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Cake day: July 5th, 2023

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  • An older friend of mine told me years back about an incident that happened on a university VAX running Unix. In those days, everyone was using vt100 terminals, and the disk drives weren’t all that quick. He was working on his own terminal when without warning, he got this error when trying to run a common command (e.g. ls)

    $ ls -l
    sh: ls: command not found
    

    So he went on over to the system admin’s office, where he found the sysadmin and his assistant, staring at their terminal in frozen horror. Their screen had something like:

    # rm -rf / tmp/*.log
    ^C^C^C^C^C^C^C^C^C^C
    # ls -l
    sh: ls: command not found
    # stat /bin/ls
    sh: stat: command not found
    

    A few seconds after hitting return, and the rm command not finishing immediately, he realised about the errant space, and then madly hammered Ctrl-C to try to stop it. It turns out that the disk was slow enough that not everything was lost, and by careful use of the commands that hadn’t been deleted, managed to copy the executables off another server without having to reinstall the OS.


  • There’s more to this than just th ORR being mean, the WCRC have not been holding up their end of the bargain:

    You are failing to ensure the health and safety of your passengers and crew, thus putting them at risk of serious personal injury, as you are not implementing the controls identified in your risk assessment for rolling stock fitted with secondary door locking, in that:

    1. Passengers are being told by train crew to operate the secondary door locks;
    2. Stewards are not preventing passengers from operating the secondary door locks;
    3. Stewards are not preventing passengers from leaning on train doors or from leaning out of the open droplight windows in train doors of moving trains; and
    4. Secondary door locks are not in the ‘locked’ position or are being opened by train crew before the train is stationary; Therefore, creating a risk of persons falling from a train or being struck by infrastructure being passed by the moving train.

    The WCRC have form for poor adherence to railway operating rules - they’ve been banned before once, see the Wootton Bassett Junction near miss (where one of their steam tours came within under a minute of colliding with a high speed train due to train crew routinely defeating safety systems) - https://en.wikipedia.org/wiki/2015_Wootton_Bassett_rail_incident - in brief, this ended up with WCRC being banned from the national rail network for a time, the notice stating “the operations of WCR are a threat to the safe operation of the railway”.





  • Debian (a very conservative distro) switched to Wayland by default in debian 10 if I’m not mistaken (we’re now on 12).

    I didn’t notice the change until I tried to run a niche program that really needs X11. Unless you’re doing this kind of thing, then you can probably just use Wayland. At least in Debian it’s really easy to switch between Wayland and X11 by selecting the session type when you log in.



  • mackwinston@feddit.uktoLinux@lemmy.mlHDD or SSD?
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    11 months ago

    But it does help give an idea of who’s making the most reliable drives (both SSD and hard disk). No, this isn’t a guarantee, but it’s still useful information especially when it’s not just a friend-of-a-friend anecdote but gained over tens of thousands of drives.


  • mackwinston@feddit.uktoLinux@lemmy.mlHDD or SSD?
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    11 months ago

    The biggest factor in making good, automatic backups for my home server wasn’t speed (it’s an older machine with a SAS array of spinning discs) but the availability of affordable cloud based backup storage (I use Backblaze and sync my files to a storage bucket once a day). Then it becomes automatic, and no one has to remember to do it, and it’s offsite.

    Even when external USB discs got cheap you had to remember to do it regularly and many people would forget.


  • mackwinston@feddit.uktoLinux@lemmy.mlHDD or SSD?
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    11 months ago

    Hard drives are not that unreliable, well, so long as you pick the right model.

    BackBlaze’s statistics are here: https://www.backblaze.com/blog/backblaze-drive-stats-for-q2-2023/ - they run tens of thousands of inexpensive drives to run their cloud backup service. Some HDDs are much better than others.

    That document also links to their SSD statistics (they don’t have that many SSDs yet, so the stats aren’t as good) but while SSDs tend to have lower failure rates, there are some models of SSD that have higher failure rates than HDDs. For example, one Seagate SSD they use has an AFR (annualised failure rate) of just under 2%, but one Toshiba HDD they use has an AFR of only 0.31%. (Another thing to be aware of is that Backblaze’s drives will all be in air conditioned data centres, not in the random temperature/humidity spreads of a PC in someone’s home).

    If you look at the stats as a whole generally SSDs have half the failure rate across the board to HDDs, but it varies a lot by make and model. So be careful on which you pick, and take backups :-) For my money, all my PCs (desktop and laptops) are pure SSD setups. My server still uses spinning disks, mainly because it’s older server class hardware with a SAS array.


  • Hydrogen is pretty much a non-starter for all transport. It’s usually an excuse to do nothing on the lines of “But we’ll have hydrogen powered X soon, so therefore we don’t have to do proven technology Y”

    The problems of hydrogen are:

    • Tragically poor energy density by volume. Hydrogen cannot be liquified at any reasonable temperature (its critical temperature is on the order of 30K, or about -243 C) so it has to be compressed to immense pressures to get any kind of energy density at all.
    • H2 is the smallest molecule, it leaks through most pressure vessels, making them brittle in the process, the last thing you want to have in a 3500+ PSI container. Because it’s constantly leaking, you’re constantly losing fuel.
    • It is only economical to make it from fossil fuels and this will be the case for some time to come. You might as well just use the fossil fuels directly and avoid the difficulty of handling hydrogen and the associated losses making it.

    Overhead wires are proven and efficient technologies. You can have more powerful locomotives running off overhead wires than anything self powered (the most powerful diesel freight locos in the UK are around ~3300 hp, and even an elderly class 87 electric loco is around ~5500 hp). For railways if it’s fast, frequent or freight, overhead electrification is best.