Ha! I’ll bet you thought this blog was dead.
Well, it was almost dead, but isn’t anymore (hopefully).
Today I’m going to talk about how to use a HP Thunderbolt G4 dock with a M4 Pro Macbook Pro laptop to get multiple displays to work.
Continue readingRecently I wanted to have the ability to use SSH to log in to my Amazon Lightsail instances from my work laptop. For privacy reasons, I didn’t want to put my SSH private key permanently on the laptop and I didn’t want to put the public key for my laptop on the Lightsail instances.
Since I’m very comfortable with the unix command line, I decided to put a new (password protected) private key on a flash drive so I could use that key to log in to the Linux instances.
The problem is permissions.
SSH won’t let you use a private key file with open permissions. If the key file is world readable, it will display an error and refuse to use it. There isn’t a workaround that I’ve been able to find (other than recompiling SSH from source with modifications).
This mean that the most common flash drive file systems (FAT, FAT32, & exFAT) can’t be used. None of those file system formats support permissions.
I could have formatted the flash drive using the MacOS HFS format, and installed the necessary packages on my Ubuntu Laptop to support that, but I wanted to go for something more generic.
After some research, I decided to give the User Defined File system (udf) a try.
I did have to install UDF support on the Ubuntu system, but that wasn’t a big deal.
sudo apt-get install udftools
To format the flash drive on my Mac, I used this command:
sudo newfs_udf -m blk -v <label> /dev/disk<n>
Important to note, the device file (/dev/disk<n>) must be the device itself, not a partition of the device (on Mac systems a partition will be denoted with ‘s9’ after the device name where 9 is the partition number, for example /dev/disk4s1).
After the UDF file system is created on the flash drive, you must … eject the drive, physically remove the device, and re-insert it. The device will now show up on the system as “/Volumes/<label>”.
Interestingly, the owner of the mounted device is the currently logged in user.
macbook-pro:newkey david$ ls -l /Volumes/FLASHDRIVE/ total 3 -rw-------@ 1 david staff 1073 Jul 11 10:11 aws-key
I copied the new SSH private key file to the flash drive, made sure the permissions were correct, and ejected the drive.
I then inserted the drive into my Ubuntu system. It mounted correctly right away.
I was then able to log in to my Lightsail instances using the command
slogin -i /media/<my linux user id>/<flash drive label>/<private key file> ec2-user@<aws hostname>
Interestingly, when the UDF formatted flash drive is mounted, the owner is the logged in user, but had the correct permissions.
user@linux:~#: ls -l /media/user/FLASHDRIVE/ total 2 -rw-------- 1 user user 1073 Jul 11 10:11 aws-key
So far it’s been working well. I’m pleased with this little project.
If you’re using an Apple Mac computer, you may have observed that the fantastic backup system Time Machine, may run slowly. This is especially noticeable when you are doing the very first backup (when it has to backup the entire system).
I was frustrated by this a while ago when I purchased a new hard drive to do my backup’s on.
After a bit of digging, I found that time machine’s performance is throttled so as not to impact system performance.
There is a way to remove performance throttling using a system control statement.
debug.lowpri_throttle_enabled
If you use the sysctl command to set this to 0 (zero) then time machine will not be throttled. If it’s set to 1 (one), it will be throttled.
I created a little script called ‘speedup-timemachine’ that lets me turn the option on and off.
‘speedup-timemachine on’ will remove the throttling.
‘speedup-timemachine off’ will return the throttling.
Below is the script. Just copy the script, paste it into a text editor, save the script to a location on the path, and make it executable (chmod a+x scriptfile).
Continue readingAs a Mac user, I sometimes find my self needing to use Windows 10. To do this, I run it using the Parallels virtual machine manager.
One thing that bothered me, when was running Windows in full screen mode, was that the MacOS dock would pop up when I moved the mouse pointer to the Windows task bar.
I would have to move the mouse pointer away from the dock, let it drop back down, and then move the pointer back to the Windows task bar without going to the bottom of the screen.
Continue reading