From: mutazilah@gmail.com
"Dan Cross" wrote in message
news:vqq89k$ak4$1@reader1.panix.com...
> >> It's interesting that there was a port of Unix to the XT that
> >> was, of course, subject to the same limitations. Sometimes you
> >> are just constrained, so you make due with what you have. But
> >> Unix at least used the segmentation facilities in the processor
> >> to _attempt_ to shield the kernel from errant user processes;
> >> DOS made no such attempt.
> >
> >Absent any means of hardware protection, "segmentation" on the part of
> >the OS is a gentle suggestion at best; it cannot even protect against
> >an *errant* process, let alone a malicious one. DOS also uses the
> >segmented model to allocate space to applications/drivers/etc., but
> >pretending that this actually impedes hazardous behavior is just empty
> >security theater.
>
> The point is that DOS actively encourages users to side-step it
> and do their own thing.
Pardon? DOS "encourages" WHAT? Loading a far address
is as normal as loading a normal linear address in a 68000.
If you are using more than 64k of memory, it is something
you do. If you aren't, there may not be any need. It depends
what you are doing.
Be specific about your apparently specious claim.
> >> Not true. It supported segmentation. It's harder to corrupt
> >> RAM if it's not in a segment that's currently addressible.
> >
> >Again *there is no protection.* None whatsoever. Altering the segment
> >registers is a non-privileged operation on the 8086, and the address-
> >translation mechanism is a simple shift-and-add; it is trivial for any
> >process to write to any part of memory, whatever its initial segment-
> >register values were.
>
> I'm aware of how the 8086 segmentation model works, thanks, but
Sure doesn't sound like it.
> you miss the point. In order to manipulate with memory outside
> of a presently loaded segment,
What do you mean a "presently loaded segment"? Far memory
isn't "loaded", it is merely allocated/assigned and accessed.
> a program must first load a
> segment register to point to some segment that contains the
> memory you want to manipulate.
Yes, and on a S/370 or 68000 you load a linear address
for the memory you wish to address. That's just a different
way of accessing more than 64k of memory. You can use
a flat 32-bit address or you can use two 16-bit registers.
In both cases it is unrelated to a separate concept of
memory protection - which doesn't exist on either the
68000 or 8086.
> Conversely, if no such segment
> is loaded, that memory cannot be manipulated, even if I know its
> linear address. Loading the segment registers is an _explicit_
> operation; a random store won't necessarily overwrite memory.
Loading a linear address on a 68000 - accidentally or
deliberately pointing to the OS, is also a logically
equivalent identical _explicit_ operation.
> Crude and fallible as it is, MS-DOS (again) encourages stepping
> past even this feeble mechanism to provide some primitive
> semblence of protection.
I have no idea what you are talking about. Be specific.
> >> Now my question to you: why do you care what specific label
> >> people apply to MS-DOS?
> >
> >Primarily because Certain Types insist on parroting the same pithy
> >dismissals over and over again, year after year after year, for no
> >readily apparent reason and despite their arguments being predicated on
> >nonintuitive definitions of common terms, which are in the best case
> >overly narrow and,
>
> "Nonintuitive" to whom, exactly?
Anyone speaking English - both natives and non-natives.
> >in the least charitable interpretation, pretty
> >clearly constructed to support the argument they wanted to make.
>
> Honestly, it strikes me that it's really the other way around.
> Some people appear to have gotten much of their identity wrapped
> so up in the idea that MS-DOS is an "Operating System" that the
> suggestion that that might not be how people doing serious work
> in the field universally see it, that it's akin to someone
> calling their baby ugly.
Ok, first of all, no group speaks with one voice. So your
"universally" is complete horseshit. It's only true if you
DEFINE "serious work" as "anyone who agrees with me"
and DEFINE "in the field" as "anyone who agrees with me".
And I personally don't mind you calling (someone else's -
Tim Patterson in this case)'s baby "ugly" (although I would
dispute that). But what is unacceptable is calling his baby
an orangutan when it is absolutely definitely homo sapiens.
It's just dishonest. And note that you have a history of being
dishonest - including just above where you claim that an
entire group of "serious" OS developers "in the field" speaks
with one voice as if you've surveyed them all - when reality
is you're just talking about of your ass.
> I stand by that, though I admit that I don't feel the need to
> condescend to those who might see it differently. However, you
> _do_ have to bring a better definition that "lol because it is
> because I'm tired of people making fun of it and this is what an
> English langauge dictionary says about it." My copy of Merriam
> Webster has definitions for all kinds of common words that have
> nothing to do the definition of those same words in specialist
> contexts.
The "specialist context" you are talking about is "a select
group of wankers that I associate with".
You are using that "specialist term" in alt.os.development
where everyone who isn't a complete and utter wanker
uses the Merriam Webster definition because we're
TALKING IN ENGLISH.
If you want to say that "alt.os.development" is itself a
"specialist context" - and your non-English use of the
term should apply, well I can guarantee you that we
don't speak with one voice in this "specialist context"
either.
So you will only cause confusion and/or annoy people.
If you want to do that - deliberately - fine - but you may
as well be lying about something else too - like PDOS
containing code that is copyrighted by others. Oh - you
do that too.
> >So why the semantic games? What is the actual *point* to this argument?
>
> It may be hard to accept, but words have meaning, and
> specialists in the field get to define those meanings, not
> dictionary editors.
No they don't. Not in this group where not everyone is a
wanker and we are speaking in English.
> If you want to talk seriously about
> operating systems, then one has to engage with _those_ meanings,
> and not what is merely intuitive.
If you want to talk seriously about operating systems, where
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--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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