Ubuntu won't start, kernel doesn't see disk?

Question

linux

Good afternoon, there is an old linux server, the system itself does not boot with the following error:

VFS: Cannot open root device "hda1" or unknown-block(0,0)
Please append a correct "root=" boot option
Kernel panic - not syncing:  VFS: Unable to mount root fs on unknow-block(0,0)

I connected the hard drive to the computer with ubuntu, the hard IDE itself, but at the moment it is loaded through the adapter (controller), IDE -> USB because I have no other options for checking and loading the hard drive. When viewing the hard drive from ubuntu, I have no access to the root and var package. In / dev "hda1" is available. Can I somehow find out the configuration of the mounted system from my friend? there is no var/log as a matter of fact? Prompt please.
UPD: In the home folder there is a folder that contains another linux system, as I understand it, this is a virtual machine. It's just that all the root folders were empty and it was annoying.

Answer 1

In your bootloader, the root system is most likely taken from the initrd. Did you unpack it to make sure /dev/hda1 is still there?
And yes, try booting with root=/dev/sda1