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Groups > comp.lang.java.programmer > #20855 > unrolled thread
| Started by | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| First post | 2013-01-01 12:23 -0800 |
| Last post | 2013-01-16 15:09 -0800 |
| Articles | 20 on this page of 100 — 15 participants |
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single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-01 12:23 -0800
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-01 16:40 -0500
Re: single instance Robert Tomsick <robert+usenet@tomsick.net> - 2013-01-03 01:20 -0500
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-03 00:55 -0800
Re: single instance Knute Johnson <nospam@knutejohnson.com> - 2013-01-03 19:31 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-03 19:49 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-03 19:56 -0800
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-04 12:18 -0500
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-04 10:22 -0800
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-04 13:44 -0500
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-04 11:03 -0800
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-04 14:12 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-05 21:56 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 19:22 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 20:23 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 20:43 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 20:47 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 20:51 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 20:24 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 20:46 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 20:58 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 21:08 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 21:19 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 21:31 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 21:41 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 22:00 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 22:11 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-07 00:23 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-02-24 18:20 -0500
Re: single instance Joshua Cranmer <Pidgeot18@verizon.invalid> - 2013-01-06 21:39 -0600
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-07 00:30 -0500
Re: single instance lipska the kat <lipskathekat@yahoo.co.uk> - 2013-01-07 08:53 +0000
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-02-24 18:18 -0500
Re: single instance lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-25 08:31 +0000
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-02-24 18:17 -0500
Re: single instance Lew <lewbloch@gmail.com> - 2013-01-06 17:32 -0800
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 20:47 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 20:53 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 21:01 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-05 21:59 -0500
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 19:34 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 20:00 -0500
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-03 07:12 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-03 09:56 -0800
Re: single instance Martin Gregorie <martin@address-in-sig.invalid> - 2013-01-03 21:05 +0000
Re: single instance Martin Gregorie <martin@address-in-sig.invalid> - 2013-01-03 22:08 +0000
Re: single instance "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-01-05 12:48 +0000
Re: single instance Martin Gregorie <martin@address-in-sig.invalid> - 2013-01-05 17:43 +0000
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-05 09:49 -0800
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-05 13:02 -0500
Re: single instance Martin Gregorie <martin@address-in-sig.invalid> - 2013-01-05 20:29 +0000
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-05 19:07 -0800
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-06 20:04 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-05 21:40 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-05 22:10 -0500
Re: single instance Knute Johnson <nospam@knutejohnson.com> - 2013-01-05 19:49 -0800
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-05 23:09 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 11:00 -0500
Re: single instance Lew <lewbloch@gmail.com> - 2013-01-06 09:41 -0800
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 20:41 -0500
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-15 22:51 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-15 23:12 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-15 23:49 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-15 23:16 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-15 23:52 -0800
Re: single instance Knute Johnson <nospam@knutejohnson.com> - 2013-01-16 08:46 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-16 10:46 -0800
Re: single instance markspace <markspace@nospam.nospam> - 2013-01-16 13:01 -0800
Re: single instance Knute Johnson <nospam@knutejohnson.com> - 2013-01-16 17:10 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-15 23:50 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-16 00:13 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-16 02:48 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-16 07:28 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-16 10:46 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-16 16:53 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-16 23:44 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-17 07:03 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-17 14:25 -0800
Re: single instance Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-17 16:31 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-17 22:11 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-17 22:36 -0800
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-16 13:34 -0500
Re: single instance Knute Johnson <nospam@knutejohnson.com> - 2013-01-16 08:45 -0800
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-16 13:29 -0500
Re: single instance Knute Johnson <nospam@knutejohnson.com> - 2013-01-16 17:14 -0800
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-16 20:20 -0500
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-16 23:52 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-17 01:44 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-18 01:47 -0800
Re: single instance Knute Johnson <nospam@knutejohnson.com> - 2013-01-18 20:50 -0800
Re: single instance Roedy Green <see_website@mindprod.com.invalid> - 2013-01-20 00:53 -0800
Re: single instance Lew <lewbloch@gmail.com> - 2013-01-20 12:00 -0800
Re: single instance Knute Johnson <nospam@knutejohnson.com> - 2013-01-20 13:33 -0800
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-02-24 18:12 -0500
Re: single instance Arne Vajhøj <arne@vajhoej.dk> - 2013-01-20 21:33 -0500
Re: single instance "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-01-06 13:34 +0000
Re: single instance Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-01-04 10:26 -0800
Re: single instance Twirlip of the Mists <twirlip@killfile.me.now.invalid> - 2013-01-04 14:04 -0500
Re: single instance stledger@lanl.gov - 2013-01-16 14:51 -0800
Re: single instance stledger@lanl.gov - 2013-01-16 15:09 -0800
Page 4 of 5 — ← Prev page 1 2 3 [4] 5 Next page →
| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-15 22:51 -0800 |
| Message-ID | <vajcf81hgbr7sj6o79dlu8uphiknm6qs4f@4ax.com> |
| In reply to | #21010 |
On Sat, 05 Jan 2013 19:49:08 -0800, Knute Johnson <nospam@knutejohnson.com> wrote, quoted or indirectly quoted someone who said : > >The risk is, that in Windows anyway, where the system clock granularity >is 17ms it is possible to start two copies of a program with a batch I have been studying Knute's code and Peter's commentary hoping to come up with a canned package for ensuring single Instance. Using system.nanotime aught to help avoid granularity trouble. I am puzzled about "227.228.229.230" the IP used. Where did that value come from? Can this be made to work with IPV6? -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-15 23:12 -0800 |
| Message-ID | <pikcf8pnkfchvbnc8p9accls5eddpfcrdj@4ax.com> |
| In reply to | #21423 |
On Tue, 15 Jan 2013 22:51:45 -0800, Roedy Green <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted someone who said : > >I am puzzled about "227.228.229.230" the IP used. Where did that >value come from? Can this be made to work with IPV6? I discovered that 224.x.x.x - 239.x.x.x are reserved for IP multicast. I could pick a random number in the range, or is it ok that everyone uses the same IP or is it REQUIRED that everyone use the same IP -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> |
|---|---|
| Date | 2013-01-15 23:49 -0800 |
| Message-ID | <sytfjgl8wjt5$.14bwiza7lsfhw$.dlg@40tude.net> |
| In reply to | #21424 |
On Tue, 15 Jan 2013 23:12:12 -0800, Roedy Green wrote: > On Tue, 15 Jan 2013 22:51:45 -0800, Roedy Green > <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted > someone who said : > >> >>I am puzzled about "227.228.229.230" the IP used. Where did that >>value come from? Can this be made to work with IPV6? > > I discovered that 224.x.x.x - 239.x.x.x are reserved for IP multicast. > I could pick a random number in the range, or is it ok that everyone > uses the same IP or is it REQUIRED that everyone use the same IP If they want to receive multicast messages for a given group, they have to listen for them on that group's address (i.e. "required").
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-15 23:16 -0800 |
| Message-ID | <upkcf89mpoq2vapcshn44sdpo2hkjcvjlb@4ax.com> |
| In reply to | #21423 |
On Tue, 15 Jan 2013 22:51:45 -0800, Roedy Green <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted someone who said : > >I have been studying Knute's code and Peter's commentary hoping to >come up with a canned package for ensuring single Instance. If you had two machines on a LAN, would they prevent the other from running a new instance? You don't want, that, just on the same machine. If you wanted that behaviour -- e.g. to enforce a single instance licence across the LAN, what do you do have make the all one group? -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> |
|---|---|
| Date | 2013-01-15 23:52 -0800 |
| Message-ID | <1b36h02mtn70a.1or1v8j4itc7u.dlg@40tude.net> |
| In reply to | #21425 |
On Tue, 15 Jan 2013 23:16:56 -0800, Roedy Green wrote: > On Tue, 15 Jan 2013 22:51:45 -0800, Roedy Green > <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted > someone who said : > >> >>I have been studying Knute's code and Peter's commentary hoping to >>come up with a canned package for ensuring single Instance. > > If you had two machines on a LAN, would they prevent the other from > running a new instance? You don't want, that, just on the same > machine. > > If you wanted that behaviour -- e.g. to enforce a single instance > licence across the LAN, what do you do have make the all one group? One option is to compute the multicast group address from the machine's own local address. For example, on many LANs UDP broadcasts (including multicast) are not routed past the 255.255.255.0 subnet, and so you could just use the last octet of the IP address for the last octet of the multicast group address. Depending on the LAN topology, that or some variation on the idea could work. But more reliable would be to just transmit the machine's IP address as part of the app-singleton protocol you design, so that each recipient of the multicast address can distinguish between instances on the local machine and those elsewhere. Pete
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| From | Knute Johnson <nospam@knutejohnson.com> |
|---|---|
| Date | 2013-01-16 08:46 -0800 |
| Message-ID | <kd6lhj$go$2@dont-email.me> |
| In reply to | #21425 |
On 1/15/2013 11:16 PM, Roedy Green wrote: > On Tue, 15 Jan 2013 22:51:45 -0800, Roedy Green > <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted > someone who said : > >> >> I have been studying Knute's code and Peter's commentary hoping to >> come up with a canned package for ensuring single Instance. > > If you had two machines on a LAN, would they prevent the other from > running a new instance? You don't want, that, just on the same > machine. > > If you wanted that behaviour -- e.g. to enforce a single instance > licence across the LAN, what do you do have make the all one group? > Same IP and port. -- Knute Johnson
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-16 10:46 -0800 |
| Message-ID | <7ctdf85ci3ets58u7qf72vqt30orabna85@4ax.com> |
| In reply to | #21439 |
On Wed, 16 Jan 2013 08:46:42 -0800, Knute Johnson <nospam@knutejohnson.com> wrote, quoted or indirectly quoted someone who said : > >Same IP and port. But how far does this ripple? -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | markspace <markspace@nospam.nospam> |
|---|---|
| Date | 2013-01-16 13:01 -0800 |
| Message-ID | <kd74fg$bt3$1@dont-email.me> |
| In reply to | #21443 |
On 1/16/2013 10:46 AM, Roedy Green wrote: > On Wed, 16 Jan 2013 08:46:42 -0800, Knute Johnson > <nospam@knutejohnson.com> wrote, quoted or indirectly quoted someone > who said : > >> >> Same IP and port. > > But how far does this ripple? > As far as I know, it only works on your network segment. Only for machines connected to the same physical router or gateway. The multicast stuff is really more of a router protocol. A machine broadcasts to one or more addresses, and the routers along the way take care of passing the stream to interested client machines. Also note that as far as I know, absolutely no routers implement this. It's a dead protocol.
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| From | Knute Johnson <nospam@knutejohnson.com> |
|---|---|
| Date | 2013-01-16 17:10 -0800 |
| Message-ID | <kd7j2q$2di$1@dont-email.me> |
| In reply to | #21443 |
On 1/16/2013 10:46 AM, Roedy Green wrote: > On Wed, 16 Jan 2013 08:46:42 -0800, Knute Johnson > <nospam@knutejohnson.com> wrote, quoted or indirectly quoted someone > who said : > >> >> Same IP and port. > > But how far does this ripple? > Routers are the usual place that the Multicast packet is stopped. But you could certainly use it in your local network. -- Knute Johnson
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-15 23:50 -0800 |
| Message-ID | <hamcf85ejcefc9veso4dr08rb88tet8b9u@4ax.com> |
| In reply to | #21423 |
On Tue, 15 Jan 2013 22:51:45 -0800, Roedy Green <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted someone who said : > >I am puzzled about "227.228.229.230" the IP used. Where did that >value come from? Can this be made to work with IPV6? This is beginning to come clear. This the name of the group. Everyone sends and receives on the same socket on the same group. Just as you have a problem assigning an unused socket, you have assigning an unassigned group. I don't see how this works between machines yet. I think it should work like this: You ask the OS , please assign me a free port. Here is a UUID. If anyone asks for a port presenting the same UUID, please give him the same one, no matter if he is calling from within the machine or without. With such a scheme, you would not need reserved ports (except for the port assigning port), and you could not have collisions. Internally arrays of sockets could be dense. You can then hard code in UUIDs into apps. Users don't need to worry about collisions. Perhaps in IPV8. -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> |
|---|---|
| Date | 2013-01-16 00:13 -0800 |
| Message-ID | <pfudiv6pp55j.19556bqp3b6dg.dlg@40tude.net> |
| In reply to | #21427 |
On Tue, 15 Jan 2013 23:50:05 -0800, Roedy Green wrote: > On Tue, 15 Jan 2013 22:51:45 -0800, Roedy Green > <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted > someone who said : > >> >>I am puzzled about "227.228.229.230" the IP used. Where did that >>value come from? Can this be made to work with IPV6? > > This is beginning to come clear. This the name of the group. Everyone > sends and receives on the same socket on the same group. > > Just as you have a problem assigning an unused socket, you have > assigning an unassigned group. > > I don't see how this works between machines yet. See my other replies. > I think it should work like this: > > You ask the OS , please assign me a free port. Here is a UUID. If > anyone asks for a port presenting the same UUID, please give him the > same one, no matter if he is calling from within the machine or > without. With such a scheme, you would not need reserved ports > (except for the port assigning port), and you could not have > collisions. Internally arrays of sockets could be dense. You can > then hard code in UUIDs into apps. Users don't need to worry about > collisions. Perhaps in IPV8. Since the problem is solveable using the existing mechanisms, I don't see a compelling reason the above feature should be included in future versions of IP. Also, I'm no expert, but I'm not sure that any of the IP specifications concern themselves with ports at all. That might be at the TCP and UDP protocol levels, independent of the IP stuff. So neither IPv6 nor IPv8 _could_ address this issue. If we ever do get a new TCP and/or UDP in which there's a change to how ports work, I would expect the solution to be simpler than what you propose. I.e. just as IPv6 gave us essentially globally-unique IP addresses, any update to TCP or UDP should give us globally unique port numbers. You wouldn't need the OS to associate a UUID with a port; the UUID would _be_ the port. Pete
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-16 02:48 -0800 |
| Message-ID | <eeucf89l4dikvceinp68r8rni72esdjovl@4ax.com> |
| In reply to | #21429 |
On Wed, 16 Jan 2013 00:13:06 -0800, Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted someone who said : >You wouldn't need the OS to associate a UUID with a port; the UUID would >_be_ the port. the UUID would be the port. The 16-bit port would just be an shorthand abbreviation for it. You could even have a hybrid system. The assigner just avoids well known ports or ports that have been explicitly assigned. don't port numbers appear in UDP packets and TCP/IP packets, though the assignment of them may not be part of the protocol? RFC 322 says that UCLA will maintain the list of reserved port numbers. -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> |
|---|---|
| Date | 2013-01-16 07:28 -0800 |
| Message-ID | <1i1ry0rsgaxnm$.blszeyxb737b$.dlg@40tude.net> |
| In reply to | #21433 |
On Wed, 16 Jan 2013 02:48:23 -0800, Roedy Green wrote: > On Wed, 16 Jan 2013 00:13:06 -0800, Peter Duniho > <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted > someone who said : > >>You wouldn't need the OS to associate a UUID with a port; the UUID would >>_be_ the port. > > the UUID would be the port. The 16-bit port would just be an shorthand > abbreviation for it. We call that, in the programming community, a "hash code". It's not unique, and therefore not useful as an actual port ID. > You could even have a hybrid system. The > assigner just avoids well known ports or ports that have been > explicitly assigned. > > don't port numbers appear in UDP packets and TCP/IP packets, though > the assignment of them may not be part of the protocol? As I said, I'm not an expert. But TCP and UDP are transported over IP, and as far as I know, IP datagrams do not store the port #. Those are part of the TCP and UDP formats layered above IP. Thus changes to IP would not address port numbers. > RFC 322 says that UCLA will maintain the list of reserved port > numbers. Uh, so? Even if there's a TCPv2 and UDPv2 that support UUID for port identification, there will still be a need for reserved port numbers and someone will have to maintain the list of those numbers. Pete
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-16 10:46 -0800 |
| Message-ID | <m3tdf8deu2g60jffpd4jarqgi44kakshlm@4ax.com> |
| In reply to | #21434 |
On Wed, 16 Jan 2013 07:28:38 -0800, Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted someone who said : >> the UUID would be the port. The 16-bit port would just be an shorthand >> abbreviation for it. > >We call that, in the programming community, a "hash code". It's not >unique, and therefore not useful as an actual port ID. A hash is different. The assignment process might work with a HashMap or like a HashMap. If hashes collide you assign different 16 bit numbers. It is a dynamic process. You don't always get the same 16 bit port from the same UUID. If you are sure the port is reserved for you, you just use the 16 bit version. If not, you ask for a port reservation (good for perhaps one second) given the UUID. Then you use the 16 bit port. When you close it, the reservation disappears. -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> |
|---|---|
| Date | 2013-01-16 16:53 -0800 |
| Message-ID | <9g02074ucl0a.1pdynjyqd1bgs$.dlg@40tude.net> |
| In reply to | #21442 |
On Wed, 16 Jan 2013 10:46:21 -0800, Roedy Green wrote: > On Wed, 16 Jan 2013 07:28:38 -0800, Peter Duniho > <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted > someone who said : > >>> the UUID would be the port. The 16-bit port would just be an shorthand >>> abbreviation for it. >> >>We call that, in the programming community, a "hash code". It's not >>unique, and therefore not useful as an actual port ID. > > > A hash is different. No, it's not. If you have a UUID larger than 16 bits, then any "16-bit shorthand" is necessarily non-unique for all possible UUIDs, and is thus a hash code. > The assignment process might work with a HashMap > or like a HashMap. If hashes collide you assign different 16 bit > numbers. It is a dynamic process. You don't always get the same 16 > bit port from the same UUID. > > If you are sure the port is reserved for you, you just use the 16 bit > version. If not, you ask for a port reservation (good for perhaps one > second) given the UUID. Then you use the 16 bit port. When you close > it, the reservation disappears. If you are simply asking the OS to enforce uniqueness for your 16-bit port number, then why bother? You need to update the software to handle the full UUID anyway; you might as well just always use that for the port number. Pete
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-16 23:44 -0800 |
| Message-ID | <1qaff8p3p38ts67fjk5en8bu94cee1hgi7@4ax.com> |
| In reply to | #21454 |
On Wed, 16 Jan 2013 16:53:46 -0800, Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted someone who said : >No, it's not. If you have a UUID larger than 16 bits, then any "16-bit >shorthand" is necessarily non-unique for all possible UUIDs, and is thus a >hash code. The 16 bit code is assigned only for a short time, then they can be recycled for use by a different UUID. Unless a UUID is in use on a particular machine it does not have a 16 bit assignment. 16 bits are plenty for IN USE UUIDs on one machine. I am not suggesting UUIDs get assigned universally to a 16 bit id, e.g. being assigned a permanent well known port number. That would fail in minutes. -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> |
|---|---|
| Date | 2013-01-17 07:03 -0800 |
| Message-ID | <1xeeh2v8glf1m$.143zfbqwfmh7g$.dlg@40tude.net> |
| In reply to | #21469 |
On Wed, 16 Jan 2013 23:44:57 -0800, Roedy Green wrote: > On Wed, 16 Jan 2013 16:53:46 -0800, Peter Duniho > <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted > someone who said : > >>No, it's not. If you have a UUID larger than 16 bits, then any "16-bit >>shorthand" is necessarily non-unique for all possible UUIDs, and is thus a >>hash code. > > The 16 bit code is assigned only for a short time, then they can be > recycled for use by a different UUID. Unless a UUID is in use on a > particular machine it does not have a 16 bit assignment. > > 16 bits are plenty for IN USE UUIDs on one machine. > > I am not suggesting UUIDs get assigned universally to a 16 bit id, > e.g. being assigned a permanent well known port number. That would > fail in minutes. Whatever you mean, it doesn't make sense for a program that has to know the UUID to bother with a 16-bit port value also. If a UUID is involved, then just use it. Mapping the UUID to a 16-bit value doesn't fix anything when to get the 16-bit port value, you have to know the UUID. Just use the UUID.
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-17 14:25 -0800 |
| Message-ID | <tdugf8pdnclcbgk2uf2jpfpr4r2k4bhl2h@4ax.com> |
| In reply to | #21476 |
On Thu, 17 Jan 2013 07:03:54 -0800, Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted someone who said : > >Whatever you mean, it doesn't make sense for a program that has to know the >UUID to bother with a 16-bit port value also. If a UUID is involved, then >just use it. Mapping the UUID to a 16-bit value doesn't fix anything when >to get the 16-bit port value, you have to know the UUID. > >Just use the UUID. There is no need to put a pair of UUID socket numbers in every packet. That is a waste of bits. You do want a 16 bit shorthand. Maybe eventually a 64 bit port number, but for now such as conversion would be considered too disruptive. What I am calling for now would just be an optional add-on mechanism to assign a free port. -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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| From | Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> |
|---|---|
| Date | 2013-01-17 16:31 -0800 |
| Message-ID | <1y5zyjmcxgwp$.eqtqlj3dt5hr.dlg@40tude.net> |
| In reply to | #21491 |
On Thu, 17 Jan 2013 14:25:57 -0800, Roedy Green wrote: > On Thu, 17 Jan 2013 07:03:54 -0800, Peter Duniho > <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted > someone who said : > >> >>Whatever you mean, it doesn't make sense for a program that has to know the >>UUID to bother with a 16-bit port value also. If a UUID is involved, then >>just use it. Mapping the UUID to a 16-bit value doesn't fix anything when >>to get the 16-bit port value, you have to know the UUID. >> >>Just use the UUID. > > There is no need to put a pair of UUID socket numbers in every > packet. Oh, yes...there's absolutely is. The mapping you describe could only be valid locally, as part of the application API. On the network, the numbers have to be unique. Otherwise there's no way for the OS to know who actually sent or should receive the message. It's bad enough even when the port #'s are known to be unique. It's why we have TIME_WAIT. A transient mapping would be even worse. > That is a waste of bits. Have you looked at how much data a typical TCP connection involves these days? 48, or even 112 more bits is nothing. > You do want a 16 bit shorthand. Maybe > eventually a 64 bit port number, but for now such as conversion would > be considered too disruptive. What I am calling for now would just be > an optional add-on mechanism to assign a free port. It would not be possible in the way you seem to envision it. Pete
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| From | Roedy Green <see_website@mindprod.com.invalid> |
|---|---|
| Date | 2013-01-17 22:11 -0800 |
| Message-ID | <7sphf81sraa1uqmtsv56pu2t63qju9loif@4ax.com> |
| In reply to | #21503 |
On Thu, 17 Jan 2013 16:31:14 -0800, Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> wrote, quoted or indirectly quoted someone who said : > >It would not be possible in the way you seem to envision it. We are going around in circles. Would a someone else like to weigh in? -- Roedy Green Canadian Mind Products http://mindprod.com The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ~ Tom Cargill Ninety-ninety Law
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