How safe or dangerous would it be to stop and restart the
Linux Bluetooth service itself ?
It should not affect the running of the Linux system at all. It might leave any connected bluetooth devices "orphaned", I.E. with a connection that the kernel doesn't know about, but I really do not know. You almost certainly can't damage the linux system beyond needing a reboot to get back to where you were, so if I were you I'd try it and see what effect it has. In particular I'd look to see if currently connected devices keep working, and if the stuck process recovers quickly after the restart. I suspect that restarting the service won't affect the stuck hcitool process. It probably has all it needs to do its work, so restarting the bluetooth service won't affect it. You should probably take a look at what hcitool is doing when its stuck - it may be a bug in the process, which you could report to the developer, or it may be due to some bluetooth device not properly implementing the discovery protocols, which leads to problems, or, well, anything!
All sounds reasonably safe. I am sure you are correct - I should look into how hcitool scan is implemented.
This is something I will never understand - Bluetooth is "implemented " in Linux kernel.
It uses "blueZ" "stack"... "blueZ" source code is "available" in several versions and ALL of them are lacking code comments or function descriptions ... basically a code nobody maintains...
My Linux version runs a "bluetooth manager " and my QT implementation of "blueZ" library interact with this flaky manager - perhaps by using the Linux " blueZ stack "...
A "stack" is the set of programs and/or system services needed to supply a given end-user (in this case) service.
As I understand it, for bluez there's
User programs : e.g. hcitool
System software : e.g. whatever system processes are needed to monitor/provide bluetooth services
System libraries : e.g. libbluetooth this provides interfaces for both system and user programs
Kernel module : e.g. bluetooth module, which provides the kernel side implementation details
As you can see, this forms a "stack", with each layer needing services from the layer below it to provide the services it needs to the layer above.
I am making sure this forum can accept / discuss and resolve "Bluetooth" as DEVICE.
With that let me make a statement:
For many reasons , irrelevant to the following post,
I do not fancy to utilizing "blueZ" library.
And please let us NOT discuss that.
i do prefer to use one of many open or hidden derivatives of "blueZ" library.
End of story.
I am pretty much done using "hcitool" .
Unfortunately "hcitool" has no easy or visible means to "pair" Bluetooth devices.
It looks as "bluetoothctl" can be used to pair.
hcitool and bluetoothctl DO NOT use same terminology describing Bluetooth processes.
device became controller
and who knows what is "agent" ?
Think of RAID as providing long term reliability. A RAID cluster can normally survive at least one drive going bad. A backup, on the other hand, is what you need in the event of anything from "finger trouble" erasing data, or a bug writing bad data, to a critical systems failure, such as a flood or file, from which you need to rebuild your operating environment.
If the only way to loose your files is a hard disk failure, then you may consider RAID5 to be a "backup" solution (the "backup" being stored in the redundancy bits of the non-crashed disks.
For all other issues - fire, flooding, machine/disk stolen/lost, inadvertent file deletion or content modification, ransom virus, discovering that a virus has infected a lot of your files, ... - you need a decent backup. For a great number of the risks, you also need offline, offside backup. You need frequent backup, at least daily, which implies that you need incremental backup.
My "grub" identifies a partition ( dev/sde7 ) as bootable.
It attempts to boot, but ends up in "maintenance mode ".
I like to recover SOME of the contents of the partition
but preferably REMOVE the OS.
I have had a very limited success using Linux maintenance / recovery
options and would prefer to remove the OS from the partition.
What makes a microprocessor different from a microchip? Is is the ability of a microprocessor to load information into transistors, use it/process it and then reset it`s state so that new information may be loaded and used again. Microchips are just an entity meant to direct information based on a hardcoded algorithm, rather than execute mathematical operations. Is this exact?