Two methods to reboot an iPhone, from my friend CK:
- hold down volume-up + power for 10 seconds
- volume up button, 1 second later: volume down button, 1 second later hold power button
Force reboot on iPhone
Reply
Category Archives: Sys Admin
Mail log IP address count
The following monster will parse the mail log and report on unique host connections along with a count.
cat /var/log/mail.log | \
grep ' connect from unknown' | \
awk '{ print $8 }' | \
sort | \
sed -n 's/.*\[\([0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\)\].*/\1/p' | \
awk '{count[$1]++} END {for (word in count) print count[word], word}' | \
sort -n
cathode ray dude dot com
This guy, Cathode Ray Dude [CRD], does some fun stuff. He’s on the web via HTTPS at gekk.info and HTTP at www.cathoderaydude.com.
Network outage
I’m in the process of moving some of my web systems to new servers. The blog.jj5.net has been completed, svn.jj5.net is a working progress, and some of www.jj5.net is broken until I can get around to fixing that too. This outage will manifest as some images which won’t load in blog posts. I’m sleepy now, so I’ll try and fix this tomorrow when I wake up.
blog.jj5.net
I’ve been meaning to make this change for a while now, and finally got around to it this evening.
I started blogging at blog.jj5.net back in November 2003 and continued through to May 2005. After that I stopped blogging for a while, but I started again at progclub.org in August 2011.
The ProgClub blog was imagined to be a group blog, my plan when I set it up was to have all the ProgClub members have an account on the blog, but that turned out to be a pretty poorly received idea. Eventually, and for a long time now, it has just been me (your host, jj5) over on the ProgClub blog.
Since this has become a personal blog, I figured it was time to move it from ProgClub back to blog.jj5.net, where it all began.
The transition should be seamless, old links should be properly redirected, old logins should continue to work, but if you run into any problems please let me know.
Bluetooth signal quality on MacBook Pro
If you press the Option key then click the Bluetooth icon on your MacBook Pro then MacOS will show you the signal strength (RSSI) and other info about your Bluetooth devices. RSSI is the “Received Signal Strength Indicator” as explained by ChatGPT. The current RSSI for my bluetooth speakers is -67dBm, which ChatGPT explains:
An RSSI value of -67 dBm is generally considered a good signal strength when it comes to WiFi, and the same could be roughly said for Bluetooth and other wireless communication technologies. In terms of qualitative interpretation:
- -30 to -50 dBm: Excellent signal strength. This is about as good as it gets. Usually, this is only seen when you’re very close to the access point or device.
- -50 to -70 dBm: Good signal strength. For most general applications, this range provides a reliable, strong connection. Voice, streaming, and even video applications usually work well in this range.
- -67 dBm: This specific value is often cited in WiFi scenarios as the minimum strength for reliable voice applications.
- -70 to -90 dBm: Fair signal strength. The connection is more susceptible to interference and might not be reliable for all applications. Data rates will be lower, and minor obstructions can cause the signal to drop.
- Below -90 dBm: Poor signal strength. The connection is unreliable and might drop frequently. It’s challenging to maintain a stable connection in this range.
So, an RSSI of -67 dBm is generally good for most applications, including voice and streaming. However, the actual performance can vary based on the specific wireless technology in use, the environment (presence of physical obstructions, other interfering signals), and the application’s specific requirements.
USB Hub Chain
Well. Turns out you can only chain up to five USB hubs. I know, because I tried to chain six. I feel like this is a life accomplishment, and it should unlock a secret level or something. After finding this limitation myself, ChatGPT confirmed it.
Bluetooth!
For a long while now I have been having intermittent problems with the audio in my lab. I stream the GoaPsy channel from di.fm, and I really love it, but not when there’s skipping! I figured the problem was related to latency and jitter on my broadband connection, and if so, there was little to be done, except to wait for network conditions at my ISP to change.
But this evening I noticed that when I sat close in to my workstation to type the skipping would start. Then if I moved back in my chair, it would stop. I found I could actually cause the skipping to start or stop just by moving around in my chair!
Turns out the problem wasn’t my internet connection, the problem was the bluetooth connection between my laptop and my speakers! To fix the problem I got underneath my desk and moved my sub woofer about one foot to the left. Now when I move around in my chair my music doesn’t skip anymore! Happy days!
Video streaming quality
I found Google’s video streaming quality report. It seems to be context sensitive, so for me it reports results for my ISP (Dodo) in the Sydney region.
Amphetamine
I wanted to know how to stop my MacBook Pro from going to sleep when I closed its lid, so I asked ChatGPT and discovered Amphetamine. Good work, Internet; you have come a long way since the nineties.
p.s. I always wanted to blog about amphetamines.