Computing notes 2020 part one

Computing notes 2020 part one

This document contains only my personal opinions and calls of judgement, and where any comment is made as to the quality of anybody's work, the comment is an opinion, in my judgement.

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2020 June

20200614 Sun A sign of the times

Just noticed than Linux kernels on boot they used to print:

[    0.000000] KERNEL supported cpus:
[    0.000000]   Intel GenuineIntel
[    0.000000]   AMD AuthenticAMD
[    0.000000]   Centaur CentaurHauls
	  [    0.000000] tseg: 00bd800000
and this has recently become:
[    0.000000] KERNEL supported cpus:
[    0.000000]   Intel GenuineIntel
[    0.000000]   AMD AuthenticAMD
[    0.000000]   Hygon HygonGenuine
[    0.000000]   Centaur CentaurHauls
[    0.000000]   zhaoxin   Shanghai
[    0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'

Both Hygon HygonGenuine and zhaoxin Shanghai are from China. But then both previously listed Centaur and newly listed zhaoxin are related to VIA which is also from China (Taiwan).

2020 May

20200515 Fri: Configuring XScreenSaver for HiDpi

Configuring XScreenSaver for HiDPI must be done using X resources, and to work around limitations in XFLD handling the font sizes are best specified in pixels with DPIs specified as 0-0 to pray for scalability, as in this example that looks tolerable to me on my 3840×2160 27in display that has a nominal DPI of 160:

! Look at '/etc/X11/app-defaults/XScreenSaver'
XScreenSaver.Dialog.logo.width:		512
XScreenSaver.Dialog.logo.height:	768
! Date in 'strftime'(3) format.
XScreenSaver.dateFormat:		%Y-%m-%d %H:%M %Z %A
! Fonts. These pattern select by bit size.
XScreenSaver.Dialog.headingFont:	-misc-ubuntu mono-bold-r-*-*-32-*-0-0-*-*-*-*
XScreenSaver.Dialog.buttonFont:		-misc-ubuntu mono-bold-r-*-*-48-*-0-0-*-*-*-*
XScreenSaver.Dialog.bodyFont:		-misc-ubuntu mono-medium-r-*-*-48-*-0-0-*-*-*-*
XScreenSaver.Dialog.labelFont:		-misc-ubuntu mono-medium-r-*-*-40-*-0-0-*-*-*-*
XScreenSaver.Dialog.dateFont:		-misc-ubuntu mono-medium-r-*-*-32-*-0-0-*-*-*-*
XScreenSaver.Dialog.unameFont:		-misc-ubuntu mono-medium-r-*-*-48-*-0-0-*-*-*-*
XScreenSaver.passwd.passwdFont:		-misc-ubuntu mono-bold-r-*-*-48-*-0-0-*-*-*-*
! Timeout bar (background is actually determined by Dialog.text.background).
XScreenSaver.passwd.thermometer.width:	16
XScreenSaver.passwd.thermometer.foreground: #999911
XScreenSaver.passwd.thermometer.background: #000000
! General dialog box (affects main hostname, username, password text).
XScreenSaver.Dialog.foreground:		#000000
XScreenSaver.Dialog.background:		#eeeeee
XScreenSaver.Dialog.topShadowColor:	#000000
XScreenSaver.Dialog.bottomShadowColor:	#000000
! Username/password input box.
XScreenSaver.Dialog.internalBorderWidth: 24
XScreenSaver.Dialog.borderWidth:	2
XScreenSaver.Dialog.shadowThickness:	4
XScreenSaver.Dialog.text.foreground:	#aa4411
XScreenSaver.Dialog.text.background:	#eeeeee
XScreenSaver.Dialog.Button.foreground:	#001122
XScreenSaver.Dialog.Button.background:	#eeee99
20200512 Tue Android 9 and 10 and Ethernet

So I have poor WiFi reception in a part of my dwelling, and I decided to try attaching an USB2 Ethernet interface to my Motorola ONE which has an USB-C port and I discovered that:

  • It works (as soon as WiFi is disabled). The USB-C port as expected also switches automagically to OTG mode, that is to USB master mode. This works with both Android ONE 9 and 10. Evidently Google have not removed from the Android kernel the usual Linux drivers.
  • That USB-C port can also, in OTG mode, charge other USB devices, as Android says; it obviously has to be able to power slave USB devices like an Ethernet interface, so that works for charging.
  • Using a powerline Ethernet converter and that USB Ethernet adapter gives a much better connection than WiFi, and may even take less power. Not very surprising though.

Sadly the same Ethernet interface does not work with an Ubuntu Touch phone, and it looks as it the relevant Linux kernel drivers have been remove: after all they must have thought that nobody would use a tablet or cellphone with an Ethernet cable.

2020 April

2020 March

2020 February

2020 January