Subject: Re: Ideas on one-floppy installation
To: None <>
From: Greg A. Woods <>
List: current-users
Date: 10/19/1994 11:29:41
[ On Tue, October 18, 1994 at 10:42:11 (-0400), Perry E. Metzger wrote: ]
> Subject: Ideas on one-floppy installation
> I don't think, however, that the "memory filesystem" approach to
> booting is impossible. Here is an idea.

The ideas Perry outlines are very similar to what many commercial
systems do to install.

For example, the SysVr3.x releases on NCR Tower-32's does almost exactly
that, if I remember correctly.  You boot from something (usually tape),
the kernel then gives up some memory to a ram disk driver, and the init
process is a kernel process which makes a filesystem on the ram disk,
mounts it as the root filesystem, cpio's the next file off the tape into
the new root filesystem created in the ram disk.  It then starts the
real init from the new root filesystem, and you either enter a
maintenance shell, or begin the installation procedure.

I've also seen a three stage boot system where the first stage copies a
boot loader off tape and this loader then copies a root filesystem image
into a pre-determined area of memory.  The system then re-boots from
this in-core filesystem image as if it were a normal boot.  Of course
the kernel there knows it's using a ram disk as a root filesystem.

Perhaps each of us who know various different schemes employed by other
systems should outline them in detail, and then an ideal scheme for
NetBSD (esp. i386) could be put together from these ideas.

						Greg A. Woods

+1 416 443-1734			VE3TCP		robohack!woods
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