Sigh, another April 1, and another visitation of the annual useless Slashdot day is upon us. It's Friday so expect more than the usual crop of articles like this.
Is Friendster making phones now? The only reason I ask is that I'm puzzled how this article could have be categorized under Hardware. I know the Slashdot category taxonomy calls for this but communications is a universe of concepts beyond merely hardware.
Remote desktops on Linux have been a persistent and annoying problem for a few reasons. Two obvious answers people usually give are "Use VNC and "Use X Windows" but the heart of the problem is in the configuration and setup of these tools and it doesn't address the TS/Citrix and XDCMP method of starting up independent sessions for multiple users.
When I had to jump around from building to building in order to support developers using my software I worked out a solution that I was very happy with. I didn't have to install anything on the client and I had persistent desktop that I could access from anywhere--even from home via SSH tunnel.
The solution is to start up Xvnc but instead of running the usual X clients you start up XDM (or GDM or KDM). Additionally, but not required, enable the Java HTTP listener so you can use your desktop from any location.
When you turn on your computer VNC starts up in the background with a traditional XDM login screen. I preferred to use the lightweight and relatively secure XDM with XDCMP turned off. I think some versions of Red Hat have GDM if you enable the VNC service. You visit your computer with any Java-enabled web browser and are presented with a familiar X Windows login screen and can log in and do your thing.
The big limitation is that you can only support one user in this fashion. I presume that what you wanted is an application server a la Citrix Metaframe (or the less popular Microsoft Terminal Server in Application mode) when you have multiple users log in remotely to run applications on one machine. For that, you need multiple VNC sessions and it's not really easy to get the computer to understand that you are "user1" wanting to connect to a new desktop session as opposed to "user2" who wants to connect to an existing and already-running desktop session.
I am not sure what I was doing wrong on Windows 2000 Server but I was never able to reconnect with a session that was supposedly still running. I deduced that the session timed out after 30 minutes (admins don't like zombie Terminal Server sessions, naturally).
I'm going out on a limb but I suppose it might be an interesting project to develop a smart VNC server session hosting thinger--users are presented with a login screen and given the option to connect to an existing session if it already exists or a new session if one doesn't. I think running VNC off of inetd along with screen number randomization is a good start. I'm excited to see if anyone knows if such a product exists already.
I guess it's slightly off-topic but if all you want to do is connect to a Windows Terminal Server from Linux you can use an open-source project called "rdesktop." It implements the RDP protocol fairly well but has big trouble with keyboard mapping and that's an entirely differnet topic.
Back when it was easy to get Socket 370 VIA C3 processors I built several computers based on them between 600 and 1000 MHz with bus clocks at 100 and 133 MHz. I found that even the 667 and 800 MHz C3 CPUs at 133 MHz bus had significant performance gains over the 100 MHz bus counterparts at the same rated internal clock speed. I finally settled on 800 MHz at 133 MHz bus. The systems are faster than the 1000 MHz at 100 MHz bus. I stopped caring around the time the Ezra-T came out because then the EPIAs started coming out.
SiSoft Sandra clocks the 800 MHz at 133 MHz as equivalent to a 600 MHz Pentium 3 but the memory bandwitch is much, much higher by about 30%. That's enough to make an integrated video motherboard a perfect desktop computer for web, office applications, and MAME gaming. For $25 per CPU that's not terribly bad! Some of the motherboards I got from Tigerdirect.com were $30 with embedded C3 processor for 667 MHa and 800 MHz at 130 MHz bus. Not terrible at all.
If you're not talking about economical computing then look elsewhere.
While you will be able to find some IAX and IAX2-compatible units around, they aren't cheap, and they aren't plentiful. The trend is to use IAX/IAX2 for the trunking and plain old SIP for the desk sets.
Add some cheap SIP hardware from voipsupply.com
on
Build Your Own PBX
·
· Score: 3, Informative
Not a commercial, but you can add regular telephones to this great PBX system by going to www.voipsupply.com Most consumer SIP equipment is locked for Vonage, CallVantage, or Net2Phone. This shop sells non-configured versions which you can simply plug into your network, configure, and go. There are single- and dual-port analog adapters with FSX support, and fairly nice (and cheap) desktop phone sets, all SIP compatible.
KDE realized this years ago and moved to the lightweight DCOP for inter-process communications. Come on, GNOME team, CORBA is for inter-computer communications and should be abandoned immediately in favor of a lightweight replacement. Bonobo doesn't count.
One who knows about such things was discussing this with me just the other day. It was in respect to digital communications. There is RS-232 which is always +/- 5, 10, 12, or 15 volts (depending on what kind of power is in the system) and measures voltage drop for the bits. The limitation is that you can only send 15 volts so many feet of cable before the gauge gets too low (or high, depending on how you look at it) to be practical--the cable just gets too thick for reliable communications.
The alternative at that time was to use high voltage cables and modulate the current. This way they could send the signal over arbitrarily long distances--they just needed to increase the voltage. Even this had limitations: 50 milliamps at 15,000 volts?!
This information is relevant to demonstrate that if you want to send high current through DC you're going to need to increase the gauge of the wire. You might notice that the wires coming out of your power supply in your computer are rather short wires. Some of those wires are carrying 30 amps at 12 volts and it gets mighty unreliable after travelling what seems a short distance.
Are you putting your computers in a big stack with very short cables? You're not going to be able to send the 30 amps at 5V to one component without some seriously thick cable. I don't even know how much noise shielding you'd need because this sounds dangerous already. You will need to purchase special DC-to-DC adapters, anyway, them as the commercially-accepted DC power sources today are 48 volts. Since you want to feed your components from one source I'd also worry about keeping the current and voltage constant for every component because the more components you add to the circuit both the current and voltage will change and it could affect the reliability of the components.
Economically it appears not to make sense.
Wikipedia could do without the commentary
on
FUD-Based Encyclopedias
·
· Score: 3, Informative
Wikipedia could do without the commentary and gonzo-style reporting in the articles, even in areas as mundane as satellite communications.
Contrary to popular belief, digital C band does in fact[sic] exist.
And another passage which is not only inflammatory but factually incorrect:
This contrasts with direct broadcast satellite, which is a completely closed system used to deliver subscription programming to small satellite dishes connected to proprietary receiving equipment.
Note this anecdotal comment that the author, whoever it may be (there is no way to tell) had evidently pulled out of thin air:
Service is generally spotty and expensive, but it generally superior to dial-up service and is often the only option.
Over in an article on the use of L Band, there is a curious comment about how its allocation affects satellite radio but the entry doesn't offer any supporting facts.
In the U.S., the L band is held by the U.S. Military for telemetry, thereby forcing digital radio to in-band on-channel (IBOC) solutions.
Television receive-only, or TVRO, refers to satellite television reception equipment that is based primarily on open standards equipment. This contrasts sharply with direct broadcast satellite (DBS), which is a completely closed system that uses proprietary reception equipment.
I'm sure this kind of commentary cannot help Wikipedia's credibility. Wikipedia needs a huge content enema.
Cool, my point however is that the economies of scale (lots of generic SIP hardware) brings the cost of SIP down. For better or worse the industry has decided on SIP and not IAX.
THe disabling of JavaScript would have made it possible to use Gecko to render HTML in things like instant messages and email. Without this possibility you'd need to filter every conceivable security exploit on the server-side. The solution is to not use Gecko (oh well).
Well, this isn't technically true or necessary anymore.
Asterisk was a vehicle to get people to buy Digium products that interface the telephones with the PBX, and interface the PBX with the telcom lines (PRI, T1, etc.).
Now that you can purchase SIP-to-POTS adapters for $50 and real SIP desk phones for under $70 from www.voipsupply.com and hook them directly into your network, there really isn't a need for Asterisk anymore. We really needed and wanted a pure SIP solution.
Asterisk wants to use its IAX protocol for PBX communications which admittedly is a nice lightweight protocol but isn't standardized and you cannot buy affordable IAX-compatible products. If you're building a medium-to-large PBX and want to tie yourself into Digium hardware you can get a deal on the the PCI cards that interface Asterisk with PRI and T1 lines. Forget the IAX-to-POTS adapters (for your analog desk phone)--they are horribly expensive compared to the $50 2-line SIP adapters you get from VoIPSupply.com. Of course Asterisk will talk SIP but it really wants you to talk IAX and it will gateway the SIP to IAX protocol, imposing a slight, but sometimes significant, delay in voice communications which is never acceptible.
Thank you SIPfoundry for the sipX project! I have been looking for alternatives to the Asterisk product for a long time. The key to affordable technology is commodity hardware based on standards. I can't argue with that.
One of the two things that a large ISP didn't like about Mozilla was the fact that it required 18 megabytes of memory just to run the Gecko engine so they stuck with their own renderer for "rich text" email and other UI elements.
The second thing they didn't like was the total inability to remove JavaScript from the product. JavaScript is (evidently) required to render HTML pages by Gecko.
While there are a few notable exceptions where existing trade-secret software packages are released into Open Source, such as AOLserver, Netscape, and Solaris, much effort is expended into producing unencumbered versions of existing proprietry software projects. The many Open Source projects such as glibc, HURD, GNOME, OpenSSL are duplicates of existing technologies. I do not see how these projects are innovative except for being in themselves unencumbered versions of existing, known-good, encumbered products. In the linguistics field there is a move to produce a duplicate of an existing, proprietary pronunciation lexicon; there is nothing better than the "free" version except that it's "free". In fact, the "free" version is very unlikely to become a viable alternative. Imagine if that effort could be used elsewhere how much further along we might be?
At the same time, the important technologies that are in Solaris, AOLserver, or Netscape are truly innovative. The improvements that go into these projects are even more so.
Unfortunately too much effort is spent to produce unencumbered clones of known-good projects.
Taiwanese manufacturer makes the "Zippy" keyboards that can be had for under $25 at www.directron.com and other vendors. If you happen to be in HK they cost as low as US$6 each.
I have a collection of SIIG Minitouch Plus low-profile keyboards. They are slightly more than $25 but are the perfect form-factor. They have a full-sized CAPSLOCK key suitable for use as a CTRL key.
There is typically a 4-year vesting schedule. What is the vesting schedule for Google? Surely they are worth $1 million on paper, but how much will they actually be worth at year 1, 2, 3, and 4 on the customary 4-year vesting schedule?
The human resource costs of supporting Linux systems that aren't directly supported by a major hardware vendor can be high. What experiences have people had with vendors that really, truly, officially support Linux? I haven't seen too much direct support from the likes of Dell or Toshiba, especially when it comes to Laptops.
I'm rather concerned of the trend in today's journalism where the news aggregate is quoted as reporting something when it's really the Associated Press that is reporting something.
Get your citations straight! Don't be like the radio!
And, in fact, the original design would split in half without warning. The remedy was to install a steel collar around the entire ship. So much for quality. Very few people talk about quality, or lack thereof, in the Liberty Ships, but as the other poster noted the quality was not necessary to achieve the ships' intended purpose.
I think the figures are confused by the authors of the stories. The column of mud/water/metal would be 1,000ft (0.3km) high and 10,000ft (3km) wide according to one story, and vice-versa in another. Which set of figures do you think is true?
Does this mean that AMD is phasing out the Cyrix MediaGX GEODE platform in favor of an Athlon/NexGen-based platform? Do they keep the Cx55x0 companion chipset or does it also go away?
I think that Sun can bring much valuable technology to Apple, especially the technology, such as a 64-bit clean operating system, that Apple has had trouble implementing. Solaris is one of the more portable commercial Unix variants. The SunOS 5 revision of SunOS was designed explicitly for portability and modernization including the ability to run on 64-bit processors in 64-bit mode. Apple has still not yet done that. With a purchase of Sun, Apple gets a 64-bit clean POSIX-compliant architecture that runs on desktops and servers. Apple finally gets a serious server product and 64-bit bragging rights. And at today's prices Sun is a steal. Plus, Apple finally gets the attention they deserve with Java and have a useful Java environment on both the desktop and server. Finally, Apple can easily move onto whatever 64-bit architecture they desire with impunity given the 64-bit clean nature of Solaris--something, again, the bastardized FreeBSD/Mach that the NeXT developers have been desperately hacking to support today's OSX product, cannot yet do.
Slashdot Mirror
Sigh, another April 1, and another visitation of the annual useless Slashdot day is upon us. It's Friday so expect more than the usual crop of articles like this.
Is Friendster making phones now? The only reason I ask is that I'm puzzled how this article could have be categorized under Hardware. I know the Slashdot category taxonomy calls for this but communications is a universe of concepts beyond merely hardware.
Am I missing some obvious reason that you're using AFP and APF acronyms interchangeably? The wire service's name is AFP.
Remote desktops on Linux have been a persistent and annoying problem for a few reasons. Two obvious answers people usually give are "Use VNC and "Use X Windows" but the heart of the problem is in the configuration and setup of these tools and it doesn't address the TS/Citrix and XDCMP method of starting up independent sessions for multiple users.
When I had to jump around from building to building in order to support developers using my software I worked out a solution that I was very happy with. I didn't have to install anything on the client and I had persistent desktop that I could access from anywhere--even from home via SSH tunnel.
The solution is to start up Xvnc but instead of running the usual X clients you start up XDM (or GDM or KDM). Additionally, but not required, enable the Java HTTP listener so you can use your desktop from any location.
When you turn on your computer VNC starts up in the background with a traditional XDM login screen. I preferred to use the lightweight and relatively secure XDM with XDCMP turned off. I think some versions of Red Hat have GDM if you enable the VNC service. You visit your computer with any Java-enabled web browser and are presented with a familiar X Windows login screen and can log in and do your thing.
The big limitation is that you can only support one user in this fashion. I presume that what you wanted is an application server a la Citrix Metaframe (or the less popular Microsoft Terminal Server in Application mode) when you have multiple users log in remotely to run applications on one machine. For that, you need multiple VNC sessions and it's not really easy to get the computer to understand that you are "user1" wanting to connect to a new desktop session as opposed to "user2" who wants to connect to an existing and already-running desktop session.
I am not sure what I was doing wrong on Windows 2000 Server but I was never able to reconnect with a session that was supposedly still running. I deduced that the session timed out after 30 minutes (admins don't like zombie Terminal Server sessions, naturally).
I'm going out on a limb but I suppose it might be an interesting project to develop a smart VNC server session hosting thinger--users are presented with a login screen and given the option to connect to an existing session if it already exists or a new session if one doesn't. I think running VNC off of inetd along with screen number randomization is a good start. I'm excited to see if anyone knows if such a product exists already.
I guess it's slightly off-topic but if all you want to do is connect to a Windows Terminal Server from Linux you can use an open-source project called "rdesktop." It implements the RDP protocol fairly well but has big trouble with keyboard mapping and that's an entirely differnet topic.
Kris
Back when it was easy to get Socket 370 VIA C3 processors I built several computers based on them between 600 and 1000 MHz with bus clocks at 100 and 133 MHz. I found that even the 667 and 800 MHz C3 CPUs at 133 MHz bus had significant performance gains over the 100 MHz bus counterparts at the same rated internal clock speed. I finally settled on 800 MHz at 133 MHz bus. The systems are faster than the 1000 MHz at 100 MHz bus. I stopped caring around the time the Ezra-T came out because then the EPIAs started coming out.
SiSoft Sandra clocks the 800 MHz at 133 MHz as equivalent to a 600 MHz Pentium 3 but the memory bandwitch is much, much higher by about 30%. That's enough to make an integrated video motherboard a perfect desktop computer for web, office applications, and MAME gaming. For $25 per CPU that's not terribly bad! Some of the motherboards I got from Tigerdirect.com were $30 with embedded C3 processor for 667 MHa and 800 MHz at 130 MHz bus. Not terrible at all.
If you're not talking about economical computing then look elsewhere.
While you will be able to find some IAX and IAX2-compatible units around, they aren't cheap, and they aren't plentiful. The trend is to use IAX/IAX2 for the trunking and plain old SIP for the desk sets.
Not a commercial, but you can add regular telephones to this great PBX system by going to www.voipsupply.com Most consumer SIP equipment is locked for Vonage, CallVantage, or Net2Phone. This shop sells non-configured versions which you can simply plug into your network, configure, and go. There are single- and dual-port analog adapters with FSX support, and fairly nice (and cheap) desktop phone sets, all SIP compatible.
KDE realized this years ago and moved to the lightweight DCOP for inter-process communications. Come on, GNOME team, CORBA is for inter-computer communications and should be abandoned immediately in favor of a lightweight replacement. Bonobo doesn't count.
One who knows about such things was discussing this with me just the other day. It was in respect to digital communications. There is RS-232 which is always +/- 5, 10, 12, or 15 volts (depending on what kind of power is in the system) and measures voltage drop for the bits. The limitation is that you can only send 15 volts so many feet of cable before the gauge gets too low (or high, depending on how you look at it) to be practical--the cable just gets too thick for reliable communications.
The alternative at that time was to use high voltage cables and modulate the current. This way they could send the signal over arbitrarily long distances--they just needed to increase the voltage. Even this had limitations: 50 milliamps at 15,000 volts?!
This information is relevant to demonstrate that if you want to send high current through DC you're going to need to increase the gauge of the wire. You might notice that the wires coming out of your power supply in your computer are rather short wires. Some of those wires are carrying 30 amps at 12 volts and it gets mighty unreliable after travelling what seems a short distance.
Are you putting your computers in a big stack with very short cables? You're not going to be able to send the 30 amps at 5V to one component without some seriously thick cable. I don't even know how much noise shielding you'd need because this sounds dangerous already. You will need to purchase special DC-to-DC adapters, anyway, them as the commercially-accepted DC power sources today are 48 volts. Since you want to feed your components from one source I'd also worry about keeping the current and voltage constant for every component because the more components you add to the circuit both the current and voltage will change and it could affect the reliability of the components.
Economically it appears not to make sense.
Witness the article about Satellite C Band:
And another passage which is not only inflammatory but factually incorrect:
Note this anecdotal comment that the author, whoever it may be (there is no way to tell) had evidently pulled out of thin air:
Over in an article on the use of L Band, there is a curious comment about how its allocation affects satellite radio but the entry doesn't offer any supporting facts.
Another article about Television receive-only satellite has an opening sentence that is even worse:
I'm sure this kind of commentary cannot help Wikipedia's credibility. Wikipedia needs a huge content enema.
Cool, my point however is that the economies of scale (lots of generic SIP hardware) brings the cost of SIP down. For better or worse the industry has decided on SIP and not IAX.
Kris
THe disabling of JavaScript would have made it possible to use Gecko to render HTML in things like instant messages and email. Without this possibility you'd need to filter every conceivable security exploit on the server-side. The solution is to not use Gecko (oh well).
Well, this isn't technically true or necessary anymore.
Asterisk was a vehicle to get people to buy Digium products that interface the telephones with the PBX, and interface the PBX with the telcom lines (PRI, T1, etc.).
Now that you can purchase SIP-to-POTS adapters for $50 and real SIP desk phones for under $70 from www.voipsupply.com and hook them directly into your network, there really isn't a need for Asterisk anymore. We really needed and wanted a pure SIP solution.
Asterisk wants to use its IAX protocol for PBX communications which admittedly is a nice lightweight protocol but isn't standardized and you cannot buy affordable IAX-compatible products. If you're building a medium-to-large PBX and want to tie yourself into Digium hardware you can get a deal on the the PCI cards that interface Asterisk with PRI and T1 lines. Forget the IAX-to-POTS adapters (for your analog desk phone)--they are horribly expensive compared to the $50 2-line SIP adapters you get from VoIPSupply.com. Of course Asterisk will talk SIP but it really wants you to talk IAX and it will gateway the SIP to IAX protocol, imposing a slight, but sometimes significant, delay in voice communications which is never acceptible.
Thank you SIPfoundry for the sipX project! I have been looking for alternatives to the Asterisk product for a long time. The key to affordable technology is commodity hardware based on standards. I can't argue with that.
One of the two things that a large ISP didn't like about Mozilla was the fact that it required 18 megabytes of memory just to run the Gecko engine so they stuck with their own renderer for "rich text" email and other UI elements.
The second thing they didn't like was the total inability to remove JavaScript from the product. JavaScript is (evidently) required to render HTML pages by Gecko.
I guess one out of two ain't bad.
While there are a few notable exceptions where existing trade-secret software packages are released into Open Source, such as AOLserver, Netscape, and Solaris, much effort is expended into producing unencumbered versions of existing proprietry software projects. The many Open Source projects such as glibc, HURD, GNOME, OpenSSL are duplicates of existing technologies. I do not see how these projects are innovative except for being in themselves unencumbered versions of existing, known-good, encumbered products. In the linguistics field there is a move to produce a duplicate of an existing, proprietary pronunciation lexicon; there is nothing better than the "free" version except that it's "free". In fact, the "free" version is very unlikely to become a viable alternative. Imagine if that effort could be used elsewhere how much further along we might be?
At the same time, the important technologies that are in Solaris, AOLserver, or Netscape are truly innovative. The improvements that go into these projects are even more so.
Unfortunately too much effort is spent to produce unencumbered clones of known-good projects.
Taiwanese manufacturer makes the "Zippy" keyboards that can be had for under $25 at www.directron.com and other vendors. If you happen to be in HK they cost as low as US$6 each.
Kris
I have a collection of SIIG Minitouch Plus low-profile keyboards. They are slightly more than $25 but are the perfect form-factor. They have a full-sized CAPSLOCK key suitable for use as a CTRL key.
Kris
There is typically a 4-year vesting schedule. What is the vesting schedule for Google? Surely they are worth $1 million on paper, but how much will they actually be worth at year 1, 2, 3, and 4 on the customary 4-year vesting schedule?
Kris
The human resource costs of supporting Linux systems that aren't directly supported by a major hardware vendor can be high. What experiences have people had with vendors that really, truly, officially support Linux? I haven't seen too much direct support from the likes of Dell or Toshiba, especially when it comes to Laptops.
Kris
I'm rather concerned of the trend in today's journalism where the news aggregate is quoted as reporting something when it's really the Associated Press that is reporting something.
Get your citations straight! Don't be like the radio!
It's a Homelink transmitter for turning on lights, opening garage doors, etc.
And, in fact, the original design would split in half without warning. The remedy was to install a steel collar around the entire ship. So much for quality. Very few people talk about quality, or lack thereof, in the Liberty Ships, but as the other poster noted the quality was not necessary to achieve the ships' intended purpose.
Kris
I think the figures are confused by the authors of the stories. The column of mud/water/metal would be 1,000ft (0.3km) high and 10,000ft (3km) wide according to one story, and vice-versa in another. Which set of figures do you think is true?
Does this mean that AMD is phasing out the Cyrix MediaGX GEODE platform in favor of an Athlon/NexGen-based platform? Do they keep the Cx55x0 companion chipset or does it also go away?
I think that Sun can bring much valuable technology to Apple, especially the technology, such as a 64-bit clean operating system, that Apple has had trouble implementing. Solaris is one of the more portable commercial Unix variants. The SunOS 5 revision of SunOS was designed explicitly for portability and modernization including the ability to run on 64-bit processors in 64-bit mode. Apple has still not yet done that. With a purchase of Sun, Apple gets a 64-bit clean POSIX-compliant architecture that runs on desktops and servers. Apple finally gets a serious server product and 64-bit bragging rights. And at today's prices Sun is a steal. Plus, Apple finally gets the attention they deserve with Java and have a useful Java environment on both the desktop and server. Finally, Apple can easily move onto whatever 64-bit architecture they desire with impunity given the 64-bit clean nature of Solaris--something, again, the bastardized FreeBSD/Mach that the NeXT developers have been desperately hacking to support today's OSX product, cannot yet do.