User:Andrew Linden/Office Hours/2008 10 28

Transcript of Andrew Linden's office hours:

[11:03]	Simon Linden:	I'm multitasking, so ping me if I'
[11:03]	Simon Linden:	I'm not responding
[11:03]	Andrew Linden:	how do you want your ping?
[11:03]	Simon Linden:	Hi Arawn
[11:03]	Arawn Spitteler:	I was just getting that camera oscillation, with my back to the fence. I hope that means we aren't on the next release.
[11:04]	Arawn Spitteler:	Hi, Andrew, Simon. Where's everybody else?
[11:04]	Andrew Linden:	We're definitely not at the next release yet.
[11:04]	Simon Linden:	yes, this is still 1.24.9
[11:04]	Andrew Linden:	ah ha! turns out 1.25-Server is up on the aditi grid
[11:05]	Andrew Linden:	it made it there on Friday
[11:05]	Andrew Linden:	which means it is open to the public, and that camera oscillation bug fix can be tested and verified
[11:05]	Andrew Linden:	(or re-opened... let us consider all options)
[11:06]	Arawn Spitteler:	Hi, Ella, Gaius, Gaius is finally rezzing
[11:06]	Andrew Linden:	Ok, since 1.25-Server is now on the open preview grid (aditi) I need to go find all the "fix pending" bugs and add comments
[11:06]	Arawn Spitteler:	I haven't my browser open, yet. How's SVC-2931 doing?
[11:06]	Andrew Linden:	for anyone who happens to be watching those public jira items.
[11:06]	Gaius Goodliffe:	Hello. Sorry to pop in in the middle of the convo -- if you're saying the camera oscillation bug is fixed, I'm gonna have to kiss you. :)
[11:07]	Andrew Linden:	SVC0-2931 has not yet been updated
[11:07]	Simon Linden readies SL movie capture
[11:07]	Gaius Goodliffe:	Heh
[11:07]	Arawn Spitteler:	It's supposed to be in the preview, so give him a Beta Kiss
[11:07]	Gaius Goodliffe:	Ah okay, it can wait until it deploys main grid.
[11:07]	Gaius Goodliffe:	;)
[11:07]	Andrew Linden:	Test it first
[11:08]	Andrew Linden:	Ok so Simon proposed some ground rules for this meeting...
[11:08]	Andrew Linden:	no discussions about OpenSpace regions
[11:08]	Andrew Linden:	Actually, I think that is the only rule
[11:09]	Andrew Linden:	there is nnnnnooooooo..... rule number two
[11:09]	Simon Linden:	I think it was specifically 'no discussion of @#$@ OpenSpace policies' -- I'm unhappy enough :(
[11:09]	Gaius Goodliffe:	Roger that.
[11:09]	Gaius Goodliffe:	I did have a performance issue I wanted to ask about...
[11:09]	Andrew Linden:	I have not yet read the internal email thread we're having about it
[11:09]	Simon Linden:	If there's a specific OS issue that's not just 'performace is bad' we can discuss it
[11:09]	Arawn Spitteler assumes this will be discussed Thursday, at 11AM: You might like to go see the fun. Is it possible, to set an avatar for Streaming Media?
[11:10]	Andrew Linden:	What is going on Thursday 11 AM?
[11:10]	Simon Linden:	You mean the textures on an avatar are streaming media? Cool
[11:10]	Arawn Spitteler:	I was unable to log in, with the RC, earlier, and Bleeding Edge got me to Help Island.
[11:10]	Andrew Linden:	I think he means... right now we can specify streaming media on a per-parcel basis
[11:10]	Andrew Linden:	so why not have a streaming media setting per-avatar?
[11:11]	Arawn Spitteler:	No, Video Streams on Textures is old, but an avatar that can act as a streaming media server, so you guys can watch Jack TV, on Thursday Morning.
[11:11]	Simon Linden:	Probably because too many streams would be a way of overloading clients
[11:11]	Simon Linden:	Ah, I see .. that's great. Do you know how they do the vidoe capture?
[11:12]	Andrew Linden:	also, right now the SL client only has one channel for streaming media... the avatar setting would conflict with the parcel one
[11:12]	Simon Linden:	I've had a pet feature idea for a while ... pipe the video output of the viewer as a virtual camera so it can be used by any streaming software
[11:12]	Andrew Linden:	Make it so Simon (in your copius spare time)
[11:13]	Gaius Goodliffe:	It woudl be nice if those with more powerful computers to do like you do with particles - adjust how many streams we cna view at once. Make it 1 by default but allow people to up the number...
[11:13]	Simon Linden:	I haven't been able to find the 'cut and paste' camera source sample code
[11:13]	Andrew Linden:	hehe
[11:13]	Andrew Linden:	So Gaius, you had a question about performance?
[11:14]	Gaius Goodliffe:	I was just wondering if openspaces deliberately cull events? I've noticed events not getting delivered reliably in openspaces. Even when there's no apparent load...
[11:14]	Andrew Linden:	State the question, but we reserve the right to discard it... if it violates Simon's ground rule.
[11:14]	Simon Linden:	No, I don't think there's any deliberate culling of events
[11:15]	Arawn Spitteler:	Might be overloaded.
[11:15]	Simon Linden:	The script performance might be really low, however, and they are getting dropped or it's getting overloaded
[11:15]	Andrew Linden:	Oh, script events.
[11:15]	Gaius Goodliffe:	Hmm. I have missiles that explode on contact in full sims, but in openspaces they frequently collide and keep going. I saw one bounce off various targets four times before finally getting its collision_start event.
[11:16]	Simon Linden:	The time spent on scripts is calculated as "whatever's left over in the current frame" with some minimum
[11:16]	Simon Linden:	So if it's running at less that 45fps, it will be the minimum
[11:16]	Gaius Goodliffe:	I've also seen examples of llSay(somechannel, text) getting discarded, like you say something 10 times and only 5 are received by the target.
[11:16]	Andrew Linden:	Uh... Gaius, that might be aggravated by one of the bugs in SVC-2511. You should test on the preveiw grid.
[11:16]	Gaius Goodliffe:	I shall try that, see if it makes any difference on preview.
[11:17]	Simon Linden:	yeah, Andrew, you fixed up collision events recently, right?
[11:17]	Arawn Spitteler:	Are open sims old enough, to be on preview?
[11:17]	Andrew Linden:	Not recently... months ago.
[11:17]	Simon Linden:	But it's coming out in 1.25? Or should it already be out?
[11:17]	Andrew Linden:	but it didn't get in before MONO... so it has been sitting around for 1.25-Server, yes.
[11:18]	Gaius Goodliffe:	Ah cool. I seem to be ahving a lot of collision related issues lately. I'll make a trip to preview this week...
[11:19]	Andrew Linden:	ah yes Arawn, I spoke with Michael Linden about the railroad system
[11:19]	Andrew Linden:	SLRR -- he says they are working on a replacement system now
[11:19]	Andrew Linden:	the moles are working
[11:19]	Andrew Linden:	supposedly there is about 9 miles of track to overhaul
[11:19]	Andrew Linden:	they are going to tear it out and replace with new track (new script system)
[11:19]	Arawn Spitteler:	I think that would be just the start
[11:20]	Arawn Spitteler:	Tuliptree to Jubata?
[11:20]	Andrew Linden:	dunno which regions or where it is
[11:20]	Andrew Linden:	also don't know the ETA of the project
[11:20]	Andrew Linden:	however Michael hasn't forgotten
[11:21]	Andrew Linden:	and no one wants to dissect Nigel Linden's scripts, so I think they are going for a rewrite.
[11:21]	Arawn Spitteler:	Scripts are likely easier for the Sims to handle, but Collision is easier conceptually, for new builders. How does a Sniffer cross a border?
[11:21]	Andrew Linden:	Too bad Kitto isn't here
[11:21]	Andrew Linden:	perhaps he could try to sell some working trains to Michael and his moles
[11:21]	Andrew Linden:	yeah, they are fighting with border crossings
[11:22]	Andrew Linden:	that is one of the things the RR moles were working on.
[11:22]	Arawn Spitteler:	Kitto might be able to debug Nigel's Scripts, but Garth Fairchang certainly should.
[11:22]	Andrew Linden:	Yes
[11:23]	Arawn Spitteler:	If we're going to cross borders, I've no idea what a sniffer could do.
[11:23]	Andrew Linden:	what is a snifffer?
[11:23]	Arawn Spitteler:	A nice feature would be, if a script could ask to sense, "In that sim over there."
[11:23]	Gaius Goodliffe:	"sniff" on a chat channel. Ping and listen for the response. This works reliably, even across borders.
[11:23]	Andrew Linden:	ah
[11:24]	Arawn Spitteler:	Huggers collide with the rails, sniffers look for them, and I don't know what the Bots do, but those are the three types of Rail Vehicle
[11:24]	Andrew Linden:	I think they were experimenting with sniffers
[11:25]	Andrew Linden:	I wonder where the preview release notes are published these days
[11:25]	Andrew Linden:	Anyone know?
[11:26]	Arawn Spitteler:	It shouldn't be impossible, to get the Nigel Rail Running, but the trains would have to have their hugs retooled, and the Bato Solution wouldn't hurt on the rails, but it requires a regular Linden Touch, on the restart button
[11:27]	Arawn Spitteler:	Who's the IC ofPreview Grid?
[11:27]	Andrew Linden:	IC?
[11:27]	Arawn Spitteler:	In Charge, who decides when to update the snapshot
[11:28]	Andrew Linden:	Oh, there is a team. I call them the #deploy team since they tend to hang out on our internal #deploy IRC channel.
[11:28]	Andrew Linden:	Almost anyone on that team should know the answer to that question.
[11:29]	Andrew Linden:	The main IC's are Josh Linden and Prospero Linden
[11:31]	Andrew Linden:	Simon, what are you working on these days?
[11:31]	Simon Linden:	Odds and ends ... mostly bugs and minor projects
[11:32]	Simon Linden:	There are some avatar improvements that I'm getting involved in (one new texture getting passed around, I'm not sure what it's used for yet)
[11:33]	Andrew Linden:	I'm working on some internal tools and will probably continue on that project for another two weeks at least.
[11:33]	Simon Linden:	I did recently get into the issues with controls, and will be looking at the restriction and problem with only one script being able to take control events
[11:33]	Simon Linden:	There are some more internal performance things I want to move along as well
[11:34]	Andrew Linden:	ok thanks, just curious
[11:35]	Andrew Linden:	Arawn, you attend other Linden office hours right? Whose hours to you attend?
[11:35]	Arawn Spitteler:	Depends what I can catch. Often CG's, Sometimes Michael's or Jack's.
[11:36]	Arawn Spitteler:	I used to do Zero's, but suffer some language limitations, and sometimes Documentation
[11:36]	Gaius Goodliffe:	Oh, any news on the "ghost objects" issue? I remember last time Andrew was wondering the the ghost objects show up in the parcel prim count. I can now confirm they do, although you can't return the object from the About Land > Objects tab. You see the prims there, but they can't be manually returned or auto-returned.
[11:36]	Andrew Linden:	Oh, do they get all technical in Zero's office hours?
[11:37]	Andrew Linden:	I suppose that makes sense. That is one of the main hours for discussing open platform protocol stuff.
[11:37]	Arawn Spitteler:	The only meaning I know for POST is Power On Self Test
[11:37]	Andrew Linden:	hehe
[11:37]	Andrew Linden:	POST, GET, DELETE
[11:38]	Andrew Linden:	the three communication types of a RESTful protocol
[11:38]	Arawn Spitteler:	What's REST?
[11:38]	Andrew Linden:	REST = ... I'll have to google for it
[11:39]	Gaius Goodliffe:	hehe
[11:39]	Andrew Linden:	REST = representational state transfer
[11:39]	Arawn Spitteler:	The Acronyms don't tell as much, as they used to. I could give you the formula for NaPalm, and that might still be top secret
[11:39]	Andrew Linden:	http://en.wikipedia.org/wiki/Representational_State_Transfer
[11:41]	Andrew Linden:	Oh... it seems I forgot the PUT method
[11:41]	Andrew Linden:	although... seems like you could do without PUT and just use POST
[11:42]	Arawn Spitteler:	Put goes with Get
[11:42]	Andrew Linden:	oh well, supposedly one of the reasons HTTP has been such a success is because it is a RESTful protocol
[11:42]	Andrew Linden:	REST describes the general qualities a protocol must have to be "good"
[11:43]	Andrew Linden:	that's what I gather, anyway
[11:44]	Andrew Linden:	I'm not involved in the protocol design, and I've got too much stuff to do as it is, so I haven't been keeping up to date with that project
[11:44]	Arawn Spitteler:	I read another article, that said Structured Programming would eliminate Memory Leaks.
[11:44]	Andrew Linden:	And it has eliminated them... just use JAVA
[11:44]	Simon Linden:	That's sort of like saying "safe driving will eliminate accidents" :)
[11:44]	Andrew Linden:	... except when the JAVA engine itself has memory leaks
[11:44]	Andrew Linden:	or resource leaks (almost the same thing)
[11:45]	Andrew Linden:	The problem with such paradigm's is when the paradigm's fail
[11:45]	Arawn Spitteler:	Single Point of Return, is what it mentioned.
[11:46]	Simon Linden:	That is good programming practice ... I can't stand it when I find a routine with a lot of return paths
[11:46]	Andrew Linden:	<_<
[11:46]	Andrew Linden:	>_>
[11:46]	Arawn Spitteler:	But you still have to leave little piles of data product, lying about, with no idea of who will ever ask for it next.
[11:47]	Arawn Spitteler:	Some sort of Archive Algorhythm is needed.
[11:48]	Arawn Spitteler:	That's going to morph, with system resource upgrades.
[11:48]	Andrew Linden:	I got lost
[11:49]	Andrew Linden:	So we don't have many pressing issues that need to be raised today.
[11:49]	Arawn Spitteler:	I think we drifted. Anyways, I should learn enough about Structured Programming, to do some intelligent scripting.
[11:50]	Andrew Linden:	Should be end the hour early? Or do we want to talk about misc stuff?
[11:50]	Arawn Spitteler:	miscellaniae, leads to the best ideas.
[11:50]	Arawn Spitteler:	Would it be possible, for a script, to ask for an early sim transfer?
[11:50]	Andrew Linden:	Earlier today I saw an article about the "new interest in virtual worlds"...
[11:51]	Andrew Linden:	lemme see if I can find the link
[11:51]	Andrew Linden:	"Early sim transfer"? You mean some sort of region crossing optimization?
[11:52]	Andrew Linden:	No... I lost the link
[11:52]	Arawn Spitteler:	Yeah, maybe run a script in another Sim's engine, or just ask for the wearing avatar to be in the other sim. "I'm going that way!!!"
[11:53]	Andrew Linden:	well... the main problem with that is LSL scripts can only run on one region... we don't have any mirroring features for them
[11:53]	Andrew Linden:	so the region that the script is in must wait until the last minute to save the script state off...
[11:54]	Andrew Linden:	it would be hard to try to save it off, send that over, and then journal new changes to state and stream them over
[11:54]	Arawn Spitteler:	So, it would be a protocol to optimize, "Which Sim Do I Want To Be In?"
[11:54]	Andrew Linden:	I guess to sum up the idea I'm talking about... save the object state and send it over
[11:55]	Andrew Linden:	early, and then only send the diff changes to that state at the last minute
[11:55]	Arawn Spitteler:	Which is currently triggered by exiting the boundaries of a sim
[11:55]	Andrew Linden:	that is one of those projects that is easier said than done
[11:55]	Simon Linden:	Sorry gotta run to another meeting .... bye everyone
[11:56]	Arawn Spitteler:	It's just as easy as picking up that little piece of paper, that the entire library is resting on.
[11:56]	Andrew Linden:	there are a lot of corner cases... the object never actually crosses would be the biggest one
[11:56]	Andrew Linden:	in which case the original state was sent over for nothing
[11:57]	Arawn Spitteler:	Yeah, electing which Sim a Script is running on, could be taken to excess.
[11:57]	Arawn Spitteler:	Still, Sniffers should be able to cross region boundaries.
[11:57]	Andrew Linden:	right now the simulator code has direct access to the LSL script in memory
[11:58]	Andrew Linden:	if the script were on a different process, or different server
[11:58]	Andrew Linden:	then accessing the data of the script would take much longer
[11:58]	Andrew Linden:	it would have to go through some weird cross-process pipeline
[11:58]	Andrew Linden:	or network pipeline
[11:59]	Andrew Linden:	so I think the most likely improvements to genera cross-region problems and border crossings could be fixed by simply smarter software
[11:59]	Andrew Linden:	that is... optimizing the existing parts that are slow
[12:00]	Andrew Linden:	cause if you can't optimize those...
[12:00]	Andrew Linden:	it's just going to be a mess when the system gets even more complicated.
[12:00]	Andrew Linden:	er... a bigger mess
[12:01]	Arawn Spitteler:	It's a mess, I'm sure. Sensor could be replaced, by asking the Specified Server as to what's in a Bounding Box.
[12:01]	Andrew Linden:	That is... if you can't optimize the simple system... what makes you think you can optimize the complex one?
[12:01]	Arawn Spitteler:	Scalable Optimizations?
[12:02]	Andrew Linden:	Yes, the Sensor query needs an overhaul.
[12:02]	Arawn Spitteler:	I wonder that Gravity doesn't shut down, when we cross Region Borders.
[12:02]	Andrew Linden:	Perhaps a general query like "what is in this box?" would be useful
[12:02]	Arawn Spitteler:	BoundingBoxQuery?
[12:03]	Andrew Linden:	however... I think a better way to optimize would be to supply a more specific query, and only return hits for the specific hits
[12:03]	Andrew Linden:	in other words... let the deep-down C++ code cull the sensor results better
[12:03]	Arawn Spitteler:	With Wild Cards, so we can ask if there's anything thsat starts "Kitto Track #"
[12:04]	Andrew Linden:	right, searching by "regular expressions" would help (wildcards)
[12:04]	Andrew Linden:	and if the search could better specify its range of interest, that would help
[12:05]	Andrew Linden:	... if the simulator could cull the relevant objects quickly
[12:05]	Andrew Linden:	turns out, our own object culling system is not very fast or clever
[12:05]	Arawn Spitteler:	Object Culling for Sensor?
[12:05]	Andrew Linden:	that is, the culling of the LSL sensor pipeline is not very smart
[12:05]	Andrew Linden:	Yeah
[12:06]	Arawn Spitteler:	The term, Awful, comes to mind.
[12:06]	Andrew Linden:	Perhaps. There are different levels of awful.
[12:06]	Arawn Spitteler:	A box wold make more sense, than a cone.
[12:07]	Arawn Spitteler:	Havok doesn't use Solids of Anticipation, does it?
[12:07]	Andrew Linden:	well... a box is a little ambiguous... there is an AAB (axis-aligned box) which is not to be confused with a local box
[12:07]	Andrew Linden:	AAB's can be optimized much easier
[12:08]	Andrew Linden:	however, they are counter-intuitive, perhaps, to a LSL scriptor who is focusing on the local orientation of their object
[12:09]	Andrew Linden:	alright, I've got to go too
[12:09]	Andrew Linden:	Thanks for coming.
[12:09]	Gaius Goodliffe:	Nice seeing everyone :) Take care
[12:09]	Arawn Spitteler:	Glad to have you
[12:10]	Arawn Spitteler:	I think I've solved the problem of the Wankel, by the way
[12:10]	Andrew Linden:	You mean the Wankel engine?
[12:10]	Arawn Spitteler:	Yeah, they have aluminum housings, that chill the air, you're trying to get work out of.
[12:11]	Arawn Spitteler:	Stratified Charge, of a Direct Fuel Injector, should work until they have better housing materials.
[12:11]	Arawn Spitteler:	Aluminum Nitride might make sense.
[12:12]	Andrew Linden:	Hrm... perhaps. I don't know enough about the problem to really say.
[12:12]	Andrew Linden:	the only Wankel engine in production these days is the one in the Mazda RX7, right?
[12:12]	Arawn Spitteler:	It seems to obvious, to me, so there might be some problems that it leads to.
[12:12]	Arawn Spitteler:	Renesis, as far as I know.
[12:13]	Arawn Spitteler:	Elegant Engine, but I think it's got basic material problems.
[12:13]	Andrew Linden:	the engines are small and light... but the complexity of the emissions systems tend to make up for the saved mass
[12:13]	Arawn Spitteler:	That's because they're letting the flame touch the housing.
[12:13]	Andrew Linden:	Yeah, they weren't able to make the RX7 engine until the material science could produce the right alloys
[12:14]	Andrew Linden:	I expect electric vehicles to come into fruition before the Wankel engine reaches its full potential.
[12:15]	Arawn Spitteler:	Electrics have distoance trouble, or would have dominated the Century
[12:15]	Arawn Spitteler:	They're trying to run them on Nuclear Power.
[12:15]	Andrew Linden:	right, so it comes down to the battery
[12:16]	Arawn Spitteler:	I'd like a Diesel with a battery, but the Wankel still has potential
[12:16]	Andrew Linden:	batteries have been improving, but the improvements have not come fast or in spurts
[12:16]	Andrew Linden:	it has been a gradual improvement curve
[12:16]	Andrew Linden:	but it is still going up
[12:16]	Andrew Linden:	and then super-caps are approaching from another angle
[12:17]	Arawn Spitteler:	Super Caps sound like a virtual rechargable battery, but we both have to go.
[12:17]	Andrew Linden:	Ok Arawn, see you later.