On Mon, 23 Jun 2008 01:54:08 GMT, Roedy Green
<see_website@[EMAIL PROTECTED]
> wrote, quoted or indirectly quoted
someone who said :
>Today, when we have RAM coming out our ears we have reverted back to
>SINGLE buffering. We alternate between processing and waiting for I/O
>on the same buffer.
I will offer this hypothesis. Double buffering requires multitasking.
This is perceived as complicated, and hence was left out of early
personal OSes such as CPM where you might have had only 4 to 64K to
play with.
In the 1940s to circa1970 , computers primarily did batch processing
and worked on one problem at a time. Hence the elapsed time for batch
processing was very im****tant. Double buffering helps this.
Later with mainframes, you had several batch jobs running at once.
Here the computer could work on some other job while a batch job was
blocked on i/o. Double buffering became less im****tant.
Today with desktops there is little sequential batch processing.
Double buffering is for sequential batch processing. Unlike COBOL, C
and Java don't have the notion built in. Even if the OS offered it, it
would take a while for it to become sup****ted again.
In my world, I tend to read/write entire files in one i/o operation..
Double buffering could not beat that.
The reason may be that sequential batch processing is now considered a
niche application.
--
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com
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