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What does "booting" mean to you?
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Rod Pemberton
Apr 5, 2012, 10:13:35 AM4/5/12
to
I just realized that my understanding of "booting" and "to boot" is very
different from at least one other person here. This seems to have colored
both my understanding of recent posts by others, and the understanding of
others of my posts.
To me, "to boot" and "booting" means to start an OS (operating system). So,
if no operating system starts, then nothing has booted, even if some code
was executed. On a normally setup x86 OS, that requires MBR code, partition
tables, a boot flag set for the bootable partition, a formatted partition,
PBR code for the partition, an OS installed to the bootable partition. So,
when someone says: "What does the BIOS boot?" It means that some fixed-disk
MBR code executed, a partition marked bootable was found, then PBR code for
that partition executed, and the OS was loaded executed from the bootable
partition.
The different definition which seems to be in use for "to boot" and
"booting" means the BIOS executes the MBR code on a fixed-disk.
What does "booting" and "to boot" mean to you guys?
If the MBR code executes, fails to find an active partition, and returns to
the BIOS via an Int 18h or 19h, is that a "boot"? Or, does that just mean a
valid master bootsector was found and executed?
Does the meaning of "booting" require that the OS is started?
Rod Pemberton
Bjarni Juliusson
Apr 5, 2012, 11:33:29 AM4/5/12
to
On 04/05/2012 04:13 PM, Rod Pemberton wrote:
>
> What does "booting" and "to boot" mean to you guys?
To me it means for a computer to get from an initial power-up state into
>
> What does "booting" and "to boot" mean to you guys?
a useful state running some program. That program is not necessarily an
operating system. Examples of non-operating system directly booted
programs include many old computer games as well as special-purpose
control software.
> If the MBR code executes, fails to find an active partition, and returns to
> the BIOS via an Int 18h or 19h, is that a "boot"? Or, does that just mean a
> valid master bootsector was found and executed?
useful state.
Bjarni
--
INFORMATION WANTS TO BE FREE
s_dub...@yahoo.com
Apr 5, 2012, 11:02:43 PM4/5/12
to
On Apr 5, 9:13 am, "Rod Pemberton" <do_not_h...@notemailnot.cmm>
wrote:
'Bootstrapping' is the original notion, the answer to the question:
"How do I load executable code/data when there isn't any code in
memory to load data yet?"
.. but I digress..
Bjarni's explanation is good with the caveat case of 'warm boot', that
is, the reset of machine state without going to power-down state
first.
My quibble with your statement above is in regard to a requirement of
a MBR at all, does the firmware really require it to proceed. (but I
concede the signature word AA55h would be required for the firmware
that checks for its presence). I know you are giving a conventional
case, enough said.
I have 3 or 4 (well I don't know what to call them, I've used the term
'diagnostic bootstrap's' but all they bootstrap is themselves) -
diagnostic code snippets (programs) - just to report the register
contents, to find machine state, IPL Stack SS:ESP settings, etc.
(different btw, between power-on cold boot and ctrl-alt-del warm
boot). Certainly not OSen and not intended to be. In a way, these
fall into the same class as your MBR that can't find a bootable
partition. Most MBR's do what they should do: don't load anything and
complain -they fulfill their purpose in that case. I'll accept your
definition, its good that you state it. But then how should I refer
to these other power-on or reset executions?
And so when someone says: "What does the BIOS boot?" they should be
challenged to ask "What does the Bios Bootstrap load & execute?" -to
which the answer is: 'the first sector of the first (eligible)
device'.
> If the MBR code executes, fails to find an active partition, and returns to
> the BIOS via an Int 18h or 19h, is that a "boot"? Or, does that just mean a
> valid master bootsector was found and executed?
>
> Does the meaning of "booting" require that the OS is started?
>
I guess we could recall the original ibm pc, no hard drive or
floppy(an option), cassette tape for storage, Basic in rom.
Can we say it doesn't boot? :)
Steve
> Rod Pemberton
wrote:
> I just realized that my understanding of "booting" and "to boot" is very
> different from at least one other person here. This seems to have colored
> both my understanding of recent posts by others, and the understanding of
> others of my posts.
>
> To me, "to boot" and "booting" means to start an OS (operating system). So,
> if no operating system starts, then nothing has booted, even if some code
> was executed. On a normally setup x86 OS, that requires MBR code, partition
> tables, a boot flag set for the bootable partition, a formatted partition,
> PBR code for the partition, an OS installed to the bootable partition. So,
> when someone says: "What does the BIOS boot?" It means that some fixed-disk
> MBR code executed, a partition marked bootable was found, then PBR code for
> that partition executed, and the OS was loaded executed from the bootable
> partition.
>
> The different definition which seems to be in use for "to boot" and
> "booting" means the BIOS executes the MBR code on a fixed-disk.
>
> What does "booting" and "to boot" mean to you guys?
>
Next you can ask 'what is an OS'..
> different from at least one other person here. This seems to have colored
> both my understanding of recent posts by others, and the understanding of
> others of my posts.
>
> To me, "to boot" and "booting" means to start an OS (operating system). So,
> if no operating system starts, then nothing has booted, even if some code
> was executed. On a normally setup x86 OS, that requires MBR code, partition
> tables, a boot flag set for the bootable partition, a formatted partition,
> PBR code for the partition, an OS installed to the bootable partition. So,
> when someone says: "What does the BIOS boot?" It means that some fixed-disk
> MBR code executed, a partition marked bootable was found, then PBR code for
> that partition executed, and the OS was loaded executed from the bootable
> partition.
>
> The different definition which seems to be in use for "to boot" and
> "booting" means the BIOS executes the MBR code on a fixed-disk.
>
> What does "booting" and "to boot" mean to you guys?
>
'Bootstrapping' is the original notion, the answer to the question:
"How do I load executable code/data when there isn't any code in
memory to load data yet?"
.. but I digress..
Bjarni's explanation is good with the caveat case of 'warm boot', that
is, the reset of machine state without going to power-down state
first.
My quibble with your statement above is in regard to a requirement of
a MBR at all, does the firmware really require it to proceed. (but I
concede the signature word AA55h would be required for the firmware
that checks for its presence). I know you are giving a conventional
case, enough said.
I have 3 or 4 (well I don't know what to call them, I've used the term
'diagnostic bootstrap's' but all they bootstrap is themselves) -
diagnostic code snippets (programs) - just to report the register
contents, to find machine state, IPL Stack SS:ESP settings, etc.
(different btw, between power-on cold boot and ctrl-alt-del warm
boot). Certainly not OSen and not intended to be. In a way, these
fall into the same class as your MBR that can't find a bootable
partition. Most MBR's do what they should do: don't load anything and
complain -they fulfill their purpose in that case. I'll accept your
definition, its good that you state it. But then how should I refer
to these other power-on or reset executions?
And so when someone says: "What does the BIOS boot?" they should be
challenged to ask "What does the Bios Bootstrap load & execute?" -to
which the answer is: 'the first sector of the first (eligible)
device'.
> If the MBR code executes, fails to find an active partition, and returns to
> the BIOS via an Int 18h or 19h, is that a "boot"? Or, does that just mean a
> valid master bootsector was found and executed?
>
> Does the meaning of "booting" require that the OS is started?
>
floppy(an option), cassette tape for storage, Basic in rom.
Can we say it doesn't boot? :)
Steve
> Rod Pemberton
Benjamin David Lunt
Apr 6, 2012, 1:23:42 PM4/6/12
to
"Rod Pemberton" <do_no...@notemailnot.cmm> wrote in message
news:jlk9ah$8j9$1...@speranza.aioe.org...
>
<content snipped>
> Does the meaning of "booting" require that the OS is started?
Just a small note to say that I am not ignoring these latest
threads. I do plan to read them in detail, do my own tests,
and then respond. I have just been preoccupied with many
other things at the moment.
Ben
--
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http://www.fysnet.net/The_Universal_Serial_Bus.htm
To reply by email, please remove the zzzzzz's
Batteries not included, some assembly required.
James Harris
Apr 9, 2012, 3:04:08 PM4/9/12
to
On Apr 5, 3:13 pm, "Rod Pemberton" <do_not_h...@notemailnot.cmm>
wrote:
else's words should be understood from context.
From a user's point of view to boot a computer probably means getting
it to a working and usable state. We might boot-up Windows, for
example.
If we talk about specifically "booting an OS" we probably mean
similar.
This newsgroup possibly has many posts about booting an OS.
Similarly, we could bootstrap something else such as a piece of test
code meaning to get the computer to run our test code from power on.
(Take memtest86 as an example. A computer has to go through a
bootstrap process to get that loaded and running but there is no OS
involved and there may not even be a hard disk with partitions and the
like. The memtest86 software could be loaded from a floppy or an
optical disk.)
As programmers we may have a different viewpoint. Probably more
accurately than the view of a user of a computer, to boot means to get
a computer from power on to loading the *first* piece of code that is
not burned in to ROM. The piece of code thus loaded can then load the
next piece and so on. I suppose you could call these later loads part
of the bootstrap sequence if you are looking to get something specific
running.
> If the MBR code executes, fails to find an active partition, and returns to
> the BIOS via an Int 18h or 19h, is that a "boot"? Or, does that just mean a
> valid master bootsector was found and executed?
Well, the MBR writer would probably would consider that the machine
had booted the MBR but the OS writer would consider that the boot
process hadn't happened!
> Does the meaning of "booting" require that the OS is started?
As you can guess, I wouldn't say so unless it was apparent that that's
what was meant by the context. A computer can boot without even
running an OS. If someone said specifically, "boot an OS" I would view
that as meaning the the OS had to be started. Similarly, to boot an
MBR means to me to load and start an MBR.
But those are colloquialisms - but nevertheless useful. Strictly,
though, I would say that to boot (without saying to boot some specific
piece of software) means to load the first piece of code from storage
of some sort and to start it.
Of course, YMMV.
James
wrote:
> I just realized that my understanding of "booting" and "to boot" is very
> different from at least one other person here. This seems to have colored
> both my understanding of recent posts by others, and the understanding of
> others of my posts.
>
> To me, "to boot" and "booting" means to start an OS (operating system). So,
> if no operating system starts, then nothing has booted, even if some code
> was executed. On a normally setup x86 OS, that requires MBR code, partition
> tables, a boot flag set for the bootable partition, a formatted partition,
> PBR code for the partition, an OS installed to the bootable partition. So,
> when someone says: "What does the BIOS boot?" It means that some fixed-disk
> MBR code executed, a partition marked bootable was found, then PBR code for
> that partition executed, and the OS was loaded executed from the bootable
> partition.
>
> The different definition which seems to be in use for "to boot" and
> "booting" means the BIOS executes the MBR code on a fixed-disk.
>
> What does "booting" and "to boot" mean to you guys?
Good questions, Rod. I guess that ultimately the meaning of someone
> different from at least one other person here. This seems to have colored
> both my understanding of recent posts by others, and the understanding of
> others of my posts.
>
> To me, "to boot" and "booting" means to start an OS (operating system). So,
> if no operating system starts, then nothing has booted, even if some code
> was executed. On a normally setup x86 OS, that requires MBR code, partition
> tables, a boot flag set for the bootable partition, a formatted partition,
> PBR code for the partition, an OS installed to the bootable partition. So,
> when someone says: "What does the BIOS boot?" It means that some fixed-disk
> MBR code executed, a partition marked bootable was found, then PBR code for
> that partition executed, and the OS was loaded executed from the bootable
> partition.
>
> The different definition which seems to be in use for "to boot" and
> "booting" means the BIOS executes the MBR code on a fixed-disk.
>
> What does "booting" and "to boot" mean to you guys?
else's words should be understood from context.
From a user's point of view to boot a computer probably means getting
it to a working and usable state. We might boot-up Windows, for
example.
If we talk about specifically "booting an OS" we probably mean
similar.
This newsgroup possibly has many posts about booting an OS.
Similarly, we could bootstrap something else such as a piece of test
code meaning to get the computer to run our test code from power on.
(Take memtest86 as an example. A computer has to go through a
bootstrap process to get that loaded and running but there is no OS
involved and there may not even be a hard disk with partitions and the
like. The memtest86 software could be loaded from a floppy or an
optical disk.)
As programmers we may have a different viewpoint. Probably more
accurately than the view of a user of a computer, to boot means to get
a computer from power on to loading the *first* piece of code that is
not burned in to ROM. The piece of code thus loaded can then load the
next piece and so on. I suppose you could call these later loads part
of the bootstrap sequence if you are looking to get something specific
running.
> If the MBR code executes, fails to find an active partition, and returns to
> the BIOS via an Int 18h or 19h, is that a "boot"? Or, does that just mean a
> valid master bootsector was found and executed?
had booted the MBR but the OS writer would consider that the boot
process hadn't happened!
> Does the meaning of "booting" require that the OS is started?
what was meant by the context. A computer can boot without even
running an OS. If someone said specifically, "boot an OS" I would view
that as meaning the the OS had to be started. Similarly, to boot an
MBR means to me to load and start an MBR.
But those are colloquialisms - but nevertheless useful. Strictly,
though, I would say that to boot (without saying to boot some specific
piece of software) means to load the first piece of code from storage
of some sort and to start it.
Of course, YMMV.
James
smilinggoomba
May 13, 2012, 3:24:54 PM5/13/12
to
To me, booting means to load some code *as long as it is loaded before
the operating system is loaded*.
>If the MBR code executes, fails to find an active partition, and returns to
>the BIOS via an Int 18h or 19h, is that a "boot"? Or, does that just mean a
>valid master bootsector was found and executed?
I call this a "partial" or "failed" boot.
--
"If you want to be a hacker, keep reading. If you want to be a
cracker, go read the alt.2600 newsgroup and get ready to do five to
ten in the slammer after finding out you aren't as smart as you think
you are. And that's all I'm going to say about crackers."-Eric S.
Raymond
the operating system is loaded*.
>If the MBR code executes, fails to find an active partition, and returns to
>the BIOS via an Int 18h or 19h, is that a "boot"? Or, does that just mean a
>valid master bootsector was found and executed?
--
"If you want to be a hacker, keep reading. If you want to be a
cracker, go read the alt.2600 newsgroup and get ready to do five to
ten in the slammer after finding out you aren't as smart as you think
you are. And that's all I'm going to say about crackers."-Eric S.
Raymond
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