From: Niall O Broin (niall at domain linux.ie)
Date: Fri 01 Jun 2001 - 01:11:26 IST
On Thu, May 31, 2001 at 10:01:12PM +0100, Darragh Rogan wrote:
> What is this? Does this mean that a network of shity computers could have
> their os installed on just one machine, and they access the os remotely?
It means just what it says - the computer can boot from a network instead of
a local disk. On PCs this is accomplished by having a special boot ROM on
the network card. Other hardware e.g. Sun and other Unix workstations, X
terminals, newer Macintoshes, have integrated support for this.
> Anyone ever seen this in action before? How does it work?
Yes. How it works is quite simple - there is a defined protocol which client
and servers both use. In fact, there are a number of such protocols. How
well it works is a different matter. If you had a couple of PCs booting DOS
and Netware on as slow a network as Arcnet (1 or 2 Mb/s ?) it was actually
tolerable, as the machines weren't getting that much across the net.
OTOH if you have a bunch of Unix machines all trying to bootstrap the OS,
mount everything on NFS filesystems, complete the entire boot process from
those NFS filesystems, and have swap on an NFS filesystem too, performance
may suffer :-)
I remember a number of years ago when Maynooth University installed a
network of diskless ELCs (bit like an iMac, except it was a Sun Sparc
workstation running SunOS, and of course an iMac is diskful) it was an
unmitigated disaster. AFAIR, and it wasn't yesterday, turning a machine on
at peak time (9.00 a.m.) could result in a 15-30 minute wait before you
could work. Some re-organisation of the boot process and partitioning of the
network brought the worst case down to about 10 minutes, which is still a
tad long. AFAIR they eventually bought external disks for all the machines
which were used for at least swap (can't remember what else) and that
brought matters into the realm of tolerability.
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