January 8 2019 BlueJ, chargers, Python scripts and Wireguard Meet

Darren reported that he had not been able to download a version of BlueJ which was compatible with the version used by the Open University.

He also shared a problem with a laptop not charging. John said that, if it was an Acer, it might well be a problem with the charger connection to the laptop as this could break over time. David S said that if it could run on mains but not charge the problem was likely to be the tantalum capacitors which could be replaced but the job was very fiddly. Also Dell chargers have a third wire which identifies the charger as a Dell; if this breaks a Dell laptop may refuse to charge. One way round it is to make a permanent connection of the third wire in the laptop.

David C reported that he had written a number of Python scripts, one to distinguish a ‘good’ from a ‘bad’ file for the purpose of archiving and another for the purpose of exporting files from Myriad as transport files. These end up as zip files but John wondered if, perhaps when unzipped, they would turn out to be MPEG transport files which can be converted to normal MPEG files.

Brian had been hoping to give a demonstration of Wireguard but BCB’s networking topology prevented this. So he took us through the steps he had taken to install Wireguard, create key pairs for the server and for the client and then configure Wireguard. David S commented that, if he had the facilities, he could get further privacy by using IPv6 addresses.

Brian also went through the process for setting up passwordless SSH (see the Respberry Pi documentation for an example) and mentioned

• the use of alias to save remembering complex commands
• Pi-hole to block Internet adverts, and
• etc/hosts to specify particular Internet addresses.

John commented that the last could also be used to access a development website before it was added to the DNS.

David S drew attention to 75 Internets worth of addresses being used to light up a Christmas tree interactively.

Brian rounded things off by pointing out that some registrars do not allow the use of facilities like DynDNS; so, if you want to use it, you need to find a registrar who will permit it.

Past Meetings