UEFI, EFI, elilo and Slackware

 I recently came across a system that would not allow me to use legacy boot, so...

Convert gamma system server to virtual box vm

 This is a work in progress...

Kill a process on OpenVMS

show system

stop/id=nnnn (where nnnn is the PID from the above command)

Restarting processes on Alpha

 

Reset Windows password

Reset Windows password

Adding a PATH variable on the Mac

We can modify the /etc/paths file or we can create a file under /etc/paths.d such as /etc/paths.d/docker

which could contain;

~/.docker/bin

where the docker bin was located at /Users/my_username/.docker/bin

See also [here] for an example of adding JAVA to the System PATH in Linux.

Install command line tools on Mac

xcode-select --install 

MySQL flush-hosts and ERROR 1129 (HY000)

Often we see an error such as:

ERROR 1129 (HY000): Host 'nn.nn.nn.nn' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'

SSH HostkeyAlgorithms

 A note for .ssh/config

Limit max number of characters in a java text field.

 

Java Method Overriding v Overloading

 I found this useful and interesting, especially as the terms are so easily mixed up (by me at least).

Nexus 5

Unlocking, rooting, installing a custom recovery, installing Kali and reverting my Nexus 5 back to stock.

Serial ports

Serial port pinouts

Fig's 1&2 show the more common 9 pin serial pinouts, on both the computer side and also the device side respectively. Fig.3 gives a more visual representation of the male variant, most commonly found non the PC side. I think this was historically due to a male being more prone to damage, hence the female end being more commonly used on cables, but I may be wrong.

Fig.5 is particularly useful when testing cables, although I have only really connected pints 2&3 for this purpose. The idea here is that you make a plug that connects the pins together and then you can open the port and whatever you type should be echoed back exactly. 

Fig's 6-10 provide details about Null Modem connectivity.

Fig.11 provides more pinout details for the DB25 connectors

Printing control characters

We can echo a control char as per the below;

echo -e '\x07'

The above will give us a BEL

if we want to add control characters to a file, we can do;

printf 'hello there \x07 my name is Snake' > test.txt

if we then cat test.txt, well see the text and a BEL

We can of course send this to a serial port with something like cat test.txt > /dev/ttyS0