10 Apr
2019
10 Apr
'19
4:51 p.m.
Long ago, I could swear I'd read a paper (or a TM, or something) that
described the process of a Unix system booting. It presented a timeline
describing the sequence of how the boot blocks are loaded, the kernel
is loaded, MMU turned on, etc.
However, other than that, I can't recall a thing about it - can't remember
the title, the author, or where I found it. I don't remember if it talked
about this process on a Bell Labs Unix system, or a BSD system (though it
had to be one of those - either 7th Edition or BSD). The timeframe was
probably mid to late 1980's, though I could be wrong about that.
Does this ring a bell with anyone? I really wish I could find it again...
--Pat.
10 Apr
10 Apr
5:20 p.m.
Pat,
Any such description is either going to be very hardware/system specific, or vague to the
point of uselessness. The experience of the NetBSD community, which prides itself on
extreme portability and working around broken or ... let's say
"incomplete" vendor firmware, is that such things are highly system-specific.
The vague description is easy:
some booter or firmware loads the kernel into RAM,
the kernel initializes the MMU and the rest of the processor(s),
devices are somehow probed or listed and device drivers called to
initialize minimally necessary I/O devices (console, data storage so
you can mount / (root)),
a process is created, and /sbin/init is exec'd.
Details of firmware or booter provided environment and parameters to the kernel vary a
lot; thus that famously small-ish percentage of any Unix kernel that is written in
assembler for the processor involved, rather than C.
See also
https://www.quora.com/Are-bootloaders-like-GRUB-and-LILO-hardware-specific/…
https://www.quora.com/What-is-a-concise-explanation-for-the-UNIX-bootstrap-…
Erik
5:57 p.m.
On Wed, Apr 10, 2019 at 1:00 PM Pat Barron <patbarron(a)acm.org> wrote:
Long ago, I could swear I'd read a paper (or a
TM, or something) that
described the process of a Unix system booting. It presented a timeline
describing the sequence of how the boot blocks are loaded, the kernel
is loaded, MMU turned on, etc.
However, other than that, I can't recall a thing about it - can't remember
the title, the author, or where I found it. I don't remember if it talked
about this process on a Bell Labs Unix system, or a BSD system (though it
had to be one of those - either 7th Edition or BSD). The timeframe was
probably mid to late 1980's, though I could be wrong about that.
Does this ring a bell with anyone? I really wish I could find it again...
The book "The Design and Implementation of the 4.3BSD Unix Operating
System" by Leffler et al has a lengthy explanation of booting 4.3BSD on the
VAX towards the beginning of the book. Could that be it? I thought I had a
copy in my office, but don't see it on my bookshelf at the moment. Bach's,
"The Design of the Unix Operating System" contains a brief and very
high-level overview in the chapter on process control, but I recall Leffler
et al having significantly greater detail.
- Dan C.
19 Apr
19 Apr
10:31 p.m.
It may not be exactly what you were thinking of, but there have been a few “bring-up”
papers to come out of NetBSD about getting it working on new CPU architectures and new
system types. Perhaps one of those is what you read?
-- Chris
1837
days inactive
1846
days old
3 comments
4 participants
participants (4)
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Chris Hanson -
Dan Cross -
Erik E. Fair -
Pat Barron