I was encouraged by an Administrator of Linuxmint.com to share my experience.
Since, this will be a lengthy post let me first list the topics I should touch here, so that you all know beforehand and could decide whether or not to take a look.
1. Reasons for abandoning Windows and picking up Mint
2. First taste of Linux Mint portable version, installing Mint
3. First steps, Software Manager, Timeshift, devices, keyboard inputs limit
4. Sharing folders in the home network dominated by Windows platforms, syncing software, Remote Desktop Application that works with Windows platforms
5. Crashes of Linux Mint and a little bit about VPNs
6. More about synchronizing folders and files with regard to time stamps
7. Setting and using VirtualBox
8. Further intentions
First of all I am posting this from the Visoki Dečani monastery, from Kosovo region, which is a World Cultural Heritage Site since 2004 (https://www.decani.org/en/). I am here a monk, but also a Power Systems Engineer in charge of the site's infrastructure spanning over 15 buildings and more than 8.000 m². I need PCs basically to store all the documentation related to various utilities of the infrastructure, to supervise the wiring system and central heating system, to monitor and program OMRON PLCs (programmable logical controllers) and OMRON touch panels and, of course, to communicate.
1. Reasons for abandoning Windows
Well, I was Windows user from very first versions of it in mid 1990s. I even use to work in IBM DOS before that for a while. Some Windows versions I liked more (XP, ME, 7), some less (Vista), but got use to carry out my job on those platforms. So when I was first prompted to switch to Win10 I quickly accepted, as I was promised that the transition will be smooth and all the applications continue to work properly. A month or so later Win10 installed itself and after only a day or two I experienced deep dissatisfaction. Not only that at least one half of applications did not work, especially software for OMRON PLCs which I depended immensely on, but also old printers could not be any longer connected. Than I realized that Win10 is doing all sorts of things on Internet without even asking a consent from the user (only afterwards a message would pop up 'Windows did this or that') and very soon I decided I won't stay on Win10 so I installed again Win7. Still to use Win7 I had to learn over the years to check first on forums which updates to install and which to skip, since there were issues with a number of updates. However, I would feel comfortable once I made System Disc Image and a bootable Rescue disc. I also always hated that User folder in Windows would grow all the time for no obvious reason whatsoever. Very soon I would get 5-10GB of junk inside this folder. Well at some point Microsoft announce they would end their support for Win7 and for a while I was thinking what to do since I did not like staying on an unsupported platform. So when the time grew closer I wanted to learn more about Linux platforms (now I learned these are called distributions) and I checked on Internet.
2. First taste of Linux Mint removable version, installing Mint
Once I read that Linux Mint was created to facilitate the switch to Linux for Windows users, and that also a portable version is available for experimenting and tasting Linux I went for it. I downloaded this Linux Mint 19.2 Cinnamon version, put it on a bootable USB and played with it for a few days and basically I liked it. All the devices were up and running very quickly and many applications were there from the very outset. Very soon I learned that this Linux Mint can be installed to dual-boot with Windows7 (of course also with many other operating systems or OSs) and I said why not give it a try. Well I quickly learned that the portable version of Linux Mint need to be set again after each reboot and this prevented deeper experiments. So I decided to take the dual-boot option and install Linux Mint on my laptop which is HP Envy, quad-core i7 Intel processor, 16 GB RAM, one SSD disc 256 GB and one HDD 1 TB (This one comes originally with Win10 licence). Windows 7 was already on the SSD disc so I made some room on the HDD and tried to install Linux Mint, but I would get information that this was not possible. So I resorted to Internet and read someone's recommendation that Linux should be installed on a separate hard disc which was not used and formatted previously by the Windows. So this meant that all my user data needed to go somewhere else. I never kept this data on the same hard disc (not even on a different partition) with Windows. So I used a 4 TB MAXTOR Seagate external USB hard disc and copied all my data there and deleted the entire internal HDD. Now it was possible for the installer to install Linux Mint as dual boot with Windows 7. Basically I let the installer pick mostly if not all the defaulted options and very quickly Linux Mint 19.2 was installed. For a first few days I had to go manually at the boot to pick the booting option, but after that something - I later realized was called GRUB2 - was installed and now I could have 30 seconds to decide if I want to start Win7, or just let the MINT boot up. Before proceeding let me write here that very soon (a week or ten days later) Linux Mint 19.3 update was announced and the transition was very smooth.
3. First steps, Software Manager, Timeshift, devices
Upon installation I read the Welcome Tutorial, as well as recommendations from this link (https://fossbytes.com/things-to-do-afte ... inux-mint/), went through the Software Manager and was glad to find so many applications so easily available and did install some of them. The only one I regretted installing from Software Manager was Virtual Box, but later on there will be more words about it. In Software Manager it was nice to see that most of the applications had comments from users who already installed them and sometimes also a suggestion to go directly to certain sites for download if a newer version was needed or a comment what can and what can't be done with a particular application. It is really great to have something like Software Manager on your OS even if sometimes you don't get all the newest versions.
The tutorial also advised me to use Timeshift to make snapshots of my system (which later on helped me recover from some serious crashes) which I did and opted to have at least once a week a snapshot made automatically by the OS.
As was said for the portable version of Mint regarding the devices was also valid for its installed version. Most of the devices were available as soon as the system was first started. Laptop monitor and another external Monitor were started with the best possible resolution (various Windows platforms would never start with your monitor at its best resolution, but some basic, and later on Windows would search for drivers and it would take a couple of days for me to start using my monitors at their best parameters) I was offered, though, to switch to another NVIDIA driver and accepted it, but never saw any difference in the quality of the screen display. I did not see any problem or anything else regarding the plugged-in USB devices (wireless keyboard and mouse, wired mouse, external HDDs) and they were operative from the first second. Many printers on our internal network were automatically added as well. I only had to manually add one Kyotsera network printer (did not find exactly the same model on the offered list, but the second attempt resulted with the driver working properly and it all took no more than three minutes), and one old HP LaserJet A3 printer, connected through an Ethernet-to-paralel adapter was also very quickly installed being manually picked from the list of available HP printers. This one would never get hooked with Win10.
My scanner was installed following these directions, which was among the first hits when Internet was searched for this scanner:
https://www.ubuntu4u.com/howtos/how-ins ... r-1804-lts
I set keyboard layouts and there was my first disappointment, since I could not get more than four inputs. I sincerely hope this limit (I learned soon it was imposed only on Linux Mint, while other Linux distributions, or distros, don't have it) will be removed in some future versions. Basically I need at least six keyboard inputs to function normally. Two inputs for my mother tongue: Serbian Cyrillic and Serbian Latin, than I need English, Italian, German and Albanian. So this does represent a little trouble for me (still not enough to take me back to Windows) so I searched for options. Two languages I use less than others are Albanian and German so I needed some possibility to type characters particular for those two inputs. It took me a couple of hours and I found a solution known as 'Compose Key Sequences'. First I needed to follow this link (2. part of the instruction titled as Compose Key)
https://www.maketecheasier.com/quickly- ... ers-linux/
still this was not enough for LibreOffice Write and Calc and the next part really took me quite some time to figure out. Finally I read somewhere (could not find the link afterwards) I needed to go to System Menu (bottom left corner) and type Keyboard. Than go to Layouts Tab and click on 'Options' button. There select a 'Key to choose the 3rd level. No key was selected and I selected 'Menu' key, which is next to 'right CTRL' key on my keyboard, which was the one I selected to be the compose key. So now I was finally able to use compose keys sequences (https://tstarling.com/stuff/ComposeKeys.html). Still, I join all the multilingual Mint users who kindly ask the Developers to remove this restriction and enable more language keyboard inputs. We would all be really gratefull.
4. Sharing folders in the home network dominated by Windows platforms, synchronizing software, Remote Desktop that works with Windows platforms
Now a very tough task was next in line for me to solve. I have a number of Desktop PCs connected to various OMRON Programmable Logical Controlers (PLCs in further text) and OMRON touch panels related to these PLCs, that I needed occasionally to check, reprogram or just access from a locally connected PC. These are all part of the wiring system and central heating system monitoring. So all these PCs run Win7 (without any permission to access Internet) and I used to access them from my office PC through inner Ethernet network of our complex. So I was looking for a way to now have Remote Desktop kind of access but not from Windows7 but from Linux Mint. After checking only a few hits on a web search engine I learned about the Application named 'Remmina'. This one was available on Software Manager and I installed it, run it, typed the local address of the PC I first wanted to connect to and hit 'connect' button. First time it failed stating that the desired platform did not support 32-bit graphic (now throughout my learning process it was great to know why something is not possible when it wasn't possible, unlike Windows who would just write some error codes and left you wander about what was going on). I reduced to 16-bits and it worked. Later on I increased to 24-bit graphic and it still worked. So this task actually turned out as a very easy task contrary to my expectations.
However sharing folders was not that easy. I went through many dozens of "how-to" posts, made sure I installed System-config-samba (from Software Manager), tried with File Manager turning on folder sharing both without and with root privileges (right-mouse-click menu), was changing permission on folders and files both from File Manager and from the Terminal and who knows what not. It took me several days and then it just started to work. Initially I thought that restart of samba services did the trick. I got access for other PCs to shared folders on Mint and was able to access folders on those PCs as well. In Chapter 6 I will write more about my experience with Folder Sharing, once it stopped working, as unexpectedly as it had started, but here let me only mention that now I learned how to address PC with shared folders (smb://ip-address) in File Manager on Mint, while on Windows there was no need for smb:// and //ip-address would suffice. Let me also mention here that since I made multiple attempts on some folders to share them, there were new folders now with digits 1 or 2 attached at the end of their name. Interestingly, the main folder I wanted to share was not any longer just Maxtor, but also Maxtor1 and actually folder Maxtor appeared empty, while Maxtor1 had all the data inside. I had to deal with this later on and that is also in Chapter 6 of this post.
Next step, once sharing was made possible, was to find a way to synchronize data across the home network with only Windows7 PCs on other ends. I did not want to risk with full automated terminal commands or software who don't let you select options on file-per-file base, but wanted to have options how to run syncing once comparison is done. I went through just a few posts on Internet and soon two application stood out - FileZilla and Unison. They caught most of my initial attention and I first searched for both on the Software Manager (as I basically always do resort to this software source initially) and both were available, but for FileZilla there were user comments that it won't work with network folders. Anyhow I installed both and tried first FileZilla, but it did not work with Network folders. Unison was different story and only complication was actually how to find the way to enter the full path of the shared folder on another PC. So the format turned out to be like this
The bold-italic letters need to be change to reflect your real situation.
Unison's Graphic User Interface (or GUI for 99% of PC users, still let me think here of the remaining percentage who are not so comfortable with all the acronyms like I wasn't a few years back) was not great and that added to some difficulties in learning how to point to the shared folder outside of the PC with Unison. Once I was done pointing I let it do the comparison. I got only one question at the end of setting which was about whether any of the folders was of FAT format type. I clicked no, since for many years I have been using only NTFS format, and the syncing did not work. I went through more posts on Internet and quickly learned that actually I have to check out this option so that Unison would work with a folder on Windows OS. So I did it and the comparison was initiated. It was taking time and I let it work over night. Next mourning I got the list of files to be synchronized and was able to pick file by file, which direction to do it, or which to omit etc. When I clicked the 'Go' button, I was able to carry out the syncing and it again took much time. Let me also mention here that I learned that syncing won't start unless the network folder had been previously accessed (from File Manager). Well even in Windows you can not access unmounted network folders. Well, before I could delve more into the matter of syncing I dealt with the matter of VirtualBox (chapter 7), but let me write about it a little bit later.
So, as was mentioned above the folder sharing stopped working at some point and I had no idea why. Again I resorted to Internet 'how-to' pages, posts and forums and I tried everything described above. This time nothing worked. After at least 50 Internet pages about this matter (counting my first attempts) I learned that sharing an external USB hard drive folder in Linux Mint was not the same as sharing folders on internal HDDs. So, now I made my 'how-to' Internet search more specific. Again going through various posts for two more days and spending each day three or four hours on it, but to no avail. Then one post suggested I should try setting how my external USB HDD initially mounts and change fstab configuration file (/etc/fstab). Most likely it was this post
I was really tired and I just mechanically followed what was written, without even backup-saving the original fstab file.
5. Crashes of Linux Mint and VPNs
Well, I am sure that even moderately experienced Linux users would have immediately recognized that this was a recipe for disaster. So reboot attempt resulted with endless attempts to boot up the Linux and occasional messages to check the System log file. I really felt devastated and that I lost so much energy in vain. I tried to go back to GRUB2 and start Win7, which worked, and also from GRUB2 to start whatever diagnostic tool was available, but nothing helped. I even wrote an email to one of the Administrators on the linuxmint.com wondering whether I should quit the very idea of switching to Linux Mint. The Administrator kindly enough responded very quickly suggesting I should use my installation USB to boot up Linux Mint and try from there to solve the problem and repair the fstab file. I tried, but since there was no backup of this file I could not remedy anything. With my mindset used to handle occasional Windows issues of a similar nature my first thought next day was to search for a Linux Mint bootable repair utility. After checking like 10 Internet pages dealing with this issue I decided to try Boot Rescue Disc software utility. Bear in mind that I was now back on Windows7. I burned a bootable DVD with this software (using ImgBurn software) and tried to boot from there, but to my great surprise BIOS did not list DVD in the Boot-from Menu, which has happened to me never before. I tried to put it on USB with Rufus (later I learned not to make bootable Linux USBs with Rufus), but now USB was not among the options for boot-from. I was really at the brink of deserting the very idea of Linux. I put again DVD (forgetting to unplug the USB) and now to my huge surprise everything started without me even having to chose booting option. I have no explanation since previously I also would let everything play without my intervention, which would lead to GRUB2. However since Boot-Rescue-Disc did start up I went through recommended set of actions and tried again to reboot my PC. Well what I saw past GRUB2 wasn't much promising. I reached the so called 'tty' terminal and logged into it. Above I saw several lines with errors listed, all of them stating that various things were not possible due to the fact that some files were found to be read-only. I gathered my last ounce of energy and typed this error in the search engine. I checked several articles and all of them pointed to only two directions: A) Disc check with '$ sudo fsck -Af -M' ; and B) Remounting of all HDDs with read-write permissions with '$ mount -o remount,rw'
The latter option seamed to be quicker for check-up and I went with it. As soon as I typed it I realized that the booting process has resumed and finally there was normal login-screen with all the desktop screen graphics at the background. Only thing I initially noticed was that Internet was not working as opposed to Ethernet working and Remmina was able to access other PCs.
'$ sudo service network-manager restart' quickly solved this issue and I quickly went for Timeshift and chose to go to a past Snapshot before this crash. Timeshift listed soon all the files that shall be changed and I felt great relief to find fstab among those files. So Timeshift got me out of a really huge trouble.
Let me also mention here that I tried two VPN providers. First, I tried TrustedZoneVPN and I did put much effort, but I could not make it work. surfshark-VPN was my second attempt and it worked immediately on Mint. You don't get it with GUI and have to type from a terminal, but it is rather simpe 'sudo surfshark-VPN' to start 'sudo surfshark-VPN down' to stop and 'sudo surfshark-VPN status' for status. Initially I reported having troubles after stopping the service, or when it loses connection to the connected server. They do have great support and instructed me to do a certain step and after a few days I noticed an update for SurfShark in the UpdateManager, and did not have any problems afterwards.
6. More about synchronizing folders and files with regard to time stamps
Well I felt I should rest for a few days prior to making further forays into Linux Mint settings, and so I did. I sent a 'thank-you' email to the mentioned linuxmint.com Administrator and promised I should consider writing about my experience, as was suggested, once I really get somewhere.
So when I was back in action I again went through so many attempts already described for putting my folders again available for sharing but for another day or two there was no result. At some point I wondered why I was able to access shared folders on other PCs from my Linux Mint and they were not able to access mine. I talked to our IT Administrator (I knew that he used Linux distros on our two servers, one for Internet access point with Fire Wall, and the other for Data Server. I also learned those are openSUSE.). He told me to check my fire wall and iptables setting. Fire Wall was off so I set on learning more about iptables. I could not recall iptables being much mentioned in all the posts and tutorials I went through while trying to set folder share. After reading more than 10 different Internet pages and having spent several hours I finally somewhere ran across this simple command to flash (maybe it also means refresh) iptables. It was as simple as
'$ sudo iptables -F'
As if somebody had waved a magic wand my folders were again available for sharing. Since I made many attempts so there were also many folders now available, some with even three different names, like Maxtor, Maxtor1, Maxtor2, but now all of them were with its expected content, non was empty like in my previous experience. I tried to reduce the number of shared folders and went to File Manager to do it from there. I was only able to eliminate two of them, while five more excessive folders remained. I searched for more explanation where to look for them and tried with system-config-samba (only could be started from root terminal), and '$ sudo smbstatus --shares' but it yielded no result till I read this article
https://serverfault.com/questions/38954 ... ectory-act
and it directed me to folder '/var/lib/samba/usershares' - where I found the rest of the rules for folder sharing. Each one of the rules was in separate file which could be opened with Text Editor. I deleted these files and finally all the excessive folders were gone. I did not even use samba restart or iptables flash. I basically left only one folder for share plus printers, which was visible in system-config-samba with GUI. Once I learned about creating link with 'ln' command I decided I should in future just put links in this folder should I ever need to share something more.
A few days rest felt well earned and needed.
Than I decided to go deeper into syncing issues. Obviously it was taking too much time just to compare files with Unison. I searched Internet more for this issue and then I ran across another syncing application 'FreeFileSync'. This one was not in the SoftwareManager but I had to download it from the site. It would come as a portable version. You just have to unpack it and you run it from that folder. Well this one had much better GUI than Unison and also it was much closer to ViceVersa, which I preferred using on Windows. I now think it is better since ViceVersa I used did not have an option of background syncing while you work. OK I went for 'File Content' type of comparison, knowing that files are almost synced. It took much less time to compare these files, but it was still 50 minutes, as oposed to 3 or 4 hours Unison took to compare. I synced the remaining files and then ran compare again but with the option of 'File time and size'. It took less than five minutes, but I get all the files listed as non-synchronized due to different time-stamp.
Now, this was something new to me. The same external USB HDD, now connected to Mint, was previously synced with the folder on my Desktop PC when both laptop and desktop were running on Win7. Still, now no time stamp matched. I did not like that, but also did not like to copy everything again and was not even sure if this would fix the problem. As I did before I searched Internet for and explanation and learned that Windows clock and Linux clock are different. This link was helpful was helpful for me
https://www.howtogeek.com/323390/how-to ... l-booting/
and I decided to switch my Mint to work with local time, like Windows. I also recalled that many years ago, when our complex was first introduced with data servers, I could not get the folder on those servers have time stamps like on my Windows folder. Well, still I had hundreds of thousands of files with different time stamp and I did not like that at all. Autocad software would regularly come with 75.000+ files and folders. In short I zipped some Autocad folders to reduce the number of files. I even experimented whether Windows 7zip application is faster than Mint's archive manager, both zipping to 7zip format. Archive Manager on Mint was way faster. My Install folder for Windows application was now on ca. 5.500 files and folders, with no time stamp match. I would expect many users switching from Windows to Mint (or other Linux distro) to encounter this kind of problem at some point. Well, since for me it did not matter what time stamps I have in this particular folder I came up with an idea of changing all the time stamps so that they would match. There were two many files (~4.800) and folders (~770) to do it manually. Basically this link (number 51)
https://askubuntu.com/questions/62492/h ... -of-a-file
was ultimately helpful and after a couple of attempts (on a folder that was safe for experiments) I came up with these lines which changed the time stamp of everything inside the folder and its subfolders It has to be executed from terminal being in the folder that requires time stamp change.
Code: Select all
$ find -print | while read filename; do > touch -a -m "2020-01-13 15:00:00" "$filename; > done
Once I was sure this worked properly I moved to the source folder and executed it there, than to the destination folder and again executed it and finally I had two folders with all the same time stamps. Now FreeFileSync would compare two folders very quickly and return positive match for all the files. In another folder (also on this same external USB HDD) I was much luckier and only had 10 files with time stamps non-matching. I will try to write to FreeFileSync and suggest a new option so that after making comparison with 'file content' option all the matching files whose time stamp doesn't match would be offered to adjust these time stamps. Another thing I noticed about FreeFileSync are the errors related the 'File-Safe' syncing option, which basically first renames the file that will be over-written, then once it is done tries to move it to the Trash bin. When you have Windows on one end it fails and it reports "Unable to move to Trash bin". Still, it's not a big deal. Not to forget FreeFileSync also gives you option to sync more than one pair of folders, as well as syncing a folder between more than two computers.
I was really relieved that I found a way to share and sync folders, and I still have to run 'iptables -F' after rebooting (I am positive I will find a way to make it run during the boot-up process). Still, I have to conclude that Sharing Folders in Linux Mint (I cannot generalize for other Linux distros) is rather complicated for someone like me and that a proper tutorial would really be great. A kind of tutorial that would touch all the layers of folder protections and restrictions that interfere with folder sharing. Maybe a 'Welcome Screen' for some future edition could have a line leading to this tutorial. So far I learned something in general about SAMBA, NMBD, samba GUI, iptables, chmod and chowe (both not working on mounted folders) and masks that restrict those two commands, fire wall, all sorts of applications both within Software Manager and on Internet, dealing with the 'Folder sharing' issue, but I am still far away from getting even a remote idea of the full canvas. I also don't doubt that all of this was for a good reason - the security of user data, for which Linux is famous. My persistence did pay off but I could easily imagine that others might easily just quit Linux when they face this kind of obstacle.
7. Setting and using VirtualBox
Before starting the this Chapter let me state here that I was aware of the Wine application for Linux Mint and that it enables certain number of Windows applications to run directly from Mint. There was also a link to the site enlisting all the various Windows applications that could to full or limited degree be used with Wine. Well, mostly there were all sorts of games I did not need since I am no gamer. I tried if Autocad can be used and I believe something like AutoCad2004 was the last version successfully used with Wine. At some point I might recheck the situation but for now I realized this won't do for me.
Well, if you don't intend to use VirtualBox for any Windows (or MacOS) application that is unavailable for Linux you might as well skip this section.
As mentioned before I still need OMRON programming and monitoring Software for PLCs and Touch Panels which is only available for Windows platforms. This is why I had to deal with this issue. I assume that other users switching from Windows to Mint might still need something to run on Windows. Other then that, I learned, VirtualBox is indeed a great tool to experiment with other Linux distributions.
As mentioned before this is the only software I would recommend be installed from the www.virtualbox.org and not with Software Manager. The reason is that you will miss some great options especially selectively sharing devices on USB ports (even scanner). Well it was not a big deal to install VirtualBox (I only had to know I needed a version for Ubuntu 18.04). Please, also download the Extension Pack to be able to use all the features.
Since I downloaded VirtualBox from Software Manager before realizing it's way better to do it from the VirtualBox site I searched a way how to switch to newer version. Some of the links I ran across advised me to delete the unused repository files, which I did and the Mint application that watches over System Stability immediately warned me that system is unstable and could easily crash. Fortunately there was enough time to execute Timeshif and restore to a previously saved Snapshot. But I did learn here that some of the tutorials can be dangerous. Than I just followed the instructions from the VirtualBox site and it worked. To be short with Windows 7 I installed everything and it went smoothly. The USB devices had to be set for USB 2.0, otherwise there were problems with keyboard and mouse if they were left on USB 1.1 or USB 3.0. Important thing with VirtualBox was to make one's user name part of the VirtualBox group since this application does not care if you use Terminal as root user or as a standard user it only cares whether you are part of the VirtualBox group (this I did very simply with User and Group application from the Main Menu). Later on I found some instruction written by Windows users stating that in Windows you need to run Terminal (known as CMD) as Administrator to be able to execute some commands related to VirtualBox. They would than say if you are Linux user you need to log as root into Terminal. But this was not true and VirtualBox on Linux would execute Terminal Commands only when I was logged as standard user, and only once I made my account member of the VirtualBox group. Still, this did not take too much time to figure out.
Once Windows was installed and started as GuestOS I realized I needed to install the mentioned Extension pack from the GuestOS. This would enable some great features, first of all sharing folders with the HostOS. Well, when at home I am connected to our servers and sharing is possible as was above discussed to great length. Still when away and not connected to any server, this is really great. The only problem I faced was related to expanding the drive for GuestOS. After making at least 20 attempts related to posts on Internet I could not make my GueosOS adopt this modification so I posted a question on Linuxquestions.org and got the answer
https://www.linuxquestions.org/question ... 175666422/
Later on I experimented if OMRON software running on this GuestOS Windows platform could grab some of the USB ports and use the usb to serial convertor to connect to OMRON PLCs and it worked perfectly. This was main reason why I needed the last version of VirtualBox. So I can now even consider abandoning completely the dual-boot option with Mint and Win7.
Than, since I was already experimenting with VirutalBox I decided to try installing MacOS. This was way more difficult than Windows. I won't get into details and would only summarize that if you should need this I believe the best site to turn to should be www.geekrar.com and if you download any package there you'll need this password to unzip it Geekrar.com
Mojave worked great after I installed it and was able to update itself. To use mouse and keyboard I needed to set USB3.0 in VirtualBox. There was no sound transferred to HostOS, but it was rather easy to get sound with Bluetooth speakers, as is recommended by many posts related to this issue.
Catalina could not update itself and it worked with USB2.0.
For both versions as mentioned before you needed to run some Terminal command sequences (related to the description of the virtual PC architecture) but not as root user.
Once this experiment with MacOS on VirtualBox was done I sincerely hope I'll never need to use MacOs. Everything is just different from what I got used to in Windows.
As for backup-ing my GuestOSs in VirtualBox I experimented with Snapshots, Cloning and Exporting. Frankly, Exporting (and eventually Importing Back when Catalina would crash after an update) worked best for me. Snapshots did not help me with it and Cloning takes more disc memory but than you have one more GuestOS and if your next experiments fails you recover quickly.
8. Further intentions
Well I did have some hard time but I will stay with Linux Mint on my laptop. Eventually maybe switch my desktop PC to some other Linux distribution and make it my data server. Our IT Administrator suggests CentOS or OpenSUSE. Well, it is great thing that I can first try it more and at much slower a pace in VirtualBox.
Other Newbies I kindly ask not to rush to implement any part of my experience before more experienced user get enough time to make their comments about what should have been done differently and in better fashion.