Slashdot: Providers Ignoring DNS TTL?

Valdis.Kletnieks at vt.edu Valdis.Kletnieks at vt.edu
Sun Apr 24 06:00:48 UTC 2005


On Sat, 23 Apr 2005 16:13:22 EDT, Dean Anderson said:

> I'm reminded of the arguments in the late 80's about threading:  People
> (like you) said there are no multithreading operating systems, and
> multiprocessor systems existed only in labs.  So designing threadsafe
> libraries or writing multithreading capable languages was a total waste of
> time.  And they showed as evidence all the programs written from 1975 to
> 1985.

Odd, seeing how IBM's OS/360 supported multithreading in the mid-60s (well, OK,
only the MVT variant did it really well - MFT had some restrictions, and PCP
was basically a program loader on steroids), as did Multics, early Unix, the
various PDP-8/11 and DEC-10/20 operating systems, and most supported
multiprocessor systems before 1970.

What you're actually talking about is the "I don't have to worry about *THAT*"
syndrome that's always been the bane of program portability.  Those of us who
were around at the time remember all too well "Not all the world's a VAX" when
programs that ran fine under BSD on a VAX would bomb out under SunOS 3.2 -
because the VAX allowed dereferencing a NULL pointer and SunOS didn't.

And anyhow, you're looking at it totally backwards - things like system libraries
didn't support multithreading well at first because nobody was *interested* in
doing it.  The support did happen once there was an actual demand for it.
Remember that there's a *cost* to supporting multithreading - you have to drag
along all this ugly locking code and stuff like that.  It's really hard to
justify putting in code that slows down the 95% of the applications that are
single-threaded for the 5% that are multi-threaded, and even harder to justify
putting the support in the library "just in case somebody wants to use it in
the future".

> Well, PPLB isn't the end of the world. But PPLB is coming, and the smart 
> people will be prepared for it.  They dumb people, well, they're dumb. 
> What can be expected from dumb people?

What you seem to be missing is that the *really* smart people will be prepared
for it when it actually gets here - and will take advantage of it's lack of
arrival in the meantime.

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