Date: Thu, 16 Oct 2003 03:46:35 -0400 From: Tom Rhodes <trhodes@FreeBSD.org> To: Ken Smith <kensmith@cse.Buffalo.EDU> Cc: freebsd-docs@FreeBSD.org Subject: Re: Second change to Architecture Manual Message-ID: <20031016034635.02278753.trhodes@FreeBSD.org> In-Reply-To: <20031015012650.GC15466@electra.cse.Buffalo.EDU> References: <20031015012650.GC15466@electra.cse.Buffalo.EDU>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, 14 Oct 2003 21:26:50 -0400 Ken Smith <kensmith@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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20031016034635.02278753.trhodes>