March 2020 - 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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security threats of Open Source
by D. Hugh Redelmeier 25 Nov '20

25 Nov '20

<https://www.zdnet.com/article/microsoft-spots-malicious-npm-package-stealin…> This article list six cases of malware contributed to npm (the repo for sharing node.js and JavaScript source). How many undetected cases exist? I've alway pretended that Linux distros vet their code. I'm not sure how true that is. Probably the greatest protection is the time delay between contribution and distribution. I wonder what can be done about this problem. I've said so at our meetings a few times too. Of course the problem is worse with closed source: it is impossible to audit the source. But closed source might have fewer contributors and more supervision. Of course much closed soure is built on top of open source and thuse all its weakness

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Acer Aspire 3 A315-21 laptop has mono sound only?
by Ken Heard 03 May '20

03 May '20

I think that this particular laptop has mono sound. I have been using it temporarily to stream content by HDMI to a LG HD monitor and then by fibre optical cable to a NED D3020 V2 hybrid amplifier and finally to a pair of bass reflect speakers. Unfortunately sound comes out of only one speaker. After extensive tests I have determined to my satisfaction that the problem is in the laptop. I can test the two speakers built in the laptop separately, but I have no way of knowing whether the sound so produced is mono or stereo. I could find no specs for this laptop with details about the sound card. Lack of such specs indicates to me that Acer does not want people to know that this laptop is mono only. Is mono sound the norm for low market laptops such as this one and notebooks? Ken Heard

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Oculus Quest now available
by Evan Leibovitch 12 Apr '20

12 Apr '20

Hi all. For those of you experimenting with Virtual Reality: The $550 Oculus Quest, best VR headset that doesn't require tethering to a PC, has been nearly impossible to get (at regular price) since September. It's now for sale at both Amazon and Best Buy. Delivery only -- no in-store pickup because the stores are closed. Best Buy can ship faster right now but its just being available for purchase on either site is not very common. -- Evan Leibovitch, Toronto Canada @evanleibovitch or @el56

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Planning April Meeting
by Alex Volkov 06 Apr '20

06 Apr '20

Hello Everyone, We're thinking of doing April meeting online, we're thinking of having a Q&A. Which of the teleconference software do you find the most comfortable to work with? * Zoom * Hangouts * Jitsi * Something completely different * Let's just skip a meeting Please reply to this email so we can gauge the interest in the next meeting. Thank you, Alex.

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[GTALUG-Announce] GTALUG: COVID-19 Impact
by Christopher Browne 31 Mar '20

31 Mar '20

The ongoing COVID-19 problem has made it impossible to hold our monthly meetings at Ryerson. Our meetings are held at Ryerson University; the University has declared [1] that, to help diminish the spread of the virus, they are eliminating all discretionary activities on (and off) campus until May 1, 2020. GTALUG certainly falls in the "discretionary activity" category, therefore we do not have availability of that space. It is, of course, entirely likely that the May 1 date will shift as the situation evolves. Further, the Ontario Government has banned getting together in groups of 50 or more [2] (it would be no surprise for that to go down further), and in view of the risks of the virus, it would not be at all responsible for GTALUG to attempt to shift to other locations; that would not fit well with the "social and physical distancing" concept in use to try to diminish spread of the virus. We are trying to see what we can do about alternative mechanisms, so that discussions may take place online. The mailing list remains active, of course; we hope to see more ideas emerge over the next couple of weeks. [1] https://www.ryerson.ca/news-events/news/2020/03/president-mohamed-lachemi-a… [2] https://www.ontario.ca/page/2019-novel-coronavirus -- Chris Browne --- GTALUG Announce mailing list announce(a)gtalug.org https://gtalug.org/mailman/listinfo/announce

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What have people been using for remote meetings?
by Dave Collier-Brown 29 Mar '20

29 Mar '20

My work has the usual dreck, plus bluejeans which is passible, but do people have favorites for non-one-to-one work? --dave -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest dave.collier-brown(a)indexexchange.com | -- Mark Twain CONFIDENTIALITY NOTICE AND DISCLAIMER : This telecommunication, including any and all attachments, contains confidential information intended only for the person(s) to whom it is addressed. Any dissemination, distribution, copying or disclosure is strictly prohibited and is not a waiver of confidentiality. If you have received this telecommunication in error, please notify the sender immediately by return electronic mail and delete the message from your inbox and deleted items folders. This telecommunication does not constitute an express or implied agreement to conduct transactions by electronic means, nor does it constitute a contract offer, a contract amendment or an acceptance of a contract offer. Contract terms contained in this telecommunication are subject to legal review and the completion of formal documentation and are not binding until same is confirmed in writing and has been signed by an authorized signatory.

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Video of our march meeting
by Alex Volkov 26 Mar '20

26 Mar '20

Hello Everyone, Here's the video of our March meeting. Ham Radio with a side of Linux with Alan Heighway -- https://www.youtube.com/watch?v=fzE3nnzs9PM Alex.

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VM Support in Linux
by William Witteman 25 Mar '20

25 Mar '20

I am poking around in Android development, and I have run into a snag as my machine is pretty old, and doesn't have, or doesn't have enabled, some virtual machine features. Specifically: > To use VM acceleration on Linux, your computer must also meet these requirements: > > For Intel processors: Support for Virtualization Technology (VT-x), Intel EM64T (Intel 64) > features, and Execute Disable (XD) Bit functionality enabled. > For AMD processors: Support for AMD Virtualization (AMD-V). I am not at all sure that my machine will do this - if I was looking for a new machine, are there any caveats, warnings, red flags to watch for? I'd prefer not to have to spend a ton of time/money thinking about my hardware - I'd like it to run Debian with as little messing about as possible. Thanks! William

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Concrete suggestions for all our employers! Pass it on
by David Collier-Brown 16 Mar '20

16 Mar '20

https://leaflessca.wordpress.com/2020/03/15/what-my-companys-doing-for-covi… --dave -- 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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