September 2018 - Talk - lists.gtalug.org

war story: power failure makes CentOS system unbootable
by D. Hugh Redelmeier 30 Sep '22

30 Sep '22

tl;dr / spoiler: change fstab so that /boot/efi is not automatically mounted. See the recommendation at the end of this message. My gateway computer is a little PC running CentOS. It does not come back after a power failure. The reason (as best I can tell) is interesting and I think that I have a fix. My system is UEFI. It boots from a UEFI system partition, known as /boot/efi to Linux. If this gets corrupted, it won't boot. It is a VFAT partition. On my gateway (a Zotac Zbox RI321, a cute little box with two ethernet ports), the UEFI firmware apparently won't boot if the dirty bit is set in the system partition. CentOS normally runs with /boot/efi mounted. So when the system isn't shut down cleanly, the dirty bit will be on. Consequence: the system is not going to boot after a power failure. Odd observation 1: if I put a live Fedora 25 USB stick in the system and try to boot in this otherwise-unbootable state, CentOS boots from the main disk. So this really looks like a firmware bug/quirk. Odd observation 2: fsck doesn't seem to automatically fix the system partition. Once CentOS 7 booted, I dismounted /boot/efi and did an fsck on it. $ sudo fsck /dev/sda1 fsck from util-linux 2.23.2 fsck.fat 3.0.20 (12 Jun 2013) 0x25: Dirty bit is set. Fs was not properly unmounted and some data may be corrupt. 1) Remove dirty bit 2) No action ? 1 Leaving filesystem unchanged. /dev/sda1: 16 files, 2420/51145 clusters Googling got me to <https://www.centos.org/forums/viewtopic.php?t=50917> In particular, this advice seemed quite good: ==== recommendation ==== Two other changes I recommend for UEFI systems, to each OS's /etc/fstab. - For the /boot/efi mountpoint, add the mount options x-systemd.automount,noauto - Change fs_passno (last column) to a 1 or 2; the canonical fstab instructions suggest 2, but systemd treats 1 and 2 as the same. The first change means the EFI System partition will not be automatically read-write mounted at boot time; it's a bad idea this is the default because it puts the ESP at risk especially if ther are crashes, FAT has no journal and will therefore always be marked dirty in such a case; no other UEFI OS mounts the ESP by default. Second, if anything tries to access /boot/efi (read or write), systemd will automatically mount it, and because of the fs_passno 1 or 2, it will fsck it first and that fixes and clears the dirty bit in case it's set. Right now without these changes, it's just a matter of having the right number and bad timing of crashes to render the EFI System partition corrupt.

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Dinner tonight?
by David Collier-Brown 13 Nov '18

13 Nov '18

What's the current state of thought??? https://wiki.gtalug.org/pre-meeting_dinner -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest davecb(a)spamcop.net | -- Mark Twain

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FSOSS 2018 registration
by D. Hugh Redelmeier 05 Oct '18

05 Oct '18

The registration page just went up. - Oct 25 & 26 (Thursday and Friday) - early bird (cheap) registration ends Oct 15. $75 for non-students, non-staff (note: any (educational?) institution is good for a discount. - seems to be at the Seneca @ York campus (I had heard that they were going to be moved; maybe next year) - for the first time it will be on the subway! I've enjoyed FSOSS for the years I've attended. I recommend it. You can even give a talk!

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tr: Illegal byte sequence
by Giles Orr 02 Oct '18

02 Oct '18

I wrote a random password generator shell script, the core of which is this one-liner: dd if=/dev/urandom bs=1 count=256 2>/dev/null | tr -dc 'A-Za-z0-9!@$%^&*(){}[]=+-_/?\|~`' | head -c 32 The very ugly string 'A-Za-z0-9!@$%^&*(){}[]=+-_/?\|~`' is the ALLOWED values. The two counts are replaced by variables, the first 'count=' needing to be a lot bigger than the final '-c <number>' which is the length of the password generated. The size difference is necessary because 'tr' throws away a lot of values. I've never had a problem with this on Linux, but on a Mac under some circumstances we get: tr: Illegal byte sequence My coworker, who's also using the script, always got that error. It seems to come down to locale settings. Mine by default are: $ locale LANG="en_CA.UTF-8" LC_COLLATE="en_CA.UTF-8" LC_CTYPE="en_CA.UTF-8" LC_MESSAGES="en_CA.UTF-8" LC_MONETARY="en_CA.UTF-8" LC_NUMERIC="en_CA.UTF-8" LC_TIME="en_CA.UTF-8" LC_ALL= My co-worker's settings are: LANG="en_US.UTF-8" LC_COLLATE="en_US.UTF-8" LC_CTYPE="en_US.UTF-8" LC_MESSAGES="en_US.UTF-8" LC_MONETARY="en_US.UTF-8" LC_NUMERIC="en_US.UTF-8" LC_TIME="en_US.UTF-8" LC_ALL="en_US.UTF-8" A reliable fix (so far ...): $ export LC_CTYPE=C $ export LC_ALL=C $ dd if=/dev/urandom bs=1 count=256 2>/dev/null | tr -dc 'A-Za-z0-9!@$%^&*(){}[]=+-_/?\|~`' | head -c 32 z%V;d9uZfWLTgsT*J]Bz`mAmA I'd really like to understand what the problem is, why 'tr' barfs, and what the 'locale' settings have to do with this. Thanks. (Should anyone have arguments against this as a method of password generation, I'll entertain those too. And yes, I'm aware of 'apg' but it's not readily available for Mac and this is much lighter weight.) -- Giles https://www.gilesorr.com/ gilesorr(a)gmail.com

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glittery cheap but useless toy computers
by D. Hugh Redelmeier 30 Sep '18

30 Sep '18

The price of this looks very attractive: <https://www.zapals.com/nexbox-a95x-tv-box-4k-android-7-1-amlogic-s905w-quad…> - US$23.99, with free (very slow) shipping, probably no tax - only FullHD - 1G RAM, 8G eMMC (a little light) - Amlogic S905w: quad core Arm Cortex A53 processor; penta core Mali 450MP GPU. There are a lot of cheap boxes meant for running Kodi and this is one of them. Technically, they run Android and easily hook up to your TV. But they don't run Android TV (a subtle but important difference). Because of "Digital Rights Management", they cannot run Netflix at a good resolution. I don't remember if YouTube also limits them. So what's left? Unauthorized content discovered through Kodi plug-ins. I've never tried this. I understand that there is a large turnover in plug-ins as they get taken down. For TV use, I much prefer a Xiaomi Mi Box with genuine Android TV (US$70 from US Walmart). BUT. The raw hardware for these cheap boxes is interesting. Faster than a Raspberry Pi. And these come with a box, remote control, and power supply. Expandability and openness in general is a lot worse. The worst thing is that all their GPUs are proprietary (and a few other things too) so you cannot drop an ordinary Linux on them. I think that they all use uboot and device tree, but in an idiosyncratic way, adding to the difficulty. I bought a (less) cheap S912 box that I intend to play with. Apparently you can run Linux on these if you don't need video output. I won't give links because I don't know which efforts are the best.

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Replacement keys (was Lenovo ThinkPad Compact Bluetooth Keyboard with TrackPoint)
by Michael Hill 27 Sep '18

27 Sep '18

On Tue, Aug 28, 2018 at 6:35 PM, Scott Sullivan via talk <talk(a)gtalug.org> wrote: > I've had a number of folks express interest after seeing me use mine. > So I'm just going to drop the links here for general reference. > > Lenovo ThinkPad Compact Bluetooth Keyboard with TrackPoint Mine has been indispensable for five years. Last week, sadly, the X key was dislodged and fell out of my backpack somewhere. Can anyone recommend a supplier for replacement keys? I took a look on eBay and the selection seemed pretty spotty. Mike

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September talk with Marcel Gagne is on youtube
by Alex Volkov 25 Sep '18

25 Sep '18

Hey Everyone, You can now watch the recording of our September 2018 meeting -- How Open Source Destroyed the Past, Created the Present, and Will One Day, Save the Future with Marcel Gagne. Presentation -- https://youtu.be/llHkWbVHpR0 Q&A -- https://youtu.be/nyKg0L_xld0 The video is also available on the meeting page -- https://gtalug.org/meeting/2018-09/ In fact past meeting pages link to all recorded videos. Cheers, Alex.

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Old vs new logo on Mastodon
by Seneca Cunningham 25 Sep '18

25 Sep '18

Hi all, I got stuck on the IPv6ternet for a bit this morning, and two of the handful of websites I could visit were gtalug.org and Mastodon. I noticed that we’re still using the old logo there. Will this be updated? Seneca

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Lenovo ThinkPad Compact Bluetooth Keyboard with TrackPoint
by Scott Sullivan 23 Sep '18

23 Sep '18

I've had a number of folks express interest after seeing me use mine. So I'm just going to drop the links here for general reference. Lenovo ThinkPad Compact Bluetooth Keyboard with TrackPoint https://www.newegg.ca/Product/Product.aspx?Item=N82E16823218058CVF https://www.lenovo.com/ca/en/accessories-and-monitors/keyboards-and-mice/ke… The also make a USB only version, which I have two of as daily drivers for at home and work. https://www.lenovo.com/ca/en/accessories-and-monitors/keyboards-and-mice/ke… -- Scott Sullivan

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Fedora 28 Xsane on Brother MFC now working
by Russell Reiter 23 Sep '18

23 Sep '18

I'm still confused tho. My Brother printer/scanner is working now. I had added the legacy libnsl (not currently shipped with glibc) and created the unit files but the scanner didn't respond until I added "brother4" to /etc/sane.d/dll.conf. Thanks Hugh for the suggestions/advice and a wayback to David CB. Apparently there really is Better Living Through Dynamic Linking. I actually looked for my notes of the day, as this was a kind of a head scratcher for me. Still is. Although I stumbled through systemd while trying to target a moving target, systemd apparently wants a stationary one. I've disabled the unit files which I had added. Sane just works, also removing the error below. I'm not exactly sure what does the switching and hw endpoint stitching, but it is working. # systemctl --failed UNIT LOAD ACTIVE SUB DESCRIPTION ● saned.socket loaded failed failed saned incoming socket LOAD = Reflects whether the unit definition was properly loaded. ACTIVE = The high-level unit activation state, i.e. generalization of SUB. SUB = The low-level unit activation state, values depend on unit type. 1 loaded units listed. Pass --all to see loaded but inactive units, too. To show all installed unit files use 'systemctl list-unit-files'. Also thanks Hugh, Wayland fixed my stuttering display widget. I'd thought I was using Wayland by default, but it was actually running gdm.

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