Mailinglist Archive: opensuse (908 mails)

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Re: [opensuse] On redundant technology and the context for its use
On 06/05/2016 09:59 AM, Anton Aylward wrote:
On 06/04/2016 09:59 PM, James Knott wrote:
On 06/04/2016 08:18 PM, Anton Aylward wrote:
So? My point is that, like buggy whips and horses, its still being
made and sold.
Still being made? I doubt that.
Horses have a lifetime of what, 20-30 years? They are still around, so
they must "still be made" somewhere, somehow.
Outside the city, certainly Out West, there are a LOT of them.

How many people still use horses as a means of transport? Outside of a
few small groups, no one in the western world. How many still use them
to plow fields? Same answer. People have horses for riding, as pets,
for races, for show etc., but they are no longer the beasts of burden
they were for centuries.

On the other hand, hubs and switches have but one function, that is
connecting devices together in a network. At the time, hubs were a big
improvement over the old coax based networks they replaced. Back in
those days, a single cable fault could bring down the entire network.
That problem disappeared with hubs, but the performance remained the
same. You still had a half duplex 10 Mb network, where the more devices
connected, the greater the risk of collisions and declining throughput.
That is the big improvement that switches bring, in that there are no
collisions and switches can have full bandwidth between multiple pairs
of devices. Switches also reduce "noise" on the wire, in that packets
not intended for a device generally don't reach it. So, given the
function that hubs and switches do, switches are vastly superior. I
don't recall hearing of anyone keeping a hub or switch as a pet or
racing one.

Heck, here in the city there are horse and carriage rides; its a
speciality for weddings! And guess what? Those carriage drivers have
'horse
whips'. maybe they are only for show, but they are there.

A business guru once commented that today's horse whip manufacturers
must be VERY efficient to have stayed in business!


Why would anyone still make something that's so inferior to what's
current?
In short, because there is a market for it.

A Rolex is a remarkable watch but there is a market for Timex.

A Rolex is also a status item.




What possible use could there be when switches are so much better.
* BIG SIGH *

I keep saying "Context is everything" but you don't seem to take it in.

Its like saying "An accelerator pedal is better than a horse whip",
which is quite true of your context is that you are driving a Ferrari on
a limited access highway with a posted minimum speed limit. But there
are many palaces a Ferrari can't go that a horse (or mule or donkey)
can. There are many places a off-rad FWD can't go, many places a
mountain bike can't go, that a horse (or mule or donkey) can.

The fact that YOU don't go on hiking trips in the high Andes or
Himalayas, though deep gorges or places where the nearest gas station is
40,000km away though UN-drivable territory but there is forage for a
horse (or mule or donkey) is quite beside the point. Other people do.

I'm sure you can explain to use the fundamental difference between a
switch and hub, and also describe the situations in which a switch is
not just "better" and what its "better" at doing than a hub, but also a
CONTEXT where the hub can do things that the switch can't and from there
come up with the "Andes trek" whereby a hub is a "better" solution than
the switch.

If you can't, someone can.


I'd like to hear it. The only thing a hub can do that an unmanaged
switch can't do is monitor traffic. But sticking a 10 Mb half duplex
device into a modern network is going to kill performance. On the other
hand, a managed switch, with port mirroring, is capable of monitoring at
full wire speed.


At least whips still have a use with horses, as there hasn't been
something better developed.
Ah, so you admit that (a) horses are still around and (b) horse whips
are still around and hence (c) they are, in context, a superior
technology.

The real issue isn't whether horse whips are a better technology but
that the production of horse whips needs to be efficient


That hub, from 1998 would be among the
last of those devices, as by the mid 90s, switches were appearing.
At the time, hubs were still cheaper, but that day has long gone.
So?
Back in the 1880s horses where cheap.
Back in around 1910 horses were cheaper than automobiles.
That held true though WW1 and even into the beginning of WW2 before
"production of hydrocarbon fuelled engines' ramped up.

The fact that horses are expensive has not decreased their popularity IN
CERTAIN CONTEXTS.

The issue is the knowledge and awareness of the people interested.

When it comes to the hub/switch issue, most people, even most people in
IT & networking, neither know nor care. Certainly most consumers of
consumer grade devices, which I admit I have more of than I like, almost
all with a LinkSys label, don't care and couldn't tell the difference
anyway. Price and the length of the bullet list of features on the box
matters more. The fact that many of those features are irrelevant to
them is beside the point. This is about marketing, not utility and
utilization.

And even a 10 Mb switch can outperform a 10 Mb hub by a wide margin
You care, I care, most consumers have other concerns.


In the networking world, performance is a key consideration. In my
work, I see up to 10 Gb on copper and much higher on fibre. Further, if
you are trying to resolve a problem, such as buffer overflow, using a
hub may slow down the network so much that you hide the problem you're
trying to solve.

Are you aware of any company that still makes Ethernet hubs? I haven't
seen a new one in many years. On the other hand, I recall one project I
was working on, when someone was trying to find out why the network was
so slow. It turned out someone had used a hub, instead of a switch. In
this applications, a lot of computers were being reimaged via the
network and the 10 Mb hub really killed performance.


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