Second change to Architecture Manual

[Tom Rhodes]

On Tue, 14 Oct 2003 21:26:50 -0400
Ken Smith <kensmith at cse.Buffalo.EDU> wrote:

> 
> This is a second change I was thinking might make a good addition
> to the Architecture Manual.  Virtually every book that talks about
> UNIX devices describes character and block devices.  Developers new
> to FreeBSD sometimes wonder what happened to block devices.  And a
> lot of places in lots of manual pages, books, etc. still at least
> slightly suggest there could be more than just Character devices.
> 
> Is this worth adding?  Thanks...
> 
> --- chapter.sgml_orig	Fri Oct 10 09:37:18 2003
> +++ chapter.sgml	Tue Oct 14 21:21:07 2003
> @@ -527,6 +527,22 @@
>      </para>
>    </sect1>
>  
> +  <sect1 id="driverbasics-block">
> +    <title>Block Devices (Are Gone)</title>
> +
> +    <para>Developers familiar with other UNIX systems expect there to
> +      be a second type of device known as block devices.  On those other
> +      UNIX systems block devices are associated with the buffer cache.
> +      Data blocks from block devices are buffered inside the kernel 
> +      and filesystems get mounted on block devices.  This improves
> +      I/O efficiency.  &os; has shifted the management of the buffer
> +      cache away from block devices.  It is associated it with the virtual
> +      memory system and vnode system used to keep track of open files inside
> +      the kernel.  As a result &os; no longer needs block devices and they
> +      have been removed from the system.  Only character devices remain.
> +    </para>
> +  </sect1>
> +
>    <sect1 id="driverbasics-net">
>      <title>Network Drivers</title>

I think it would add value.  I'm sure someone will read it, hell, I
just read over it.

You may want to use the &unix; entity, use 'file systems', and perhaps
use a semicolon to 'hook' the last sentence to the previous.

How does that sound?  :)

-- 
Tom Rhodes