

The Google Play store will now be available. Click “Let’s go!”:

Finally, accept the Terms of Service. I suggest leaving the “opt-in” unchecked:

Installing WhatsApp

Immediately after setting up BlueStacks, you’ll be taken to the Play Store:

From there, search for WhatsApp:

Click “Install”:

Accept the permissions:

WhatsApp will now install:

Once installed, click “Open”:

Agree to the WhatsApp terms:

Enter the mobile number that you’re going to link to this installation of WhatsApp (remember, one mobile phone number per device) and click “OK”:

Double-check and click “OK”:

WhatsApp tries to send and detect an SMS. The SMS message will go to your phone of course, not BlueStacks, so this detection will fail (you’ll need to wait for this):

Instead, click “Call me” and be ready to enter the verification code:

An automated message will tell you the code you need to enter into WhatsApp on BlueStacks:

Verify your profile:

WhatsApp will spend some time initialising:

Once it’s done, the “Continue” button appears. Click it:

That’s it; you’re in. From now on, you can run WhatsApp from the Home screen:

You should see your list of contacts from your Google address book:

If you have any chat history from using WhatsApp on a different device, this will not be pulled across to BlueStacks – history is not saved on WhatsApps’ servers.

So there we are; it has its limitations, but if you’re happy to use WhatsApp on your computer instead of your phone or tablet, this is probably the easiest way to do it. Having said that, I will personally carry on using WhatsApp on my Galaxy Note phone or tablet, both of which I’m more likely to have with me than my computer!

5 December 2013

Review: Geek’s top 5 Christmas tech gifts for 2013

As you know, Dummy and I are constantly on the lookout for good-value, great gadgets. Are you stuck for gift ideas for the tech-lover in your life? Look no further. Dummy has already offered you his “top five” list; here’s mine.

Network-enabled media streamer: Roku LT

I’ve yet to review this device, but I bought one earlier this year, when Roku discounted them from £50 to £35. They’re not quite that cheap now (up to £45), but they’re still great value, very competent devices.

Roku’s set-top boxes appeal to me, because rather than buying one of those super-expensive “smart TVs” (like Dummy did), instead for a relatively trivial sum, you can upgrade virtually any television with this small, unimposing gizmo. There are a few different media streamers in the series, but this bottom-of-the-range LT was more than sufficient for my needs – to stream media (from a wireless network connection) to a 32 inch television. The LT offers 720p HD video and has a super-low power consumption profile.

The idea is that you add various different “channels” from Roku’s huge library, which includes iPlayer, Demand 5, 4oD, Plex, Netflix and a host of others. The LT’s big brother, the 3, has more tricks up its sleeve, like a wired ethernet port, USB in, headphone socket on the remote (genius!) and games. I needed none of those though and have been absolutely delighted with the LT.

If Roku doesn’t quite float your boat, you might want to consider an Apple TV. More expensive, feature-for-feature, but simple to use and well-appreciated by all its owners.

Low-cost hobby PC: Raspberry Pi

As you might have noticed, we’re real fans of this British innovation. You are more or less limited only by your imagination. People are using Pis to run media centres, provide home surveillance, as a web server, for time-lapse photography, as a custom games console, and on and on. Prices start from about £24 for the model A, but I recommend starting with the B for the best experience.

Great value tablet: Nexus 7

This is a close call. There are more and more tablets on the market these days and the quality is increasing as manufacturers weed out early production problems. You won’t get anything that I’d call “great value” from Apple or Microsoft, so that leaves us with the Android platform. And wow, there’s an awful lot of choice now.

I’m torn on this one. Amazon is pushing out better and better Kindles at keener and keener prices. The Kindle Fire HD is a serious contender for this top 5 list – £120 now; that’s a bargain. But ultimately, the fact that the Nexus 7 doesn’t need to be hacked (“rooted”) to get the best from it means that this tablet is the better choice in my opinion. You can pick one up for under £200 and I don’t think anyone could be disappointed to find one of these in his or her stocking.

Portable Bluetooth speaker: Soundwave SW100

I’ve had more than six months with this speaker that I reviewed back in May this year. I just can’t fault it. Great at what it does and a real steal at £20.

Budget Android phone: Huawei Ascend Y300

In an extremely saturated market, it’s really hard for one phone to stand out from amongst the crowd. If we’re going to continue the theme of great value for money though, I think you can’t go wrong with the Ascend Y300 from rising star Huawei. Under a hundred quid. It’ll do the job. And if you’re buying for someone who’s a little accident prone, better this than a four hundred quid Galaxy S4 (which is a really great phone by the way, but expensive).

27 November 2013

Review: Bluetooth OBDII OBD2 Diagnostic Scanner

DUMMY: I’d been excited about doing this review for quite some time but describing delivery of this item from China as “slow” and “a bit dodgy” is an understatement. Now it has at last arrived though, I can say it massively exceeded my expectations.

GEEK: It was one of those occasions where the seller pretends to have “UK stock”, but quotes a 30 day delivery time… And then the package turns up with a customs declaration, describing the item as a “gift”. Not to mention the hassle associated with returns, should the unit prove to be faulty. So it pretty much goes without saying that we would only advocate buying from abroad for low-cost, low-urgency items like this. All that said, Dummy is right: great piece of kit, for buttons.

DUMMY: Let’s wind this back a stage. Virtually every modern vehicle – even my Land Rover Defender – comes equipped with an OBD-II (On-Board Diagnostics) port. Similarly these vehicles are fitted with an ECU (Electronic Control Unit) and this little computer will be monitoring hundreds, if not thousands of events that are going on in your vehicle every millisecond. The OBD port is like a network cable into that information and the OBD Bluetooth Diagnostic Scanner is the device that can take that information and send it to a program where it can be processed.

GEEK: He almost sounds like he knows what he’s talking about doesn’t he?

DUMMY: [ignores Geek] Sounding complicated? It really isn’t. You find an app that works with the scanner, you plug the scanner in, you start your engine and hey presto, an immediate window to the soul of your car.

GEEK: There are a few apps out there that will translate this information into a variety of user-friendly dials and displays. At the moment, for Bluetooth adapters like the one we’re reviewing, you’re basically restricted to Android or PC devices. Apple is extremely fussy about what it will allow to connect via Bluetooth. Yet another reason to see the light and throw your iDevices in the bin.

DUMMY: You just can’t pass up an opportunity can you?!
If I’m honest, my boy racer days are behind me. Although I was mildly interested in seeing live BHP calculations and how many G’s I was pulling, the main attraction of this device to me are the diagnostics. Select the right app and it is simplicity itself to interrogate the ECU to find out how your car is feeling. Not just viewing and interpreting fault codes, but also resetting those codes as required. Yes that’s right, that job for which your dealer or local garage charges you £40 a pop, you can now do for yourself and all your friends and family for £6 – for life.

GEEK: Ha – middle-aged much?! We’ve looked at some interesting devices this year, expensive and cheap. Of them all, without doubt this has to be the simplest and most cost effective purchase of the year.

DUMMY: Ha – skinflint much? It’s a real shame that this is no use for Apple devices, in its cheaper Bluetooth form. Looks like this Apple fanboy is going to have to hand the best bit of equipment we have bought this year straight to Geek.

GEEK: Rest assured, if we can work out an easy way of making it work with iOS, we’ll be all over that. Watch this space! In the meantime, the Android apps we used in our tests were aLapRecorder HD (which unfortunately appears to have been abandoned by its developer), Carista OBD2 (free) and Torque Pro (not free, but excellent).

DUMMY: Anyway, enough chat. Here is a little road test we did together of this brilliant little device. I apologise in advance for Geek’s driving!!

[easyreview title=”Consensus” icon=”collab” cat1title=”Ease of use” cat1detail=”Couldn’t be any easier, no really.” cat1rating=”4.5″ cat2title=”Features” cat2detail=”Its feature is communciating via Bluetooth which is does faultlessly. The clever stuff happens in the software it connects to.” cat2rating=”4″ cat3title=”Value for money” cat3detail=”Can’t be beaten. Full stop.” cat3rating=”5″ cat4title=”Build Quality” cat4detail=”Feels substantial. We certainly don’t pick it up and think it’s cheap.” cat4rating=”4.5″ summary=”We can’t tell you how delighted we are with this purchase – and the price delights most of all!”]

29 October 2013

Review: JOYO JA-03 Guitar Headphone Amplifier

A couple of weeks ago, I picked up an ESP LTD F-155DX 5 string electric bass guitar. It was slightly bashed, but otherwise in great condition – in short, at only £200, a bargain. I love bargains.

There’s one small problem with electric instruments: they need amplification. And amplification can sometimes be a little… antisocial. In order to keep relations with Mrs Geek reasonably harmonious, I started looking around for a solution.

One of the problems was that I didn’t know exactly what I needed. In the past, I’ve come across micro amps, which have a built-in speaker but I wanted something even more compact, that could just drive a pair of headphones.

Eventually I stumbled across the well-reviewed Vox AmPlugs. Plug the device into the guitar, put your headphones into that, simple. At £32 though, I wondered if there might be something a bit cheaper. Since this was just going to be for quick practice sessions, I didn’t need the best that money can buy.

Casting my net slightly wider, I came across the JOYO JA-03 series of headphone amps. They look suspiciously like a clone of the AmPlug, but who knows, perhaps they’re made under licence. Anyway, the important point: they’re just a tenner. Sold!

There are a few different amps in the range, with different sounds – tube, metal and so on (see the full range on JOYO’s website). I plumped for “Acoustic“. I’d read good things about the sound of the ESP bass, so I wanted to hear it as clean as possible – and this better suits the style of music I’m going to be playing, anyway (i.e. not heavy metal).

The amp arrived very quickly, well packaged in its blister pack. Happily this was the type of blister pack that is not sealed shut, so you can open it without having to cut the pack. Fewer blister-pack-related injuries – yay!

The JA-03 is powered by a pair of AAA batteries. Happily, the amp came with fresh batteries in the pack, so you’re good to go straight away.

There’s not a lot to the device. The standard quarter inch jack is built in (no need for a separate lead – you plug it straight into your guitar). It has a 3.5mm socket for headphones and another 3.5mm socket for an auxiliary/line input. In this way, you can feed music through the amp and play along.

You get four controls: gain, tone, volume and power. The volume control affects the level of the input from your instrument. I expected the gain control would alter the volume of the auxiliary input, but not so. It’s hard to describe what this does – it doesn’t change the overall volume of any input; instead it makes it sound more like you’re playing through an amplifier. If you crank the gain control all the way up, you hear that characteristic hiss and the sound from your instrument is more like it is being played through a compressor – a little “thin”. I found I had the cleanest sound with gain turned right down.

The volume of the auxiliary input is not controlled by the JA-03. I plugged in my phone using a 3.5mm cable and then set the volume of the music on my phone. Using my phone’s volume control and the the volume mixer on the amp, I was able to find a perfect balance between the music I was playing and the output of the bass, very easily.

Skipping over the power control (which I trust requires no further comment!) the remaining control is the tone dial. This is a pretty low grade adjustment. I didn’t like the effect it had on the sound of my bass, so I left it in the neutral centre position.

With the mix right and all the tone adjustment coming from the excellent active pickup set on the ESP bass, I was frankly blown away. Not by my playing, I hasten to add, but by the convenience of the set up and the great sound I achieved through some fairly cheap and nasty in-ear headphones. For practice purposes, this is all you need.

I went one step further though, and connected the output of the JA-03 to my humble home stereo. With tunes coming from my phone, it was a joy to play along in my living room and Mrs Geek didn’t seem to mind at all. In fact the 9 year old twin junior Geeks loved the show (I know, the “hero worship” bubble will burst soon enough – let me have my moment of glory).

If you’re very fussy about the quality of your audio, you might want to look for something built with more expensive circuitry, but honestly at this price, you cannot beat this. Highly recommended. Pick one up from Amazon (or somewhere else if you prefer), today!

At the time of writing, the JA-03 can be yours for just £9.49.

[easyreview title=”Geek rating” icon=”geek” cat1title=”Ease of use” cat1detail=”Very, very straightforward.” cat1rating=”5″ cat2title=”Features” cat2detail=”It’s hard to think of anything else I’d add – maybe a distortion effect? But that’s just me being greedy.” cat2rating=”4.5″ cat3title=”Value for money” cat3detail=”Can’t be beaten. Full stop.” cat3rating=”5″ cat4title=”Build Quality” cat4detail=”Feels like it’s made from slightly brittle plastic. Not sure how well it would survive a serious bash in a soft case. Made from cheap materials as you’d expect at this price point. Otherwise it’s assembled well enough and feels solid.” cat4rating=”3.5″ summary=”I can’t tell you how delighted I am with this purchase – and the price delights most of all!”]

25 October 2013

How-to: Overcome “critical temperature” problem with CloneZilla

In case you don’t know, Clonezilla is an excellent (and free) disk/partition imaging tool. It’s essentially a customised Linux distribution. You boot from a CD and then follow a text-mode wizard to backup or restore images of hard drives or other storage devices. You can see the process in action in my Raspberry Pi SD card backup/restore article.

The process can be quite intensive for hard drives and processors. One of the things Clonezilla does is compresses the image of the drive to save space wherever you’re storing the image. Compressing a 2GB file is a big job for an older processor. I was finding with one of my older laptops that the processor was working so hard, it caused the temperature to rise at a point where it triggered a Linux “panic”. The system immediately halted with an error message about “critical temperature”, half way through making an image. So of course that image is not usable.

What’s supposed to happen in normal usage is that when the temperature rises dangerously, the operating system slows down the processor. This allows the machine to cool down (at the obvious expense of a performance penalty). I’m not sure if this is fixed in later versions of Clonezilla – there’s some talk of it in the mailing lists. I’m indebted to those mailing lists for some parts of workaround that follows.

One thing you can try is using the i486 version of Clonezilla. This assumes older processor hardware and so (I suspect) doesn’t make full use of your processor’s theoretical potential. Just select i486 architecture from the download page for the latest stable version.

As a belt-and-braces approach (and this is the method I’ve adopted), you can also issue commands that tell the Linux kernel to run the processor at a particular frequency. In my case, I’m telling an Intel Core i3-330M to run at 1.6GHz instead of the usual 2.13GHz.

You can do this as follows:

Once you’re in the Clonezilla wizard, press Alt-F2, to access a login shell.
Issue the command cpufreq-info. In my case, I saw the following, as well as some other information:
analyzing CPU 0: driver: acpi-cpufreq CPUs which run at the same hardware frequency: 0 CPUs which need to have their frequency coordinated by software: 0 maximum transition latency: 10.0 us. hardware limits: 933 MHz - 2.13 GHz available frequency steps: 2.13 GHz, 2.00 GHz, 1.87 GHz, 1.73 GHz, 1.60 GHz, 1.47GHz, 1.33GHz, 1.20 GHz, 1.07 GHz, 933 MHz ...
You may see more than one CPU listed – mine shows just the one (single CPU, dual core). Most importantly, this lists the frequencies to which you can set your processor clock.
Pick a frequency from the list that’s lower than the maximum. E.g., if the list shows that the processor can run at a lower speed of 1.60 GHz, set the clock speed as follows:
sudo cpufreq-set -c 0 -f 1.60GHz
The -c 0 parameter refers to the CPU number, starting from 0. Repeat the command, changing this number, for each CPU.
Press Alt-F1 to return to the Clonezilla wizard and continue with the cloning process.

This approach sets the clock speed just for this particular session, so normal service will be resumed upon reboot.

If this all sounds like too much hard work, you could try one of the good commercial solutions instead, such as Norton Ghost or Acronis True Image.

10 October 2013

How-to: Raspberry Pi tutorial part 3: Web & file hosting with Webmin & Virtualmin

[easyreview title=”Complexity rating” icon=”geek” cat1title=”Level of experience required, to follow this how-to.” cat1detail=”You’ll need to keep your wits about you!” cat1rating=”4″ overall=”false”]

Part 1: Getting started with the Raspberry Pi
Part 2: Creating/restoring an image of the Pi’s SD card
Part 3: Using the Raspbery Pi to host multiple web sites and as a file server
Coming up – Part 4: Creating a Dropbox replacement from a Raspberry Pi
Coming up – Part 5: Using a Raspberry Pi as a thin (or remote desktop) client

Right, so our basic Raspberry Pi is set up and ready to go. You’ve got the Pi, you’ve got the case and you’ve got a decent SD card. What next? How about turning it into a low-powered file server and web host?

To do this, we’re going to install Webmin (a web-based server management application) and Virtualmin (a virtual hosting platform that sits on Webmin). This will leave us with a convenient graphical interface for managing the Pi and a full blown web hosting environment.

Prepare the Pi

I’ll assume for the purposes of this exercise, that we’re picking up from where we left off, from tutorials 1 and 2. That is, you have the Rasbian operating system installed on your Pi, and a backup to revert to if it all goes horribly wrong.

Next step: we need to install a few packages that Webmin and Virtualmin depend on, plus the services we’ll be managing. From a root SSH shell, issue the following commands:

apt-get update apt-get -y upgrade apt-get -y install apache2 apache2-suexec-custom libnet-ssleay-perl libauthen-pam-perl libio-pty-perl apt-show-versions samba bind9 webalizer locate mysql-server

Due to the Pi’s limited power, you may find these operations take a while. I’m installing locate for my own convenience – it’s handy for tracking down obscure files on your system. You can install PostgreSQL instead of MySQL if you prefer.

Install Webmin

According to the official site:

Webmin is a web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. Webmin removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from the console or remotely…

When I install packages that I’ve downloaded (rather than directly through a package manager), I like to keep them in one place, so I can keep track of what’s installed. I’ve formed the habit of keeping these packages in a directory belonging to root. So, to get Webmin, whilst logged in as root:

cd mkdir installed-packages cd installed-packages wget http://prdownloads.sourceforge.net/webadmin/webmin_1.660_all.deb

That last command downloads Webmin’s package. The version number will inevitably change – you can make sure you have the latest version by browsing to the official Webmin website and looking for the “Debian Package” link on the left hand side of the page.

Install Webmin with:

dpkg -i webmin_1.660_all.deb

Again, this is fairly intense for the Pi, so be patient! Once complete, you should be rewarded with a response like:

Webmin install complete. You can now login to https://my-pi:10000/ as root with your root password, or as any user who can use sudo to run commands as root.

Connect to the relevant page with a web browser, accept the SSL certificate warning and you should see something like the following:

For some reason when I logged in, it wouldn’t accept the root password. Webmin actually tracks the root password separately from the Linux password database. If like me you find you can’t log on as root, you can fix this by running the following command:

/usr/share/webmin/changepass.pl /etc/webmin root [new password]

Configure Apache

Earlier, we installed the apache2-suexec-custom module. This allows us to run Apache websites securely for multiple users, under a directory other than /var/www. Using your favourite text editor, load up the file /etc/apache2/suexec/www-data. Change the first line from /var/www to /home.

Enable some modules that Virtualmin will need, and restart Apache:

a2enmod suexec a2enmod actions service apache2 restart

If you see an error message “Could not reliably determine the server’s fully qualified domain name, using 127.0.1.1 for ServerName”, you can safely ignore this. It doesn’t matter, for the correct functioning of Virtualmin.

Install Virtualmin

At the official site, you’ll read:

It is a Webmin module for managing multiple virtual hosts through a single interface, like Plesk or Cpanel. It supports the creation and management of Apache virtual hosts, BIND DNS domains, MySQL databases, and mailboxes and aliases with Sendmail or Postfix. It makes use of the existing Webmin modules for these servers, and so should work with any existing system configuration, rather than needing it’s [sic] own mail server, web server and so on.

You can install Virtualmin from within Webmin. Proceed like this:

Log in to Webmin
From the Virtualmin download page, find the link entitled “Virtualmin module in Webmin format”. Copy the link (it will end in “.wbm.gz”).
In Webmin, go to Webmin–>Webmin Configuration–>Webmin Modules. Select the radio button next to “From ftp or http URL” and paste the link you copied into the field. Then click “Install Module”.
Do the same for the link for the “Virtualmin theme in Webmin format”. You’ll find the necessary link on the Webmin site, called “Virtualmin theme in Webmin format (for FreeBSD, MacOS and Solaris)”. The link will end in “.wbt.gz”, this time.
To activate this theme, go to Webmin–>Webmin Configuration–>Webmin Themes. From the drop-down box, choose “Virtualmin Framed Theme” and click “Change”. Ignore the “Post-Installation Wizard” for now, and hit F5 to refresh your browser and use the Virtualmin theme for Webmin. You should arrive at a screen like this:
Click Next, to arrive at the “Memory Use” screen. My guess is that for most cases, it would be best to answer “No” here (don’t pre-load Virtualmin). Click Next.
The next choice is database servers. This is up to you, but I switch MySQL on and PostgreSQL off. Click Next.
You’ll see a message “MySQL has been enabled, but cannot be used by Virtualmin. Use the MySQL Database module to fix the problem.”. Click the “MySQL Database” link.
Enter your root username/password combination for MySQL (you will have been asked this when you installed MySQL via apt). After saving this, hit F5 to refresh and return to the Post Installation Wizard.
Proceed through the wizard up to where we left off (just after database server selection).
Leave the MySQL password unchanged and click Next.
I would suggest setting MySQL memory usage to 256M and clicking Next.
In the DNS config screen, check the box “Skip check for resolvability” and click Next.
Set password storage mode to “Store plain-text passwords” and click Next.
At the “All done” screen, click Next. We’re not all done, by the way!
You’re now at the main Virtualmin screen. Click the “Re-check and refresh configuration” button.
You’ll see a complaint about DNS. Click the link “list of DNS servers”. Enter 127.0.0.1 as the first DNS server, make sure the hostname is a fully qualified domain name and click Save. Then hit F5 to go back to Virtualmin.
Click the “Re-check and refresh configuration” button again.
The next complaint is about email. I’m not planning to use the Pi as an email server, so we can just disable that Virtualmin module. Go to Virtualmin->Systems Settings->Features and Plugins. Uncheck the “Mail for domain” module, slick Save, then hit F5.
If your screen now looks basically like this, you’re good to start hosting websites (using the “Create Virtual Server” link).

Setting up virtual hosting is a big subject and beyond the scope of this tutorial, but that’s the basic platform in place. Have a read of the official Virtualmin documentation for pointers. If you happen to browse to your Raspberry Pi’s IP address or DNS name, you’ll be rewarded with a very simple test page:

Running a file server

With Webmin and Virtualmin up and running, you can now start creating file shares. How you approach this depends a bit on how you want to use the server. Probably (!) this will be a personal/hobby server. In that case, I would suggest creating a new virtual server for each user first. That creates all the initial Virtualmin linkage for hosting websites and databases. Then having done that, you can create a fileshare for the user(s) by browsing to Webmin->Servers->Samba Windows File Sharing.

Again, the specific details are best not discussed here, because there are so many possible different configurations. You are however ready to start customising your file/web server to your heart’s content. So now would be a perfect time to take a snapshot of your Pi, so you have a good restore point.

Happy hosting!

19 September 2013

How-to: Raspberry Pi tutorial part 2: SD card backup/restore

[easyreview title=”Complexity rating” icon=”geek” cat1title=”Level of experience required, to follow this how-to.” cat1detail=”This is wizard-driven. Very simple. You’ll need to be able to burn a CD, nothing more taxing than that.” cat1rating=”1″ overall=”false”]

Part 1: Getting started with the Raspberry Pi
Part 2: Creating/restoring an image of the Pi’s SD card
Coming up – Part 3: Using the Raspbery Pi to host multiple web sites and as a file server
Coming up – Part 4: Creating a Dropbox replacement from a Raspberry Pi
Coming up – Part 5: Using a Raspberry Pi as a thin (or remote desktop) client

In my last Raspberry Pi tutorial (the first in this series), I mentioned that we can take a snapshot of the Raspberry Pi’s SD card at any time. This will give us a “restore point”, so we can skip a few installation steps if we want to wipe the Pi and start again. Quite a few Raspberry Pi projects will require that we start with a working installation of Raspbian so that’s the snapshot I’m going to take. You can of course take a snapshot whenever you like. If you’ve honed and polished your Rasbmc box, it would make sense to take a snapshot in case it becomes horribly corrupted at some point or melts.

There are many different ways of skinning this cat (or squashing this ‘berry), but my preferred method is the tried and tested customised Linux distribution, Clonezilla. I’ve been using CloneZilla personally and professionally for years and persuaded many colleagues of its merits (besides the obvious, that it’s free). It can be a bit intimidating with all the options it presents. If this is your first experience of CloneZilla, following this tutorial will also give you a gentle introduction to this powerful toolkit.

What you’ll need

A copy of Clonezilla, burned to disc.
A computer (desktop or laptop) configured to boot from CD.
An external hard drive, with enough space to store the image (you’ll only need a few gigabytes spare).
A USB reader for your SD card. You can buy one here.

Take a snapshot

Power down your Pi, with the command halt, shutdown or poweroff.
Boot your PC from the Clonezilla disc. You will arrive at a simple menu/boot screen. It will boot automatically within 30 seconds – you can hit enter at any time, to proceed.
You’ll be treated to rows and rows of gibberish while Clonezilla boots up.
Choose your language and keyboard setting.
Hit enter to start Clonezilla (yeah, you thought it had already started, didn’t you).
Insert your Raspberry Pi’s card, in its reader.
Choose “local_dev”.
A screen prompt will tell you to insert your external hard drive.
Insert the external drive and then wait for 5 seconds or so.
A few lines will indicate that Clonezilla has registered the presence of the drive.
Hit enter and Clonezilla will mount the various partitions now available to it.
Select the external hard drive as the drive to which we’re copying the snapshot (in my case, the largest partition on the list).
Hit enter. If the drive wasn’t cleanly dismounted before (oopsie), Clonezilla will check and fix as required.
Choose a directory to store the SD card image and hit enter.
Clonezilla will spit some more gibberish at you. Ignore it and hit enter.
Though it makes me feel a little silly, choose Beginner mode.
Choose “savedisk”.
Give your disk image a meaningful name.
Select the SD card, to save the image. You use cursor keys and the space bar here.
Select Ok to continue.
If you’re confident your SD card is in good shape, you can skip checking it.
I’d recommend checking the saved image though. It doesn’t take long and gives you peace of mind that you should be able to restore from this image.
Clonezilla will helpfully point out that you can do all this from the command line (yeah, right).
Press Y and enter to continue.
Shouldn’t take too long.
When it’s all done, it’ll report progress. Press enter.
Enter 0 to power off (or whatever you prefer) followed by enter.
Clonezilla will eject the disc. Hit enter to carry on.

You should now have an image (consisting of several files) on your external hard drive, which you can later use for restoration. Job done.

Restore a snapshot

In this scenario, we’re starting with everything powered off, ready to begin.

Boot your PC from the Clonezilla disc. You will arrive at a simple menu/boot screen. It will boot automatically within 30 seconds – you can hit enter at any time, to proceed.
I’ve got to say, this screen full of strange foreign characters is pretty unnerving. But don’t worry. It’ll pass.
Choose your language.
I’ve never found I’ve had keyboard problems, even though I use a UK keyboard…
Hit enter to begin.
Insert the SD card/reader. Some nonsense will appear on screen. Don’t worry – just hit enter.
Select “local_dev” and hit enter.
Insert your external hard drive and wait 5 seconds or so for it to be recognised.
It’ll detect the drive – hit enter.
Next, it will mount your various partitions.
You may have a few…
Choose the external drive from the list then hit enter.
Clonezilla will check the drive.
Choose the directory where your saved image is stored and hit enter.
Clonezilla will give you an overview of its file systems. You will be thrilled. Hit enter.
Choose “Beginner”, no matter how patronised you may feel.
Choose “restoredisk”.
Select the previously saved image.
Choose the SD card. Hit enter.
Clonezilla reckons you really want to do this at the command line. Hit enter.
This is a destructive operation and will wipe your SD card. Press Y then enter.
Clonezilla doesn’t trust your judgment. Hit Y and enter again.
There are two partitions to restore to this card. You’ll get a progress report for each restoration.
Clonezilla will let you know once it’s done.
Press enter to continue.
Choose 1 to reboot (or whatever you prefer) then hit enter.
Once the CD is ejected, you can also disconnect the SD card and hard drive. Hit enter.
Witness the majesty of the Linux death rattle.

If all went well, you can now install this SD card back in your Pi, boot up and continue.

9 September 2013

How-to: Raspberry Pi tutorial part 1: Getting started

[easyreview title=”Complexity rating” icon=”geek” cat1title=”Level of experience required, to follow this how-to.” cat1detail=”The geek factor is quite high here, but this process is not particularly taxing.” cat1rating=”2.5″ overall=”false”]

Part 1: Getting started with the Raspberry Pi
Part 2: Creating/restoring an image of the Pi’s SD card
Part 3: Using the Raspbery Pi to host multiple web sites and as a file server
Coming up – Part 4: Creating a Dropbox replacement from a Raspberry Pi
Coming up – Part 5: Using a Raspberry Pi as a thin (or remote desktop) client

In the line of my work, I’ve recently had cause to become better acquainted with every geek’s favourite cheap computer, the Raspberry Pi. At the time of writing, you can pick up a Pi for an extremely reasonable £30, but the first thing I discovered was that this is only half the story. For a workable system, you need all the necessary cables, some storage and a case. Here’s my shopping list:

The Pi plus extra bits, in all their glory

The latest model B Raspberry Pi: £29.99.
A decent case. The case I chose has received good reviews, (to which I would add my own). The Pi fits snugly inside and the case comes with status indicators plus a VESA mounting kit if you want to attach it to the back of a monitor. £8.99.
A branded, 32GB Class 10 Micro SD card with full-size adapter (it’s a full size slot on the Pi). This seemed to be the best trade-off of price vs. capacity at £16.85.
A 1m HDMI cable. It probably goes without saying, but make sure your monitor/TV has an HDMI input – otherwise choose whichever cable is most appropriate. £2.44.
A generic 1A USB power supply with a reasonably long cable. For sure there are lots of other ways of powering your Pi, but this was a simple, self-contained (easily replaced) option. £4.75.
SanDisk Cruzer Blade 16GB thumb drive, in case I needed extra storage. £6.93.

So my total is £69.95 – over twice the price of buying just the Pi. But still pretty cheap, considering. You’ll also need a USB mouse/keyboard for initial input. I’m going to run my Pi headless (no screen or input devices needed, just a network connection), so I’m borrowing my Microsoft Natural wireless desktop for this purpose, which the Pi detected without issue.

Hardware installation

This may well be the easiest hardware installation you ever perform. The case has a couple of punch outs that you need to remove for the model B Pi. I forgot to photograph them I’m afraid, but it will be obvious – when you try and put the Pi in the case, it won’t fit without these pieces removed (e.g. for the ethernet port).

Put the Pi in the case.

Put the case together and fasten the screws. Make sure you put the VESA mount between the screws and the case, if you’re going to monitor-mount the Pi.

That’s it.

What to do, what to do…

There are lots of potential uses for your Pi. It has limited processing power and memory but apart from that, the only real limit is your imagination. I have no imagination to speak of, so I’m going to do what I do with every other gadget: put Linux on it and set it up as a home web/file server. I’ll cover the web/file server setup in a subsequent tutorial.

Here’s the plan:

Install Rasbian (a Pi-centric version of the venerable Debian GNU/Linux distribution).
Set up Webmin/Virtualmin for management of the server/web sites.
Install OwnCloud and create my own Dropbox replacement.
Experiment with using the Pi as a remote desktop client or thin/fat terminal.

In the process, I’m looking for any major issues or gotchas – things you might want to be aware of if you’re thinking of getting into Pis in a big way.

Prepare the SD card

For this step, you’ll need an SD card reader. If you don’t have a laptop/computer with a built-in reader, you can buy an external reader here. Note: my laptop’s built-in card reader was not supported by the SD Formatter program (see below) so I used an external reader.

From the SD Association’s official website, download and install the SD Formatter.
Format the SD card using SD Formatter:
Download NOOBS (“New Out of Box Software” – chortle) from the official Raspberry Pi website. This file is currently over 1GB. I tried the direct download and it was pretty slow, so I’d recommend using the torrent if you’re so equipped. NOOBS gives us a choice of different operating systems to install on the Pi.
Extract the contents of the NOOBS zip file onto the newly formatted SD card.

Whack the SD card into the Pi and connect everything up (power last of all, since there’s no power switch). If at this point you don’t see any output, the chances are that your SD card has not been recognised. I’m using a Class 10, but I’ve read that some people have had problems with Class 10 cards and better results with Class 6. If your card is recognised, you should be rewarded with a few pretty lights when powered up.

Install and configure Raspbian

At the NOOBS screen, choose Rasbian and click Install OS, then Yes. Go grab yourself a quick coffee.

The install will take a few minutes (the speed of your SD card is a factor here). Once it’s done, you’ll see a message “Image applied successfully”. Click Okay to reboot the Pi with your new OS.

raspi-config will launch with some initial setup options. I’ll work through them one by one.

Expand the filesystem: You can skip this, because this option isn’t needed for NOOBS-based installations. Otherwise, this ensures you’re using the whole of the SD card.
Change the password for the “pi” user. The default password is “raspberry”. Improve on that.
Enable/disable boot to desktop: I’m not planning to use a desktop system with this Pi. X Windows is such a resource hog that we definitely want to set this to “No”. Of course if you want to use the Pi as a desktop system, you’ll select “Yes” here.
Internationalization options: I’m in the UK, with a UK keyboard layout. It’s not a huge problem since generally I’ll be accessing the Pi via a web interface or service, but I am fussy, so I set everything up to be UK-centric. My correct locale was already selected. In these dialogue boxes, use the spacebar to select/deselect options, tab to move between fields, up and down cursors keys to navigate and enter to select.
Enable camera: do this if you’ve bought the optional camera module (I haven’t).
Add to Rastrack: this puts you on the Rastrack map of Pi installations. Not for me, but you might be interested.
Overclock: if you need to squeeze more juice out of your Raspberry, you can force it into a more frantic mode of operation. I’m not going to do this, at this stage.
Advanced options: Here, I’m going to set the hostname of the Pi and reduce the Pi’s use of GPU memory to 16MB (since we’re not running a graphical desktop). I’m also going to ensure that SSH is enabled (for later remote logon purposes).
Finish and reboot to an ordinary logon prompt.
For demo/proof of concept servers where security is less of a concern, I like to be able to log on as root. You can give the root user a password by logging in, then entering sudo passwd root and following the prompts.

Configure networking

I need this Pi to have a static IP address. You can use a DHCP reservation for this purpose if you like, but I prefer to create a fixed IP address on boot. Like this:

Log in.
If you didn’t log on as root, give yourself an elevated shell: sudo su
Install your favourite console-based text editor. For me this is vim: apt-get --force-yes -y install vim
Use the editor to edit the /etc/network/interfaces file. Replace the line iface eth0 inet dhcp with iface eth0 inet static address 192.168.1.11 netmask 255.255.255.0 gateway 192.168.1.1
adjusting the values to match your network as appropriate.
My DNS was already correctly configured, but you may need to check the contents of your /etc/resolv.conf file to ensure DNS is set up. If in doubt, this configuration should work:
nameserver 8.8.8.8
Save the files then back at the command prompt, enter reboot to restart the Pi with the new network configuration.

Once the Pi is up and running you’ll be able to connect via SSH using your favourite terminal emulation program (mine’s PuTTY).

As you’ll see from the Contents section above, I have a few ideas for things to do next. It’s a good plan to take a snapshot of the Pi in its current state, so we can hit the ground running any time we want to try something different, with a Raspbian base, so this will be the subject of my next how-to. In the meantime, if you have any questions about what we’ve done so far, or if you have any ideas for later tutorials, let us know in the comments!

Until next time. 🙂

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Test rig

The Tests

Conclusion

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BlueStacks Android Emulator

Set up BlueStacks

Installing WhatsApp

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Contents

Prepare the Pi

Install Webmin

Configure Apache

Install Virtualmin

Running a file server

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Contents

What you’ll need

Take a snapshot

Restore a snapshot

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Contents

Hardware installation

What to do, what to do…

Prepare the SD card

Install and configure Raspbian

Configure networking

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