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From: David Lamb <dalamb@cs.queensu.ca>
Newsgroups: comp.lang.java.programmer
Subject: Re: RAM FileDescriptor
Date: Mon, 15 Oct 2012 15:07:58 -0400
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On 15/10/2012 2:41 PM, Jeff Higgins wrote:
> On 10/15/2012 02:08 PM, bob smith wrote:
>> Let's say you have a function that plays a movie that is passed in as
>> a FileDescriptor.  Is there any way to load the movie into RAM and get
>> a FileDescriptor for the RAM?
> Looking here:
> <http://docs.oracle.com/javase/7/docs/api/java/io/class-use/FileDescriptor.html>
> the most likely route seems to be java.io.RandomAccessFile.getFD(). But
> I don't know what "a FileDescriptor for the RAM" means. Will you clarify?

I doubt it exists as a general concept and thus probably doesn't exist 
in Java. I seem to recall that some operating systems from many years 
ago let you map a file into RAM and operate on it from there, but I'm 
moderately sure that feature either went through the standard file 
system stuff and was (nearly) invisible, or you accessed a massive byte 
array directly. The former corresponds to people's advice to use a 
FileInputStream amd the latter to a ByteInputStream as appropriate.

Wouldn't your movie exceed the capacity of RAM? or are you limiting 
yourself to short ones?