On Mon, 3 Dec 2001, Andy Ball wrote:

>   GF> How big a disc do you have in the client machines?
>
> I don't know yet.  This was a semi-hypothetical question,
> although I do have some systems that might be suited to this
> type of configuration.  I think they generally have disks of
> just over 100Mb, although I've not verified this.  How does
> 128Mb sound for a target?  128Mb solid state flash 'disks'
> are available (although I'd probably be using mechanical
> disks myself).

That's certainly big enough for the root partition.

> If I were burning an EPROM, I'd probably look at putting
> a monitor program and perhaps boot-loader on it, and have
> the thing load the kernel from disk, or across the LAN
> (that way I wouldn't have to re-blow the ROM every time I
> changed the kernel).

I believe you can get a similar effect with a network card that supports
PXE...

> However, if I had a huge ROM disk (or even a CD-ROM!), how
> much of the filesystem hierarchy could be read-only?  Is
> this even a remotely sensible question?

Hmm.. this is a question that's been touched on a few times, maybe a
search of the mailing list archives will give some more concrete
information. As far as I know, you need a writeable /tmp, and now I come
to think of it, some sort of writeable /var. But, as always, the best way
to know for sure is to take a disc and actually mount / and /usr
read-only, and see what breaks.

>   GF> Having said that, you might get away with a kernel,
>     > and a minimal /, with a memory disc for /tmp, and nfs
>     > mounting everything else...
>
> I think part of my motivation for a disk-light workstation
> rather than diskless was to avoid having gobs of memory
> eaten up by RAM disks.  Admittedly RAM is fairly inexpensive
> these days, but if I were to try this with some of the gear
> I have laying around, RAM upgrades wouldn't really be an
> option.

I doubt you need a huge amount of writeable filesystem space. But that's
not a promise. :)

-- 
Gillette - the best a man can forget