sawyl: (A self portrait)
Finally worked out how to get my camera — a Lumix G-series — to dump its contents directly to a network drive — Samba running on a Raspberry PI — rather than copying the contents of the SD card directly. I'm not sure it's any easier or quicker, but here are the steps for posterity:
  1. Fire up the Raspberry PI
  2. Install samba
  3. Install samba-common-bin
  4. Create a new user, e.g. lumix
  5. Set a password with smbpasswd
  6. Create an upload directory for the lumix
  7. Update /etc/samba/smb.conf to add the upload directory and set the correct permissions
  8. Connect the camera to the wifi point and authenticate
  9. Select the drive share and authenticate
  10. Select the correct media type when prompted
  11. Select the images to transfer
  12. Wait...

It's worth noting that if you select an invalid media type — e.g. jpeg when you only ever shoot in raw format — the camera still prompts you to select images for transfer but returns an unhelpful message that implies that there is insufficient space on the remote file store...

sawyl: (A self portrait)
A couple of weeks ago, on a bit of whim, I bought myself a Raspberry Pi as a bit of a toy. Having done this I promptly noticed a minor snag: my my total lack of USB input devices and the absence of HDMI ports on any of my monitors.

After a bit of thought, I realised that I was being a fool and that I could use my long-honed command line skills to set up a headless box in no time at all. Thus, I grabbed a copy of Raspbian, dd'd it to my SD card, booted the Pi off the network, used ssh to install a VNC server, installed and configured Avahi to register the VNC with OS X, and used the Screen Sharing App on my iMac as my VNC client.

The gory details... )

Easy!

sawyl: (A self portrait)
After my machine at work was upgraded to add a second monitor, I couldn't work out why I couldn't get it to power on. So I did the obvious: I checked I hadn't missed an extra switch; I reconnected the kettle flex at the back; and I dived under my desk and confirmed that the socket was on. What I didn't do was check to see whether the guys who'd done the upgrade had simply plugged it into the desk strip and failed to turn it on. Which, of course, they had. Typical.
sawyl: (Default)
Well that was easy. Missing my WindowMaker email notifier and unhappy with the replacements, I spent my lunch hour whipping up a new one using a bit of python and libnotify.
sawyl: (Default)
Having ported the most essential of my emacs configuration settings — narrowing, electric minibuffer, post mode, and a couple of minor customisations — I'm starting to feel more at home with RHEL6 and with GNOME.

I like the fact that the latest versions of konsole supports the standard foreground and background escape sequences, allowing me to ditch xterm and still have my login sessions automatically colour code themselves and automatically change colour on disconnect — a big deal for me, because I use it as an extra safeguard to make sure I'm working on the right machine. I like the way that this allows me to accumulate different sessions on the same machine in a single window and to switch between them using tabs. I'm not convinced by the tab naming scheme. It should be possible to set the tab and window names separately, and it ought to be possible to set the tab name using the icon name, i.e. to get it to pick up the name set by the standard icon name escape sequence. But that's a trivial gripe.

I still don't like fact that it doesn't seem to be possible to hide windows — something I've come to expect from OS X and WindowMaker — and I miss being able to shade windows, although I can live without either of them. But the the window manager's apparent inability to open applications in particular workspaces? Hopeless lossage.
sawyl: (Default)
I've passed a deeply ineffective day, wasting time I didn't really have to waste, trying to get my desktop system into a semi-usable state after the support people upgraded to Red Hat 6. To be fair, it wasn't so much the upgrade to RHEL6 that did the damage — although I noticed a few of my existing tools had been struck down by 64bit disease — but the switch over to the GNOME desktop.

Despite the limited range of my standard set of applications — emacs, firefox, xterm, mutt — it took me an hour or so to get things into a semi-usable state. And then something like that again to duplicate the most heavily used — and hardwired into muscle memory — keyboard shortcuts. All of which served to put me in a less than delightful mode.

But on the plus side, I've realised just how much garbage has accumulated in my setup over the year. I'm starting to wonder whether now might not be a good time to declare configuration file bankruptcy and, instead of trying to copy everything forward, just to copy the stuff that I really can't live without. That alone should be enough to keep me out of mischief for the next month or so...
sawyl: (Default)
It's amazing how linuxocentric the world has become. Thus, I was discussing the installation of a piece of GPL software on a box, one not admined by our group, with one of my colleagues. I'd already investigated — and discarded — the idea of installing sudo on the machine, when I realised how many of the necessary tools where missing. But my colleague, buoyed up with linux induced optimism, was unable to conceive of either a non-Linux system or one without the full spread of development tools:

Them You've installed [a specific bit of monitoring software], haven't you?
Me [ guardedly ] Yes. Why?
Them I'm going to install it on the Library Station to monitor tape mounts. I've talked to the admins and they're happy with it. All I've got to do is raise a change for it...
Me [ trying to temper the enthusiasm] I don't think it's quite that easy
Them ...all I need its the RPM. Where is it kept?
Me You do realise it's running Solaris, don't you? So an RPM would really be any use...
Them [ crushed ] Oh. [ cheering up again ] Well, maybe [ the beloved vendor ] could give me a packaged version...
Me I doubt it. I think that you'll probably have to build it from scratch but...
Them OK, I'll go and get the tarball. Which version do I need?
Me ...first you need to check whether the admins have got a working compiler — I doubt they'll have bothered since it's not supposed to be a general purpose machine.
Them I'll go and check [ he goes and returns ] No. They don't think they've got one. But they're going to have a look around to see what they can find. I just assumed everything was like Linux...

There then followed a painful conversation in which I explained to him the concept of a chargeable extra and how, in the bad old days, the vendors deliberately hobbled the C compiler shipped with the system in such a way that it could only rebuild the kernel. And my colleague's eyes were as big as saucers.

Oh, to be young and idealistic again...

sawyl: (Default)
Just before Easter, I was asked to look into the behaviour of threading under Linux. One of my colleagues had noticed that some multi-threaded processes being run on a machine running 2.6.9 generated multiple processes, whereas others generated a single process.

After confirming that both programs were using the same threading libraries, we attempted to investigate whether they were running with the same process scoping. We varied the scope with pthread_attr_setscope() only to discover that the call is not supported under Linux.

We then looked at the applications in more detail and found that the multi-process executable was actually a shell script. This set the environment variable LD_ASSUME_KERNEL to 2.4.10 prior to launching the actual application binary.

We then used a small piece of C to test the hypothesis: source code )

When the test application was run without any special options, it generated a single process with three threads: first test )

When the same application was run with LD_ASSUME_KERNEL set to 2.4.10, it generated four separate processes: second test )

Mystery solved!

sawyl: (Default)
Bit of a dead loss day, workwise. My workstation was down for much of the day for an OS upgrade then, when it finally did come back up, it was virtually unusable because all my extra magic had been dumped to make way for the upgrade. I suspect I'm going to have to spend most of the coming week trying to get things back up and running.

Bah.

nfswatch

Sep. 21st, 2006 07:54 pm
sawyl: (Default)
After spending most of the last week munging the output of nfswatch in an attempt to work out why all our file servers seem to have gone into a pathological slowdown, I've concluded that nfswatch might just be the greatest tool ever. It certainly knocks spots of the standard NFS tools bundled with our obsolete version of Linux.
sawyl: (Default)

I've been working with one of my colleagues on a plan to upgrade the production version of Linux on one of the tin gods. Being supremely laid back about the whole thing, I produced a plan with three steps:

  1. Install new kernel
  2. Shutdown
  3. Reboot

Needless to say, my colleague and the High Commander wanted more detail, so we came up with a plan with 0 steps and scheduled some downtime for next week. Unfortunately, it looks like there's way too much work to do in next to no time, so it looks like we're going to have to ditch a load of stuff. While attempt to cheer up my despairing cow orker, I remembered Karl von Clausewitz' famous quote:

No Battle Plan Survives First Contact With the Enemy.

I bet if he were alive today, Clausewitz would be a sysadmin.

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