Technical notes

This list contains a small knowledge base of problems I encountered, and the solutions I found.

Calibrating an APC UPS on RHEL 8 13 April 2025
Git cheat sheet 13 April 2025
Installing wildcard LetsEncrypt certificates with certbot 17 February 2025
C code using readdir() fails to read directory contents on Linux 12 January 2025
A QR code generator 29 November 2024
Thunderbird sends useless links instead of images 11 October 2024
Sendmail TLS error 15 September 2024
Turning off screen blanking on an old Raspberry Pi 2/3 11 September 2024
Force XFS root filesystem check on CentOS/RHEL/Oracle Linux 19 June 2024
Using GitHub's fine-grained tokens 23 May 2024
Locked out of RV320 admin interface with "Bad Gateway" 09 May 2024
A Mandelbrot set 07 April 2024
Intrusion response 03 September 2023
Copying a Joomla! site 04 August 2023
GPT-4 the programmer 29 April 2023
GPT-4 and chess 28 April 2023
Mail forwarding with Dovecot virtual accounts 07 April 2023
Printing formatted code in ChatGPT 29 March 2023
Audio delay with ffmpeg copy 28 November 2022
Click OK to automatically reload Skype for Web 02 October 2021
Setting up DKIM with sendmail 17 April 2021
Getting rid of full-screen Windows 10 nag prompts 09 June 2020
Advanced search in Outlook 06 June 2020
Windows Update fails with 0x8024a21e 02 June 2020
Android 10 phone turns back on after power button is pressed 04 February 2020
Making Redmine display PDFs in-browser 15 November 2019
Setting up Dovecot and Sendmail with virtual domains 02 November 2019
CHM (Help file) viewer show TOC but not content on Windows 10 29 October 2019
Changing the aspect ratio at constant resolution using ffmpeg 27 August 2019
External drives and Windows Update 21 August 2019
Upgrading PHP to 5.6 on CentOS 7 10 April 2019
CentOS 7: yum keeps installing debug kernel entries in grub2.cfg 15 August 2018
TV repair: Loud buzz from circuit board of SANYO AVM-2664U CRT television 18 March 2018
Fixing The Saboteur 20 January 2018
Cannot rename (move) /home in CentOS 7 02 December 2017
Prevent Windows from using external drives for installs 02 December 2017
SharePoint 2016 stand-alone configuration 08 August 2017
Reverse DNS for Azure VM 08 August 2017
Windows debugging 06 August 2017
Failure to view Windows 10 shares on Linux host 20 July 2017
Joomla 3.7 error on PHP 5.4.16 06 May 2017
Broken Ghostscript and related tools in CentOS 7 29 March 2017
Let's Encrypt certificates not trusted by Chrome on Android 12 February 2017
How iptables are processed (packet traverse map) 19 January 2017
Disappearing Notification Area tooltips 01 June 2016
No HDMI audio after AMD driver update 06 March 2016
Chrome breaks MathJax - a workaround 22 January 2016
Hardware hacking cable decoders, part II 14 October 2015
Joomla folders not writable on CentOS 7 21 September 2015
Google Chrome: Server has a weak ephemeral Diffie-Hellman public key 12 September 2015
Rooting, encrypting, unbricking a Galaxy S3 31 March 2015
Joomla 3.4 upgrade, weblinks and allweblinks 20 March 2015
Hardware hacking cable decoders 17 February 2015
No non-HDMI audio after updating AMD graphics driver 03 January 2015
Quora answer: Reverse engineering code 18 November 2014
Converting Excel charts to EPS 16 November 2014
Quora answer: Turning off terminal buffering 16 July 2014
Rewriting the URL in the browser title bar 15 July 2014
MySQL replication and IP address change 14 September 2013
A slide-show screensaver for the Windows 7 login screen 11 September 2013
Flickering windows, "Not Responding" in title bar 11 September 2013
Joomla error 'You cannot access the private section of this site' when logging in 03 September 2013
Moving or deleting Outlook's IMAP PST file 30 June 2013
Windows Media Player crashes when opening AVI files 27 June 2013
Reading old AWD (FaxView) files 17 December 2012
TSCLIENT share no longer accessible in Windows XP mode 08 December 2012
Internet Explorer (IE8) crashes when attempting to update the "Windows Update" control 10 July 2012
Plotting derivatives in GNUPLOT 18 May 2012
Deleting hidden columns in SharePoint 2010 03 March 2012
Anonymous access to a SharePoint 2010 Web site 04 January 2012
SharePoint 2010 Central Administration - controls disabled 04 January 2012
Windows 98/ME Samba access failure 02 January 2012
Perl and CPAN (and SpamAssassin) 14 December 2011
Superscript in CSS 14 December 2011
SharePoint 2010 development 06 December 2011
OpenCOBOL environment variables, external functions 05 December 2011
Corrupt /var/run/utmp on Linux 14 January 2011
What is the password for the XPMUser account? 14 January 2011
Infinite redirect loop (ErrorPage.aspx) in Axosoft OnTime's Customer Portal 04 May 2010
Maple and Meijer's G-function: a numerical instability and a cure 26 August 2007
Recompiling Qt for Slackware 15 July 2007
Error "unresolved external symbol WinMain" when compiling for WinCE 29 May 2007
ATIRW.DLL failed to register during ATI Remote Wonder installation 31 March 2007
Remote Desktop Fails to Shut Down after Application Exits 20 March 2007
The Win 16 Subsystem has insufficient resources 04 November 2006
How to stop Ora9ias_homeEMWebsite without a popup dialog 05 September 2006
Oracle 9i Application Server restart failure 27 August 2006
Using mktime() to convert UTC dates 24 February 2006
Oracle 9i AS error "No ApplicationInfo is associated with application named: appname" 13 February 2006
FoxPro application fails with I/O Operation Failure 13 October 2005
HTML combo boxes 11 October 2005
Unexpected error (1072) occurred at line 5218 in setup.c 11 October 2005
Copying encrypted files to a non-encrypted destination in Windows 04 October 2005
How to enable software RAID (mirroring) in Windows XP 14 August 2005
Creating a bootable Windows XP CD with custom drivers 30 July 2005
Error 1024 in InstallShield X Express 25 July 2005
Oracle 9i AS installation fails with "Invalid database domain name" 25 July 2005
Oracle Cheat Sheet 25 July 2005
Energizer FileSaver application handle leak 15 January 2005
Ability to record MP3 format lost on Windows XP 14 January 2005
Windows 2000 multilink connection ignores hang-up rules 14 January 2005
Where did my default beep go? 27 December 2004
Numbered equations and other scientific publishing tips 15 November 2004
IDispatch::Invoke returns E_PARAMNOTFOUND 13 November 2004
ProFTPD failure (hangs with 100% CPU utilization) 13 August 2004
Compiling Regina on Slackware 9.1 02 July 2004
Invalid Drive X:\ (Error 1327) when attempting to reinstall Office 2003 05 February 2004
Using pcAnywhere on TCP-only connections 05 February 2004
Running VMware in a virtual frame buffer 09 November 2003
Window Placement in Mozilla Firebird 30 October 2003
Testing sendmail relay filtering 13 August 2003
Soundblaster-16 Driver Parameters for Linux 11 August 2003
IDEA plugin fails to work with GPG/GnuPG 03 August 2003
Error: bad register name `%%eax' when compiling in-line assembly with GNU C 30 July 2003
Jump logic with inline assembly in Visual C++ 30 July 2003
Intermittent mouse movement and other VMware performance issues 11 July 2003
Browser bookmarks on a Motorola Timeport 280 phone 21 May 2003
Bandwidth limiting in Apache server 08 April 2003
Using regex maps in sendmail 03 March 2003
Apache upgrade disables secure Web site 27 February 2003
PHP fails with 'Call to undefined function: mysql_connect()' 27 February 2003
Internal error when trying to renew a DHCP lease 17 February 2003
Checking the argument of HELO/EHLO in sendmail 21 December 2002
Bootable Linux on a mirrored partition 11 December 2002
HTML special characters 10 December 2002
Using Portage Plus (Rogers AT&T GPRS data service) with Linux 07 September 2002
Rogers AT&T GPRS data service without Portage Plus software 06 September 2002
Graphical traffic monitoring 24 August 2002
ODBC and MySQL crash with OpenOffice 16 August 2002
Linux cdrecord fails (and system may hang) 27 July 2002
Linux cdrecord stops with "No such device. Cannot open '/dev/pg0'" 26 July 2002
Samba Prints Blank Page After Print Job 15 June 2002
A Simple Encryption Method 12 June 2002
Broken NTP daemon 30 May 2002
Broken SIGALRM on Linux 30 May 2002
System Hangs at "Verifying DMI Pool Data" Message 23 May 2002
Failure to start PCMCIA CD-ROM drive under Linux 22 May 2002
Undefined symbol 'dbm_fetch' with the Apache server 20 April 2002
Using the TENSOR packages in GPL MAXIMA 25 February 2002
No Internet subscription option with Norton Antivirus 19 October 2001
Sound for DOS Programs under Windows NT 03 September 2001
Windows 2000 Setup Failure on a SuperMicro P6DLF Motherboard 03 September 2001
Window Placement in Internet Explorer 28 March 2001
How can noise improve signal quality? 27 December 2000
Dead keyboard = dead motherboard? Not necessarily 31 October 2000
Invalid command 'LoadModule' with the Apache Server 23 August 2000
Using Two NE2000-compatible Network Cards in a Linux machine 19 August 2000
Mixing digital audio 13 August 2000
An IP tunnelling problem: A case study 28 February 2000
Creative DVD on multiprocessor NT systems 05 May 1999