Le 2012-02-02 05:26, Invisible a écrit :
>>> I would have thought that needing more disk space is such a crushingly
>>> rare event that it makes almost no sense to optimise for it.
>>
>> No it's not. You may need to run an app in debug mode for a while and
>> need extra space to store the dumps. You may run into seasonal peeks and
>> need extra storage just for that period. Etc... Sizing hundreds of
>> servers for a worst case scenario is not efficient use of the company's
>> money. You are much better off having some amount of slack space that
>> you can swing around when needed.
>
> Maybe that's the problem. I cannot imagine any task that would ever
> require "hundreds of servers". I'm struggling to think of a task that
> would require more than about a dozen at worst. I mean, unless you work
> for one of the largest companies on the planet, which almost nobody does.
>

While it's true that most tasks performed by the Fortune 1000 rarely 
take more than a dozen or so servers.  Each of those companies have 
dozens of such tasks.

For example:
- A bank of web servers for their corporate web site
- A handfull of DNSes
- A couple entreprise directory servers, authentication servers, etc...
- 1 mail server per 1000 employee
- 1 file server per 1000 employee
- A dozen servers for the HR apps
- A dozen servers for the Finance/accounting dept.
- A couple dedicated server for the law dept. (Confidentiality)
- Server monitoring servers.
- Network monitoring servers.
- Environment monitoring servers (Heating/air conditioning, power 
consumption, generators, battery banks, etc...)
- and then... more servers for the actual business that company does, be 
it putting people on planes, managing people's money, building cars, or 
selling drugs.

Split those across a few data centres for geographical proximity to the 
user base and duplicate all the mission-critical servers.

Tada!

I don't understand why you somehow think one needs to actually work for 
British Airways, Siemens, Yamaha or IBM to be able to imagine what's 
it's like to work in a company with 100,000+ employees.

>>> You claimed that it's not insane to run a SAN over the Internet,
>>
>> When did I say that?
>
> Francois Labreque wrote:
>  > We've also had the performance discussion before. Yes, the
>  > theoretical access speed of a local SATA drive is much faster than
>  > that of a SAN attached logical disk, but in actual real world
>  > practice, with real world data, there's not much of a difference,
>  > even on SANs located halfway across town in another building.
>

"In another building" DOES NOT mean "over the Internet".  Private data 
circuits predate the internet, and no company would use the Internet to 
link two data centres together.  Remote offices, maybe, but definitely 
not data centres.  15 years ago, it would have been done via data-grade 
telco circuits (such as an E1 or E3 line, usually called a WAN circuit). 
  Nowadays, it's done via DWDM optical circuits (usually called a MAN or 
Metronet).

>> Not that SANs are infaillible, but why do you assume that it will fail?
>
> They want to back up 200GB of data per day over a 5 Mbit/sec Internet
> connection. You do the math.

So their backup strategy will fail.  Not the actual SAN.  Gotcha.

>
> Plus, since when does rolling out a brand new complex system go
> smoothly? ;-)
>

When it's planned properly.  I've seen it happen.  But, I must admit, 
that I've seen quite a few disasters, too.

>>> So what you're saying is that a handful of the richest companies on
>>> Earth can afford to do this?
>>
>> There's more than a handful of companies who can afford it. A few £M in
>> extra telco costs per year is nothing compared to the prospect of going
>> out of business because your data centre had a 110-story building crash
>> on top of it.
>
> So you're saying that more than "a handful" of telco companies exist?
>

There are, in fact, more than a handful of telcos in most countries. 
while the actual wires underground usually belong to one or two 
companies, the other ones will buy bandwidth from the 
cable-owning-entity and resell it to other corporations.  This is why, 
for example, I can rent circuits from BT in Canada, even though they do 
not own any of the fibre optics here.

But this has nothing to do with the fact that I was talking about 
businesses buying telecommunications services from the telcos, not the 
telcos themselves.  Last time I checked HSBC was not a telco, and I do 
know that they've had 10Gbps links between their data centres for over 
10 years.

-- 
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
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> I don't understand why you somehow think one needs to actually work for
> British Airways, Siemens, Yamaha or IBM to be able to imagine what's
> it's like to work in a company with 100,000+ employees.

It's like the thing with Google's data centre. A "computer" is a 
low-power device. Unless you've ever worked with thousands of them at 
once, it just doesn't occur to you what there might be power supply or 
cooling issues to overcome.

I imagine the reverse also applies; somebody who works for Google would 
probably think that the solution to "our tape drive just died" is "so go 
buy a new one". They probably wouldn't even realise that to a small 
company, £3,000 for a new tape drive is actually /a crapload of money/. 
It probably wouldn't even occur to them.

In short, you don't really understand what it's like to work within a 
given set of constraints unless, you know, you've had to work within 
that set of constraints...

>> Francois Labreque wrote:
>> > We've also had the performance discussion before. Yes, the
>> > theoretical access speed of a local SATA drive is much faster than
>> > that of a SAN attached logical disk, but in actual real world
>> > practice, with real world data, there's not much of a difference,
>> > even on SANs located halfway across town in another building.
>
> "In another building" DOES NOT mean "over the Internet". Private data
> circuits predate the internet, and no company would use the Internet to
> link two data centres together.

How is that even *possible*? It's not like you can just go to the 
hardware store and buy 25km of copper wire and then put it into the 
ground with a shovel on your day off or something...

>>> Not that SANs are infaillible, but why do you assume that it will fail?
>>
>> They want to back up 200GB of data per day over a 5 Mbit/sec Internet
>> connection. You do the math.
>
> So their backup strategy will fail. Not the actual SAN. Gotcha.

Well, given that backup is what this SAN is *for*, I guess I mixed up 
the two things.

>> Plus, since when does rolling out a brand new complex system go
>> smoothly? ;-)
>
> When it's planned properly. I've seen it happen. But, I must admit, that
> I've seen quite a few disasters, too.

Given the company that *I* work for, would you expect a smooth rollout? ;-)

>> So you're saying that more than "a handful" of telco companies exist?
>
> There are, in fact, more than a handful of telcos in most countries.
> while the actual wires underground usually belong to one or two
> companies, the other ones will buy bandwidth from the
> cable-owning-entity and resell it to other corporations. This is why,
> for example, I can rent circuits from BT in Canada, even though they do
> not own any of the fibre optics here.
>
> But this has nothing to do with the fact that I was talking about
> businesses buying telecommunications services from the telcos, not the
> telcos themselves. Last time I checked HSBC was not a telco, and I do
> know that they've had 10Gbps links between their data centres for over
> 10 years.

OK, so a major /bank/ can also accord crazy technology. None of this 
alters the fact that the next tiny company I end up working for won't be 
able to afford this kind of thing.

Post a reply to this message

Le 2012-02-02 10:05, Invisible a écrit :
>> I don't understand why you somehow think one needs to actually work for
>> British Airways, Siemens, Yamaha or IBM to be able to imagine what's
>> it's like to work in a company with 100,000+ employees.
>
> It's like the thing with Google's data centre. A "computer" is a
> low-power device. Unless you've ever worked with thousands of them at
> once, it just doesn't occur to you what there might be power supply or
> cooling issues to overcome.
>
> I imagine the reverse also applies; somebody who works for Google would
> probably think that the solution to "our tape drive just died" is "so go
> buy a new one". They probably wouldn't even realise that to a small
> company, £3,000 for a new tape drive is actually /a crapload of money/.
> It probably wouldn't even occur to them.
>
> In short, you don't really understand what it's like to work within a
> given set of constraints unless, you know, you've had to work within
> that set of constraints...
>

Agreed.  When I have a $250,000* piece of equipment that fails, I call 
the toll-free number of the hardware vendor and they send me a 
replacement in less than 24 hours, meanwhile its redundant mate keeps 
the network running.  I don't have to deal with purchasing, maintenance 
contracts or any of that.

BUT - and that's the important part - I thanks the FSM every chance I 
get to not have to deal with these issues.  I've read too many horror 
stories in comp.dcom.sys.cisco of people who had mission-critical 
hardware fail and were asking for help trying to get the device back up 
while trying to convince management to buy a new one, or looking for 
spare parts on eBay.

*I assume that's how much these things cost as I have absolutely never 
had to use the $ key on my keyboard, unless I was programming in Perl.

>>> Francois Labreque wrote:
>>> > We've also had the performance discussion before. Yes, the
>>> > theoretical access speed of a local SATA drive is much faster than
>>> > that of a SAN attached logical disk, but in actual real world
>>> > practice, with real world data, there's not much of a difference,
>>> > even on SANs located halfway across town in another building.
>>
>> "In another building" DOES NOT mean "over the Internet". Private data
>> circuits predate the internet, and no company would use the Internet to
>> link two data centres together.
>
> How is that even *possible*? It's not like you can just go to the
> hardware store and buy 25km of copper wire and then put it into the
> ground with a shovel on your day off or something...
>

You don't do it yourself, unless you are in a campus environment and can 
easily rip up the parking lot and lay down your own fibre or copper.

Step 1.  Call your telco rep and order a circuit between site A and site A.
Step 2.  Telco will forward the request to a planner who will determine 
if the existing cabling between both sites and central offices (CO) has 
enough available bandwidth.
Step 3a.  If not, the planner will forward the request to their 
infrastructure group who will get diging permits from the 
city/county/whatever and lay down new bundles of cables.
Step 3b.  If the answer is yes, or once the new cables have been laid, 
the telco planner will forward your request to an enabler who will 
configure the CO switches to map the circuit from Site A's demarcation 
point to Site B's demarcation point.
Step 4.  Technicians will come on site, at both locations, and terminate 
the circuit from their demarc point to the exact rack you ask them to.
Step 5.  You plug in the circuit in your equipment (router, switch, or 
mainframe front-end-processor, to name a few)

Tada!

Usually, all of this is done for a small nominal fee.  Any work they 
have to do between demarc points will be undertaken at their own 
expense, which they will recoup on your monthly usage bill, of course.

By the way, if you ordered an "internet" link, the exact same steps 
would have to take place, except that they would be duplicated for site 
A to ISP and ISP to site B, and then the ISP would add its own routers 
at both ends and charge you twice as much and more for the "managed 
services".

>>>> Not that SANs are infaillible, but why do you assume that it will fail?
>>>
>>> They want to back up 200GB of data per day over a 5 Mbit/sec Internet
>>> connection. You do the math.
>>
>> So their backup strategy will fail. Not the actual SAN. Gotcha.
>
> Well, given that backup is what this SAN is *for*, I guess I mixed up
> the two things.
>

I thought the SAN would replace some of the servers' internal disks. Sorry.

>>> Plus, since when does rolling out a brand new complex system go
>>> smoothly? ;-)
>>
>> When it's planned properly. I've seen it happen. But, I must admit, that
>> I've seen quite a few disasters, too.
>
> Given the company that *I* work for, would you expect a smooth rollout? ;-)
>
>>> So you're saying that more than "a handful" of telco companies exist?
>>
>> There are, in fact, more than a handful of telcos in most countries.
>> while the actual wires underground usually belong to one or two
>> companies, the other ones will buy bandwidth from the
>> cable-owning-entity and resell it to other corporations. This is why,
>> for example, I can rent circuits from BT in Canada, even though they do
>> not own any of the fibre optics here.
>>
>> But this has nothing to do with the fact that I was talking about
>> businesses buying telecommunications services from the telcos, not the
>> telcos themselves. Last time I checked HSBC was not a telco, and I do
>> know that they've had 10Gbps links between their data centres for over
>> 10 years.
>
> OK, so a major /bank/ can also accord crazy technology. None of this
> alters the fact that the next tiny company I end up working for won't be
> able to afford this kind of thing.

What makes you think you can't find work in a large company?

-- 
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/*    flabreque    */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
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/*   gmail.com     */}camera{orthographic location<6,1.25,-6>look_at a }

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On Thu, 02 Feb 2012 10:05:04 +0000, Invisible wrote:

> On 02/02/2012 02:50 AM, Darren New wrote:
>> On 1/31/2012 1:12, Invisible wrote:
>>> As usual with Wikipedia, the page babbles about updates and feeds and
>>> XML and "syndication" and something about RDF, but utterly fails to
>>> explain WHAT IT IS.
>>
>> I have to ask... Do you start reading at the beginning of the article,
>> or do you skip over the part that comes before the table of contents or
>> something?
>>
>> First sentence in the article:
>>
>> "RSS ... is a family of ... formats used to publish frequently updated
>> works ... in a standardized format."
>>
>> How is that not telling you what it is?
> 
> HTML is "a family of formats used to publish works [frequently updated
> or not] in a standardized format". As is PDF. As is PostScript. How is
> RSS different?
> 
> Sometimes the dictionary definition of what something is turns out not
> to be very enlightening. For example, you could say that
> 
>    "A knife is a device constructed from a hard material, usually in the
> shape of a triangular prism who's cross-section has a very acute angle
> between two of the sides."
> 
> Or you could say "a knife is a device for cutting things". The latter is
> infinitely more illuminating.

You're being fairly obtuse here, Andy.

Go have a look at reader.google.com.  There's a tour on the site that 
shows you how RSS feeds are useful.

Jim

Post a reply to this message

On Thu, 02 Feb 2012 10:24:48 +0000, Invisible wrote:

>> But if you're unaware of what Citrix even *does*, then that calls into
>> question (in an interview) whether you even know what's going on in IT.
> 
> I can see that knowing about how (say) Google manages their data centres
> might be quite useful if you're applying to Google. If you're applying
> to somebody who isn't Google, I'm not sure how that's useful.
> 
> ...unless it *isn't* useful at all, it's just another one of those
> worthless things that "create the right impression".

Being aware of technology is important.

You find yourself in a job that you'd like to get out of, but you have no 
idea how to do it.

People give you ideas, and you assert "that can't possibly work" or "that 
can't possibly be useful".

But people who do those things actually find other jobs.

You don't do those things, and you don't have luck finding another job.

What does this tell you?

>>> As usual with Wikipedia, the page babbles about updates and feeds and
>>> XML and "syndication" and something about RDF, but utterly fails to
>>> explain WHAT IT IS.
>>
>> <sigh>
>>
>>  From wikipedia:
>>
>> --- snip ---
>>
>> RSS feeds benefit publishers by letting them syndicate content
>> automatically.
> 
> WTF does "syndicate" mean?

http://dictionary.reference.com/browse/syndicate

Definition 8.


>> A standardized XML file format allows the information to be published
>> once and viewed by many different programs.
> 
> Because XHTML isn't an XML format already. Oh, wait... actually yes it
> is. And many different programs can view it. So...?

Again, go look a the tour of Google Reader.

>> They benefit readers who want to subscribe to timely updates from
>> favorite websites or to aggregate feeds from many sites into one place.
> 
> This at least hints at what RSS is actually about. But it still seems
> quite vague. I'm still not clear exactly what it's getting at.

Look at the tour.

>> RSS feeds can be read using software called an "RSS reader", "feed
>> reader", or "aggregator", which can be web-based, desktop-based, or
>> mobile-device-based.
> 
> So... you need software that supports RSS in order to use RSS? OK, fair
> enough.

Yes, now you're understanding it.  Software or - surprise - another 
website.

>> The user subscribes to a feed by entering into the reader the feed's
>> URI or by clicking a feed icon in a web browser that initiates the
>> subscription process.
> 
> We still haven't established exactly what point "subscribing" serves,
> but OK...

Yes, actually, we have.  Subscribing means that instead of going to 
Orphi's blog to see what he's written recently, I can go to my reader and 
see what he's written recently.  Along with a bunch of other sources all 
at once.

>> The RSS reader checks the user's subscribed feeds regularly for new
>> work, downloads any updates that it finds, and provides a user
>> interface to monitor and read the feeds.
> 
> This is all very abstract. It checks "regularly" for "new work",
> downloads any "updates", and provides a UI to "monitor" such updates. So
> what does that *mean*, in real world terms?

It means I can see that you've written something new in your blog without 
going and visiting your blog.

And about 100 other sites that I keep an eye on without visiting them 
each every day to see what's new.

>> RSS allows users to avoid manually inspecting all of the websites they
>> are interested in, and instead subscribe to websites such that all new
>> content is pushed onto their browsers when it becomes available.
> 
> As best as I can tell, the idea behind RSS seems to be that you can see
> if any of your subscribed websites have been updated, without having to
> visit each of them one at a time. (As if that's in some way "hard" or
> something.) Why the heck the article doesn't just /say/ this on line
> one, I don't know. Instead it talks obliquely about how "all new content
> is pushed onto the browser when it becomes available". (Funny, when it
> says a feed reader "regularly checks for updates", that sounds to me
> like a /pull/ model, not /push/...)

It's time consuming to visit 100 sites to see if there's anything new.  
It's far easier to be alerted when there's something new that might be of 
interest.

>> I have the feed set up in Google Reader so that when you post something
>> new on your blog, I see it as part of the Reader page.
>>
>> That way I don't have to visit your blog to see what's going on in your
>> blog.  I see an item show up in my reading list so, as wikipedia says,
>> I "avoid manually inspecting all of the websites [I] am interested in"
>> and can see what's new.
> 
> So what does that actually look like? I'm still trying to get my head
> around how this actually works. What counts as "new content", how it
> displays all this stuff in an intelligible form, and so on.

Look at the Google Reader tour.

>>>>> I usually visit Tom's Hardware when I want to see what's happening
>>>>> in the hardware world.
>>>>
>>>> I doubt you're going to get that by reading some text on a screen.
>>>
>>> That's why I just built a new PC - to experience the Core i7
>>> first-hand.
>>> :-P
>>
>> So then why bother going to Tom's Hardware again?
> 
> Sarcasm? :-P

Or perhaps to find out what the latest processor is that you might be 
able to afford?
 
>>> The BBC's iPlayer system "works". I mean, it's so horrifyingly blurry
>>> that you sometimes can't see people's faces clearly enough to
>>> recognise who's who, and often the end credits are unreadable. But
>>> technically that still counts as "works", right?
>>
>> I don't know what kind of connection you use, but I stream on iPlayer
>> occasionally from halfway around the world (did that with last night of
>> the proms IIRC) and projected it onto a 10' screen.  Didn't look
>> particularly blurry to me.
> 
> Want to bet that the BBC has servers all over the world?

So you just happened to get a crappy connection, while I got a good one?

> With the latest update to our set top box, we can actually access
> iPlayer and display it on a real TV. I can actually compare the recorded
> TV broadcast directly next to the iPlayer version of the exact same
> program. And let me tell you, the image quality is incomparable. (And
> that's only SD, not HD.)

Then your eyes are better than mine, or you got a really crappy 
connection.

> On top of that, at peak times iPlayer becomes almost unusable. It
> freezes constantly. I'm not sure whether it's the BBC servers or the ISP
> network that can't keep up, but you just can't watch anything. But then,
> if you select "high quality mode", then it runs like that all the time.
> 
> I don't think an 8 Mbit/sec Internet connection would be considered
> especially slow...

And yet I apparently get a better picture at half the speed from the 
other side of the planet....

>>> I just looked it up. The transfer rate of a DVD is 10.5 mbit/sec. The
>>> maximum broadband speed you can get is 8 mbit/sec. So... does that
>>> mean that people in America have something faster than ADSL or
>>> something?
>>
>> I don't - I have 3 Mbps down ADSL.  I have to not be doing other things
>> with the network connection when I'm streaming Netflix, but I do get a
>> high quality HD image with 5.1 sound with programmes that include it.
> 
> The sound isn't the problem, it's the video. Sound is easily streamable.
> But I'm baffled as to how you can download video in anything approaching
> real-time, unless the quality is diabolically poor.

Except that it isn't.  Part if it is called compression.

>> But more to the point, do you now understand what streaming is?
> 
> Yes. Although I'm still puzzled as to how anybody could make money out
> of selling such poor quality stuff...

Convenience is a huge motivational driver for consumers.  But more to the 
point, most people don't see the quality as being "poor".

Jim

Post a reply to this message

On 2/2/2012 7:05, Invisible wrote:
> £3,000 for a new tape drive is actually /a crapload of money/. It 
probably

When I first started at Bellcore, I joined during the budgeting time of 
year. My manager asked "Do you foresee needing any equipment for your wor
k?" 
I said "Well, I'll need a desktop computer of course." He says "No, I mea
n 
equipment. Anything over $50K? If so, we need to budget it." :-)

That said, google does everything with such redundancy that it's not a 
question of spending $3K to buy a tape drive, but a question of how many 
$3K 
tape drives you need to buy to back up 3 petabytes/day of data[*] and how
 
long are those drives going to last before you need to replace them, 
factoring the salaries of the guys doing the fixing and the writing of th
e 
code to allocate tapes to data.  ([*] All numbers ass-pulled, mind.)

> How is that even *possible*? It's not like you can just go to the hardw
are
> store and buy 25km of copper wire and then put it into the ground with 
a
> shovel on your day off or something...

That's exactly what the companies that do this for a living do.

-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.

Post a reply to this message

On 2/2/2012 2:05, Invisible wrote:
>> How is that not telling you what it is?
>
> HTML is "a family of formats used to publish works [frequently updated or
> not] in a standardized format". As is PDF. As is PostScript. How is RSS
> different?

Well, maybe you need to read the *second* sentence, hmm?

-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.

Post a reply to this message

> I have absolutely never
> had to use the $ key on my keyboard, unless I was programming in Perl.

This comment makes the whole discussion worth it! :-D

>>> "In another building" DOES NOT mean "over the Internet". Private data
>>> circuits predate the internet, and no company would use the Internet to
>>> link two data centres together.
>>
>> How is that even *possible*? It's not like you can just go to the
>> hardware store and buy 25km of copper wire and then put it into the
>> ground with a shovel on your day off or something...
>
> You don't do it yourself, unless you are in a campus environment and can
> easily rip up the parking lot and lay down your own fibre or copper.
>
> Step 1. Call your telco rep and order a circuit between site A and site A.
> Step 2. Telco will forward the request to a planner who will determine
> if the existing cabling between both sites and central offices (CO) has
> enough available bandwidth.
> Step 3a. If not, the planner will forward the request to their
> infrastructure group who will get diging permits from the
> city/county/whatever and lay down new bundles of cables.
> Step 3b. If the answer is yes, or once the new cables have been laid,
> the telco planner will forward your request to an enabler who will
> configure the CO switches to map the circuit from Site A's demarcation
> point to Site B's demarcation point.
> Step 4. Technicians will come on site, at both locations, and terminate
> the circuit from their demarc point to the exact rack you ask them to.
> Step 5. You plug in the circuit in your equipment (router, switch, or
> mainframe front-end-processor, to name a few)
>
> Tada!
>
> Usually, all of this is done for a small nominal fee. Any work they have
> to do between demarc points will be undertaken at their own expense,
> which they will recoup on your monthly usage bill, of course.
>
> By the way, if you ordered an "internet" link, the exact same steps
> would have to take place, except that they would be duplicated for site
> A to ISP and ISP to site B, and then the ISP would add its own routers
> at both ends and charge you twice as much and more for the "managed
> services".

Think is, if you order an Internet link, the telco has to run a few 
hundred yards of cable to the nearest junction box at one end, and a few 
hundred yards at the other end. If you want a dedicated circuit from one 
end to the other without going via the Internet, they have to run 
several miles of cable just for you. Who the /hell/ can afford that? o_O

>>> So their backup strategy will fail. Not the actual SAN. Gotcha.
>>
>> Well, given that backup is what this SAN is *for*, I guess I mixed up
>> the two things.
>
> I thought the SAN would replace some of the servers' internal disks. Sorry.

Actually, I am now 100% sure what the plan is here. Certainly the /main/ 
function of the SAN is routine data backup. I'm unsure whether we're 
also going to use it for online storage too. (Hey, why would they tell 
*me* such things? I'm only the person who's going to be running it...)

>> OK, so a major /bank/ can also accord crazy technology. None of this
>> alters the fact that the next tiny company I end up working for won't be
>> able to afford this kind of thing.
>
> What makes you think you can't find work in a large company?

1. How many large companies are there? How many small companies are 
there? Exactly.

2. How many people apply to each large company? How many people apply to 
each small one?

To be sure, it's not /impossible/ to work for a large company. Just less 
likely.

Post a reply to this message

On 03/02/2012 02:48 AM, Darren New wrote:

> "No, I mean equipment. Anything over $50K? If so, we need to budget it."
> :-)

That's more than our entire IT budget for a year. As in, the entire 
corporation.

Then again, I think it may also be more *profit* than we make in a year, 
so... :-P

Post a reply to this message

>> ...unless it *isn't* useful at all, it's just another one of those
>> worthless things that "create the right impression".
>
> Being aware of technology is important.
>
> You find yourself in a job that you'd like to get out of, but you have no
> idea how to do it.
>
> People give you ideas, and you assert "that can't possibly work" or "that
> can't possibly be useful".
>
> But people who do those things actually find other jobs.
>
> You don't do those things, and you don't have luck finding another job.
>
> What does this tell you?

Well, for one thing, it tells me that now Christmas is over and it's 
February, I really ought to start applying for jobs again. I haven't 
done that in ages...

>>> A standardized XML file format allows the information to be published
>>> once and viewed by many different programs.
>>
>> Because XHTML isn't an XML format already. Oh, wait... actually yes it
>> is. And many different programs can view it. So...?
>
> Again, go look a the tour of Google Reader.

Not something I've ever heard of, but sure. That sounds like it might be 
much more enlightening than Wikipedia.

>> As best as I can tell, the idea behind RSS seems to be that you can see
>> if any of your subscribed websites have been updated, without having to
>> visit each of them one at a time. (As if that's in some way "hard" or
>> something.) Why the heck the article doesn't just /say/ this on line
>> one, I don't know. Instead it talks obliquely about how "all new content
>> is pushed onto the browser when it becomes available". (Funny, when it
>> says a feed reader "regularly checks for updates", that sounds to me
>> like a /pull/ model, not /push/...)
>
> It's time consuming to visit 100 sites to see if there's anything new.
> It's far easier to be alerted when there's something new that might be of
> interest.

100 sites?! o_O

Damn, you actually follow that much stuff? Jees...

>>>>>> I usually visit Tom's Hardware when I want to see what's happening
>>>>>> in the hardware world.
>>>>>
>>>>> I doubt you're going to get that by reading some text on a screen.
>>>>
>>>> That's why I just built a new PC - to experience the Core i7
>>>> first-hand.
>>>> :-P
>>>
>>> So then why bother going to Tom's Hardware again?
>>
>> Sarcasm? :-P
>
> Or perhaps to find out what the latest processor is that you might be
> able to afford?

For that, I go to various shopping websites. I visit Tom's Hardware to 
find out which products have good performance.

>> Want to bet that the BBC has servers all over the world?
>
> So you just happened to get a crappy connection, while I got a good one?

Or the BBC offers different quality levels in different parts of the 
world? Heck, maybe they're even using a different codec or something? I 
don't know.

>> With the latest update to our set top box, we can actually access
>> iPlayer and display it on a real TV. I can actually compare the recorded
>> TV broadcast directly next to the iPlayer version of the exact same
>> program. And let me tell you, the image quality is incomparable. (And
>> that's only SD, not HD.)
>
> Then your eyes are better than mine, or you got a really crappy
> connection.

Yes. Because it's the connection that determines the picture quality, 
not the sender. Oh, wait...

>> I don't think an 8 Mbit/sec Internet connection would be considered
>> especially slow...
>
> And yet I apparently get a better picture at half the speed from the
> other side of the planet....

*sigh*

Do you want me to go grab a frame? Would that make you happy?

>> The sound isn't the problem, it's the video. Sound is easily streamable.
>> But I'm baffled as to how you can download video in anything approaching
>> real-time, unless the quality is diabolically poor.
>
> Except that it isn't.  Part if it is called compression.

Sure, it's all compressed. But that almost always means lossy 
compression. You have to trade how much bandwidth you have for what 
level of picture quality you want. And that's the problem - it seems 
that to stream realtime over the Internet, you have to accept really low 
picture quality.

>>> But more to the point, do you now understand what streaming is?
>>
>> Yes. Although I'm still puzzled as to how anybody could make money out
>> of selling such poor quality stuff...
>
> Convenience is a huge motivational driver for consumers.  But more to the
> point, most people don't see the quality as being "poor".

Well, FM radio isn't exactly "high fidelity", and yet it's quite popular.

Then again, FM isn't so bad as to render the content /unrecognisable/. 
Right, let me go grab a frame from iPlayer...

Post a reply to this message

Attachments:
Download '0006.png' (111 KB)

Preview of image '0006.png'

On 02/02/2012 10:24 AM, Invisible wrote:
> On top of that, at peak times iPlayer becomes almost unusable. It
> freezes constantly. I'm not sure whether it's the BBC servers or the ISP
> network that can't keep up, but you just can't watch anything. But then,
> if you select "high quality mode", then it runs like that all the time.

There is free software you can use that will download and save the 
streaming media to your hard drive. So that you can watch or listen to 
the programmes without all those buffering waits.

-- 
Regards
     Stephen

Post a reply to this message

On 03/02/2012 12:45 PM, Stephen wrote:
> On 02/02/2012 10:24 AM, Invisible wrote:
>> On top of that, at peak times iPlayer becomes almost unusable. It
>> freezes constantly. I'm not sure whether it's the BBC servers or the ISP
>> network that can't keep up, but you just can't watch anything. But then,
>> if you select "high quality mode", then it runs like that all the time.
>
> There is free software you can use that will download and save the
> streaming media to your hard drive. So that you can watch or listen to
> the programmes without all those buffering waits.

Oh, iPlayer lets you do that anyway. But yeah, it would be kinda useful 
if I could do that to YouTube. (E.g., there used to be a video of a 
really great performance on a Wurlitzer. It's now vanished...)

Post a reply to this message

On 03/02/2012 12:58 PM, Invisible wrote:
>
> Oh, iPlayer lets you do that anyway. But yeah, it would be kinda useful
> if I could do that to YouTube. (E.g., there used to be a video of a
> really great performance on a Wurlitzer. It's now vanished...)

http://www.youtubedownloadersite.com/


-- 
Regards
     Stephen

Post a reply to this message

Le 2012-02-03 04:22, Invisible a écrit :
>> I have absolutely never
>> had to use the $ key on my keyboard, unless I was programming in Perl.
>
> This comment makes the whole discussion worth it! :-D
>
>>>> "In another building" DOES NOT mean "over the Internet". Private data
>>>> circuits predate the internet, and no company would use the Internet to
>>>> link two data centres together.
>>>
>>> How is that even *possible*? It's not like you can just go to the
>>> hardware store and buy 25km of copper wire and then put it into the
>>> ground with a shovel on your day off or something...
>>
>> You don't do it yourself, unless you are in a campus environment and can
>> easily rip up the parking lot and lay down your own fibre or copper.
>>
>> Step 1. Call your telco rep and order a circuit between site A and
>> site A.
>> Step 2. Telco will forward the request to a planner who will determine
>> if the existing cabling between both sites and central offices (CO) has
>> enough available bandwidth.
>> Step 3a. If not, the planner will forward the request to their
>> infrastructure group who will get diging permits from the
>> city/county/whatever and lay down new bundles of cables.
>> Step 3b. If the answer is yes, or once the new cables have been laid,
>> the telco planner will forward your request to an enabler who will
>> configure the CO switches to map the circuit from Site A's demarcation
>> point to Site B's demarcation point.
>> Step 4. Technicians will come on site, at both locations, and terminate
>> the circuit from their demarc point to the exact rack you ask them to.
>> Step 5. You plug in the circuit in your equipment (router, switch, or
>> mainframe front-end-processor, to name a few)
>>
>> Tada!
>>
>> Usually, all of this is done for a small nominal fee. Any work they have
>> to do between demarc points will be undertaken at their own expense,
>> which they will recoup on your monthly usage bill, of course.
>>
>> By the way, if you ordered an "internet" link, the exact same steps
>> would have to take place, except that they would be duplicated for site
>> A to ISP and ISP to site B, and then the ISP would add its own routers
>> at both ends and charge you twice as much and more for the "managed
>> services".
>
> Think is, if you order an Internet link, the telco has to run a few
> hundred yards of cable to the nearest junction box at one end, and a few
> hundred yards at the other end.

Which is exactly what I have described above, except the dealing with 
the telco is done by the ISP's engineers, not you.

> If you want a dedicated circuit from one
> end to the other without going via the Internet, they have to run
> several miles of cable just for you. Who the /hell/ can afford that? o_O
>

No. No. No. No.  What makes you think they would have to lay more cable 
for a dedicated circuit than for an internet connection?  Re-read step 2.

A dedicated circuit from my company's site A to site B goes:

Site A -> Telco CO 1 -> Telco Cloud -> Telco CO 2 -> Site B.

An Internet VPN goes:

Site A -> Telco CO 1 -> Telco Cloud -> Telco CO 3 -> ISP -> Telco CO 3 
-> Telco Cloud -> Telco CO 2 -> Site B.

Now, can you see that connecting to an ISP is effectively ordering TWO 
dedicated circuits instead of one?

Using an Internet VPN only makes sense when the costs of a dedicated 
cricuits becomes prohibitive and you must share the cost with others, at 
the expense of latency and garanteed bandwidth.

-- 
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/*    flabreque    */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/*        @        */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/*   gmail.com     */}camera{orthographic location<6,1.25,-6>look_at a }

Post a reply to this message

> What makes you think they would have to lay more cable
> for a dedicated circuit than for an internet connection?

The fact that rather than connecting you to an existing circuit, they're 
building a brand new one from scratch.

> A dedicated circuit from my company's site A to site B goes:
>
> Site A -> Telco CO 1 -> Telco Cloud -> Telco CO 2 -> Site B.

If it goes through their main cloud, it isn't a dedicated circuit. It's 
a shared circuit.

Post a reply to this message

Le 2012-02-03 09:49, Invisible a écrit :
>> What makes you think they would have to lay more cable
>> for a dedicated circuit than for an internet connection?
>
> The fact that rather than connecting you to an existing circuit, they're
> building a brand new one from scratch.

I never said they would build a new one from scratch, unless there was 
no bandwidth available on their existing infrastructure.

>
>> A dedicated circuit from my company's site A to site B goes:
>>
>> Site A -> Telco CO 1 -> Telco Cloud -> Telco CO 2 -> Site B.
>
> If it goes through their main cloud, it isn't a dedicated circuit. It's
> a shared circuit.

You can have dedicated bandwidth allocated to you on a shared physical 
circuit.  For example, on a DWDM link, if I assing the 720nm frequency 
to you, and the 680nm frequency to me, we would both have dedicated 
bandwidth on that fibre strand as it is physically impossible for our 
signals to suddenly merge or impact the other.  Likewise for TDM 
circuits, where each fram is divided into timeslots, and each customer 
is allocated a certain amount of timeslots.  There is no possibility of 
overlap or oversubscription.

A "shared" bandwdith scenario would be ATM, Frame-Relay SVCs, X.25, 
etc... where packets are sent through the cloud on a 
first-come-first-serve basis and where there is the possibility of 
oversubscription.

I apologize for using the word dedicated, instead of point-to-point.
-- 
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/*    flabreque    */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/*        @        */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/*   gmail.com     */}camera{orthographic location<6,1.25,-6>look_at a }

Post a reply to this message

On 2/3/2012 6:49, Invisible wrote:
> If it goes through their main cloud, it isn't a dedicated circuit. It's a
> shared circuit.

SONET. That's what it's for.  It's dedicated isochronous bandwidth on a 
shared circuit, designed to let you merge them together onto a faster 
circuit and back out again.

You think when you make an ISDN call you're not getting a 64kbps dedicated 
circuit for the duration of the call?

In any case, when you lay cable, you lay down way more than you need, 
because the cost of the physical cable is trivial. THe first guy who asks 
for a connection causes 900 pairs to be laid. The next 899 require none of 
that work.

-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.

Post a reply to this message

On 2/3/2012 4:58, Invisible wrote:

> Oh, iPlayer lets you do that anyway. But yeah, it would be kinda useful if I
> could do that to YouTube. (E.g., there used to be a video of a really great
> performance on a Wurlitzer. It's now vanished...)

It is called, not surprisingly, "Download Helper"

-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.

Post a reply to this message

On Fri, 03 Feb 2012 11:19:04 +0000, Invisible wrote:

>> It's time consuming to visit 100 sites to see if there's anything new.
>> It's far easier to be alerted when there's something new that might be
>> of interest.
> 
> 100 sites?! o_O
> 
> Damn, you actually follow that much stuff? Jees...

Yes, I do.  Now for things like Slashdot or The Register, I skim 
headlines in Google Reader.  I don't always read the full article - but 
if a headline is intriguing, I'll dig in a little deeper.

With Slashdot, if I read the headline and it looks interesting, I'll read 
the story there.  If it looks more interesting, then I'll open the link 
to the /. story and follow the links to the actual story.

>>>>> That's why I just built a new PC - to experience the Core i7
>>>>> first-hand.
>>>>> :-P
>>>>
>>>> So then why bother going to Tom's Hardware again?
>>>
>>> Sarcasm? :-P
>>
>> Or perhaps to find out what the latest processor is that you might be
>> able to afford?
> 
> For that, I go to various shopping websites. I visit Tom's Hardware to
> find out which products have good performance.

Bingo.  Thank you, you've made my point.  You *can* actually learn stuff 
by reading about it on the 'net.

>>> Want to bet that the BBC has servers all over the world?
>>
>> So you just happened to get a crappy connection, while I got a good
>> one?
> 
> Or the BBC offers different quality levels in different parts of the
> world? Heck, maybe they're even using a different codec or something? I
> don't know.

I see.  So the BBC offers really crap quality to those who pay the 
licensing fee in the UK, but offers really good quality to those who 
don't?

>> Then your eyes are better than mine, or you got a really crappy
>> connection.
> 
> Yes. Because it's the connection that determines the picture quality,
> not the sender. Oh, wait...

Yes, it is the connection that determines the picture quality.  If I only 
have a 32 Kbps connection, I'm not going to get a good quality HD picture.

> Sure, it's all compressed. But that almost always means lossy
> compression. You have to trade how much bandwidth you have for what
> level of picture quality you want. And that's the problem - it seems
> that to stream realtime over the Internet, you have to accept really low
> picture quality.

Would you like me to take a picture of Netflix streaming on my 10' wide 
screen with a 3 Mbps ADSL connection?  Would that make you happy?

Jim

Post a reply to this message

On 05/02/2012 11:05 PM, Jim Henderson wrote:
> I see.  So the BBC offers really crap quality to those who pay the
> licensing fee in the UK, but offers really good quality to those who
> don't?

Hmm!
I use get_iplayer to download progs and the blurb on the site says:

The iPhone H.264 feeds from the BBC are higher quality than in the Flash 
iPlayer (normal quality). See the beebhack wiki for a comparison. They 
are intended for the Apple iPhone and are consequently difficult to 
download for any other OS. The same goes for the iPhone MP3 radio 
streams. get_iplayer also allows recording of the high-quality (even HD 
720p) flash based content using rtmpdump. None of the above content is 
‘protected’ by DRM. get_iplayer cannot remove DRM.

http://www.infradead.org/get_iplayer/html/get_iplayer.html

BTW Just a minute starts its 62nd series on Monday. Happy 45th Birthday, 
Just A Minute!
http://www.bbc.co.uk/programmes/b01blgp6


-- 
Regards
     Stephen

Post a reply to this message

On Sun, 05 Feb 2012 23:27:58 +0000, Stephen wrote:

> On 05/02/2012 11:05 PM, Jim Henderson wrote:
>> I see.  So the BBC offers really crap quality to those who pay the
>> licensing fee in the UK, but offers really good quality to those who
>> don't?
> 
> Hmm!
> I use get_iplayer to download progs and the blurb on the site says:
> 
> The iPhone H.264 feeds from the BBC are higher quality than in the Flash
> iPlayer (normal quality). See the beebhack wiki for a comparison. They
> are intended for the Apple iPhone and are consequently difficult to
> download for any other OS. The same goes for the iPhone MP3 radio
> streams. get_iplayer also allows recording of the high-quality (even HD
> 720p) flash based content using rtmpdump. None of the above content is
> ‘protected’ by DRM. get_iplayer cannot remove DRM.

That's the same software I use.  :)

It does seem odd, though, that they don't do HD streaming for iPlayer 
itself.  I thought I saw a switch for that (but then again, iPlayer video 
isn't something I can get my hands on easily without using get_iplayer 
and a UK-based proxy).

> http://www.infradead.org/get_iplayer/html/get_iplayer.html
> 
> BTW Just a minute starts its 62nd series on Monday. Happy 45th Birthday,
> Just A Minute!
> http://www.bbc.co.uk/programmes/b01blgp6

:)

Jim

Post a reply to this message

>> 100 sites?! o_O
>>
>> Damn, you actually follow that much stuff? Jees...
>
> Yes, I do.

Damn. How do you ever get anything done?! o_O

> Bingo.  Thank you, you've made my point.  You *can* actually learn stuff
> by reading about it on the 'net.

You can /totally/ find out prices or technical specifications or look up 
instructions. I'm saying you can't really comprehend a fundamentally 
different world-view just by reading about it.

>>> Then your eyes are better than mine, or you got a really crappy
>>> connection.
>>
>> Yes. Because it's the connection that determines the picture quality,
>> not the sender. Oh, wait...
>
> Yes, it is the connection that determines the picture quality.

Erm, no. It's the quality that the file is transcoded at.

>> And that's the problem - it seems
>> that to stream realtime over the Internet, you have to accept really low
>> picture quality.
>
> Would you like me to take a picture of Netflix streaming on my 10' wide
> screen with a 3 Mbps ADSL connection?  Would that make you happy?

It still wouldn't explain how it's possible... Every Internet video 
system I've ever seen either has awful image quality or isn't realtime. 
And it appears that's because the necessary bandwidth doesn't exist yet.

Post a reply to this message

On Mon, 06 Feb 2012 09:20:31 +0000, Invisible wrote:

>>> 100 sites?! o_O
>>>
>>> Damn, you actually follow that much stuff? Jees...
>>
>> Yes, I do.
> 
> Damn. How do you ever get anything done?! o_O

I use Google Reader so I don't have to visit all those sites to see 
what's new.  Takes me about an hour in the evening to go through the 
day's posts and see what's new.

>> Bingo.  Thank you, you've made my point.  You *can* actually learn
>> stuff by reading about it on the 'net.
> 
> You can /totally/ find out prices or technical specifications or look up
> instructions. I'm saying you can't really comprehend a fundamentally
> different world-view just by reading about it.

Depends on who's written it.

>>>> Then your eyes are better than mine, or you got a really crappy
>>>> connection.
>>>
>>> Yes. Because it's the connection that determines the picture quality,
>>> not the sender. Oh, wait...
>>
>> Yes, it is the connection that determines the picture quality.
> 
> Erm, no. It's the quality that the file is transcoded at.

A connection that isn't fast enough isn't going to show you the full 
definition.  I defy you to demonstrate a high quality video over a slow 
connection.

>>> And that's the problem - it seems that to stream realtime over the
>>> Internet, you have to accept really low picture quality.
>>
>> Would you like me to take a picture of Netflix streaming on my 10' wide
>> screen with a 3 Mbps ADSL connection?  Would that make you happy?
> 
> It still wouldn't explain how it's possible... Every Internet video
> system I've ever seen either has awful image quality or isn't realtime.
> And it appears that's because the necessary bandwidth doesn't exist yet.

<sigh>

https://lh6.googleusercontent.com/-UJGO-U7Whto/TzAdp1huWOI/
AAAAAAAABbs/1IPtFRGNv6Q/s912/2012-02-06.jpg

Now consider that's a quick photo of a 10' screen streaming realtime at 3 
Mbps.  The bluriness you see there is an artifact of the camera used, not 
the actual image on the screen.

Obviously the necessary bandwidth exists.

Jim

Post a reply to this message

On 06/02/2012 6:42 PM, Jim Henderson wrote:
> https://lh6.googleusercontent.com/-UJGO-U7Whto/TzAdp1huWOI/
> AAAAAAAABbs/1IPtFRGNv6Q/s912/2012-02-06.jpg

Euch! The ubiquitous banker Mr Fry.

The quality looks okay or even good to me.


-- 
Regards
     Stephen

Post a reply to this message

On Mon, 06 Feb 2012 19:33:15 +0000, Stephen wrote:

> On 06/02/2012 6:42 PM, Jim Henderson wrote:
>> https://lh6.googleusercontent.com/-UJGO-U7Whto/TzAdp1huWOI/
>> AAAAAAAABbs/1IPtFRGNv6Q/s912/2012-02-06.jpg
> 
> Euch! The ubiquitous banker Mr Fry.

:)

We're watching "Stephen Fry Across America", just happened to think of 
grabbing a pic while watching it last night. :)

That quality is reported by NetFlix as "Medium/HD", which is usually what 
we get if nothing else is using the connection.

> The quality looks okay or even good to me.

It's quite viewable.  We also tend to get full 5.1 sound with movies that 
have it along with the good quality.

Jim

Post a reply to this message

Stephen <mcavoys_at@aoldotcom> wrote:
> On 06/02/2012 6:42 PM, Jim Henderson wrote:
> > https://lh6.googleusercontent.com/-UJGO-U7Whto/TzAdp1huWOI/
> > AAAAAAAABbs/1IPtFRGNv6Q/s912/2012-02-06.jpg
>
> Euch! The ubiquitous banker Mr Fry.

he's great as Sherlock's brother Mycroft in the latest flick...

Post a reply to this message

On 06/02/2012 7:43 PM, nemesis wrote:
> Stephen<mcavoys_at@aoldotcom>  wrote:
>> On 06/02/2012 6:42 PM, Jim Henderson wrote:
>>> https://lh6.googleusercontent.com/-UJGO-U7Whto/TzAdp1huWOI/
>>> AAAAAAAABbs/1IPtFRGNv6Q/s912/2012-02-06.jpg
>>
>> Euch! The ubiquitous banker Mr Fry.
>
> he's great as Sherlock's brother Mycroft in the latest flick...
>
>
He might be but personally I find him hard to watch because of his past.


-- 
Regards
     Stephen

Post a reply to this message

>> Damn. How do you ever get anything done?! o_O
>
> I use Google Reader so I don't have to visit all those sites to see
> what's new.  Takes me about an hour in the evening to go through the
> day's posts and see what's new.

It used to take me about 4 hours in the evening (i.e., my entire 
evening) just to read this newsgroup. (Although it seems a lot quieter 
lately...)

>>> Yes, it is the connection that determines the picture quality.
>>
>> Erm, no. It's the quality that the file is transcoded at.
>
> A connection that isn't fast enough isn't going to show you the full
> definition.  I defy you to demonstrate a high quality video over a slow
> connection.

If the bitrate of the source is higher than the available bandwidth, it 
just won't play in realtime. It'll constantly stall to rebuffer. So 
presumably the guys behind iPlayer (and every other Internet video 
system) have to transcode to a low enough bitrate that it will actually 
play in realtime. The result is obviously poor image quality.

Consider, for example, that it took me 3 days to download Star Wreck, 
which is only about an hour long. OK, that was only using a 2 Mbit 
connection, but I don't suppose you can download almost 4GB of data over 
an 8 Mbit connection in one hour flat either.

> <sigh>
>
> https://lh6.googleusercontent.com/-UJGO-U7Whto/TzAdp1huWOI/
> AAAAAAAABbs/1IPtFRGNv6Q/s912/2012-02-06.jpg
>
> Now consider that's a quick photo of a 10' screen streaming realtime at 3
> Mbps.  The bluriness you see there is an artifact of the camera used, not
> the actual image on the screen.
>
> Obviously the necessary bandwidth exists.

Yes, the picture looks fine. I still don't understand how that can be 
possible though. The Internet isn't fast enough. I don't see how you can 
get the data from A to B fast enough for realtime playback.

Post a reply to this message

Le 2012-02-07 04:16, Invisible a écrit :
>>> Damn. How do you ever get anything done?! o_O
>>
>> I use Google Reader so I don't have to visit all those sites to see
>> what's new. Takes me about an hour in the evening to go through the
>> day's posts and see what's new.
>
> It used to take me about 4 hours in the evening (i.e., my entire
> evening) just to read this newsgroup. (Although it seems a lot quieter
> lately...)
>
>>>> Yes, it is the connection that determines the picture quality.
>>>
>>> Erm, no. It's the quality that the file is transcoded at.
>>
>> A connection that isn't fast enough isn't going to show you the full
>> definition. I defy you to demonstrate a high quality video over a slow
>> connection.
>
> If the bitrate of the source is higher than the available bandwidth, it
> just won't play in realtime. It'll constantly stall to rebuffer. So
> presumably the guys behind iPlayer (and every other Internet video
> system) have to transcode to a low enough bitrate that it will actually
> play in realtime. The result is obviously poor image quality.

Once again, you presumed wrong, since other people are able to see the 
full image!


>
> Consider, for example, that it took me 3 days to download Star Wreck,
> which is only about an hour long. OK, that was only using a 2 Mbit
> connection, but I don't suppose you can download almost 4GB of data over
> an 8 Mbit connection in one hour flat either.
>

Bad example.  Assuming you downloaded it via bit-torrent from other 
users, you were constrained by their very limited upload speeds.  If you 
downloaded it from an FTP server, you were also porbably constrained by 
the number of connections clobbering said server.

Netflix, and other streaming sites have banks of high performance 
servers connected to very large internet pipes, in multiple sites that 
are close to the users.  This way, there are fewer bottlenecks and 
little to no latency issues that can interfere with the stream.

>> <sigh>
>>
>> https://lh6.googleusercontent.com/-UJGO-U7Whto/TzAdp1huWOI/
>> AAAAAAAABbs/1IPtFRGNv6Q/s912/2012-02-06.jpg
>>
>> Now consider that's a quick photo of a 10' screen streaming realtime at 3
>> Mbps. The bluriness you see there is an artifact of the camera used, not
>> the actual image on the screen.
>>
>> Obviously the necessary bandwidth exists.
>
> Yes, the picture looks fine. I still don't understand how that can be
> possible though. The Internet isn't fast enough. I don't see how you can
> get the data from A to B fast enough for realtime playback.

Which part of the Internet isn't fast enough?

Is HD tv available in the UK, from cable tv providers?  Stop and think 
for a few nanoseconds how that signal is delivered to your cablebox. 
Netflix and co. are the same thing, except the source server is just a 
few 10Gbps hops further away on the Internet backbone.

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>> Consider, for example, that it took me 3 days to download Star Wreck,
>> which is only about an hour long. OK, that was only using a 2 Mbit
>> connection, but I don't suppose you can download almost 4GB of data over
>> an 8 Mbit connection in one hour flat either.
>
> Bad example. Assuming you downloaded it via bit-torrent from other
> users, you were constrained by their very limited upload speeds.

Except that you're downloading it from dozens of clients at once, should 
should counteract that problem.

>> Yes, the picture looks fine. I still don't understand how that can be
>> possible though. The Internet isn't fast enough. I don't see how you can
>> get the data from A to B fast enough for realtime playback.
>
> Which part of the Internet isn't fast enough?

The last mile, as always.

> Is HD tv available in the UK, from cable tv providers? Stop and think
> for a few nanoseconds how that signal is delivered to your cablebox.
> Netflix and co. are the same thing, except the source server is just a
> few 10Gbps hops further away on the Internet backbone.

I have no idea what "cable" is. I do know you can receive HD TV with an 
aerial; presumably this uses higher bandwidth than a normal Internet 
connection.

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> > Is HD tv available in the UK, from cable tv providers? Stop and think
> > for a few nanoseconds how that signal is delivered to your cablebox.
> > Netflix and co. are the same thing, except the source server is just a
> > few 10Gbps hops further away on the Internet backbone.
>
> I have no idea what "cable" is. I do know you can receive HD TV with an
> aerial; presumably this uses higher bandwidth than a normal Internet
> connection.

it's also far cheaper, since it's broadcast, i.e. all users receive the very
same stream, not a stream per millions of users...

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On Tue, 07 Feb 2012 09:16:33 +0000, Invisible wrote:

>>> Damn. How do you ever get anything done?! o_O
>>
>> I use Google Reader so I don't have to visit all those sites to see
>> what's new.  Takes me about an hour in the evening to go through the
>> day's posts and see what's new.
> 
> It used to take me about 4 hours in the evening (i.e., my entire
> evening) just to read this newsgroup. (Although it seems a lot quieter
> lately...)

I probably spend a couple hours a day reading my 200+ newsgroups.  Again 
usually just skimming subjects for things that are interesting.

>>>> Yes, it is the connection that determines the picture quality.
>>>
>>> Erm, no. It's the quality that the file is transcoded at.
>>
>> A connection that isn't fast enough isn't going to show you the full
>> definition.  I defy you to demonstrate a high quality video over a slow
>> connection.
> 
> If the bitrate of the source is higher than the available bandwidth, it
> just won't play in realtime. It'll constantly stall to rebuffer. So
> presumably the guys behind iPlayer (and every other Internet video
> system) have to transcode to a low enough bitrate that it will actually
> play in realtime. The result is obviously poor image quality.

Clearly not, as shown in my photo.  In the case of Netflix, they use a 
dynamically adjusting algorithm so it can display lower quality if the 
bandwidth is throttled.  You'll note that I noted to Stephen that Netflix 
shows "Medium/HD" as the quality for that image - that's usually what I 
get.  If I had a slower connection, I get "High/SD" or "Low/HD".  If I 
had a faster connection, I'd get "High/HD".

> Consider, for example, that it took me 3 days to download Star Wreck,
> which is only about an hour long. OK, that was only using a 2 Mbit
> connection, but I don't suppose you can download almost 4GB of data over
> an 8 Mbit connection in one hour flat either.

That was at a fixed quality setting, not being streamed.

>> <sigh>
>>
>> https://lh6.googleusercontent.com/-UJGO-U7Whto/TzAdp1huWOI/
>> AAAAAAAABbs/1IPtFRGNv6Q/s912/2012-02-06.jpg
>>
>> Now consider that's a quick photo of a 10' screen streaming realtime at
>> 3 Mbps.  The bluriness you see there is an artifact of the camera used,
>> not the actual image on the screen.
>>
>> Obviously the necessary bandwidth exists.
> 
> Yes, the picture looks fine. I still don't understand how that can be
> possible though. The Internet isn't fast enough. I don't see how you can
> get the data from A to B fast enough for realtime playback.

Compression.  We've been over this before.

Jim

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> I probably spend a couple hours a day reading my 200+ newsgroups.  Again
> usually just skimming subjects for things that are interesting.

Damn. If I had that much stuff to look at, I'd *never* get any work 
done... Oh, wait.

>> If the bitrate of the source is higher than the available bandwidth, it
>> just won't play in realtime. It'll constantly stall to rebuffer. So
>> presumably the guys behind iPlayer (and every other Internet video
>> system) have to transcode to a low enough bitrate that it will actually
>> play in realtime. The result is obviously poor image quality.
>
> Clearly not, as shown in my photo.  In the case of Netflix, they use a
> dynamically adjusting algorithm so it can display lower quality if the
> bandwidth is throttled.

So they actually offer multiple quality levels? Well, I guess that makes 
good sense. I'm not sure how you'd automatically detect which one to 
use, but I guess with the right client software it ought to be possible.

>> Yes, the picture looks fine. I still don't understand how that can be
>> possible though. The Internet isn't fast enough. I don't see how you can
>> get the data from A to B fast enough for realtime playback.
>
> Compression.  We've been over this before.

Lossy compression allows you to make the file size be anything you want 
it to be. But this does not happen by magic; it happens by degrading the 
picture quality. So while it obviously /is/ possible to reduce a video 
stream to, say, 3KB per second, it wouldn't be worth watching. What I 
can't figure out is how they can shrink it down to realtime download 
speeds without it looking awful.

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Le 2012-02-07 09:06, Invisible a écrit :
>>> Consider, for example, that it took me 3 days to download Star Wreck,
>>> which is only about an hour long. OK, that was only using a 2 Mbit
>>> connection, but I don't suppose you can download almost 4GB of data over
>>> an 8 Mbit connection in one hour flat either.
>>
>> Bad example. Assuming you downloaded it via bit-torrent from other
>> users, you were constrained by their very limited upload speeds.
>
> Except that you're downloading it from dozens of clients at once, should
> should counteract that problem.

Not always.

>
>>> Yes, the picture looks fine. I still don't understand how that can be
>>> possible though. The Internet isn't fast enough. I don't see how you can
>>> get the data from A to B fast enough for realtime playback.
>>
>> Which part of the Internet isn't fast enough?
>
> The last mile, as always.
>

Which varies a lot from place to place.  First, because your DSL speed 
will be affected by the distance or the CO from your house, and by the 
quality of the wires.  On top of that, different carriers have different 
services.  For example, on top of various DSL packages, my telephone 
company offers fibre connections at 7, 10, 16 or 25 Mbps.  My Cable 
provider offers comparable packages as well.

>> Is HD tv available in the UK, from cable tv providers? Stop and think
>> for a few nanoseconds how that signal is delivered to your cablebox.
>> Netflix and co. are the same thing, except the source server is just a
>> few 10Gbps hops further away on the Internet backbone.
>
> I have no idea what "cable" is. I do know you can receive HD TV with an
> aerial; presumably this uses higher bandwidth than a normal Internet
> connection.

Presumably?  Again.  After having been shown 4759483758975 times in this 
thread alone that your assumptions were wrong, you still persevere!!!

Also, http://en.wikipedia.org/wiki/Cable_television

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>>> Bad example. Assuming you downloaded it via bit-torrent from other
>>> users, you were constrained by their very limited upload speeds.
>>
>> Except that you're downloading it from dozens of clients at once, should
>> should counteract that problem.
>
> Not always.

As in "you're not always downloading from that many clients", or as in 
"downloading from many clients doesn't give you greater bandwidth"?

>>> Which part of the Internet isn't fast enough?
>>
>> The last mile, as always.
>>
>
> Which varies a lot from place to place. First, because your DSL speed
> will be affected by

Yes, but given that 8 Mbit/sec is the maximum speed that current ADSL 
standard allow, we can take it as read that nobody is going faster than 
that.

> For example, on top of various DSL packages, my telephone
> company offers fibre connections at 7, 10, 16 or 25 Mbps.

Oh, really? Well, if you're getting 25 Mbit/sec then yes, streaming 
full-quality video in realtime /should/ work just fine.

(At least, for SD video. Apparently BRD has a transfer rate of 36 
Mbit/sec, so it looks like HD video still wouldn't work.)

>> I have no idea what "cable" is. I do know you can receive HD TV with an
>> aerial; presumably this uses higher bandwidth than a normal Internet
>> connection.
>
> Presumably? Again. After having been shown 4759483758975 times in this
> thread alone that your assumptions were wrong, you still persevere!!!

And to think people tell me I don't persevere enough...

At any rate, a cursory inspection of Wikipedia seems to indicate that, 
yes, digital TV is higher bandwidth.

> Also, http://en.wikipedia.org/wiki/Cable_television

Oh, is /that/ what that means? OK. I didn't know you could use this for 
anything other than analogue TV. Our house used to have this, before 
everything went digital.

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On Wed, 08 Feb 2012 09:06:03 +0000, Invisible wrote:

>> I probably spend a couple hours a day reading my 200+ newsgroups. 
>> Again usually just skimming subjects for things that are interesting.
> 
> Damn. If I had that much stuff to look at, I'd *never* get any work
> done... Oh, wait.

Certainly if you didn't have a way of handling it more quickly, you 
wouldn't.  That's kinda my point.

>> Clearly not, as shown in my photo.  In the case of Netflix, they use a
>> dynamically adjusting algorithm so it can display lower quality if the
>> bandwidth is throttled.
> 
> So they actually offer multiple quality levels? Well, I guess that makes
> good sense. I'm not sure how you'd automatically detect which one to
> use, but I guess with the right client software it ought to be possible.

You start with the lowest quality and increase the quality until you hit 
some sort of limitation.  Buffer enough so it doesn't stutter when you 
hit the limitation, and then back off.

>>> Yes, the picture looks fine. I still don't understand how that can be
>>> possible though. The Internet isn't fast enough. I don't see how you
>>> can get the data from A to B fast enough for realtime playback.
>>
>> Compression.  We've been over this before.
> 
> Lossy compression allows you to make the file size be anything you want
> it to be. But this does not happen by magic; it happens by degrading the
> picture quality. So while it obviously /is/ possible to reduce a video
> stream to, say, 3KB per second, it wouldn't be worth watching. What I
> can't figure out is how they can shrink it down to realtime download
> speeds without it looking awful.

Measuring latency and throughput.  It's not magic.

Jim

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On 2/8/2012 6:08, Invisible wrote:
> Yes, but given that 8 Mbit/sec is the maximum speed that current ADSL
> standard allow, we can take it as read that nobody is going faster than that.

It depends entirely over the distance you are from the head end. I get 
12Mbps on the DSL line that only has to go down to the street from my condo.

> (At least, for SD video. Apparently BRD has a transfer rate of 36 Mbit/sec,
> so it looks like HD video still wouldn't work.)

Have you tried watching an HD youtube video, out of curiosity?


-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.

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On 09/02/2012 03:35 AM, Darren New wrote:
> On 2/8/2012 6:08, Invisible wrote:
>> Yes, but given that 8 Mbit/sec is the maximum speed that current ADSL
>> standard allow, we can take it as read that nobody is going faster
>> than that.
>
> It depends entirely over the distance you are from the head end.

No, it does not.

http://en.wikipedia.org/wiki/ANSI_T1.413_Issue_2

"The maximum achievable downstream data rate is 8.128 Mbit/s."

If you're too far from the exchange, you will get less than 8 Mb, but 
you will never get /more/ than 8 Mb. That's like saying that if you 
connect a USB 1.0 device with a short enough cable, you can make it go 
faster than 12 Mb. Erm, no, no you cannot, because the USB 1.0 standard 
specifies a maximum data rate of 12 Mb.

So, like I said, unless you're using something other than ADSL, you 
cannot go faster than 8 Mbit/sec.

>> (At least, for SD video. Apparently BRD has a transfer rate of 36
>> Mbit/sec, so it looks like HD video still wouldn't work.)
>
> Have you tried watching an HD youtube video, out of curiosity?

I think I've tried flicking the quality switches at some point. From 
what I recall, turning the quality up makes playback a bit less 
reliable, and the picture quality a bit less awful. But it's certainly 
not as good as SD TV picture quality.

(Or rather, certain SD channels. I've noticed that some digital TV 
channels are also fairly heavily compressed...)

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