bin/60565: dump(8): units are confusing

["campbell+netbsd%mumble.net@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         60565
>Category:       bin
>Synopsis:       dump(8): units are confusing
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Aug 09 22:40:00 +0000 2026
>Originator:     Taylor R Campbell
>Release:        current, 11, 10, 9, ...
>Organization:
The NetBSDump Unit, Inc.
>Environment:
>Description:
     dump [-0123456789aceFinStuX] [-B records] [-b blocksize] [-d density]
          [-f file] [-h level] [-k read-blocksize] [-L label] [-l timeout]
          [-r cachesize] [-s feet] [-T date] [-U dumpdev] [-x snap-backup]
          files-to-dump
...
     -b blocksize
             The number of kilobytes per dump record.

	What is the default if I don't pass this?  Is there a minimum?
	Is there a maximum?

# dump -0 -a -X -S /repo/hg
  DUMP: Dumping sub files/directories from /repo
  DUMP: Dumping file/directory /repo/hg
  DUMP: Found /dev/rxbd1 on /repo in /etc/fstab
  DUMP: Date of this level 0 dump: Sun Aug  9 22:33:45 2026
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping a snapshot of a subset of /dev/rxbd1 (a subset of /repo) to /dev/null
  DUMP: Label: none
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 17955272 tape blocks.

	Can we print this in MiB/GiB/TiB too, no matter what the block
	size is?

>How-To-Repeat:

	man dump

>Fix:

	Yes, please!