| WIKI | FAQ | Tech FAQ | |
 http://csua.com/feed/ | |
| ||||||
| 2008/4/29-5/4 [Science/GlobalWarming, Computer/HW/Printer] UID:49851 Activity:nil |
4/29 http://computerworld.co.nz/news.nsf/tech/2F5C3C5D68A380EDCC257423006E71CD http://reprap.org/bin/view/Main/WebHome (Open source, low cost 3d printer that can replicate all parts necessary to build a copy of itself). -- ilyas \_ This is a really cool project. Will they someday also print the circuit boards they need to run it? |
| 2008/4/29-5/5 [Computer/SW/Languages/Perl, Computer/SW/Languages/Python] UID:49852 Activity:moderate |
4/29 Scaling your web app in the real world:
http://teddziuba.com/2008/04/im-going-to-scale-my-foot-up-y.html
\_ This article is crap. While yes, 99.9% of all websites don't
need any serious scalability plans, if any of them become worth
anything they will need to scale. If you write a web application
without careing about scalability you are writing a webapp that can
never be more than niche. Any developer should know where the
next few scaling bottlenecks live in his application and have some
basic plan for how to solve them when they become an issue.
\_ I feel the same way about language Nazis. "Java is the best!"
"No C is the best!" "Perl sucks it's not readable!" "Python rules!"
Dumb asses blame the language and not the stupid programmers.
\_ Different tools for different jobs. That said, I particularly
like python. Its syntax is very clean.
\_ I don't know python. I like Pascal the best, although I
haven't used it in 18 years.
\_ If you liked Pascal, you will love python, unless you
get hung up on the fact that blocks in python are
defined by indentation rather than by "begin/end"
\_ Yeah, I like python, but that blocks by indentation
thing drives me up the wall. Couldn't they at least
make it optional? -!pp
\_ My experience is that Ruby is a lot cleaner than Python, and
doesn't have stupid syntactical whitespace. However, I have
only used Perl for stuff at jobs etc due to familiarity.
Python's object orientedness was less complete than Ruby's
and I definitely don't like the indentation thing.
\_ I struggled, trying to like Python. Then I found Ruby and
it's the most fun I've had programming in a *long* time.
The fact that regexes are as easy as Perl in Ruby was a big
deal.
\_ Ruby is whitespace sensitive. -- ilyas
\_ Far less so than Python.
\_ I am not a huge python fan, and I don't like python's
whitespace indentation, but I found ruby's specific
whitespace sensitivity far more confusing. -- ilyas
\_ Interesting, I've never noticed a problem.
\_ Perhaps this is because you are not used to
programming with closures (blocks are
the closest thing in ruby to closures).
Ruby blocks have very odd whitespace
requirements:
(1..3).each {|x| puts x} works
(1..3).each {|x|
puts x} works
(1..3).each
{|x| puts x} does not work.
-- ilyas
\_ No, I use closures, just never have had to
break across the line.
\_ I write fairly hairy closures sometimes,
and often my closure code is nested.
I find this behavior completely bizarre
and unintuitive. I can't even imagine
why Ruby would insist on this. -- ilyas
\_ I got yer hairy closure right here,
pal.
\_ This is funny, but not really applicable to real world scaling.
I have been doing this stuff for 15 years and scaling is more of
a system architecture and capacity planning issue than a developer
issue. Of course, if your code is bad enough, no one can make
it scale.
\_ I disagree completely. I've taken courses on optimizing
applications for performance and the best bang for the buck
is almost always received by altering the code to run
faster. Sure, things like high-speed interconnects to reduce
latency can solve problems not easily solved by modifying
code, but the majority of problems are developer issues that
they (I would say unknowingly, but maybe because they don't
care) foist upon the systems people.
\_ Most cases of performance scaling problems I have encountered
have been due to the volume of data being written to disk.
These problems can be fixed by using the right RAID type,
better use of filesystem caching, a better filesystem, or
most often, simply by throwing more disks at the problem.
These are not the kinds of issues I would expect a programmer
to know or even care too much about. I haven't "taken courses"
on it, but I have worked on numerous overloaded web and
application sites in the Real World.
\_ Sounds like you have haven't encountered a large
variety of problems then. Often when a developer
profiles his code he can find all sorts of
bottlenecks. Often it seems easier to throw h/w at
problems, but the biggest gains come from writing
better code. For instance, don't write so much data to
disk or be smarter about how you do it. You are
correct that programmers don't know and care about
these issues, but they should. They usually only care
when they are forced to because their code doesn't
meet requirements, because it compares unfavorably to
competing code, or because the hardware solution has
failed or is too costly to implement.
\_ "In nearly every case the most serious bottleneck
is an overloaded or slow disk." -Adrian Cockcroft
Sun_Performance_And_Tuning (Ch 1, Paragraph 1)
\_ You ever wondered why Google search is so fast?
They have the world's largest RAM disk. They
index and keep most of their search data
***IN MEMORY***. Last time I attended a talk
I learned that they have more a shitload more
RAM than many corporations have on disk. It
is ridiculous.
\_ Thanks for making my point.
\_ Well no shit, but this is tangential. The
question isn't "Is disk slower than RAM?". It
question isn't "Is disk faster than RAM?". It
is "Is there a way to do this such that it
doesn't write to disk as much?" One example is
when developers decide to write 6 million
small files in one directory and the filesystem
bogs down. Sure, you can buy a faster
filesystem but that's correcting the symptom
and not the problem. You don't need to buy $$$
hardware that probably still can't handle that
particular issue if the code didn't do something so
stupid.
\_ I heard reiserfs is really good at storing lots
of little files.
\_ I heard reiserfs is really good at storing lots of
little files.
\_ unfortunately, it stores them in a dumpster
in San Leandro.
\- lexis/nexis was pretty fast at seearch +20 yrs
go. the old bell labs people [who after all were
working for a phone company] have lots of
interesting stories about optimizations for
various phone company applications. one of
the main altavista people wrote some code to
use a cache that was physically closer to a
processing unit to avoid die-crossing latency
[and had numbers to show the difference it
made]. google is mostly read data and it's not
authoritative but a cache/copy for much.
contrast this with say ebay. for a somewhat
interesting discussion of scaling look at
randy shoup's presentation/talk on ebay scaling.
[trivia: randy was a high school acquaintance of
mine. i thought he was going to become a lawyer
and i was mighty surprised he went into cs/
databases].
\_ Getting all your caches right is not really
a developer responsibility, but I admit that
it starts to cross disciplines. Most people
are just sort of confused how it works, so
in this case, the one eyed man is king.
\_ Whose responsibility do you think it is
if not the developer? If he doesn't
have the knowledge then he needs to
consult with someone who does, but
he's the implementer. Too often the
developer has no idea, doesn't ask
anyone, and implements something stupid.
\_ I guess I would have to say that it
is a shared responsibility between the
system architect and the developers.
A lot of times developers don't know
what is possible, especially what is
possible at a reasonable price point.
How big a RAM disk cache can you expect
to have available for your application
in a shared disk array? How would a
developer hope to possibly know that?
But far too often system administrator
types don't share this kind of info,
even if they do know it themselves.
\_ I would argue that developers
should know what they don't know -
or at least consider these issues
early (before they become a problem).
Part of the problem is that people
with systems knowledge often come
into the project late in the
development of it - too late to
make major changes. We see this
problem in spacecraft operations.
The hardware guys build a shiny new
spacecraft without consulting with
the people who are going to fly it.
They make "sound technical decisions"
and h/w design decisions that are
intended to save lots of money, but
they have no knowledge (or, worse,
just enough to hang themselves) about
how to operate the h/w they build.
This often ends up being a case
of saving $$ on the h/w and spending
$$$$ on the operations (or not being
able to operate at all - or with
greatly increased risk). The *good*
h/w guys know who to involve early in
the process and why, but they are a
small minority even in large,
experienced companies like Lockheed.
With scaled systems it's rather
the opposite. The s/w guys design and
build a system without considering
h/w (or the systems environment).
\_ I had that exact problem at one place (millions
of files in one directory). We talked about
various ways to fix this and decided that
switching from WAFL to VxFS was the best
solution. In some ways this was just because
the developers were too lazy to figure out how
to use a database, but it worked.
\_ Why not spread those millions of files
over many directories? In itself that
helps a lot and it's a simple fix. A
database is another idea. Switching
filesystems sounds pretty drastic to me.
\_ It was already hashed, so what we really
had was billions of files, millions in
each directory. There is no magic bullet
for dealing with that quantity of data.
Millions of directories is not really
a good solution either, for reasons that
should be obvious. By the time I left
the company, they had started work on
what was essentially their own filesystem
but I don't know what happened to that
project.
\_ What a disaster. This sounds like poor
s/w design.
\_ All that because the devs don't want to
figure out how to use a db?
\_ Yeah, well it was 1999 and good
developers (or sysadmins) were hard
to come by. The new filesystem I was
referring to had a DB included.
\_ You think they are easier to come
by now? If anything, it
seems to be getting worse as
a lot of Microsoft-trained,
Java-loving weenies have
entered the field and very
few hardcore assembler-loving
PDP-11 weenies still exist.
Over time it seems the
average developer/sysadmin
knows less and less about
the details of the systems
in favor of high-level constructs
like WWW and GUI design. There's
a place for both, of course,
but I am horrified by what
recent CS grads do not know.
\- I disagree as well. Some simple problems are solved by
throwing money at them ... say $20k - $100k problems.
But at some point programmer time does become cheaper than
cycles, space etc. And there are other cases where the best
hardware cant do what brainpower can. Trivial example are new
crypto attacks. Another case is reading 10gb traffic streams...
you cant just naively throw hardware at the problem. It's
combination of hardware [ASIC, FPGA other specialized network
devices], OS/kernel/devce driver hackery, and application
design.
\_ Any network with 10gb of traffic on it that cannot be easily
broken up is not scalable.
\- what you control may affect your options. we want to
do IDS on 10G. We cant tell say ESNet to tailor bandwidth
provisioning around IDS. What we can ask for is $ for
hardware as long as we're not being stupid about it.
The "web application scaling" is a different problem
than some other scaling issues ... something like the
LHC has different scaling issues, for example. |
| 2008/4/29-5/4 [Politics/Domestic/California, Politics/Domestic/Election, Politics/Domestic/Crime] UID:49853 Activity:kinda low |
4/29 How Frederick Douglass addressed the 3/5 issue:
"I answer.and see you bear it in mind, for it shows the disposition of
the constitution to slavery.I take the very worst aspect, and admit all
that is claimed or that can be admitted consistently with truth; and I
answer that this very provision, supposing it refers to slaves, is in
itself a downright disability imposed upon the slave system of America,
one which deprives the slaveholding States of at least two-fifths of
their natural basis of representation.
"A black man in a free State is worth just two-fifths more than a black
man in a slave State, as a basis of political power under the
constitution.
"Therefore, instead of encouraging slavery, the constitution encourages
freedom, by holding out to every slaveholding State the inducement of
an increase of two-fifths of political power by becoming a free State."
http://medicolegal.tripod.com/douglassuos.htm#three-fifths-clause
\_ Quite impressive, the human ability to rationalize. He practically
sounds like a Randroid. -tom
\_ The irony police are overwhelmed with tom, send in the irony
national guard!
\_ The 3/5 compromise was made by abolitionists who wanted to weaken
slave states. Go back and read history tom.
\_ It was actually done by both sides, hence the label used
"compromise."
\_ Yes, but the slave states wanted the slaves to count as 1
person.
\_ ...with their votes cast by the slave owner. -tom
\_ You are confused. The slave owner still only had
one vote. The 3/5 rule was for the number of seats
that state got in congress.
\_ Right, so if the slaves were truly free to vote,
and at 1:1 representation, the state of Georgia
might have more seats in Congress, but the people
in power in Georgia would lose power. -tom
\_ Well, at the time women were counted as 1
person but couldn't vote. People under
voting age are still counted as 1 person but
obviously can't vote.
\_ Parents are the legal representatives of
their children; slave owners and slaves
have diametrically opposed interests. -tom
\_ And womenfolk?
\_ Personally I think women's suffrage is
a good thing--you disagree? -tom
\_ The US had the choice to allow slavery, or not allow
it. It is pretzel logic to claim that, presented
with that choice, deciding to allow slavery but make
it somewhat less attractive was "encouraging
freedom." There's also no reason to believe that
slaves would vote the same way as their masters;
giving slaves full votes would likely have led to
abolition via democratic processes, for example,
rather than civil war. You could say that the 3/5ths
rule meant that "Georgia" had less power than New
York, but the people who actually had power in Georgia
were strengthened by the fact that their slaves couldn't
vote themselves freedom. -tom
\_ The current congress has the choice to continue war or not.
And? I thought you lefties thought it was conservatives
that only think in black and white.
\_ Do you think that the current Congress deciding to
continue to fund the war is "encouraging peace"? -tom
\_ Are you trying to change the topic?
\_ Umm, the US had the choice to allow slavery, or not exist.
You know when the constitution was written right?
\_ I thought you trolls believed in the power of the
free market. -tom
\_ Whaa? Am I talking to some sort of eliza program
based on tom rantings here?
\_ The idea that the US could not have existed
without slavery in 1787 is ridiculous. -tom
\_ It seems pretty obvious that the South would
not have signed a constitution that outlawed
it. Hence, the US would not exist, at least
as we know it.
\_ It's not necessarily obvious. The Southern
Colonies might have conceded, or they might
not have. That they were never forced into
position where they had to make the decision
is not evidence of which way they might
have jumped. Interesting counterfactuals
proceed from both eventualities.
\_ Don't let that whole Civil War thing
stand in the way of your hypothetical.
\_ Don't let a lack of understanding of
the causes of the Civil War or the
nearly century-long gap between it
and the signing of the Constitution
stand in the way of a one-line quip
full of sound and fury signifying
nothing
\_ is there some reason the 3/5ths compromise is suddenly big news on the motd?
did Hillary finally get behind it? Did Reverend Wright vow to travel
back in time and rip Dred Scott limb from limb? What's going on?
\_ is there some reason the 3/5ths compromise is suddenly big news on
the motd? did Hillary finally get behind it? Did Reverend Wright
vow to travel back in time and rip Dred Scott limb from limb?
\_ Rev. Wright would more
likely wish to rip Taney,
CJ, limb from limb.
What's going on?
\_ Assuming this quote is correctly attributed to
http://en.wikipedia.org/wiki/Frederick_Douglass call me crazy, but
on this one I'm going to go with the smart guy who lived through
it over tom.
\_ In what way? Frederick Douglas and tom speak to utterly
different audiences: FD to a world where legalized slavery is
still considered a possibility, whereas tom speaks to a world
where slavery is an abhorrent concept. FD had to be almost
painfully cautious in expressing his beliefs, whereas tom is
free to express his with very little fear of danger to his own
physical person. Had he had his 'druthers, FD might have said
something more strident and provocative. --erikred
\_ FD wrote tons of provocative stuff. Start with the wiki
link. Not buying it. Also tom is claiming the union could
have somehow existed with the south agreeing to end slavery.
No. Ridiculous. If that were the case there would have been
no need of the 3/5th "compromise". You really think they
didn't talk about all this stuff at the time? Wow!
\_ FD also had his house burned down. I'm sure they talked
about it at the time; that doesn't change the fact that
deciding to encode slavery in the Constitution is not
"encouraging freedom." -tom
\_ /shrug. FD was being politic, working with what he had
at the time. It would be interesting to see what he had
to say post-Civil War, Emancipation Proclamation, 14th
Amendment. Also, pp's point vis-a-vis that the union
could not have existed without a 3/5ths compromise is
speculative. Carry on. --erikred |
| 2008/4/29-5/5 [Computer/HW/Drives] UID:49854 Activity:nil |
4/29 Any stock thoughts on ISLN (Isilon) and the stroage field in general?
\_ Buy low, sell high. You can never have enough storage.
\_ I think that the basic idea of using commodity pc hardware to build
scalable NAS replacements is sound and has the potential to
supplant disk arrays in the same way that clusters of PCs replaced
supercomputers, but I don't like Isilon's approach. They don't
scale well, and they're using too much proprietary hardware
(single source, and not as cheap as real off-the-shelf PCs) to
really deliver on the low cost promise. As an investment, the
greater concern is that Netapp is openly hostile to them (in a
way that they are not toward other players in this space), and
has demonstrated a willingness to sell at a loss to win deals
away from them.
\_ It actually boosts their credibility in my eyes if Netapp
perceives them as a threat.
\_ My impression that it's more personal animosity between the
management of the two companies than anything else. I expect
the interesting products in this space to come from someone
else using real commodity hardware.
\_ If Netapp is willing to give away filers to deny them
business, then they're a risky investment (even if they
are a credible technological competitor). |
| 2008/4/29-5/2 [Uncategorized] UID:49855 Activity:nil |
4/29 Why don't atheists have problems like this:
<DEAD>www.csua.org/u/lds<DEAD> (No, I did not pick "lds" http://csua.org did)
This is a video, btw.
\_ 20-year imprison-and-rape-daughter-in-basement guy was an
athiest!
\_ URL?
\_ No URL. I made it up. I'm an athiest and this is the
type of immorality people afflicted with religiousity
regularly accuse athiests of.
\_ Just looked into this. It is claimed Fritzl is jewish. |