Correct, thanks for that advice and the problem is now sorted.
FWIW, the exports manual page is not available on the client where I had been looking for it, only on the server. That's logical I suppose.

onedevone wrote :

Insanely too small or insanely too large?  Or just right? - that would be really insane!

I have 16 Gb of RAM and a 27 Gb swap partition.  I thought the advice was to have the swap area at least equal to RAM. I've never seen the swap used (maybe it does when it sleeps); but what the hell, I have six drives in my PC because I've been too lazy to take any out when I've put newer ones in. The swap is on "ancient history" spinning rust 80GB drive that has an old disused Windows XP installation on its other partition AFAIR. This reminds me to check it out for bit-rot some time.

I have not managed to see a screenshot in Synaptic for a long time (years?).  I gave up trying. Best to Google for it separately to find an image for it, if there are any.

Discover was one of the reasons I gave up kde (ceasing to allow different backgrounds for different desktops was another). So it was a package manager? I never did find out because although it kept popping up that it had updates for me, behaving like an annoying phone app, when I tried responding to it out of exasperation nothing happened. Couldn't find a way to uninstall it either, must have been baked in.

That's interesting. I have the mouse plugged into a randomly chosen USB socket, so it could be a USB3. There are about 6 sockets and I expect there are some USB2s to choose from. I will investigate further.

Thanks for the advice and I've done it now, no harm done by disconnecting SATA data cables other than finding the drive device names have changed when I re-connected and went back to Linux - sdd to sdb etc.  The single connected drive on which I installed Windows has become sda from sdd. Doesn't affect much as I use UUID identities in fstab - at least they did not change.

The Windows installation did not work anyway, although it was only to play some old games. I first tried WinXP and it said my BIOS was incompatible, I suppose because my MB BIOS is UEFI not MBR type. I then tried Win7 and it did install but without the mouse working - BIOS issue again I guess. I guess I shall just have to play Solitaire in a VM.

@stultumanto wrote :

But systemctl is in the repositories and is described as "daemonless "systemctl" command to manage services without systemd".
I must admit I don't know much about how daemons work.

Thanks for the help.  I uninstalled and re-installed tcplay and it did then turn up in /usr/sbin, which was not in my path. Seems to be working although I've not yet used it in earnest.

I am in the process of a re-installation of Devuan due to a change of motherboard which for some reason has fubarred the previous installation despite not changing anything with the drives. Long story, maybe something to do with UFEI.
 
A bit OT, wasn't there something about Debian/Devuan re-allocating files in the newest versions to cut out the /usr directory level? eg /usr/bin/ to /bin/

Add to this the effect of increasing censorship as a result of some supposed free speech governments such as resulting from the Online Safety Act (OSA) in the UK. This requires self-policing and age verification by website owners in case a troll posts "unsuitable" material, which is not defined exactly by the OSA but is being taken to include not only the obvious stuff that most people assume it is all about, but also current news of violent events such as serious crimes and the war in Ukraine, military history, rabbit breeding, and advice on sexual health.

Many website owners have taken down their websites rather than risk the severe punishments specified by the OSA, or have blocked access from the countries concerned. For example the widely used Imgur photo sharing website is now "Content not available" here in the UK and Wikipedia is under some threat.

I have been banned from a couple of harmless geek interest type forums for refusing to give my age verification (copy of passport, driving licence etc) on principle and for security reasons.

Couldn't you just wipe the whole thing and re-format it? Or are there some special data blocks at the start of flash drives and SD cards etc?