Re: NetBSD MBR boot / Error no operating system

[Steve Binkhorn <steve%prd.co.uk@localhost>]

fdisk reported the correct size (1TB) but said not bootable, recognised it as NetBSD. I had chosen standard bootblocks and a whole disk installation.

I wonder if this is an MBR/GPT issue - out of my depth here.

The target system didn't get beyond the hardware probe from an install DVD.

Sent from BlueMail

---

From: Robert Elz
Sent: Fri Apr 20 18:00:45 GMT+01:00 2018
To: steve%prd.co.uk@localhost
Cc: netbsd-users%netbsd.org@localhost
Subject: Re: NetBSD MBR boot / Error no operating system

    Date:        Fri, 20 Apr 2018 15:52:43 +0000 (UTC)
    From:        steve%prd.co.uk@localhost (Steve Blinkhorn)
    Message-ID:  <20180420155243.1AEBEB35FEF%viking.prd.co.uk@localhost>

  | But returning it to the server, it gives the message:
  |
  | NetBSD MBR boot
  | Error No operating system

This all comes from the MBR boot code (the 400 or so bytes that
follow the MBR partition table).   "No operating system" seems to
mean that the magic number of the bootable partition was not
correct.

That all was OK on the other system suggests that perhaps there's
a drive geometry mapping problem - to be as portable to ancient
systems as possible, the MBR boot code uses CHS addressing if
it believes that it should work (there's not much space there to allow
for fallbacks, and alternatives,...)

What does fdisk report about the MBR, and is that likely to be what
the system you want to boot from implements?

Also beware of sector size issues - drives in USB caddies sometimes
do not act the same way as when directly SATA connected (or so I
have read).

kre