[SOLVED] 4 x HDD all with own OS LM19.2 on board each one, all on one PC

I am trying to work out how to fit 4 x 1TB HDD's in one PC, all independent of each other, all with linux mint 19.2 installed on each.
Each drive has come's from a different pc.
1) one was from my CAD PC, The CAD program is Bricsys and does not play well with others, installing it loads other files and stops other programs working due to loading older files to work, must be kept separate from other programs.
2) one is from my normal desktop PC, all my office work on this.
3) one is from my Image PC this is for developing RAW images using dark table, over 100,000 images want to keep this separate
4) one is from my programming PC, programming Python PYQT and C++, needs to be separate, have been known to freeze this disk from time to time.

I would like to be able to choose what HDD to use from boot up, I must admit Have not figured out how to set this up on one PC
any help would be grateful

Choose from the computers BIOS/UEFI, usually a function key at start up.

Use Grub to start which one you want, (could be installed onto a pendrive), which would be started at boot.

Put the drives into USB drive cases, & attach whichever is needed prior to booting.

Just some thoughts.

There are more than a few ways. Each way has it's own issues.

What I like to do is remove data/power from each non-used drive and do clean install to single drives. That way each drive has it's own loader. Now every once in a while an update could mess up the loader on the current drive.

Personally, I'd continue to use four PCs and invest in a KVM switch.
I'm currently running an 8-port USB/PS2 combo KVM from IOGear with four 'puters connected (at the moment). MSRP in the $350 US range. EDIT: $400 with cables...sorry.
Want to do something with another 'puter? - just plug it into the KVM, connect it to the router, and go.

Originally Posted by scasey Personally, I'd continue to use four PCs and invest in a KVM switch.

Having four OSes in the same system on their own HDD seems at least power efficient but a little clunky to implement. Four boxes + KVM is the simplest way to go. If you only run one at a time you just keep the others powered down. But then why not a single system and VMs?

I'm currently running an 8-port USB/PS2 combo KVM from IOGear with four 'puters connected (at the moment). MSRP in the $350 US range.

That seems pricey for the KVM. I have a similar IOgear KVM that I got years ago -- at a monthly computer faire (back when things like that still happened) -- and I can't imagine I paid that much. I had to purchase some extra cables but it was still a bargain at "faire" prices. I wish someone was making a comparable device with HDMI ports for video at a reasonable price. (Looking to build a small farm of RaspPi4s and without such a KVM it'll require way too many HDMI-to-VGA dongles.)

Re HDMI, I have a 3 to 1 adapter that I plug into a monitor & can connect 3 computers to one monitor with it, it was quite cheap, & has its own switch, but you do need to use a keyboard & mouse on each. You could use just the one keyboard & mouse, swapping between computers.

Hi Guys

Thanks for the info,
I used Fatmac's option put all four HDD's in PC and boot up from F12 - so easy
works like a dream.

Thanks Guys

I tried the setup as stated, when upgrading to lm19.3 on sda drive it also updates all other drives and took out all indipendent operating o/s on the other drives.
I found this to solve my problem - a Kafuty HDD Hard Drive Power Supply Switch Control Module SATA Drive Reliable Selector Switcher For Desktop PC Computer.
I can now turn on or off any hard drive I like or use in any combination as I wish, with no update problems by pushing a on/off push button wired to each SATA HD
Works for me.
link: https://www.amazon.co.uk/dp/B07QPMVS...302_E_DDE_dt_1
Thanks All
Issue Solved