Raspberry Qt – Part 4
Back in the day of Bulletin Board Systems (BBS) everyone had to use a modem to connect to either a bulletin board or friend’s computer. This was long before the Internet. Ordinarily people ran their Unix/Linux desktop systems from the root (all powerful) account and DOS, well, it didn’t have the concept of user accounts. Well, it later did when Digital Research released DR MDOS, but that is a story for a different time. At any rate, if you were on the computer you had access to everything.
This has changed over the years. DOS came out with a GUI task switching front end called Windows (which was not an operating system though branded as such on the packaging) and the Unix/Linux world decided the default user account needed to be a lesser God. Those who are familiar with Ubuntu know that Debian world invented the “sudo” command and by default disable the root account. The RPM world, last time I looked at OpenSuSE, still has a root account you switch to via the “su” command and a password. The RPM world has fallen out of favor with most developers, primarily because of RPM-Hell where a partially applied RPM (Debian packages have .deb extensions) could leave your system in a broken state where your only option was to restore from backup or re-install. Yes, there are a few server type distros which still favor RPM based distributions, but on the desktop Debian based distros rule. This is also true for the embedded Linux world.
Now, by default, you don’t have access to everything. The logic behind automatically granting network access yet blocking serial port access is simply baffling. I assume this ties back to Apple and the fact they’ve never made a real computer. For some inexplicable reason Apple maintains CUPS (Common Unix Printing System) and some years ago they not only switched from the tried, true, stable and robust PostScript printing engine to the wild west of Adobe PDF. Not satisfied with gutting every printer driver ever created, they also ripped out serial and parallel port support which had always been in CUPS or at least been there since CUPS was created. Why? Because every printer created originally communicated by either serial or parallel cable.
Now, in order to use your serial port on Ubuntu you have to add yourself to the dialout. For those of you who want to screen scrape this page:
id username sudo adduser roland dialout id username
The second use of the “id” command is simply to verify your group list changed.
There are many posts on the Internet which will tell you to use usermod. DON’T DO IT. If you bludgeoned forward on the Pi without reading look at this picture to figure out how to undo your tragedy. If you already rebooted your Pi or logged out after removing yourself from sudo I do not know how to help you. I only went so far with the research for this post. If you hosed up your Ubuntu environment with that read this post.
While you are here you should change your timezone, keyboard and locale information, assuming you aren’t in the UK which appears to be the default settings. Under “Menu” then “Preferences” you will find an entry for “Raspberry Pi Configuration.” Select it, then select the localization tab. I did not bother over clocking or any other tweaks. I have worked places which tweaked all kinds of settings trying to squeeze a bit more performance out of the thing but those things cause other issues. If you _really_ need more performance, buy a Pi 3 or whatever the current faster version is. For the next few years these boards will get faster and more capable while costing the same.