System Engineering – A changelog by Daniel Mettler

August 18, 2024August 18, 2024

Fix HP 48G, 48GX, 48SX power on failure

After switching the 3 AAA batteries of my beloved HP 48G calculator, it didn’t turn anymore when hitting the “ON” button in the bottom left corner. I first thought it’s because of poor electrical contact due to poor QA batteries (I noticed the new ones were a fraction of a mm shorter than the previous ones). This might have played a rule in the sudden failure to power on my HP 48G, but it probably wasn’t the only reason.

Here are some “tricks” to try, if your HP 48 won’t turn on:

Double-check that you inserted the AAA batteries pointing with their (+) poles in the right direction (left, right, left)
If the AAA batteries have poor electric contact (particularly the middle one is susceptible to this), cut out and fold some aluminium foil (also called “aluminum foil”; historically “tin foil” was used), and put it where better electric contact to the batteries is needed.
Press the “ON” button in the bottom left corner
If that doesn’t work: press and hold “ON”, press and release the “C” button, release the “ON” button
If that doesn’t work (it didn’t for me): Press the area between the “B” and “C” buttons/keys, then press and release “ON”
If that still doesn’t work (it didn’t for me): Flip the HP 48 over and remove the upper right rubber foot. You can basically just wiggle it a bit and pop it off, there’s no need for special instruments. Underneath, there’s a little hole to reset the calculator. Use e.g. a paperclip, insert one end into the hole until you hear or feel a subtle “click” sound to reset the calculator (please bear in mind that this could also clear the memory).
Then press the “ON” button and you’ll be prompted to try recovering the memory, which you should confirm.
At this point, unless it’s a severe error of the board, your HP 48 should turn on again.
It might display “Warning: Invalid Card Data” at every start though. You can get rid of this warning message by typing “PINIT” (without double quotes) and pressing the ENTER button (source: https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv013.cgi?read=43990)

If none of the above tips help, your HP 48 probably needs repairing.

It seems to be quite a nightmare to service the HP 48, but there are a couple of videos out there of people repairing a HP 48 SX (disclaimer: know what you’re doing, follow at your own risk):

August 14, 2024August 14, 2024

Unofficial Bitwarden compatible server written in Rust

An interesting project if you want to self-host your own Bitwarden compatible server, written in Rust instead of in C#:

Unofficial Bitwarden compatible server written in Rust

(/ht https://news.ycombinator.com/item?id=41243147)

(Disclaimer: Keep in mind that every software, also formally verified one, can contain bugs, also security bugs.)

July 29, 2024

How to determine/find out whether your Mac/macOS is in Safe Mode?

In the Apple menu, click on “About This Mac”
Then click on the “More info…” button
Click on the “System Report…” button
In the appearing System Report window, click on the “Software” menu item in the left pane
In the right pane, look for “Boot Mode:”. It should be “Safe”.

(I recently noticed that it’s quite difficult to distinguish whether your Mac has really been booted in “Safe Mode”, as visually, there doesn’t seem to be much of difference anymore to how the desktop looks in regular mode)

And BTW, to boot a Mac with Apple Silicon in Safe Mode:

Shut your Mac/macOS down
To boot it again, press the power button and hold it
Select the volume to boot (i.e. click on the volume icon)
Hit and hold the shift key
Click on the appearing text (“Continue in Safe Mode” or so) below the volume icon

July 10, 2024

Zimbra ZCS: How to export and import e-mail messages using the CLI

I verified the tips on the page below. The only mistake I’ve noticed is that the date format is wrongly indicated, i.e. instead of in MM/DD/YYYY format, the dates have to be specified in DD/MM/YYYY format.

So, the 1) command should be:

$ zmmailbox -z -m alice@example.com gru "//?fmt=tgz&query=after:"20/07/2022"&before:"26/07/2022"" >> /tmp/alice.tgz

https://wiki.zimbra.com/wiki/How_to_export_import_emails_for_a_specific_date

October 20, 2021October 17, 2021

Typo in WP Increase Upload Filesize plugin

Apparently, there’s a typo in the WP Increase Upload Filesize | Increase Maximum Execution Time plugin (not really necessary, but convenient) which prevents its settings page from working:

In wp-maximum-upload-file-size/includes/class-wmufs-helper.php, line 32, update

function convertToBytes( string $from ): ?int {

function convertToBytes( string $from ): int {

October 17, 2021October 17, 2021

Solution: HP OMEN 30L GT13 Desktop/Gaming PC does not boot anymore (CMOS reset, BIOS update, Omen logo, Windows, boot loop)

Symptom:

After switching on your HP Omen Desktop/Gaming PC, the boot process gets stuck at the “Omen” logo and Windows (the default OS) doesn’t get started anymore.
Power supply, LED lights, mainboard, RAM, GPU, hard disk and SSD are working and there’s no indication that anything would be wrong with them (IOW: The PC per se isn’t dead and seems to work).
The last time you used your PC, you might (or might not) have been prompted by an HP app (maybe the “HP Gaming Hub” or similar) to update some drivers or the firmware.

Reason/root cause:

HP apps apparently tend to mess with the CMOS and BIOS (e.g. automatically install updates), which may cause the HP Omen to get stuck the next time you try booting it.
Windows 10 would thus no longer start.

Solution:

Reset the PC’s CMOS.

How to reset the CMOS in a HP Omen 30L:

Turn off the computer
I.e. hold the power button for a couple of seconds until lights go out. For double safety, you could even quickly disconnect and reconnect the power cable.
On your keyboard, press and hold the Windows + V keys
To rule out any other problem, it’s best to plug your original HP USB keyboard into a USB plug directly on the PC.
Still pressing those two keys, press and hold the Power button on the computer for roughly 1 second, then release the power button, but continue pressing and holding the Windows + V keys, until you see that the PC boots and doesn’t get stuck at the “Omen” logo again, instead, there might be notifications that further updates are being installed. Or you might get displayed a CMOS reset screen or hear beeping sounds.
Note: According to HP, one has to press the power button 2-3 seconds in this step to trigger a CMOS reset. For my HP OMEN 30L GT13, that was apparently too long however, as it shut down the PC instead. Just try it a couple of times, until you finally see something happening again on the boot screen (but do not interrupt ongoing updates!).
If there’s a message that there are pending updates, wait for them to finish.
If you see a message that the CMOS was reset, hit ENTER to reboot the PC

Credits:

https://h30434.www3.hp.com/t5/Gaming-Desktops/Omen-30L-GT13-boot-loop-after-bios-update/td-p/8056991

Some more useful tricks about the HP Omen 30L GT13

Even though booting stopped at the Omen logo, I was still able to enter the BIOS setup upon rebooting. To enter the BIOS setup, do the following:

Press and hold the F10 key on your keyboard (on the original HP USB keyboard, you’ll actually have to press the “Fn” key and the “F10” key at the same time, as F10 is a secondary functionality only)
Press and hold the power button for 3 seconds till the PC turns off, then hit the power button again to start the PC while you’re holding the F10 key (Fn + F10)

First, as I was indeed suspecting that something might have gone wrong with an accidental (or intransparent) BIOS update, I tried following a hint that if one disconnects the hard drive (and/or SSD?), the mainboard of an HP Omen would allegedly automatically fall back to the previous BIOS version.
Therefore, I tried to disconnect the HDD and start my PC like that. It didn’t have any positive effect though, as the boot process kept getting stuck at the Omen logo.

BTW, to open the HP Omen 30L case, you simply press the big “INTERNAL ACCESS” button in the upper right corner of the back side of the PC, then tilt the (plexi-)glass window, then tilt it back towards the case a bit and lift the window up and off.

A further complication in my case was that I also use a fairly new and cutting edge Samsung 49″ super wide screen monitor (Samsung LC49RG90SSUXEN, supporting natively 5120×1440 pixels at a 120 Hz refresh rate) for that PC (and sometimes also with my MacBook Pro, via a special 8k USB-C to DisplayPort 1.4 cable).
My experiences with any sort of Samsung devices have been a mixed bag so far, so for one, I don’t really trust the quality of Samsung’s hardware, firmware or software (although I can’t complain about this display, it has been all fine so far and I’d highly recommend it for simulators). Secondly, I’ve plugged some essential USB devices (like the original HP USB keyboard and the receiver of my beloved Logitech G305 mouse) directly to the display’s USB hub, rather than to the PC itself. To rule out any weird error (e.g. like a boot process stopping because of a missing keyboard, caused by a faulty USB hub or connection), I’d generally recommend disconnecting “exotic” devices (like steering wheels, web cams, joysticks, controllers, ..) that could potentially cause troubles and plugin the essential devices (keyboard, mainly, maybe also the mouse) directly to the PC.

May 1, 2020May 9, 2020

New Apple Magic Keyboard with Numeric Keypad is surprisingly good, even excellent!

Recently, I’ve managed to render my beloved old Apple Keyboard (full-size, with numeric keypad) useless – accidentally pouring half a glass of tap water over it was sufficient, unfortunately (due to the mineral ions in the tap water; distilled water wouldn’t have conducted electricity and thus wouldn’t have shorted circuits; on the other hand, drinking distilled water would probably shorten your life, so please don’t consider doing this).

Luckily, I could temporarily use a similarly old, compact Apple Bluetooth keyboard instead. As I really wouldn’t recommend that keyboard for everyday work though (poor, bubbly typing experience, odd placement of keys requiring weird function key combinations, no numeric keypad), I had to order a full-size keyboard as a replacement again, so I ordered one of the new Apple Magic Keyboards with a Numeric Keypad (in Space Gray and I really like that, but the colour doesn’t matter in regard to the typing experience):

https://www.apple.com/ch-de/shop/product/MRMH2SM/A/magic-keyboard-mit-ziffernblock-schweiz-space-grau

(above is the Swiss German version, US version: https://www.apple.com/shop/product/MRMH2LL/A/magic-keyboard-with-numeric-keypad-us-english-space-gray)

I first thought that the even smaller lift of the keys (luckily with scissor and not butterfly switches) of this new keyboard would be very disturbing and that I’d have a hard time getting accustomed to it.

To my big surprise however I got accustomed to this new typing experience within a couple of hours already and now, after about 3 weeks of using it, I can confidently say: I love this new Apple Magic Keyboard with Numeric Keypad even much more than my previous, old Apple Keyboard with Numeric Keypad and wouldn’t want to switch back anymore.

Typing with it feels so immediate, so quick and so “raw” and “crunchy”, it’s literally almost addictive. I can type considerably faster with it than with the previous keyboard, let alone any regular IBM-type keyboards (although I like those too, for their build-quality, for the interesting history and stories behind them, for their customizability and standardization, for the bustling keyboard enthusiast scene around it). Further, typing for a prolonged time feels much less tiring for the fingers, hands and forearms.

It feels as if you had to work with a wobbly tool for quite some time, then all of a sudden, get a very precise and exact instrument, like e.g. skiing with racing skis vs. with allround skis. It’s pure joy!

The difference is difficult to describe, so I would recommend you rather go experience it yourself and judge for yourself. For me, it’s my most favourite keyboard so far.

I’m even thinking of getting one for the Windows workstation at work too, it’s that good.

March 5, 2019March 5, 2019

macOS: How to remove stale/redundant entries from the “open with” context menu

To regenerate the “open with” context menu in macOS (and reopen Finder windows), execute the following two commands in Terminal:

$ /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user
$ killall Finder

March 4, 2019March 4, 2019

TCP BBR

TCP BBR looks promising and somehow managed to escape my radar so far.. need to take a look at how to improve my IT infrastructure with it:

Increase your Linux server Internet speed with TCP BBR congestion control

March 3, 2019March 3, 2019

FreeNAS 11.2/FreeBSD BTX boot loader 1.0: Very slow booting if “Legacy USB 3.0 Support” is enabled

Starting with version 11.2-RELEASE-U1, FreeNAS uses the FreeBSD BTX 1.0 boot loader instead of Grub (reason: The FreeBSD boot loader finally started supporting ZFS – years after Grub supported it, BTW).

Unlike Grub, the FreeBSD boot loader seems to have rather “suboptimal” support for storage devices (like USB sticks, USB drives) that are accessed using the legacy USB 3.0 mode at boot time. So, when I upgraded FreeNAS from 11.1-U7 to 11.2-RELEASE-U2 on my home-built ASRock FreeNAS E3C226D2I NAS appliance, booting FreeNAS from an internal 16 GB USB 3 stick took all of a sudden almost 30 minutes(!) instead of the usual 1-2 minutes.

As I found out by “trial & error” (or educated guessing, as some would say), the only reason for this huge slowdown was that “Legacy USB 3.0 Support” was enabled in the AMI BIOS (the effect is reproducible). So, just disable “Legacy USB 3.0 Support”[1] in the BIOS and FreeNAS >= 11.2 will boot quickly again.

[1] Note: There’s no need to disable “Legacy USB Support”, so you’ll still be able to use your USB 2 keyboard or mouse at boot time.