Larry Wall & Cults

[Alan Balmer]

You know, it's really rather helpful when people take the time to
read the things they are trying to discuss, since quite often
those things end up answering questions that those people
might have.

See the snapes.com article that Dave Hansen (no relation) posted
for more... and a response to your reasonable thoughts above.

The shuttle boosters are 3.7m diameter. Quite a bit larger than the
gage of any railroad I've ever seen.

More than you ever wanted to know:
http://encyclopedia.thefreedictionary.com/Space Shuttle Solid Rocket Booster

 

[Espen Vestre]

(The TI Explorer ran on a MacIIfx).

....on a nubus card (just like the MacIvory (Symbolics)), if I
remember right.

 

[Pascal Bourguignon]

It was my impression that the Motorola 68000 CPU, upon which the
original Macintosh was based, did not support memory management in
hardware. At least, that's usually given as the reason that portable
Unix systems such as NetBSD will "never" run on the earlier 68k (or,
for that matter, 8086 or 80286) chips.

That's not exactly true. There are some small problems with the
instruction set, but at the time Motorola sold 68000, they sold PMMU
and SMMU (segmented MMU) for it, and there was 68000 based
unix workstations.

Actually, the segmented MMU would have been a perfect match to the
Memory Management of the MacOS.

The problem was that they started with a 6809 and 64KB in mind for the
Macintosh...

--
__Pascal Bourguignon__ http://www.informatimago.com/

Our enemies are innovative and resourceful, and so are we. They never
stop thinking about new ways to harm our country and our people, and
neither do we.

 

[Morten Reistad]

I know nothing about those stories, but it seems reasonable to me
that the boosters would have been designed to be transportable by
railroad, which ties their dimensions to track gauge.

ISTR there was some tunnel NASA had to relate to if they wanted
to move the goods from production to launch. But that may have been
earlier products.

But rail tunnels are also descended from the same asses, so to speak.

-- mrr

 

[Rupert Pigott]

That's what I mean - it's been (and is still) "going on." It ain't
soup yet., and only recently (imo) has it been taken seriously. I
think pthreads were the defining point for me.

PThreads is considered to be a tar-pit by far wiser people than I,
so I can't blame folks for being behind the curve on this regard.

It is certainly not the case that Linux was written by following the
POSIX "recipe."

I think it's fair to say it was. As I'm sure you know : Back in the
early 90s you had two main flavours of UNIX, BSD & SYSV (still do I
guess). Where there was any disagreement Linux generally went for
the third flavour, namely POSIX...

The differences showed when you used a true BSD or a true SYSV box.
There also used to be quite a few references in the man pages and
includes. Maybe this has changed, it's been a while since I cared
enough. :/

Cheers,
Rupert

 

[Rupert Pigott]

Yes, but the first NeXTcube or NeXTstation were not much more
powerfull than even the original Macintosh. In anycase, at the time
the Macintosh appeared, there were already 680x0 based unix workstations.

It was specifically the 68000. Fixes were made that took effect in the
68010 and 68020. Dunno about 68008. IIRC the problem was that you could
not restart some instructions properly. Some UNIX workstations did use
68Ks, there was an Apollo that had two of them running in lock-step,
with one of them one instruction behind the other. When the leading CPU
barfed, action would be taken and the other CPU would take over. Someone
in comp.arch worked on the Fortune boxes and IIRC he claimed they had a
more elegant single CPU solution.

Cheers,
Rupert

 

[David K. Wall]

On Thu, 02 Sep 2004 20:32:09 +0200, "John Thingstad"

Huh? Linux is only recently paying some attention to the POSIX
standards.

Linus deliberately tried to pay attention to the POSIX standard
almost as soon as he realized that his terminal emulator project
was turning into an OS. 1991 isn't all that long ago, but I'm
not sure I would refer to it as "recent" in this context.

http://groups.google.com/[email protected]

 

[Alan Balmer]

Linus deliberately tried to pay attention to the POSIX standard
almost as soon as he realized that his terminal emulator project
was turning into an OS. 1991 isn't all that long ago, but I'm
not sure I would refer to it as "recent" in this context.

http://groups.google.com/[email protected]

I don't know that the "interest" he expresses in this post proves the
point ;-) However, Linux was based on Minix, and I think Minix was
POSIX.2 compliant.

Actually, what I'm remembering is a few years ago, when I was querying
a allegedly expert Linux developer. The question was, roughly, "Is
Linux POSIX-compliant." and the answer was, roughly, "Not very."
However, I seem to remember that we were talking POSIX.4 at the time.
Many systems don't yet support all of dot-4. I haven't looked at the
headers of my latest Linux install to see what sections are
implemented - I'll try to do that tonight.

Perhaps I'm misinterpreting John Thingstad's remarks, but I was mostly
objecting to the idea that Linus sat down with a copy of the POSIX
specifications and turned them into an OS. (Especially since not all
of the current POSIX standards existed at the time

 

[Andre Majorel]

I feel compelled to replay that Linux is based on the Posix standard
which is basically a recipie for writing unix. They did not write a
new operating system. They implemented a tested and proven one.

Are you arguing that the stability comes from the API, not from
the implementation ? If so, why has NT become more stable over
the years, since its API has not changed ?

 

[Anne & Lynn Wheeler]

The shuttle boosters are 3.7m diameter. Quite a bit larger than the
gage of any railroad I've ever seen.

but they did have to be transported from utah to florida ... so while
the gauge may not have been issue ... there were things like
bridges, tunnels, etc. My understanding was the sectioning
was specifically because of length transportion issues.

i have some recollection of competing bids building single unit
assemblies at sea coast sites allowing them to be barged to
florida. supposedly the shuttle boosters were sectioned specifically
because they were being fabricated in utah and there were
transportation constraints.

shortly have the disaster ... some magazine carried a story spoof
about columbus being told that his ships had to be built in the
mountains where the trees grew ... and because of the difficulty of
dragging them down to the sea ... they were to be built in sections
.... and then tar would be used to hold them together when they were
put to sea.

earlier thread on this subject
http://www.garlic.com/~lynn/2001c.html#83 CNN reports...

this has 149 feet long as 12 feet diameterin four sections from utah
http://www.analytictech.com/mb021/shuttle1.htm

.... making each section about 40 foot long. 12 foot high and wide on
flatbed .... 15-16 high (on flatbed) clears bridges and overpasses and
12 foot wide should hopefully be within bridge width restrictions.

 

[John Thingstad]

Are you arguing that the stability comes from the API, not from
the implementation ? If so, why has NT become more stable over
the years, since its API has not changed ?

No but the algorithms for memory management, disk mangement and FTP in
unix were
well documented at the time. Linux Pauling started out with minix and then
went on to make a (mostly) posix compliant unix.

Seem to remeber this from my student days.

Operating Systems (design and implication) Andrew S. Tanenbaum

Intrucudes minix, a mini unix compatible with version 7 of unix.
(Not to be confused with system V.. the roman numerals were introdused by
AT&T)

 

[James Keasley]

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No but the algorithms for memory management, disk mangement and FTP in
unix were
well documented at the time. Linux Pauling started out with minix and then
went on to make a (mostly) posix compliant unix.

IIRC, the only relation that Minix has with Linux is that Linus (Torvalds,
Pauling is a geneticist IIRC) was using it as an OS when he started
developing the terminal emulator that eventually became Linux, and indeed
the kernel architecture is pretty fundementally different.

Seem to remeber this from my student days.

Operating Systems (design and implication) Andrew S. Tanenbaum

Intrucudes minix, a mini unix compatible with version 7 of unix.
(Not to be confused with system V.. the roman numerals were introdused by
AT&T)

Yeah, and apparently it is still the classic text on OS design.


- --
James jamesk[at]homeric[dot]co[dot]uk

'No, `Eureka' is Greek for `This bath is too hot.'' -- Dr. Who
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[Alan Balmer]

well documented at the time. Linux Pauling started out with minix and then
went on to make a (mostly) posix compliant unix.

Linux Pauling? I know about Linus Torvalds and Linus Pauling . I don't
think the latter had much to do with Linux.

 

[Patrick Scheible]

uKernels are *NOT* a new idea at all. They weren't a new idea when
NT was unleashed on the world. What people think of as "NT" is a big
pile of shite that obscures the uKernel. Since the graphics stuff
got put into ring 0 I think that you could legitimately claim that
BSD Unix is more of a micro kernel than NT.


Remember NeXTStep ?

Yes. NeXTStep didn't have a microkernel. The Mach kernel didn't get
changed to a microkernel design until after NeXTStep split off from
it.

-- Patrick

 

[John Thingstad]

Linux Pauling? I know about Linus Torvalds and Linus Pauling . I don't
think the latter had much to do with Linux.

lol.. oops. No Pauling was a nobel prize winning chemist.
No idea why that came out. (assosiative memory can be a bich)

 

[red floyd]

It was specifically the 68000. Fixes were made that took effect in the
68010 and 68020. Dunno about 68008. IIRC the problem was that you could
not restart some instructions properly. Some UNIX workstations did use
68Ks, there was an Apollo that had two of them running in lock-step,
with one of them one instruction behind the other. When the leading CPU
barfed, action would be taken and the other CPU would take over. Someone
in comp.arch worked on the Fortune boxes and IIRC he claimed they had a
more elegant single CPU solution.

68000 - original
68010 - 68000 + SR access is privileged, CCR is unpriviliated +
instruction restart for VM access
68008 -- 68000 with 8 bit external data bus, possibly restricted address
bus (can't remember)
68020 -- 68010 + full 32-bit
68030 -- 68020 + MMU

 

[Charlie Gibbs]

lol.. oops. No Pauling was a nobel prize winning chemist.
No idea why that came out. (assosiative memory can be a bich)

They were both heavily into C. For one, it was the language;
for the other, the vitamin.

 

[David K. Wall]

40klaava.Helsinki.FI

I don't know that the "interest" he expresses in this post proves the
point ;-) However, Linux was based on Minix, and I think Minix was
POSIX.2 compliant.

Well, I'm in no way a Linux or Minix expert, but I do have a copy of
Linus' book "Just for Fun", about the creation of Linux. Just by chance, I
happened to pick it up last night and read a chapter or two, and read that
same usenet post. So I'm pretty sure that the project was Linux. He didn't
actually get a copy at that time, because he found out it would cost money
he didn't have, so he used (IIRC) some Sun manuals for reference. Just
adding a data point....

I'll snip the stuff about POSIX.4, because I'm completely ignorant of what
is actually *contained* in the POSIX standards.

 

[Patrick Scheible]

The shuttle boosters are 3.7m diameter. Quite a bit larger than the
gage of any railroad I've ever seen.

More than you ever wanted to know:
http://encyclopedia.thefreedictionary.com/Space Shuttle Solid Rocket Booster

More than the track gauge, certainly, but the edges of the train cars
-- and the largest items that can be carried on the train -- hang out
significantly outside the track. Structure gauge is how much wide
and tall a load can be carried, or the size of the cars. Even if
there are no bridges or tunnels, you have to be careful of the trains
on the adjoining tracks if you're carrying something overwidth.

3.7 meters is not impossibly large for carrying on a railroad car.
Specifics would depend on the particular route, though.

-- Patrick

 

[CBFalconer]

.... snip ...

The shuttle boosters are 3.7m diameter. Quite a bit larger than
the gage of any railroad I've ever seen.

Clearance is more or less dependant on gauge. The story is that
Lincolns assasination made the Pullman Co., because before that
many clearances were too small for his sleepers. For the funeral
train they had to widen the clearances.