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Linux mysteries

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smiling gear above the conveyor

There is an ongoing investigation about this topic. This article will be properly formatted, thoughtfully completed, proofread and will be more pictures if you will. It shouldn't take long, but usually there are a few projects happening in parallel, so you can track how I handle the load on Twitter.

A collection of things that I cannot explain

Write permissions

On one machine with Ubuntu 22.04 all files have write permission for the user group by default, but on another - Manjaro 22 - no.

apt update critical error

(appstreamcli:3459): GLib-CRITICAL **: 23:46:48.952: g_variant_builder_end: assertion '!GVSB(builder)->uniform_item_types || GVSB(builder)->prev_item_type != NULL || g_variant_type_is_definite (GVSB(builder)->type)' failed
(appstreamcli:3459): GLib-CRITICAL **: 23:46:48.952: g_variant_new_variant: assertion 'value != NULL' failed                                                                                  
(appstreamcli:3459): GLib-ERROR **: 23:46:48.952: g_variant_new_parsed: 11-13:invalid GVariant format string

E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh-cache > /dev/null; fi'

Dazed and confused

Uhhuh. NMI received for unknown reason 31 on CPU 13. Do you have a strange power saving mode enabled? Dazed and confused, but trying to continue

No handler for the interrupt. Not good, but not critical. More important is that nothing wrong with the power supply.

Source: https://utcc.utoronto.ca/~cks/space/blog/linux/NMIUnknownReasonMeaning?showcomments#comments

Sleeping COM ports

IIRC this was an issue in Ubuntu 16.04. After reboot the COM port is not sending or receiving any data. It's "sleeping". In order to wake up such port you need to open it with screen once

#!/bin/bash

# touch ports
screen -S com5 -d -m /dev/ttyS4
screen -S com7 -d -m /dev/ttyS6
screen -S com8 -d -m /dev/ttyS7

# kill screen sessions
screen -S com5 -X kill
screen -S com7 -X kill
screen -S com8 -X kill

Serial console speed

A very good Morse code operator can send/receive 30 words per minute, which is about 600bits/s. Linux serial console is only 192 times faster.

Just a random thought.

Why Linux is not dominating the market?

I think this is because there is no company with big money reserves targeted on common users. Because Linux distribution is not a product. And I think that only by doing the same things what Microsoft did 30 years ago, Linux will start dominating.

Let’s imagine Canonical is such company. Of course there are other big companies like Red Hat, SUSE, who sell Linux distributions, but they focus only on servers. And there is a reason for this skewed balance. Many products for business from Adobe, Autodesk only support Windows (and sometimes Mac)

So let’s focus on home users who need a browser, office suite, and games. First, Canonical must contract with many laptop manufacturers and make Ubuntu to be an OS installed by default, not Windows.

As some consoles maintain exclusive titles (for example, Zelda, Metal Gear Solid, Halo) and release big hits together with the launch of the new console version. So, next Call of Duty must be released only for Ubuntu.

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