Re: Good point of Linux over Windows NT

Jay Thorne (jay@result.com)
Thu, 23 Jan 1997 10:42:51 -0800


Mark H. Wood wrote:
>
<..much deletia>
>>>Linux' shortcomings how is Linux ever going to develop further?
>
> Since the guts of NT are basically VMS warmed over (hmmm, that would make
> it RSX11M mk III), "asynchronous I/O" probably means the ability to
> request that the kernel start an I/O and send a signal when it is
> complete. Meanwhile the user process goes on doing other stuff.
> Traditionally Unix-like systems do this by forking. Linux can do better
> than that, with threads. (VMS I/O forking is a special case of
> multithreading.) So probably the only thing that is missing is some
> syntactic sugar to package the I/O thread(s) conveniently.
>
> Did I get it right?
>
Pretty damn close from what I remember, but that would be RT-11 Mk VI
wouldnt it?

AST signaling is damn convienient though, conceptually not terribly
different that running two specific threads, one your "code", one the
"IO thread"
but handled in the same piece of code, and not limited to one
language. If I remember correctly
you just typed in the standard ast handler from the book (from "the grey
wall" o' doc (or the orange wall or the blue wall, depends on which
version of VMS it was) and compiled it in,
voila, instant Async IO. You could even use that in VAX Basic, since
there
was a version of the ast handler code in BASIC. Multithreaded Basic: 12
years ago: Beat that!

Too bad VMS costs your first born and the third finger of your left
hand. It was
_way_ too hardware dependent. The Alpha Chip in VMS guise implements
emulation of a bunch of that
stuff.

( Andy Tannenbaum would have given Dave Cutler (who wrote VMS and
designed NT ) a failing grade )

> Mark H. Wood, Lead System Programmer MWOOD@INDYVAX.IUPUI.EDU
> Those who will not learn from history are doomed to reimplement it.

-- 

--
Jay Thorne, mailto:jay@result.com http://net.result.com
the Net Result System Services