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Running SpinRite 6.0 on a Mac

SpinRite logo

SpinRite is a fantastic tool for repairing and maintaining hard drives, and I am proud to say that its purchase price has been more than recouped on drives that it has brought back into service that would otherwise have needed replacing!

Running it on an Intel Mac hasn’t been possible with version 6.0. It actually boots fine, but there is no way to give keyboard input, and thus there is no way to kick off a scan.

Reports that people had succeeded at getting SpinRite to work on various weird and wonderful platforms indirectly, using VirtualBox and its raw disk access mode, led me to experiment with this to run SpinRite on a Mac. This is particularly useful on iMacs where pulling the hard drive out of the case is… undesirable(!)

This is an advanced, technical process.

Performing the wrong operations when you have raw access to the disk, a technique this process uses, can cause you to lose data. You must have a backup.

Obviously, I do not accept any responsibility and cannot help if you break things by using these notes. Hard hats must be worn beyond this point. All contractors must report to the site office.

Boot from another disk

You’ll need a working MacOS install on another disk that you can boot from, as we need to unmount all the volumes on the disk to be scanned in order to gain raw access to the disk. I use SuperDuper to make bootable backups, and these work great for this purpose too.

Prepare the Environment

Make sure you have VirtualBox installed, with the optional Command Line Tools.

Turn off screen savers, sleep timers and screen lock, just in case the VM has taken keyboard input away from you and you are unable to unlock the Mac to check on SpinRite’s progress. It’s certainly not an ideal situation to have to pull the plug on the computer while that VM has raw access to your target disk!

Identify the Target Disk

It is critical that you identify the BSD device name for the whole disk that you want to operate on. In my case, I’d booted from disk1 and the SpinRite target disk was disk0.

Determine the correct disk identifiers with:

diskutil list

diskutil list

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Notes on Creating an Encrypted Bootable SuperDuper Backup

SuperDuper icon

SuperDuper is one of my favourite backup applications for the Mac, and I use it as part of my backup and recovery strategy.

One of its benefits is creating a bootable clone, so in the case of any trouble, you can connect the backup drive, hold Option/Alt and boot your alternative system.

The world has changed since I first used this tool, and full-disk encryption is now essential for maintaining privacy and “not-having-your-life-turned-upside-down” in the event of a loss of control of the drive with your life on it. FileVault on OS X since Lion works beautifully for your boot drive, but unfortunately I had to sacrifice the bootability of my SuperDuper backup in order to ensure it was encrypted.

Recently, a drive failure on my SuperDuper backup drive (yep, they do happen, and that’s why we back up!) required me to replace the drive. That gives a good excuse to play, and try and make a bootable and encrypted backup — FileVault-style, but on an external disk that we manage ourselves.

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Pushing System Center Operations Manager Alerts to iOS and Android

I’m a huge fan of the Pushover Simple Notification Service for receiving critical alerts about the servers for which I am responsible. It’s beautifully simple — in short, it takes the ‘walled garden’ of Google or Apple’s push notification system and extends it, so that you can push any text notification you want through their API, and it’ll get to your phone.

In this post, I will share how I get critical alerts from a Microsoft System Center Operations Manager instance to Pushover.

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Upgrading to MariaDB 5.5 on CentOS 6

Installing PHP 5.5 on CentOS 6 using IUS Repositories

I have been inspired once again to fire up my screencasting rig, to show you how to install PHP 5.5 on CentOS 6 using Rackspace’s IUS Community Repositories.

More and more web applications now are likely to require versions of PHP beyond 5.3. CentOS 6 users are stuck with 5.3, with backported security updates, unless they diverge from standard repositories or compile PHP themselves! Until CentOS 7 is with us, those of us trying to run a rock-solid web server on CentOS will be left out in the cold running recent web applications like Moodle 2.7 which require a newer PHP.

In this video, I show you how to use the IUS repositories to get PHP 5.5 running. These repositories, with their Rackspace backing, seem likely to be nice and stable going forward.

As always, I’d love any feedback you might have.

Creating a Custom Child Theme in Moodle 2.6

I’m spending a fair amount of my time now working on and supporting a medium-sized Moodle installation. I will not sugar coat it: Moodle is far from my favourite piece of web software — its considerable UI complexity being my chief complaint — but it does do a reasonable job and it has a rich enough feature set to make it quite an asset in the education world.

This complexity to Moodle sometimes doesn’t exactly make it easy to do the right thing as a developer, and working with themes could be somewhere where developers diverge from best practices. The temptation to clone your favourite theme just to make a few tweaks here and there leaves people unable to track changes to the base theme, and keep their site up-to-date.

So, I have put together a video showing how you can create a custom theme (a child theme in WordPress parlance) that inherits mostly from your base theme, but allows you to override CSS and even bits of the HTML structure of Moodle’s generated pages.

I think it’s actually an easier process than people think!

As always, I welcome feedback, and if you found this particularly helpful, I’m always happy to have a few pennies drop into the PayPal account!

Find this tutorial useful?





How to install Cacti on CentOS 6

It has been far too long since a video tutorial made its debut here, so I would like to introduce a new tutorial!

Cacti is a great graphing and monitoring tool, but I have struggled in the past with getting it installed, and getting it to do what I want. It can be a little bit complex and fiddly, but recently I have had more success and am putting it to good use measuring and graphing more things.

In this tutorial, I will walk you through installing Cacti on a basic CentOS 6 system with Apache, PHP and MySQL already installed. By the end of the video, it is collecting information for the default graphs in the default installation.

I hope to extend this video series soon with some details about the additional graphs I have recently succeeded at getting installed.

As always, your comments and feedback are appreciated!

Teaching Computer Security Basics

Over the past few years, I have ended up coming into contact with many computers belonging to individuals. My reason for doing so has varied, but usually I am helping them with something unrelated to security.

I found myself constantly saying the same things when I noticed bad security practices — “you really should update or remove Java”, “you need to actually stop clicking ‘Postpone’ and restart the computer some time”, “untick that box to install the toolbar” and so on.

Computer security is hard.

But, particularly when it comes to computers belonging to individuals, we have let the perfect become the enemy of the good. We have allowed anti-virus vendors to parrot messages about “total protection” instead of teaching sound principles and encouraging good practice.

Computer security, at least in this context, is in large part a human problem, not a technology problem.

So, a while ago, I had an idea to put together a really quick, 5-minute presentation that would encourage computer security principles that could dramatically lower the risk of individuals’ machines getting infected. I stripped it down to what I saw as the four most important principles (few enough that they might actually be remembered!):

  1. Keep software up-to-date — with emphasis on the importance of updates, despite the inconvenience, and mention the high-risk software titles du jour whose updates may not be entirely hands-off (Flash, Java, etc.).
  2. Keep up-to-date antivirus — with emphasis on such technology as the last line of defence, not ever a solution in and of itself.
  3. Install software from trusted sources — perhaps the most important principle that requires behaviour change, this is about getting people to feel confident enough to build a trust model for software and then make informed decisions about each and every installation they make.
  4. Be suspicious — in particular about communications that invite clicking on things and so on, including using alternative channels to verify legitimacy of things that look suspicious (e.g. never clicking unexplained links!)

I’ve not given this talk yet, but I’d like to. It feels that computer security on home PCs is, in general, so awful, that even a very basic set of ideas that are memorable enough to implement can probably make a significant difference to the health of our personal information infrastructure.

I would welcome feedback from others on these slides, as well as the idea.

I think it is quite important to keep it to five minutes, make it concise enough that it will be memorable and actionable, but I’m sure this idea can (and needs to) evolve and improve over time.

If you would like to use the slides, feel free to do so under the Creative Commons BY-NC-SA 2.0 licence. It would be great if many people could hear this message.

Restoring a Windows 8 Bootloader

Screenshot of the Hyper-V Manager on Windows 8

Microsoft’s Hyper-V is a really cool virtualisation technology I have been having fun exploring. You cannot run a Hyper-V Server on a Windows 7 host, however, so in order to run it, I installed Windows 7 and Windows Server 2008 R2 side-by-side, and used it in the latter.

All that has changed in the era of Windows 8, however, and you can run a Hyper-V Server on the client version of Windows 8, if it is Windows 8 Pro. Hooray!

So, to cut a long story short, post-upgrade, I felt I didn’t really need my separate Windows Server 2008 R2 partition for Hyper-V, so I deleted it and expanded the Windows 8 partition to fill the space. Only to find that Windows now wouldn’t boot. Oops.

I originally installed Windows 7 first, followed by Windows Server 2008 R2, following best practice to install newer operating systems after earlier ones. What had happened now, though, was that I had just wiped out the bootloader that was sitting happily on the Windows Server 2008 R2 partition.

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Protecting your browsing with Certificate Patrol for Firefox

I read this BBC News story about mistakenly issued security certificates recently, which allowed the people with those certificates to impersonate any Google websites and intercept traffic to them. It struck me as quite significant that this particular story made it to &#8216mainstream’ tech reporting.

There is a more detailed, and perhaps more accurate, commentary on this attack on Freedom to Tinker. It perhaps may not have been ‘cyber criminals’ as the BBC reported it when I first viewed the story!

Anyway, given the attention to this issue, I thought it a good opportunity to review this kind of attack against SSL/TLS — the security system upon which we all now depend. More importantly, I wanted to show Certificate Patrol, an add-on for Firefox that would allow you to notice a suspicious change to an certificate and thwart this kind of attack.

The weaknesses inherent in having too many organisations that are able to issue security certificates for any domain are becoming more clear. While this kind of attack is extremely rare, at the moment, ‘at the moment’ is a very poor security response! Hopefully, more awareness of these limitations of the internet’s authentication infrastructure can help put pressure on browser vendors, website owners and CAs to make everyone more secure.