Thank you for the reply.
Your answer is way over my head on the explanation with the diagram and entering things in Terminal App use, but I did copy & paste:
diskutil list internal
What I was originally trying to do was figure out why when I tried to do Disk Speed Check using the BlackMagicDesign app, said I couldn't because the disk was read only.
I can log into my account and everything is working. I just wanted to do a speed check to compare speed with a new external SSD.
This is what I get after entering Terminal App:
What is zsh? And what happens if I enter `chsh -s /bin/zsh` ?
////////
The default interactive shell is now zsh.
To update your account to use zsh, please run `chsh -s /bin/zsh`.
For more details, please visit https://support.apple.com/kb/HT208050.
MacBook-Pro-2:~ roypeterson$
MacBook-Pro-2:~ roypeterson$ diskutil list internal
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *500.3 GB disk0
1: EFI EFI 314.6 MB disk0s1
2: Apple_APFS Container disk1 500.0 GB disk0s2
/dev/disk1 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +500.0 GB disk1
Physical Store disk0s2
1: APFS Volume Macbook Pro 9.1 GB disk1s1
2: APFS Snapshot com.apple.os.update-... 9.1 GB disk1s1s1
3: APFS Volume Preboot 1.9 GB disk1s2
4: APFS Volume Recovery 1.7 GB disk1s3
5: APFS Volume VM 3.2 GB disk1s4
6: APFS Volume Macbook Pro - Data 262.0 GB disk1s5