Sunday, 19 April 2015
Last week at work we ran into an interesting dilemma: We have a nice set-up to enable some level of single sign-on for our external users (business partners), across a suite of applications they use. We're preparing to deploy some browser-based COTS software into that suite of applications. Like most applications, the new one has a "log out" button.
When the user logs out, we'd like to take them back to a page that says, "You have logged out. To log on again click here." But we can't, because once they click on the log-out link, our "single sign-on" becomes "single sign-off". Before they can see any page on our partner network, we have to send them to our corporate log-in page.
We have options, so it's not like this is a huge problem. But no one thought of it before, so we're going through a bit of churn while people get their head around the problem and decide how they want to deal with it.
So don't forget, "single sign-on" also means "single sign-off".
Sunday, 18 January 2015
When I read his post, I thought, "what about the marbles outside the bag." In the universe of marbles, 50 % are blue and 50 % are pink. 10 % of each colour are sparkly. So if you step outside the bag (e.g. the resumes you received for a job posting), the probability of finding a sparkly pink marble is actually greater than that of finding a blue one.
Another thought would be to get a bag of pink marbles from the factory. Then it's really easy to get pink sparkly marbles. And you'll probably get to chose amongst all the sparkly ones yourself, at least until other people clue in that this is a good way to get sparkly marbles. This is the equivalent of recruiting from women in IT meetups and suchlike. And that's not so hard.
Sunday, 4 January 2015
The Plantronics M165 Marque 2 Bluetooth headset paired very nicely with my Android phone. To pair it to my computer running Linux Mint 17 I:
- Clicked on the Bluetooth icon
- Turned on Bluetooth
- Clicked “Set up a new device…”
- Pressed and held the Call button on the headset for five or six seconds, until the computer found the headset (the Plantronics documentation is here)
The sound test in the Sound Settings dialogue didn’t sound right, but I could play music through the headset and it should sounded recognizable.
Using it with Skype gave super-sucky sound quality. Lowering the PCM level in
alsamixer to about 70 made the sound quality a lot better, but still not great (lower the PCM level was suggested here).
alsamixer is a command-line application. Open a Terminal and type:
alsamixer, then use the left and right arrow keys to find “PCM”, and use the up and down arrow keys to set the level.
Still trying to improve the sound quality, I noticed that the built-in microphone is on when the headset is on. On a Skype test call, manually turning off the microphone didn’t seem to make a lot of difference to the sound quality.
Using Audacity to record sound, the quality of the built-in microphone was even worse than the headset.
[Edit] Using the headset, I made a Skype call to my son, and he said the quality of my voice was okay. I could also hear him okay.
In case you need to know, the Bluetooth config files are in
Tuesday, 11 November 2014
I keep hearing about how we don’t need cable any more to watch movies or TV. All the talk convinced me I should try. Well, talk about some serious time wasting…
I wanted to:
- Put my DVDs onto a file server and play them, without having to load them in the DVD player
- Play on the TV anything I can see on my computer through my browser. In particular, I wanted to play TV from Guatemala. Some of the channels there stream a lot of their programming straight to the Internet
- Play Netflix, and possibly other services, with a decent selection of material. I had Netflix for a few months a couple of years ago but, living in Canada, we quickly ran out of material to watch
- Do everything in such a way that everyone else in the family can use the technology, once I get it set up
What have I managed to do?
- I can play my videos on my TVs, via a Roku 3. I’m also optimistic that I can get my WDTV Live to work as well. It required a lot of research, mostly because I had to convert the DVDs to a different format, and buy a big new storage device, a Synology DS412+ NAS device
- I can play some stuff on my TV that I can play in a browser, but not everything. To be more accurate, I can play stuff from YouTube, but not anything else. This is quite useful, but not all that I wanted
- I haven’t tried Netflix with the VPN yet, but I don’t expect any issues. I have a VPN from PureVPN. Setting up the VPN the way I wanted it was a true adventure, not covered in this post
- The younger members of the family can use it, but I’m frequently frustrated by the number of hoops I have to jump through. It’s sure not like just turning on the TV and flipping through the channels
Some of this was surprisingly easy, and some required the typical technology flailing that I get into. Overall, it’s a solution that requires a certain amount of comfort with technical topics. I’m starting to get my head around digital video, but I’m nowhere near an expert. I also know a lot about Linux, and enough about networking to have an idea of what I wanted to do.
This post will only talk about the process of getting my DVDs onto my network and playing them from the TV. I’ll cover:
- The storage device for movies
- How to play a movie from the storage device on a TV
- How to put your DVDs on the storage device
- What if you want to do something different from what I did
Video work requires lots of disk space. A non-HD movie from a DVD takes more than a GB. In my experience, a typical movie DVD has more than 4 GBs on it. And the software for playing movies on a TV, at least the software I found, doesn’t play from the ISO file (direct copy of a DVD), so you have to convert it. In the process of converting, you may need even more space.
The Synology doesn’t actually come with disks (so, for example, don’t get excited about how cheap it is when you look up the price). You buy the disks you want to put in it. That gives you the freedom to decide how much storage to buy.
I bought the maximum of four disks, 3.5 in, with 3 TB capacity each, and used the default formatting option, which is a type of RAID-5. The result is that I have just under 8 TBs of usable storage space, plus the ability to replace any single-disk that fails with no loss of data.
I ordered from NCIX, which has a big presence where I live, so they delivered in less than 36 hours. I had it running on my network in 48 hours after ordering. Total cost was around C$200 per usable TB.
(You could never get storage that fast and that cheap in the enterprise IT world. I know it’s a bit unfair to compare, as it’s not completely apples-to-apples, but seriously, CFOs need to ask their CIOs what benefit the corporation is getting from overpaying for storage from EMC, HP, NetAPP, or Hitachi. They don’t get responsiveness or agility. They sure don’t get cheap storage – at work I pay $9,000 per TB. That’s right. 45 times as much.)
I thought about putting together my own storage box using an old computer from FreeGeek. I’m sure it would have been a lot of fun for a geek like me. The reality is that it wasn’t going to be much cheaper, and it would have taken a lot more time.
Note: The DS412+ doesn’t appear on Synology’s site any more, so perhaps there’s a newer equivalent.
Once I got the Synology running, I was pleasantly surprised to discover that I had something that serves up videos to a Roku 3. The Synology comes with built-in software to be a media server.
The Roku 3 has an app called DS Media that works with the Synology media server. I had to get it from Roku’s channel store, but that’s pretty easy. It was under the “Audio and Video” category, and was free.
Once I had the DS Media channel on the Roku, all I had to do was upload my movies, in the right format, to the “video/movie” folder on the Synology. Getting them in the right format was the next trick – see the next section.
I haven’t got the WDTV working with the Synology media server, but it seems to recognize and connect to it, so I’m hoping…
I had started to play around with Plex on my home-built file server, just enough that my free trial period had run out. Since the Synology came with its own thing, I haven’t pursued Plex. A lot of people like Plex.
I figure if I buy a DVD, I can make a copy of it and watch it on my TV. (I guess that’s my disclaimer that I’m not encouraging you to make illegal copies of your videos.)
I already had a lot of DVDs copied to ISO images, by using:
dd if=/dev/cdrom of=movie-name.iso
That’s a Linux terminal command. Mac users can do something similar in a terminal. Windows users: you’ll have to figure it out for yourself. Sorry.
It turns out, in this fancy modern world, video players don’t play ISO files. It sort of makes sense. You don’t want to have to go through a DVD’s menu if you’re watching on your phone or tablet.
It turns out that converting an ISO to a file playable by a phone, tablet, or TV (like the Roku or WDTV) can be a savage journey into the morass of video encoding. The morass includes open-source telenovelas about competing projects (this seems to be a relatively unbiased summary), patent-encumbered video formats, lossy video formats, and differences in Linux distributions.
You can avoid most of that trip by doing this:
- Install VLC media player and Handbrake from your distribution’s repository. You don’t need to use VLC directly. VLC installs software that enables Handbrake to rip some, but not all, copy-protected DVDs
- Review this link for how to optimize the Handbrake conversion for the Roku. Standard DVDs don’t have HD video, so 480p is as good as it’s going to get
- Use Handbrake to rip your DVDs or ISO files to the open Matroska container format (.mkv). Matroska is now well-supported on Android and TVs/TV boxes like the Roku
If you want to play your videos on an Apple device, it’s more complicated. In fact, I haven’t got it to work yet. The version of Handbrake on distributions derived from Ubuntu 14.04, like Linux Mint 17, doesn’t support output to the MP4 container format, for software patent reasons. The MP4 container is the only format supported on Apple products.
There are suggestions that I could build my own version of Handbrake that would work, but one set of instructions I followed didn’t work, and I haven’t pursued it further.
Doing Something Different
Most of the time I spent on this was the research and learning. If you want to try exactly what I did, and you’re comfortable Googling for advice on technology topics, it’s not that hard.
However, there’s a good chance that you won’t want to do, or won’t be able to, do exactly what I did. Here are some things to watch for:
- The Linux video world is constantly in flux. If you’re using versions after Ubuntu 14.04, or distributions not derived from Ubuntu, you should definitely confirm that you can rip your DVDs before you spend a bunch of time, and money on hardware for storage or playing
- If you’re not using Linux, confirm that Handbrake and VLC work on your version of Windows or Mac OS, and can do what you need
- If you have anything other than a Roku 3 for playing Internet TV, you need to find evidence on the Internet that your device can work with the Synology media server. Look for the evidence by Googling the name of your device and the model of Synology you plan to buy
- If you want to use a different storage device, you have to figure out whether it has a media server, and whether the media server is compatible with your TV device
With a Synology NAS storage device, a Roku 3 with the DS Media channel, my own DVDs, and Handbrake, I was able to convert DVDs to movie files, store them on the storage device, and play them on a TV through the Roku.
Monday, 3 November 2014
If you do a dry run, moving a computer to a different data centre, and it works, why would you move it back?
If that still doesn't make sense, think back to the days when moving a computer included a physical activity: unplugging the computer, putting it on a truck, and shipping it to your new data centre. Would you really propose that you do a dry run of that, then, if your dry run succeeds, putting it back on a truck, moving it back to the old data centre, getting it running again, only to then do it "for real" some time later?
Granted, in the world of virtual computers, you don't have to actually move the computer back. However, there is still a list of activities you have to do to move a virtual computer, that you have to undo. There's just as much a chance you'll screw up the undoing of those steps, as there is that you'll screw up the doing of them in the first place. A dry run actually increases the overall risk of the relocation.
Monday, 29 September 2014
apt-getfails, and terminates with a partially installed package. You’ll know that has happened when you get a message like this when you run an
Once that happens, you can’t use any
E: Unmet dependencies. Try using -f.
There’s lots of advice out there about what to do, but the pages I’ve found always seem to leave something out, or assume knowledge of
dpkgthat I don’t have.
So based on the last time this happened, here’s how I plan to recover the next time I run out of space. Warning: lots of Terminal commands coming up. I do everything in the Terminal for a few reasons:
- The happens to me most often with servers, as I’m trying to save space, especially for virtual machines. My servers don’t have a GUI
- Terminal works for both desktop and server machines
- It’s easier to document commands for the Terminal
Then I find out what version of the kernel I’m running:
$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda1 3.7G 3.7G 0 100% / ...
Next, I find out what kernels are installed:
$ uname -a Linux ixmucane 3.13.0-24-generic #47-Ubuntu SMP Fri May 2 23:30:00 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
If I have at least two versions older than the one I’m currently running, I can remove the oldest one (replacing the “n.nn.n-nn” with the version number I want to remove):
$ dpkg --list | grep linux-image
This should free up lots of space, but I check again with
$ sudo dpkg --purge linux-headers-n.nn.n-nn-generic $ sudo dpkg --purge linux-headers-n.nn.n-nn $ sudo dpkg --purge linux-image-extra-n.nn.n-nn-generic $ sudo dpkg --purge linux-image-n.nn.n-nn-generic
df -h. Then run:
If the amount of space it needs is less than what’s available according to
$ sudo apt-get -f install
df -h, then I go ahead and finish the install. To be safe, I also do:
If there’s not enough space, and I have more old versions of the kernel installed, I just repeat the above
$ sudo apt-get update
dpkguntil I have enough space to finish the install.
The above is the happy path. If I didn’t have two versions older than the current running kernel, I would try to remove the partially installed packages. Looking again at the output of:
if the newest version there is newer than the kernel currently running, then I would try the above
$ dpkg --list | grep linux-image
dpkgcommands to remove the partially installed packages. Some of them won’t work, of course, since the package isn’t installed, But once all the installed packages are removed, presumably there would more space and I could try:
The reason I want to have two versions older than the current version is in case for some reason the current kernel doesn’t work, I can go back to the previous version. This is a cautious approach. If I’m really stuck, I would remove all versions except the current version. I’d probably make sure that I could boot the current kernel first. I haven’t had to do this and I hope I never do, but…
$ sudo apt-get -f install
Monday, 26 May 2014
I submitted the usual paperwork like I've done a number of times before, but this time I was told that the role I selected wasn't a role in the timesheet software, and neither was the individual's official job title. The individual is an employee of the client's company.
I felt somewhat smug that I was able to completely ignore the absurdity that an employee's job title isn't acceptable to the company's timesheet software. But then I realized what I was being asked to do: I had been told two titles that weren't acceptable to the timesheet system, but I had not been told what would be acceptable. I guess I'm supposed to randomly guess until I get the right answer.
Definitely a Dilbert moment. But then I asked myself, "Why would someone respond to me this way?" The person I was dealing with is a very nice, dedicated worker. They weren't just trying to make my life difficult.
I think it's because, in the enterprise IT world, there's no upside to providing service. An IT manager has too many demands, and not enough people to meet the demands. In addition, the path to promotion for the manager is through more responsibility, and the way to get that is by having more staff and a bigger budget. If you provide good service for the same personnel level, you're not meeting your boss's needs.
Also, there's no upside to taking responsibility. If you take responsibility, you can be blamed if, sometimes, you don't achieve the desired result. Better to leave all decisions up to someone else, and don't give them any help, in case they blame you if your help turns out not to be helpful.
This culture so permeates our business that it's not absurd to just tell someone, "You got it wrong," without giving so much as a hint as to what the right answer might be.
No wonder people have such low expectations of IT.