I'm confident that you will agree with me that after all of the real-world engineering details are taken into account, a finite bandwidth signal can still be captured with a finite sampling rate although that rate needs to be higher than twice the highest frequency in the signal due to the engineering concerns.
Sure. I wasn't disagreeing with you, just expanding on the point.
when you have a sine wave it is continuous and smooth - now picture a digital representation of that (for this example, we'll talk CD-quality - 16-bit, 44.1KHz) - in the digital representation, you don't have a smooth curve, you have a stair step (I'm not sure if you've taken calc, but think of all those 'area under the curve' problems) - the sine wave gets samples 44,100 times every second which causes the stair step, as the sampling rate increases, the stair steps get smaller and as the limit (of the sampling rate) approaches infinity, the steps get infinitely small, but there will always be a stair-step/jaggy effect - this is the nature of the beast....
The stair-steps are very real and you are correct - a typical DAC will produce an output with those steps - however those steps have sharp edges which means they have extremely high frequencies. In fact, a step will have harmonics extending to infinity (albeit at constantly reducing volume). That's why every CD player has an output filter that removes frequencies above approximately 20kHz. This will "smooth" the stair-steps into a non-jaggy signal.
Now what's interesting is that the smoothing effect is not lossy! The stair steps have undesirable harmonics but the DAC introduced no new frequencies below 22.05kHz. That's right, the DAC only creates high-frequency harmonics that weren't in the original signal (NB: disclaimer below), so when you remove those harmonics with the filter you are not losing anything. The combination of the stair-step DAC and the low-pass filter is a perfect reproduction of the original signal.
The above discussion all assumes perfect filters and perfect DACs combined with perfect sampling. In practise that's impossible so there are other considerations (eg, spikes, jitter, quantisation, aliasing). But the important thing to walk away with is that your intuitive feel about stair-steps is incorrect. Admittedly you need to do a lot of maths before this becomes intuitive.
To put it into term that you can understand, if your ear cannot detect frequencies higher than 22.05 kilohertz then a sampling rate of 44.1 samples per second can perfectly reproduce any sound you can hear.
That's true for theoretical conditions but in practise it's not quite that good. The maths assumes infinitely precise sample resolution and perfect sampling points. In practise a CD is limited to 16-bit resolution and due to the vagaries of electronics the sampling points will often drift by a microsecond or two from their ideal times.
That's why when they master the CD they purposefully use a low-pass filter to cut-off the frequencies above approximately 20kHz. They lose 2kHz of frequency range that theoretically could be stored on the CD, though nobody can hear much in that range anyway so it's not a big loss. This is also why 20-bit and 24-bit recordings at 96kHz are considered useful. It's not because audiophiles (morons) have ears that can hear dog-whistle frequencies, but because it allows the encoding/decoding electronics to be simpler (simpler analogue filters) and therefore cheaper.
on another note - incompatible java technology? how the fuck did they manage that? the whole point of java is compatibility and interoperability ffs!
Microsoft intentionally modified the core classes in their JVM by adding Windows-specific methods and attributes. Sun asked Microsoft to leave the core classes alone and use subclasses for platform-specifics. Microsoft refused. Sun sued. Microsoft settled to the tune of $2billion, but that was after many years and Java had effectively been hobbled the entire time.
Its game functions, while impressive, are only part of the message.
And it sounds like an advertising message.
We've been inundated recently with Xbox stories and they're suspicious. For a start, the spelling and grammar has been too good. Look at that sentence above: the word "its" doesn't have the customary (yet incorrect) Slashdot apostrophe. The paragraph cuts to the point and is coherent. It is entirely unlikely anything I normally read on Slashdot.
Only 24 hours ago was another story where Allard was saying there would be shortages. The very unsubtle message from Allard was "Buy your Xbox 360(tm) immediately because otherwise you'll miss out". Another uncharacteristic story that reeked like a hidden advertisment.
24 hours before that, another Xbox story. I don't even recall what it was about, I just know that each day I open Slashdot and there's another fucking Xbox story. This looks to me like an astroturfing campaign. Microsoft has done this before and I wouldn't be surprised if they're doing it again.
I recently decided to try out Eclipse - after hearing how brilliant it was - to replace Anjuta for C++ development. I notice an eclipse package is in Debian so I "apt-get install eclipse-sdk". Oh, it needs a Java SDK first. No worries, I'll just install one of those using apt. I'm sure this will be easy.
Easy? Hah! Maybe it's easy for x86 users but us PPC users are out in the cold. After hours of fruitless searching I eventually chance upon the IBM Java SDK on the IBM website. It's only in RPM format, but a quick "alien" later and I have a package. I install it, go to run it, and the JRE crashes.
So I simply delete the Java SDK and any hopes of using Eclipse on Linux/PPC. I'm not going to jump through hoops; if it doesn't "apt-get install" then I don't want to know about it.
How does one confuse a leopard [google.com] with a puma [google.com], especially when the animal in question is not running, but lying dead in front of you?
Dude, this is Australia. The only ferocious animals to hunt in Australia are wild pigs and crazed rabbits. It's possibly the first big cat the hunter has ever seen, so it's no surprise he couldn't identify it.
Re:Maybe an OSS future isn't that bright afterall
on
Nessus Closes Source
·
· Score: 1
So let me just say this to most of the zealots: OSS is never going to win in the long run because developers have families to support and will not slit the throat of the goose that lays the golden eggs (though sometimes they seem a little bit like bronze) that pay the bills and support one's spouse and children.
I disagree. I think OSS will win in the long run simply because there are zealots who will happily slit your throat for you, metaphorically speaking. You can't compete with free. Not when the quality of software is this high. The OSS stuff is sometimes better, sometimes worse, but on average it's competitive with non-OSS software. Then it all comes down to price and at that point you cannot win.
Combine that with industry collaboration - companies like Novell, Sun and IBM throwing their weight behind OSS, seemingly to harm Microsoft - and there is a huge pool of funded OSS. That's right, developers writing OSS while still supporting "one's spouse and children". You can't compete with that, so you might as well stop complaining and get on the bandwagon.
Or do what I did and get out of paid development, because it has a limited future as far as I'm concerned.
It hasn't happened. As it turns out, thin clients have not taken off. And the Web has not replaced desktop applications.
You are wrong. So very very wrong.
In the old days, I did electronic banking using a fat client. It was a DOS executable that had a proprietary protocol over a dedicated leased line (serial) to the bank. That's all gone now, replaced with a much better thin client (Firefox).
I can buy my groceries online! I've done it once to see what it was like. I didn't have to install a fat client, or an executable, or anything complicated. I just logon to a webpage using my thin client (Firefox) and click on the groceries I want. They arrive on my doorstep within 8 hours.
In the old days we used to chat with each other using a variety of fat clients: news readers, chat programs, bbs frontends. They still exist - inertia is a horrendous thing - but by preference I use software-agnostic blogs like Slashdot and Fark. The fat clients have been replaced with web-apps that I access through my thin client (Firefox).
Chat programs, online banking, internet shopping, travel reservations, email (gmail/hotmail), server management (webmin, cups), embedded client access (linksys anything). At one time the ony way to access those applications was with fat clients, typically written for specific platforms like Windows or DOS. Now I access them all using a thin client (Firefox).
My desktop would actually be useless without a browser. I spend more than 75% of my work time in the browser. The network management console is browser based. The IDS is browser based. The time tracking system is browser based. The invoicing system is browser based. My mail is browser based. The bug-tracking system is browser based. The collaboration system (a wiki) is browser based. Half the network equipment is managed through a browser. Without a browser, I would have literally dozens of platform-specific applications that would need to be installed by Desktop Support. Instead, in the morning I start a single desktop application, Firefox.
Thin clients have taken off and the Web has replaced many desktop applications. Your empathic claims to the contrary are wrong because they are overstated.
It's stable but it leaks disk. Shows that are deleted while being transcoded never have their file handles properly closed, so the space doesn't get freed. That's in an old release - the dev trees might have fixed the bug.
I really don't understand Microsoft's attitude on this one. Their reasoning for not implementing OpenDocument in Office just isn't sound.
Their reasoning is extremely sound. If Microsoft Office supported the OASIS formats, then that would ease the transition from Microsoft Word to any number of other word processors. I've heard that 11 word processors now support OASIS, including a commercial product from IBM.
Microsoft isn't being stupid. They know that their success is tied to Office, and that the reason people stick with Office is because it's insanely difficult to switch to other word processors because of the cost of converting existing data. Microsoft "owns" the DOC format and so they own the market.
If Microsoft supported the OASIS format then they'd have to compete on merit. Don't expect them to enter that space willingly.
Despite being incredibly strong, polycarbonate is actually quite soft. You can try this yourself. Take a pair of polycarb safety glasses.. These things can stop a shotgun pellet,...
WARNING: Do not attempt to stop shotgun pellet while wearing polycarb safety glasses.
Question: Since Comcast et al pretty much limit your recording ability to what is being output from their cable box, how is the Tivo/DVR/MythTV device going to be able to record various shows on channels that the cable box isn't tuned to?
I don't have a cable box, so I don't have direct experience with this, but the solution is an IR Blaster which MythTV can use to change the channel on the cable box. If you google "mythtv ir blaster" you'll find plenty of websites with instructions.
I know people are going to say "blah blah, this is why you should switch to MythTV." Has anyone been successful in prototyping a Mythbox (such that it just works for long periods of time without having to worry about tweaks and workarounds)?
Sure, I've had a stable MythTV server for over 12 months. I've got 350GB striped storage, DVB tuners and multiple frontends (Mac, Xbox, Laptop).
If so, please tell me how.
Easy.
Find a reliable EPG source.
Pre and post-record every show by 5 minutes.
Ensure you have NTP installed.
Install a cron job to restart myth-backend once a week.
Once it's working, STOP FUCKING WITH IT.
That last lesson is the hardest to learn. Once you stop "tweaking" the damn thing, it stops breaking.
Apple actually implemented overlapping windows thinking that Xerox had it, but actually the first Xerox GUI computers didn't have overlapping windows.
The early prototypes of the Xerox Star did have overlapping windows. From the page that I linked to in my previous comment.
Star was the first commercial system to provide a windows user interface. Star's windowing system could overlap windows and often did (e.g., property sheets were displayed in windows that overlapped application windows). However, Star's designers observed in early testing that users spent a lot of time adjusting windows and usually adjusted them so that they did not overlap. Because of this, and because Star's 17-inch screen was large enough that there wasn't as much of a need for overlapping windows as there is in systems having less screen space, the designers decided that application windows should be constrained so as not to overlap.
I'll spell it out for you: they had overlapping windows, their testing showed it was confusing, they disabled the feature. Claiming that Xerox copied that feature Apple, as you've just gone and done, is complete nonsense. Even in the first commericial version of the Star that shipped "without" overlapping windows, that only applied to application windows, because property windows did overlap the application windows.
(ignoring facts like a single volcanic eruption spews out 500 times as much as greenhouse gases as man has every produced).
Except that's not a fact. A mere minute with google would have avoided your embarrassment.
Volcanic eruptions can enhance global warming by adding CO2 to the atmosphere. However, a far greater amount of CO2 is contributed to the atmosphere by human activities each year than by volcanic eruptions. Volcanoes contribute about 110 million tons/year, whereas other sources contribute about 10 billion tons/year. --
http://www.geology.sdsu.edu/how_volcanoes_work/cli mate_effects.html
Apple pioneered the use of overlapping windows,... and the overall desktop metaphor
I think you are mistaken.
The foundations for the present form of graphical user interfaces were in the 1960s and 1970s. This thesis recalls the invention of the mouse by Doug Engelbart and Bill English, overlapping windows and popup menus by Alan Kay, and icons by David Canfield Smith. --
http://www.mprove.de/diplom/text/5_synopsis.html
Take a look at this picture of a Xerox Star desktop and tell me again that Apple invented overlapping windows and the desktop metaphor. Those icons in the bottom right look like Manilla folders. One of the icons is titled Blank Canvas. There's an in-tray at the top right of the picture. It's without doubt an implementation of the desktop metaphor, which had been proposed in academic papers as far back as the 60s. I recommend this excellent history of the GUI.
Uh, yeah, or do you think it's a coincidence that your Windows and Linux apps all have a "File Edit View Tools Window Help" menubar, your desktop has a trash can of some sort, a control panel of some sort, unified print and save dialogs, cut-and-paste (even the term "cut-and-paste" itself), your windows have a close and maximize button, and on and on and on and on...
I think you have misunderstood the point that was being made. There is no dispute that the Mac UI was influential. The mistake is in thinking it was revolutionary. The Mac UI was an evolutionary improvement based upon decades of work by Bush, Engelbart, Kay and others. I don't think you can successfully argue otherwise.
The Macintosh was not the first personal computer, but it had a revolutionary new user interface.
The original Mac UI wasn't revolutionary, it was evolutionary. A large number of individuals and companies were working on graphical user interfaces at the time. The concepts of menus, scrollbars, viewports, cursors and so on were pioneered and implemented in the 60s. Several products either existed (Star) or were nearly ready (GEM, GeOS, AmigaOS) when MacOS arrived.
Revolutionary implies that the Mac UI made everybody change their direction. The reality is that the industry had changed direction years earlier. All the major PC/workstation companies (Digital, IBM, Commodore, Sun) were investing in graphical UIs. Apple was simply early to market. That's not revolutionary; that's the result of having a small dedicated team and a boss that drove them like slaves.
Computers connected via Ethernet don't need to have their clocks synched in order to work.
Ethernet does rely on synchronised clocks. You might be misstating that Ethernet doesn't have a clock line, meaning there is no dedicated wire with a clock signal on it.
There is a high-precision clock on every Ethernet card. An Ethernet frame has a 64-bit preamble with Manchester encoding. That preamble adjusts the skew of the receiver clock so that it's synchronised with the transmitter clock. If the synchronisation didn't occur, you wouldn't know when to latch the data on the line and you couldn't receive a frame. The synchronisation occurs on every Ethernet frame and the precision of the clock must be high enough that the synchronisation lasts for the length of a frame.
Async architectures will likely use a similar technique. The subsystems won't be driven by a system-wide clock line, as in the existing synchronous architectures, but the various clocks in subsystems will certainly be synchronised.
Slashdot Mirror
Sure. I wasn't disagreeing with you, just expanding on the point.
The stair-steps are very real and you are correct - a typical DAC will produce an output with those steps - however those steps have sharp edges which means they have extremely high frequencies. In fact, a step will have harmonics extending to infinity (albeit at constantly reducing volume). That's why every CD player has an output filter that removes frequencies above approximately 20kHz. This will "smooth" the stair-steps into a non-jaggy signal.
Now what's interesting is that the smoothing effect is not lossy! The stair steps have undesirable harmonics but the DAC introduced no new frequencies below 22.05kHz. That's right, the DAC only creates high-frequency harmonics that weren't in the original signal (NB: disclaimer below), so when you remove those harmonics with the filter you are not losing anything. The combination of the stair-step DAC and the low-pass filter is a perfect reproduction of the original signal.
The above discussion all assumes perfect filters and perfect DACs combined with perfect sampling. In practise that's impossible so there are other considerations (eg, spikes, jitter, quantisation, aliasing). But the important thing to walk away with is that your intuitive feel about stair-steps is incorrect. Admittedly you need to do a lot of maths before this becomes intuitive.
That's true for theoretical conditions but in practise it's not quite that good. The maths assumes infinitely precise sample resolution and perfect sampling points. In practise a CD is limited to 16-bit resolution and due to the vagaries of electronics the sampling points will often drift by a microsecond or two from their ideal times.
That's why when they master the CD they purposefully use a low-pass filter to cut-off the frequencies above approximately 20kHz. They lose 2kHz of frequency range that theoretically could be stored on the CD, though nobody can hear much in that range anyway so it's not a big loss. This is also why 20-bit and 24-bit recordings at 96kHz are considered useful. It's not because audiophiles (morons) have ears that can hear dog-whistle frequencies, but because it allows the encoding/decoding electronics to be simpler (simpler analogue filters) and therefore cheaper.
Microsoft intentionally modified the core classes in their JVM by adding Windows-specific methods and attributes. Sun asked Microsoft to leave the core classes alone and use subclasses for platform-specifics. Microsoft refused. Sun sued. Microsoft settled to the tune of $2billion, but that was after many years and Java had effectively been hobbled the entire time.
Business as usual for Microsoft.
And it sounds like an advertising message.
We've been inundated recently with Xbox stories and they're suspicious. For a start, the spelling and grammar has been too good. Look at that sentence above: the word "its" doesn't have the customary (yet incorrect) Slashdot apostrophe. The paragraph cuts to the point and is coherent. It is entirely unlikely anything I normally read on Slashdot.
Only 24 hours ago was another story where Allard was saying there would be shortages. The very unsubtle message from Allard was "Buy your Xbox 360(tm) immediately because otherwise you'll miss out". Another uncharacteristic story that reeked like a hidden advertisment.
24 hours before that, another Xbox story. I don't even recall what it was about, I just know that each day I open Slashdot and there's another fucking Xbox story. This looks to me like an astroturfing campaign. Microsoft has done this before and I wouldn't be surprised if they're doing it again.
... once Google has completed its 300 year mission, it will reduce the Empire's fall to barbarism from 30,000 years to a mere 1,000 years.
I recently decided to try out Eclipse - after hearing how brilliant it was - to replace Anjuta for C++ development. I notice an eclipse package is in Debian so I "apt-get install eclipse-sdk". Oh, it needs a Java SDK first. No worries, I'll just install one of those using apt. I'm sure this will be easy.
Easy? Hah! Maybe it's easy for x86 users but us PPC users are out in the cold. After hours of fruitless searching I eventually chance upon the IBM Java SDK on the IBM website. It's only in RPM format, but a quick "alien" later and I have a package. I install it, go to run it, and the JRE crashes.
So I simply delete the Java SDK and any hopes of using Eclipse on Linux/PPC. I'm not going to jump through hoops; if it doesn't "apt-get install" then I don't want to know about it.
Is "superseeding" some sort of torrent terminology I was previously unaware of?
Dude, this is Australia. The only ferocious animals to hunt in Australia are wild pigs and crazed rabbits. It's possibly the first big cat the hunter has ever seen, so it's no surprise he couldn't identify it.
I disagree. I think OSS will win in the long run simply because there are zealots who will happily slit your throat for you, metaphorically speaking. You can't compete with free. Not when the quality of software is this high. The OSS stuff is sometimes better, sometimes worse, but on average it's competitive with non-OSS software. Then it all comes down to price and at that point you cannot win.
Combine that with industry collaboration - companies like Novell, Sun and IBM throwing their weight behind OSS, seemingly to harm Microsoft - and there is a huge pool of funded OSS. That's right, developers writing OSS while still supporting "one's spouse and children". You can't compete with that, so you might as well stop complaining and get on the bandwagon.
Or do what I did and get out of paid development, because it has a limited future as far as I'm concerned.
You are wrong. So very very wrong.
In the old days, I did electronic banking using a fat client. It was a DOS executable that had a proprietary protocol over a dedicated leased line (serial) to the bank. That's all gone now, replaced with a much better thin client (Firefox).
I can buy my groceries online! I've done it once to see what it was like. I didn't have to install a fat client, or an executable, or anything complicated. I just logon to a webpage using my thin client (Firefox) and click on the groceries I want. They arrive on my doorstep within 8 hours.
In the old days we used to chat with each other using a variety of fat clients: news readers, chat programs, bbs frontends. They still exist - inertia is a horrendous thing - but by preference I use software-agnostic blogs like Slashdot and Fark. The fat clients have been replaced with web-apps that I access through my thin client (Firefox).
Chat programs, online banking, internet shopping, travel reservations, email (gmail/hotmail), server management (webmin, cups), embedded client access (linksys anything). At one time the ony way to access those applications was with fat clients, typically written for specific platforms like Windows or DOS. Now I access them all using a thin client (Firefox).
My desktop would actually be useless without a browser. I spend more than 75% of my work time in the browser. The network management console is browser based. The IDS is browser based. The time tracking system is browser based. The invoicing system is browser based. My mail is browser based. The bug-tracking system is browser based. The collaboration system (a wiki) is browser based. Half the network equipment is managed through a browser. Without a browser, I would have literally dozens of platform-specific applications that would need to be installed by Desktop Support. Instead, in the morning I start a single desktop application, Firefox.
Thin clients have taken off and the Web has replaced many desktop applications. Your empathic claims to the contrary are wrong because they are overstated.
Software engineers are not engineers. They are computer programmers in denial.
Zero
Factor
Care
It's stable but it leaks disk. Shows that are deleted while being transcoded never have their file handles properly closed, so the space doesn't get freed. That's in an old release - the dev trees might have fixed the bug.
Their reasoning is extremely sound. If Microsoft Office supported the OASIS formats, then that would ease the transition from Microsoft Word to any number of other word processors. I've heard that 11 word processors now support OASIS, including a commercial product from IBM.
Microsoft isn't being stupid. They know that their success is tied to Office, and that the reason people stick with Office is because it's insanely difficult to switch to other word processors because of the cost of converting existing data. Microsoft "owns" the DOC format and so they own the market.
If Microsoft supported the OASIS format then they'd have to compete on merit. Don't expect them to enter that space willingly.
WARNING: Do not attempt to stop shotgun pellet while wearing polycarb safety glasses.
I don't have a cable box, so I don't have direct experience with this, but the solution is an IR Blaster which MythTV can use to change the channel on the cable box. If you google "mythtv ir blaster" you'll find plenty of websites with instructions.
Sure, I've had a stable MythTV server for over 12 months. I've got 350GB striped storage, DVB tuners and multiple frontends (Mac, Xbox, Laptop).
Easy.
That last lesson is the hardest to learn. Once you stop "tweaking" the damn thing, it stops breaking.
The early prototypes of the Xerox Star did have overlapping windows. From the page that I linked to in my previous comment.
I'll spell it out for you: they had overlapping windows, their testing showed it was confusing, they disabled the feature. Claiming that Xerox copied that feature Apple, as you've just gone and done, is complete nonsense. Even in the first commericial version of the Star that shipped "without" overlapping windows, that only applied to application windows, because property windows did overlap the application windows.
Except that's not a fact. A mere minute with google would have avoided your embarrassment.
I think you are mistaken.
Take a look at this picture of a Xerox Star desktop and tell me again that Apple invented overlapping windows and the desktop metaphor. Those icons in the bottom right look like Manilla folders. One of the icons is titled Blank Canvas. There's an in-tray at the top right of the picture. It's without doubt an implementation of the desktop metaphor, which had been proposed in academic papers as far back as the 60s. I recommend this excellent history of the GUI.
I think you have misunderstood the point that was being made. There is no dispute that the Mac UI was influential. The mistake is in thinking it was revolutionary. The Mac UI was an evolutionary improvement based upon decades of work by Bush, Engelbart, Kay and others. I don't think you can successfully argue otherwise.
The original Mac UI wasn't revolutionary, it was evolutionary. A large number of individuals and companies were working on graphical user interfaces at the time. The concepts of menus, scrollbars, viewports, cursors and so on were pioneered and implemented in the 60s. Several products either existed (Star) or were nearly ready (GEM, GeOS, AmigaOS) when MacOS arrived.
Revolutionary implies that the Mac UI made everybody change their direction. The reality is that the industry had changed direction years earlier. All the major PC/workstation companies (Digital, IBM, Commodore, Sun) were investing in graphical UIs. Apple was simply early to market. That's not revolutionary; that's the result of having a small dedicated team and a boss that drove them like slaves.
Ethernet does rely on synchronised clocks. You might be misstating that Ethernet doesn't have a clock line, meaning there is no dedicated wire with a clock signal on it.
There is a high-precision clock on every Ethernet card. An Ethernet frame has a 64-bit preamble with Manchester encoding. That preamble adjusts the skew of the receiver clock so that it's synchronised with the transmitter clock. If the synchronisation didn't occur, you wouldn't know when to latch the data on the line and you couldn't receive a frame. The synchronisation occurs on every Ethernet frame and the precision of the clock must be high enough that the synchronisation lasts for the length of a frame.
Async architectures will likely use a similar technique. The subsystems won't be driven by a system-wide clock line, as in the existing synchronous architectures, but the various clocks in subsystems will certainly be synchronised.