illumos gate

Current sample session with partition menu in format:

partition> p
Current partition table (original):
Total disk sectors available: 41926589 + 16384 (reserved sectors)

Part      Tag    Flag     First Sector        Size        Last Sector
  0        usr    wm                34      19.99GB         41926622    
  1 unassigned    wm                 0          0              0    
  2 unassigned    wm                 0          0              0    
  3 unassigned    wm                 0          0              0    
  4 unassigned    wm                 0          0              0    
  5 unassigned    wm                 0          0              0    
  6 unassigned    wm                 0          0              0    
  8   reserved    wm          41926623       8.00MB         41943006    

partition> 0
Part      Tag    Flag     First Sector        Size        Last Sector
  0        usr    wm                34      19.99GB         41926622    

Enter partition id tag[usr]: 
Enter partition permission flags[wm]: 
Enter new starting Sector[34]: 0
`0' is out of range.
Enter new starting Sector[34]:

It is not too obvious why we can not use value 0. Sure, we could use 'help' there:

Enter new starting Sector[34]: help
Expecting an integer from 34 to 41943006
Enter new starting Sector[34]: 

But that also is not obvious thing to type in. Updated format:

Enter new starting Sector[34]: 0
`0' is out of range [34-41943006].
Enter new starting Sector[34]:

I think, this example above is a bit more user friendly.

Testing done: build/install/boot and manual test.

format> ver

Volume name = <        >
ascii name  = <VMware-Virtual NVMe Disk-1.3-20.00GB>
bytes/sector    =  512
sectors = 41943040
accessible sectors = 41926589
first usable sector = 34
last usable sector = 41943006
Part      Tag    Flag     First Sector        Size        Last Sector
  0        usr    wm                34      19.99GB         41926622    
  1 unassigned    wm                 0          0              0    
  2 unassigned    wm                 0          0              0    
  3 unassigned    wm                 0          0              0    
  4 unassigned    wm                 0          0              0    
  5 unassigned    wm                 0          0              0    
  6 unassigned    wm                 0          0              0    
  8   reserved    wm          41926623       8.00MB         41943006    

partition> 0
Part      Tag    Flag     First Sector        Size        Last Sector
  0        usr    wm                34      19.99GB         41926622    

Enter partition id tag[usr]: 
Enter partition permission flags[wm]: 
Enter new starting Sector[34]: 0
`0' is out of range [34-41943006].
Enter new starting Sector[34]: 
Enter partition size[41926590b, 41926623e, 20471mb, 19gb, 0tb]: 41943006b
partition> 0       
Part      Tag    Flag     First Sector        Size        Last Sector
  0        usr    wm                34      20.00GB         41943039    

Enter partition id tag[usr]: 
Enter partition permission flags[wm]: 
Enter new starting Sector[34]: 
Enter partition size[41943006b, 41943039e, 20479mb, 19gb, 0tb]: 41943040b
Number of blocks must be less that the total available blocks.
Enter partition size[41943006b, 41943039e, 20479mb, 19gb, 0tb]: 20490mb
`20490.00mb' is out of range [0-20479.98]
Enter partition size[41943006b, 41943039e, 20479mb, 19gb, 0tb]: 20gb
`20.00gb' is out of range [0-20.00]
Enter partition size[41943006b, 41943039e, 20479mb, 19gb, 0tb]: 1tb
`1.00tb' is out of range [0-0.02]
Enter partition size[41943006b, 41943039e, 20479mb, 19gb, 0tb]: 
partition>

partition> 0
Part      Tag    Flag     First Sector        Size        Last Sector
  0        usr    wm                34      20.00GB         41943039    

Enter partition id tag[usr]: 
Enter partition permission flags[wm]: 
Enter new starting Sector[34]: 
Enter partition size[41943006b, 41943039e, 20479mb, 19gb, 0tb]: $
partition> p
Current partition table (unnamed):
Total disk sectors available: 41926589 + 16384 (reserved sectors)

Part      Tag    Flag     First Sector        Size        Last Sector
  0        usr    wm                34      19.99GB         41926622    
  1 unassigned    wm                 0          0              0    
  2 unassigned    wm                 0          0              0    
  3 unassigned    wm                 0          0              0    
  4 unassigned    wm                 0          0              0    
  5 unassigned    wm                 0          0              0    
  6 unassigned    wm                 0          0              0    
  8   reserved    wm          41926623       8.00MB         41943006    

partition>

Note the first block count is actually too large (reserved partition will not fit in), but current logic does allow such partition edits (label command would have been failed there - overlapped partitions are not allowed with GPT).