Go to advanced search

by jojopi
Wed Aug 28, 2019 1:59 pm
Forum: Raspbian
Topic: Issues changing keyboard in raspi-config
Replies: 14
Views: 1301

Re: Issues changing keyboard in raspi-config

/usr/share/i18n/locales/fr_FR has: thousands_sep "<U202F>" That is Unicode NARROW NO-BREAK SPACE. This has changed since stretch, where it was just a regular ASCII space. Apparently your PuTTY font does not have a glyph for the character and is not smart enough to substitute a fixed space. You could...
by jojopi
Tue Jul 30, 2019 9:44 am
Forum: Python
Topic: Python output of ssh command vs local command
Replies: 4
Views: 266

Re: Python output of ssh command vs local command

You have quotes around 'cpu ' to tell the shell that the trailing space is part of the argument. After the local shell splits the arguments up and removes the quotes, ssh has to join them back into one string to pass to the remote system. The shell on the remote system can no longer see the intentio...
by jojopi
Sat Jul 20, 2019 8:08 am
Forum: Compute Module
Topic: File under: the gods only know why
Replies: 3
Views: 1238

Re: File under: the gods only know why

The line you transcribed is just the equivalent of "—✂—CUT—✂—HERE—✂—". Also, the panic dump is mostly useful for debugging kernel logic problems, which is probably not the issue here. You want to try to scroll back before the panic (Shift+PgUp may still work) and look for any errors relating to ext4...
by jojopi
Fri Jul 19, 2019 10:03 am
Forum: C/C++
Topic: sched: RT throttling activated
Replies: 3
Views: 308

Re: sched: RT throttling activated

Realtime processes take precedence over all other tasks. However, this is intended to ensure low latency in time-critical tasks, not to allow a process to take over the CPU completely. By default, if realtime processes use more than 0.95s of CPU time in one second the kernel assumes there is a probl...
by jojopi
Thu Jul 18, 2019 11:00 pm
Forum: Raspbian
Topic: gksudo deprecated
Replies: 10
Views: 1171

Re: gksudo deprecated

It doesn't protect files in your /home directory and some configuration files may end up owned by root (see link above). gksudo does nothing to reduce that risk, compared with regular sudo. The only file it treats specially is .Xauthority, and that file is never written to by normal clients. The re...
by jojopi
Wed Jul 17, 2019 10:26 am
Forum: Raspbian
Topic: gksudo deprecated
Replies: 10
Views: 1171

Re: gksudo deprecated

"sudo sudo -V" shows that DISPLAY and XAUTHORITY variables are preserved by default, and I cannot find any evidence that gksudo was ever really needed in Debian/Raspbian:

Code: Select all

sudo pcmanfm
I do notice that "ssh -X" sessions first require:

Code: Select all

export XAUTHORITY=~/.Xauthority
by jojopi
Thu Jul 11, 2019 6:17 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1125
Views: 49026

Re: A Final Fidonacci Challenge

I have not followed all of the past discussion on this problem, so apologies if this idea has been proposed before. Without mentioning names, I recently became aware of a solution in BBC BASIC V on RISC OS. It does not give a fully correct result do to a slight bug in the carry handling. But what re...
by jojopi
Sat Jun 29, 2019 12:46 pm
Forum: C/C++
Topic: Quick log2????
Replies: 35
Views: 1513

Re: Quick log2????

GCC provides __builtin_clz(), et al, which will emit the hardware bit counting instruction when available, or otherwise call a helper function for the architecture. Traditionally you would want to try to avoid these operations in code that needs to be both fast and portable. On platforms without the...
by jojopi
Sat Jun 29, 2019 9:17 am
Forum: Raspbian
Topic: Buster bug report thread
Replies: 215
Views: 25611

Re: Buster bug report thread

The Debian package policykit-1 provides a file /etc/polkit-1/localauthority.conf.d/51-debian-sudo.conf that says: [Configuration] AdminIdentities=unix-group:sudo In the corresponding Raspbian package, this file is missing. The omission means that admin users cannot reboot or install packages, or are...
by jojopi
Fri Jun 28, 2019 7:40 am
Forum: Raspbian
Topic: Buster bug report thread
Replies: 215
Views: 25611

Re: Buster bug report thread

The following additional packages will be installed: libjansson4 libnftables0 nftables The iptables package recommends nftables, but does not require it. Whether recommended packages are included depends on method and options such as --no-install-recommends. This is not a bug, unless you are saying...
by jojopi
Thu Jun 27, 2019 2:27 pm
Forum: Other projects
Topic: Calculating Inductance
Replies: 9
Views: 1440

Re: Calculating Inductance

If you pass a constant 1 Amp through a 1 Henry inductance, the Voltage will increase by 1 Volt per Second. No, if the current in a one henry inductor is changing at a rate of one ampere per second, the emf will be one volt. Your definition is actually a one farad capacitor. Which is going to explode.
by jojopi
Wed Jun 26, 2019 11:14 pm
Forum: Beginners
Topic: cron job not being run
Replies: 7
Views: 794

Re: cron job not being run

I am attempting to learn how to use cron on the raspberry Pi. Are you really attempting to learn about cron, or are you attempting to fix a problem with "mydevices agent" or whatever? 5 * * * * date >> /home/pi/testing_cron which I believe should run the date command every hour at 5 minutes past th...
by jojopi
Wed Jun 26, 2019 7:32 pm
Forum: Raspbian
Topic: Issues changing keyboard in raspi-config
Replies: 14
Views: 1301

Re: Issues changing keyboard in raspi-config

I love this bug! There is a typical Debian Perl script, /usr/share/console-setup/kbdnames-maker that is responsible for looking up the translations of every keyboard layout and variant in every language. This script has not changed since stretch, but apparently something has changed in Locale::gette...
by jojopi
Tue Jun 25, 2019 9:43 pm
Forum: General discussion
Topic: Users via ssh can't scan with Raspbian Buster anymore
Replies: 9
Views: 1109

Re: Users via ssh can't scan with Raspbian Buster anymore

/lib/udev/rules.d/* have changed between stretch and buster. In stretch, 60-libsane.rules identified any device supported by SANE, gave it ENV{libsane_matched}="yes", and then because of that applied a fACL granting rw access to group "scanner". In buster, 60-libsane.rules still identifies supported...
by jojopi
Tue Jun 25, 2019 7:48 pm
Forum: General discussion
Topic: Upgrading from Stretch to Buster: Any experiences?
Replies: 2
Views: 488

Re: Upgrading from Stretch to Buster: Any experiences?

I have done it. It is the kind of thing that will only ever cause problems if you do not know how to fix them—but then you could lose all your data. However, I would not really recommend version upgrading on an SD card even if you are confident of fixing any issues. For one thing, updating a hundred...
by jojopi
Thu Jun 20, 2019 1:26 pm
Forum: Beginners
Topic: Error using SSH for raspberry pi - Permission denied (public key password)
Replies: 8
Views: 539

Re: Error using SSH for raspberry pi - Permission denied (public key password)

I am using a raspberry with Ubuntu MATE OS whenever I used the default password "raspberry" If you got the image from https://ubuntu-mate.org/raspberry-pi/, then according to that page: There are no predefined user accounts. The first time you boot the Ubuntu MATE image it will run through a setup ...
by jojopi
Mon Jun 17, 2019 1:53 pm
Forum: Off topic discussion
Topic: how heavy is raspbian ?
Replies: 30
Views: 4099

Re: how heavy is raspbian ?

Given that the Pi and it's SD card will be electrically neutral no matter if the SD is programmed on blank, it will always have the same mass. The charges on those gates are balanced elsewhere. Certainly in a regular capacitor we would expect the electrons added to the negative plate to be closely ...
by jojopi
Fri Jun 14, 2019 1:49 am
Forum: Beginners
Topic: USB Numeric Keypad with RPI3
Replies: 4
Views: 338

Re: USB Numeric Keypad with RPI3

Note, a regular keyboard will control the PDF document as inteneded with the stand alone directional arrows but now with arrows on keypad, something we failed to note during first attempts. So, the unspecified application you are running treats the keypad arrows differently than the dedicated arrow...
by jojopi
Sat May 25, 2019 6:18 am
Forum: General discussion
Topic: Incorrect mapping of the 79 keys official keyboard
Replies: 9
Views: 969

Re: Incorrect mapping of the 79 keys official keyboard

It does seem strange to go with a hybrid layout that is not completely supported in the recommended operating system. However, the initial announcement last month said that these keyboards can report their country to the host, so maybe RPF/T plan to add software to configure them at some point. Out ...
by jojopi
Wed May 22, 2019 7:01 pm
Forum: Networking and servers
Topic: UnicodeDecodeError: 'utf8' codec can't decode byte 0x92 in position 532: invalid start byte
Replies: 5
Views: 757

Re: UnicodeDecodeError: 'utf8' codec can't decode byte 0x92 in position 532: invalid start byte

The error corresponds to the fancy apostrophe (right single quotation mark) in "the system’s owner". That would be 0x92 in legacy single-byte Windows encodings, such as CP1252. In UTF-8 it should be the three byte sequence e2-80-99. Alternatively it could be replaced with a non-fancy ASCII apostroph...
by jojopi
Wed Apr 17, 2019 1:57 pm
Forum: Troubleshooting
Topic: Environment variables vs. bash and lxterminal
Replies: 2
Views: 246

Re: Environment variables vs. bash and lxterminal

(Weirdly, I did `ls -lut ~/.bash*` and none of them seemed to have been accessed recently!) You cannot rely on access times. Many distros and images mount filesystems with the "noatime" or "relatime" options by default. Especially on an SD card, where small writes are costly, frequent access time u...
by jojopi
Tue Apr 02, 2019 12:13 am
Forum: C/C++
Topic: ATEXIT behavior
Replies: 17
Views: 2559

Re: ATEXIT behavior

dlclose returns and atexit calls function. By that time linux has not yet removed library. No, the function registered via atexit is called during the dlclose, before dlclose returns. By the time dlclose returns, the library and function have been removed from the address space. (POSIX does not gua...
by jojopi
Mon Apr 01, 2019 11:42 pm
Forum: Python
Topic: For Loop
Replies: 1
Views: 256

Re: For Loop

Simpler examples: for i in "abc": print(i) for i in [1,2,3]: print(i) for i in "abc", [1,2,3]: print(i) In the first case there is a string, and for iterates over the characters in the string. In the second case there is a list, and for iterates over the objects in the list. In the third case there ...
by jojopi
Mon Apr 01, 2019 10:46 pm
Forum: Advanced users
Topic: crontab and DST issue
Replies: 4
Views: 452

Re: crontab and DST issue

The job ran at the correct time, and cron jobs by default use the same timezone as cron itself. The date argument "last month" means the same as "1 month ago", or "now -1 month". The month is subtracted without changing timezone/dst values. (I am not sure if that is really as intended, and the docum...
by jojopi
Sat Mar 30, 2019 9:09 am
Forum: C/C++
Topic: ATEXIT behavior
Replies: 17
Views: 2559

Re: ATEXIT behavior

"man atexit" says that since glibc 2.2.3, functions registered from within a shared library will be called when the library is unloaded. This resolves the potential crash of trying to call them after they have been unmapped. Putting a sleep() between dlclose() and exit(), this is indeed what is happ...

Go to advanced search