[ProgClub list] So, why aren't we using Unix as god intended?

John Elliot jj5 at progclub.org
Wed Oct 26 23:14:53 AEDT 2011


On 26/10/2011 10:46 PM, Asher Glynn wrote:
> Was starting to write a blog post, but throwing an early discussion point
> out, possibly relevant to John's courses at the moment

Thanks for starting a thread! :)

p.s. Where's your blog?

> Looking at a list of key Unix features, and the way its actually used at the
> moment, its kind of interesting how little is actually used:
>
> Intent: Small processes chained together to do bigger things
> What happened: Big programs with lots of options

While I was learning to install and configure Postfix, I read that 
someone was upset because if an email was addressed to them and to a 
mailing list they were subscribed to they would get the message twice 
under Postfix, whereas Sendmail would have omitted the duplicate. The 
reason Postfix couldn't support this feature was because of its modular 
design, whereas Sendmail, being monolithic, was able to implement that 
feature. If you look at the design of Postfix you will see the modular 
spirit of Unix shining through.

> Intent: Multiple users
> What happened: Single user running a daemon process OR a single user

I think what happened there was computers became much faster and much 
cheaper very quickly.

> Intent: Multiple applications per machine managed by priority
> What happened: Single application per machine, or even virtual machine with
> the hypervisor sorting priority

That's mostly for security reasons I would say. If one of your processes 
is exploitable it can only affect the (virtual) machine running that 
process. It also makes administration simpler and introduces a level of 
redundancy which is good.

> Intent: Use process per new task
> What happened: Use a single process with a new thread per task

Well processes are more expensive than threads, and threads can share 
data without duplicating it.

> Intent: Big machines managed efficiently
> What happened: Lots of small machines managed by scale out

I think that's just how the economics played out.

> I know there's lots of reasons for this - the emergence of the Internet and
> vastly different workloads to those anticipated. But even some of the no
> brainer things like using nice and user levels for isolation we've decided
> to user hypervisors for instead, which is interesting, because one of the
> original selling features of unix was security.

I haven't quite followed your last point, what has security to do with 
hypervisors?



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