Re: PC boot sequence (was: patch: MFSv3 support (libsa) for boot2 (i386))

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

> > 4) The pbr code now reads the rest of the 8k 'boot code' area at the
> >   start of the partition
> This means "MBR partition", right?

I think "MBR_PTYPE_NETBSD" partition in the Master boot record:
http://nxr.NetBSD.org/xref/src/sys/arch/i386/stand/bootxx/pbr.S#156

> And this "boot code" is what is called "primary boot" in BSD terminology,
> right?
 :
> > this is the rest of bootxx_xxxfs.
> What do you mean by "rest of"?

See my first post:

---
sector 63:    pbr.S (first 512 bytes bootxx_ffsvN)
sector 64:    NetBSD disklabel (installboot(8) skips here)
sector 65-78: rest of bootxx_ffsvN
sector 79-:   UFS superblock
---

> > 5) The bootxx code now tries to load the 'boot' program from filesystem,
> >   it checks the following places for a filesystem:
> I don't quite get why it has to look for a filesystem. I thought 
> (and in only 8k it must have) the block numbers of /boot encoded
> into it by installboot?

No. On x86 (and alpha, pmax etc.), primary bootxx_Xfs recognizes
filie system as its name, unlike old sun ports.
(no bbinfo in src/usr.sbin/installboot/arch/i386.c)

> >   a) the start of the partition
> This again means "MBR partition", I suppose?

It seems so:
http://nxr.NetBSD.org/xref/src/sys/arch/i386/stand/bootxx/boot1.c#76

---
Izumi Tsutsui