#qi-hardware IRC log for Tuesday, 2012-03-20

kristianpauloh wow http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&No=662&from=enbanner00:28
kristianpaul"The significance lies in the fact that the entire system is completely open-source, compounding the influence immensely."00:28
Action: pabs3 thought all FPGA were proprietary00:32
kristianpaulof course they are but remenber, is "open source" 00:33
wpwrakkristianpaul: bah. i thought this bombastic comment was about M100:57
kristianpaulwpwrak: i dont get it well then..00:57
kristianpaulwpwrak: ah00:58
kristianpaulwpwrak: well00:58
kristianpaulsorry ;)00:58
kristianpaulnow i lost, you meant the link i posted right?00:58
kristianpaulbut yes sorry bring all those not very copyleft links latelly, i was reading some news.. then.. well ;)00:59
kristianpaulhmm need push a branch i created in a read-only git repo of my own..01:30
wpwrakmaybe you can just edit .git/config01:32
wpwrakelse, there's always git diff ... >~/file; cd ../good-branch; patch -p1 -s <~/file   :-)01:33
kristianpaulhehe you just read my mind01:34
kristianpaulbut found it i need add a remote branch01:34
kristianpauland i wanted to avoid that patching foo01:35
GitHub13[milkymist] kristianpaul pushed 1 new commit to gnss-sdr: https://github.com/kristianpaul/milkymist/commit/13ca0cdd2c7a383e71ab2d72f006de3cdf0ba85301:40
GitHub13[milkymist/gnss-sdr] namuru gnsssdr initial import - Cristian Paul Peñaranda Rojas01:40
rohmilled pcb today (mechanics, outline and a hole)01:46
rohhttp://yamato.hyte.de/tmp/pcb_dummy_test_fr4_front.jpg http://yamato.hyte.de/tmp/pcb_dummy_test_fr4_back.jpg01:47
rohjust taped down, milled in one round, 1mm diameter endmill01:47
kristianpaulroh: gta04 super cool acrylic case? :-)01:48
rohkristianpaul: nah. a pcb mechanical prototype for an actual customer01:48
wolfspraulcool, same idea as I had recently?01:48
rohwolfspraul: well.. doublesided tape is not really news depending on what01:49
kristianpaulyou're using tape as a case shell?01:49
wolfspraulbtw, speaking about doublesided tape. in Germany I always thought this was a relatively exotic 'tool'01:49
wolfspraulbut since I live in China, #1 I find double-sided tape in pretty much every small store, corner store, grocery store - EVERYWHERE01:50
wolfspraulI know that doublesided tape can be used to:01:50
wolfspraulSOLVE EVERY PROBLEM!01:50
kristianpaul"It is designed to stick two surfaces together, often in a way which is _not visible_ in the end product"01:51
wolfspraulyou name it, I solve it01:51
wolfsprauldoublesided tape can solve *every* problem01:51
wolfspraulit's magic01:51
wpwrakworst case, it can be used to shut up anyone complaining about the solution ;-)01:52
wolfspraulI have one (actually several) rolls in my household01:52
wolfspraulon my desk01:52
kristianpaulis not too much?01:52
wolfspraulit's magic01:52
wolfspraulwhenever I can, I buy another roll 'just in case'01:52
Action: kristianpaul imagines wolfspraul doing a doublesided ritual01:52
wpwrakroh: did you put some victim material between the PCB and the mill's table ? or are things precise enough that the tape's thickness was enough ?01:52
kristianpaulhow durable is it? i mean it solves the problem for let said a week untill ;)01:53
wpwrakwolfspraul: are you sure you're not confusing it with toilet paper ?01:53
wpwrakof course, double-sided toilet paper ... eww :)01:53
rohwpwrak: wood01:54
kristianpaulif replaces all glue uses well.. a good start01:54
wpwrakwood makes a great victim :)01:54
wolfspraulkristianpaul: ok, back to being serious01:54
kristianpaulsure :)01:54
wolfspraulI think it should be reserved for special cases01:54
rohmilled about 0.1 to 0.2 into the wood01:54
wolfspraulbecause as with every glue, it's nasty in the long run01:54
wpwrakroh: my mill doesn't have any good mounting system. you basically fix the entire table. so i made disposable tables of FR2, tape the things to them, then let the mill overshoot a bit01:56
wpwraknot great (bending), but on a good day, i get < 0.1 mm Z tolerance01:57
wpwrak(FR2 tables) of course, i can reuse them many times before they get too badly scarred01:57
wpwrakwolfspraul: you can wind it around things. since it's double-sided, you don't even need to think about which side goes where. it'll just stick to whatever :)01:59
cladamwwpwrak, one git question I don't know --> http://dpaste.com/718835/  sorry that interrupt your chats.02:00
wpwraktry to  git pull  02:01
wpwrakhopefully, this shouldn't cause any merge conflict02:01
wpwrakthen you can  git push02:01
cladamwstill to 'git pull' since I've changed a file ?02:01
wpwrakyou get this because i've committed changes since the last time you pulled, so git needs to synchronize again02:01
wpwrakthe  git pull  won't override your changes02:02
wpwrakif there's a conflict, it will tell you. but i don't think there will be any issues02:02
wpwrakwe should move those "official" things out of wernermisc. that's meant to be my personal playground. and its orderliness reflects that ;-)02:03
cladamwhttp://dpaste.com/718836/  after 'git pull' :-)02:03
wpwrakhmm, i think  git pull origin master  should do the trick02:05
wpwraki hope you're not in "detached head" mode ...02:06
cladamwtype 'git pull original master' ?02:06
kristianpaulwhat was tha famous way to reload fpga bitstream from flash using urjtag?02:06
wpwrakkristianpaul: make -C wernermisc/m1/jtag-boot boot02:07
qi-bot[commit] Adam Wang: changed J24 to p/n: TSW-105-26-H-D-009, see: (master) http://qi-hw.com/p/wernermisc/458b90d02:07
qi-bot[commit] Adam Wang: C145 -> 1uF/0402, C234 -> 10uF/0805, R62 -> 0603 (master) http://qi-hw.com/p/wernermisc/d5f6e0302:07
qi-bot[commit] Adam Wang: Merge branch 'master' of projects.qi-hardware.com:wernermisc (master) http://qi-hw.com/p/wernermisc/e22872302:07
cladamwwpwrak, nice , thanks. :-)02:08
wpwrakcongratulations ! :) these are among the scarier moments of life with git02:11
cladamwoah...poor adam , learn git while needs, but you're involved life with git. :-)02:13
kristianpaulwise words02:13
wpwrakit has its dark sides :) but the good thing is that pretty much all the questions you can possibly have have already been answered. and google is good at finding them (and the answers)02:14
cladamwwpwrak, ha...yes, i should have googled first instead of direct asked you. Sorry. :)02:18
wpwraknaw, no problem :) i don't mind showing off my recently acquired knowledge and/or google skills ;-)02:19
kristianpaulhmm i need update some threshold not getiing a lock..02:32
Action: kristianpaul manually counts capacitors from CvPCB window..03:37
Action: kristianpaul quits and open a console03:39
kristianpaulwpwrak: does boom/bom provides summary for components? ie i need x capacitors y resistor n diodes..03:41
kristianpauli dunno if is general usefull, but i'm about to make a qoute to a electronic shop here for passive smd stuff03:42
wolfspraulyou will have a very hard time competing with digikey I think03:45
wolfspraulbut definitely try and share your experiences03:45
kristianpaulwell digikey order will cost me 100usd shipping! :(03:45
kristianpaulor was 50usd..03:45
wolfspraulhow about a forwarding service?03:46
kristianpaulanyway i just need passive components i have the other ICs already here03:46
wolfspraulyes but that's the problem, if things are too cheap they become expensive again :-)03:46
kristianpaulwolfspraul: perhaps..03:46
kristianpauldont remenber me that.. :03:46
wolfspraulor the other way round - if you can deal with your cheapest/smallest problems most efficiently, the rest is a piece of cake03:48
kristianpauli hope..03:48
kristianpaullets see, one day i will order from digikey, perhaps when making my own maxim + spartan6 board ;) not now..03:49
wolfspraulI think there may be good forwarding services in florida you may want to check out03:49
kristianpaulSure i know then !03:49
kristianpaulI got my avnet board that way03:49
kristianpaulok i'll qoute on digikey too :-)03:50
kristianpaul-_- http://www.digikey.com.co/Web%20Export/hp/es/free_shipping_banner_co.gif04:00
Action: pabs3 notes there isn't any NN teardowns on iFixit, interesting comments on http://hardware.slashdot.org/story/12/03/20/0115228/ifixits-kyle-wiens-on-the-war-on-diy-electronics04:01
kristianpaulargh, i dont have SAW filer..04:07
kristianpauland digikey dont said too much about TA1575IG ..04:07
kristianpaulergh, i have it was confusing it with xtal phew ;)04:10
kristianpaulwpwrak: any suguestions for buying resistor and capacitors at digikey?04:37
kristianpauli'm getting 300 results just by writing 20K SMD 0603 04:38
kristianpaulokay size and dimension.. i need take care about that04:39
kristianpaulwow from 0.02 to 0.6... i need find diffences here too04:44
kristianpaul MQO is 1 btw04:45
Action: kristianpaul choosed P20KGCT-ND for now04:46
kristianpaul445-4839-1-ND 1.5usd :-|05:12
DocScrutinizerall about packaging06:51
DocScrutinizerI'd not worry too much about it, as long as you get enough for little money. Does it matter if you pay USD1.5 for 100 or USD2.5 for 1000, when you need 35?06:54
qi-bot[commit] Xiangfu: m1/patches/rtems/: Milkymist driver: add mic-boost support (master) http://qi-hw.com/p/wernermisc/901a48309:21
kyakxiangfu: the workaround on missing libncursesw probably breaks the UTF-8 support09:59
kyakwhy is libncursesw missing? because there are some bugs in Kconfig09:59
xiangfukyak, yes. we better fix that :) it's mark as module. and if I install the libncursesw from package repo, it will give other error 10:00
xiangfuwe needs fix all those in next release. so next release will be in 1 or 2 month :-)10:01
kyaki still wasn't able to dig to the root of this issue with libncursesw10:02
kyakeven with the help of jow10:02
kyakpackages that depend on it get deselected or libncursesw itself suddenly dissapears from the menu.. 10:03
kyakthe number of qi packages failed to build is & too big10:03
whitequarkDocScrutinizer: some Android stuff was integrated into Linux 3.310:04
whitequarkthrough not wakelocks yet, these (or, as I understand it, some more sane variant of them) are scheduled for 3.410:04
kyakhm wait a minute10:04
kyaksome packages are there in packages, but still listed as not built10:05
kyaki think it's some problem with parsing the build output log10:05
kyaksee fbterm10:05
kyakqt4 is not there.. 10:06
kyaki think i mentioned the bug and workaround to mirko...10:06
xiangfukyak, fbterm. yes. 10:07
kyakdunno if it's a good idea to release without qt10:07
kyakall qt packages are therefore failed10:08
xiangfuI want make progress on release. so I just release one image without all package that failed. 10:08
xiangfuthen we start working on this one. fix bugs.10:08
wolfspraulkyak: thanks for noticing those things!10:18
wolfspraulyep we gotta go back and bring things back up, it's tough10:19
wolfspraulwe are still lacking a strong test plan and regression testing, and regular, at least -testing images, say monthly or bimonthly?10:19
xiangfukyak, fbterm didn't find it under package.10:20
wolfspraulso the only way for xiangfu to break out of it after 4 months was to drastically cut down on packages or features that just don't build for this or that reason, so at least we have a basis to work on10:20
wolfsprauland in fact, as far as I'm concerned, I would go all the way back to boot to console if that is what is needed to come out with most recent ben images :-)(10:20
wolfspraulif someone doesn't like that, they can either take the old images, or help fix the latest10:21
wolfspraulxiangfu: we should leave the old package binaries around as well10:21
wolfspraulsay someone installs the 2011-11-xx image, what package repo does it point to?10:21
wolfspraulis that repo still there?10:21
xiangfukyak, I will test the libncursesw in next daily build.10:21
wolfspraulwe should keep the entire old images + package repo alive, especially if we cut things in more recent builds10:21
xiangfuwolfspraul, package repo. every release have one. and back well.10:22
wolfspraulso the old package repo is still there?10:22
wolfsprauland will stay there?10:22
xiangfuhere: http://downloads.qi-hardware.com/software/packages/NanoNote/Ben/10:22
xiangfuyes. people can easy switch to the one he like by edit /etc/opkg.conf10:22
wolfspraulok perfect10:22
wolfspraulso then nothing is lost10:22
wolfspraulif someone notices a missing or broken feature/package in latest, they can either use an older image and repo, or help fix latest10:23
kyakxiangfu: http://downloads.qi-hardware.com/software/packages/NanoNote/Ben/2012-03-18/ - fbterm package is there10:24
kyakthat's jfbterm :)10:24
kyakbrowser search hilightning covered the "j" :)10:25
wolfspraulkyak: so bottom line. I apologize if our build process looks rough and we seemingly trample over things done in the past. none of these things will be forgotten, it's just a matter of how we resurrect them into the latest images and sw versions...10:25
wolfsprauland it's great to see you back and even alerting us of things that broke - phew :-) let's get them back!10:25
kyakwolfspraul: yeah, probably it's a good thing to release anyway, perhaps it will motivate people to fix things.. THough i don't lack for motivvation, i lack for time10:26
xiangfukyak, yes there is something wrong on 'menuconfig'10:33
kyakxiangfu: http://en.qi-hardware.com/irclogs/qi-hardware_2012-01-22.log.html#t10:0710:43
kyakhowever, the patch is gone :)10:43
kyakoh no, i reported it: https://dev.openwrt.org/ticket/1083410:43
kyaki don't feel it's a good idea to override qt4 though10:44
kyakxiangfu: (menuconfig) - you'll find plenty of this in logs..10:44
kyaki know you can't be angry on inanimate objects, but i got really angry with Kconfig10:45
whitequarkyeesh, kconfig is nontrivial11:36
whitequarkit becomes easy once you damage your brain in exactly the same way as kconfig dev did11:36
DocScrutinizer51whitequark: (android stuff in linux) not something I start to cheer about12:00
Action: wpwrak vaguely remembers the first time he ran into wakelocks. they've been trying to get them into mainline for a mighty long time :)12:29
whitequarkseriously, never buy anything from tuxbrain. he forgot to put one atben into package and does not respond to email anymore.12:40
wpwrakhe really seems to be coming apart :-(12:50
wolfspraulwhitequark: is that all that was missing?12:50
wolfspraulmaybe I will just send you a 'free' (you already paid) atben from my side, we have to hold together...12:50
wolfsprauldavid from tuxbrain is a good guy, but retail/shop business is just crazy tough. maybe he is too good a guy to make it there.12:51
whitequarkwolfspraul: yes, otherwise it was fine (except for 2-month delay, but I can at least understand that)13:14
whitequarkI'd be very grateful if you did13:15
wolfspraulyou already paid13:16
wolfspraulI'll email you13:16
whitequarkwolfspraul: ok, thank you13:43
DocScrutinizerhi $channel21:25
DocScrutinizerwpwrak: nice doc about tuned line termination :-) also nice (for me) that I was right about optimum design is termination (50R) on *both* ends21:27
DocScrutinizeralso the mystery about impedance of *input* still the same, they just mentioned 15R driver output impedance21:28
DocScrutinizermaybe the 3pF parasitc load of input that they postulated in their virtual schematics IIRC, that's the effective load impedance at input? 21:30
DocScrutinizermakes little to no sense to me21:30
wpwraki've seen input capacitances in that range mentioned a few times21:36
wpwrakthe FETs and clamps (if present) should have little else on terms of impedance, no ?21:36
DocScrutinizerwpwrak: anyway see figure 2 in  http://download.micron.com/pdf/technotes/TN4606.pdf p2, that's what I'd expect. for a real circuit with a chip input pin they seem to imply this input also has 18R impedance (fig 5)21:38
wpwrakah, you mean including the termination21:40
DocScrutinizerin fig5 the RX 18R is labeled "Receiver"21:41
DocScrutinizerI read that as "inside chip"21:41
wpwrakthere are two "receivers"21:41
DocScrutinizerfig7 is completely different in that respect21:41
wpwraki think "receiver" is actually source. and "receiver (2)" is the actual receiver.21:42
wpwrakfig. 5 is bidirectional. and confusing ;-)21:42
wpwrakyes, fig 7 is cool. just terminate in the middle ;-)21:43
DocScrutinizerwpwrak: whatever fig5 is meant to be, the schematics are clearly more like fig2 rather than fig7, regarding terminating impedance on both ends21:44
DocScrutinizerwhatever that 18R in fig2 right end means, it's there21:45
DocScrutinizertheir simulation net in fig7 is completely messed up regarding that21:45
DocScrutinizererr s/fig2/fig521:46
wpwrakthey admit that: "From the above discussion this is not an optimal configuration."21:47
wpwrak(page 4. right column)21:47
wpwrakthey may be concerned that people trying to achieve a perfect but complicated termination would do more damage than good :)21:48
DocScrutinizerthey picked that compromise solution for sake of BOM21:58
DocScrutinizeras they state somewhere21:58
DocScrutinizerthis doesn't put any sense into fig7 for me21:58
DocScrutinizeras this sim net assumes termination impedance of infinite + 5pF21:59
DocScrutinizeror zero, which wouldn't make any more sense22:00
DocScrutinizeractually the sim net is garbage, they neither placed any proper source symbol in there, nor a proper sink that in any way siggests what impedance (4) shall have22:01
DocScrutinizer*usually* you assume impedance of zero for sources and infinite for sinks, in such cases22:01
DocScrutinizerzero for surce is in line with 15R at left side, which models the actual driver impedance22:02
DocScrutinizerI don't see anything at right side modelling the sink impedance (unless we assume the chip actually has near to infinite resistive component, and 5pF capacitive component)22:03
DocScrutinizeractually this might match the real chip's input characteristics22:06
DocScrutinizerfor me the 7nH and 5pF on right side fig7 are similar to left side, and indeed part of the chip pin sim22:07
DocScrutinizerlooking into fig9* you see the effect of this mismatching: overshots22:09
DocScrutinizerwpwrak: also note please that this is an optimization for DQ line, aka bidir22:12
wpwrakyes. for unidirectional, they use more traditional termination22:13
wpwrakwhich makes me wonder ... do we ? checking ..22:13
DocScrutinizerat least for unidir you should stick with fig222:13
DocScrutinizerwhich directly leads to a series R for source, and a parallel R to GND for sink22:14
DocScrutinizeralso note that even a transmission line with massive mismatch at one end still can work reasonably well when other end is optimally matched22:16
wpwrakmicron actually recommend to do the same for bidir and unidir22:16
DocScrutinizerthere will be reflections (aka overshots) but they get killed after one travel along the line22:16
wpwraktransmission lines are fun :)22:17
DocScrutinizerand actually I think that's what they do with their center termination22:17
wpwrakyup. sounds like it's that22:17
DocScrutinizeranyway, doesn't that give you an invincible desire to do your own spice tests?22:20
wpwrakso totally not ;-))22:21
DocScrutinizerthey offer ready made spice data ;-)22:22
DocScrutinizer>> Micron provides both IBIS and Spice models to help in this area (see ww.micron.com/models).22:23
wpwrakfeel free ;-)22:24
DocScrutinizerI'm actually tempted, alas it's again almost midnight here22:24
DocScrutinizerI start to hate this making_money22:24
wpwrakhaving a dayjob kinda sucks ;-)22:25
wpwrakand it's not the money. it's the day :)22:25
DocScrutinizerthere's a design glitch in this big simulation22:25
DocScrutinizermaybe the parameter "MONEY" been a totally useless change to the original setup22:26
wpwrakmmh ? what original setup ?22:27
Action: DocScrutinizer wanders off, searching for the RED PILL22:27
wpwrakah, the hour of the tranquilizer :)22:27
DocScrutinizernah, RED PILL isn't tranquilizer, rather a POP on stack22:28
wpwrakreturn to sleep mode :)22:29
DocScrutinizerbut we all learnt from Matrix, that it's a SIM in a SIM in a SIM (btw a concept that's as old as "Welt am Draht" at least)22:30
wpwraka film that would have greatly benefited from some cutting :)22:31
DocScrutinizerso maybe not going to take RED PILL will be the more comfortable alternative / the better SIM, despite this MONEY thing22:31
wpwrakheh :)22:32
DocScrutinizertw as cool as those delay elements in FPGA may be, they need nasty config - I strongly suggest to try and keep traces same length22:34
Action: whitequark has read 10 lines of backlog22:35
DocScrutinizerwhitequark: then yu missed all the good stuff ;-)22:36
wpwrakah, you've dropped off the cc again22:36
whitequarkwpwrak: cc?22:36
wpwraki forwarded you the missing mails22:36
wpwrakno, DocScrutinizer 22:36
wpwrakwhitequark: he prefers if we copy him explicitly on our mails instead of simply subscribing to the list. so every once in a while, the cc: is lost and the thread goes on without him22:37
wpwrakwhitequark: then he gets confused when we discuss in a context that has already changed. until someone detects the problem and forwards him what seem to be the missing mails22:37
whitequarkhmm, context22:38
wpwrakthey're of course unthreaded then, possibly increasing the confusion :)22:38
whitequarkDocScrutinizer: looks like your SP gets corrupted sometimes22:39
whitequarkand you suddenly find yourself in a middle of a wrong stack frame22:39
whitequarkerr... recompile yourself with -fstack-smashing-protector ?..22:39
DocScrutinizerno increased confusion here :-D22:41
DocScrutinizeryep, a slightly caring layout should result in a routing that "just works"22:42
DocScrutinizerexcept for those "differential lines"... o.O - we got any of those?22:43
wpwrakyes, the clock is differential22:43
DocScrutinizerso you may consider 2-laxered design for those traces22:44
wpwrakhmm. just parallel should do the trick. otherwise you need to consider the vias as well22:48
DocScrutinizeryou can easily make via length identical22:49
wpwrakbut they're on the same side. so one would go down and then up again22:50
wpwrakunless you have a pcb with buried components. that would be fun ;-)22:50
DocScrutinizer2/6 via + trace + 4/6 via, vs n/6 via + trace + (6-n/6) via22:51
DocScrutinizerdown and then up, what's wrong about it?22:51
wpwrakbut why ?22:52
wpwrakjust seems to make things more complicated22:52
DocScrutinizerto do sth about your concerns regarding via length22:52
wpwrakyou mean trace22:52
DocScrutinizernope, via22:53
wpwraknow you lost me :)22:53
DocScrutinizer>>>... otherwise you need to consider the vias as well22:53
wpwraksimplest design: everything on the surface22:53
wpwraknext to simplest: both dive out of the FPGA, then come back up together somewhere22:54
DocScrutinizeras long as your traces are straight line, yes22:54
DocScrutinizerhave some bend in them and you run into length issues22:54
wpwrakas long as they are exact copies of each other22:54
DocScrutinizerand 0.5mm i actually a bit demanding22:55
wpwrakyes. different radii would be trouble.22:55
wpwrakthey're probably exaggerating ;-)22:56
wpwrakjust consider the propagation speed of the signal22:56
wpwrakunits 0.5mm/c ps  -> 1.66722:57
DocScrutinizerc on PCB is not what you might think it is22:58
wpwrakeven if we assume 66% of c, that's merely 2.5 ps22:58
DocScrutinizerI frown on that unit, mil22:58
DocScrutinizermaybe they meant millimeter?22:59
wpwraki doubt it :)22:59
DocScrutinizerhah, http://openbookproject.net/electricCircuits/AC/AC_14.html23:12
DocScrutinizerTL for dummies23:12
DocScrutinizer>>> Velocity factor is a fractional value relating a transmission line's propagation speed to the speed of light in a vacuum. Values range between 0.66 and 0.80 for typical two-wire lines and coaxial cables23:13
wpwrakthat sounds like "chess in hyperbolic n-spaces for dummies" :)23:14
wpwraksee. 2/3 was already a pessimistic estimate.23:14
DocScrutinizerno really, it's nice23:14
wpwraki think it should be a bit faster on the pcb (if i interpret wikipedia right :)23:15
DocScrutinizereven with extremely slower velocity we get not even in pall park where 0.5mm matters23:15
wpwrakyes, seems to me that way,too23:18
DocScrutinizer0.1ns results in ~0.025mm if my math doesn't suck23:20
wpwraki think it does :)23:21
wpwrakunits 0.1ns*0.66c mm  ->  19.78630223:21
DocScrutinizeryeah, sth is wrong with my math23:23
DocScrutinizermy feeling tells 23:23
DocScrutinizer1ns = 1GHz23:24
DocScrutinizerGHz wavelength is not sub-mm23:24
wpwrakonly for very slow light :)23:24
wpwraktardions, not tachyons23:24
DocScrutinizermeh, time for zzZZzz23:25
wpwraksweet suspend ! :)23:25
DocScrutinizerone last thing, I think I heard they built some sort of TL for light, that was actually in range of mm/s23:27
DocScrutinizeralso c inside sun is astonishingly low23:30
DocScrutinizerneeds several 1000 years to reach surface from center23:30
wpwrakmust be a huge traffic jam for those poor photons23:30
DocScrutinizerindeed, it is23:30
DocScrutinizerluckily they can crowd up really dense23:31
DocScrutinizerafaik they won't ever collide with their own kind23:32
wpwrakcan't have the same kind of particle at the same place at the same time23:34
wpwrakthat's why you never read of, say, rolls royces colliding23:34
DocScrutinizerI think they never are in one place at one time, since Heissenberg23:36
DocScrutinizerbut they must have *some* mass. I guess e/c^223:36
DocScrutinizerso too many of them crowded up in one spot may result in a black hole23:37
DocScrutinizeris there any theoretical upper limit for frequency of electromagnetic waves?23:41
DocScrutinizerIOW what's that radiation that starts where gamma spectrum ends?23:44
wpwrakone period per Planck length ?23:45
wpwrakand only relativistic mass. m0 = 0. or they couldn't travel at c.23:45
DocScrutinizersure, as I said, e/c^223:47
DocScrutinizerplanck length, hmmm23:49
DocScrutinizerPlanck-Kreisfrequenz  1,85487 · 10^43 s123:55
wpwrakfuture generations will have a heck of a time getting their layout constraints right :)23:57
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