2014-09-18 00:12 OMG, that thing is set as GPIO for the keyboard 2014-09-18 00:12 ! 2014-09-18 00:13 I want to kill myself 2014-09-18 00:36 do any of you know what an ethernet network transformer is for? 2014-09-18 00:36 sung: sure 2014-09-18 00:36 i'm reading through schematics and i was wondering why ethernet pins aren't going str8 to a jack 2014-09-18 00:36 but rather hittnig up a network transformer, and then a jack 2014-09-18 00:37 ethernet uses differential signalling; the transformer removes DC offsets and allows pulses to pass through 2014-09-18 00:37 DC offset* 2014-09-18 00:38 since you have a twisted pair, any voltage that's induced in the pair due to external interference is induced with roughly same magnitude in both wires 2014-09-18 00:38 ohhhh. 2014-09-18 00:39 okay, so just because an IC has a PHY, doesnt necessarily mean it has a built-in network transfoemrmer 2014-09-18 00:39 there's also Power over Ethernet, which puts 48V between some two pairs 2014-09-18 00:39 with a transformer, you can still use them for data 2014-09-18 00:39 yeah, putting a transformer into an IC is a pain ;D 2014-09-18 00:40 bro, thank you. 2014-09-18 00:46 and it looks like i can find ethernet jacks called magjack that has it builton 2014-09-18 00:46 yes, plenty 2014-09-18 00:46 "magjack" though? not sure. I always seen some noname chinese connectors, never with a fancy name like that 2014-09-18 00:51 https://www.sparkfun.com/products/8534 is what i'm looking at 2014-09-18 00:51 sparkfun is super overpriced in general 2014-09-18 00:51 $1.95 seems ok though 2014-09-18 01:00 my end goal is to get an rt5350f ic and basically make my own vocore 2014-09-18 01:00 and i don't care if it costs me 10 times what the vocore costs because i'm trying to learn stuff while i do it 2014-09-18 01:00 what i've learned so far is that It's Hard(tm) 2014-09-18 01:39 atommann has joined #qi-hardware 2014-09-18 02:19 xiangfu has joined #qi-hardware 2014-09-18 03:26 atommann has quit [Ping timeout: 272 seconds] 2014-09-18 05:05 atommann has joined #qi-hardware 2014-09-18 05:24 xiangfu has quit [Remote host closed the connection] 2014-09-18 05:51 viric has quit [Ping timeout: 255 seconds] 2014-09-18 05:56 viric has joined #qi-hardware 2014-09-18 07:17 wolfspraul has joined #qi-hardware 2014-09-18 07:18 wej has joined #qi-hardware 2014-09-18 07:19 wej_ has quit [Ping timeout: 250 seconds] 2014-09-18 07:25 porchaso0 has quit [Ping timeout: 246 seconds] 2014-09-18 07:29 jow_laptop has quit [Ping timeout: 246 seconds] 2014-09-18 07:30 panda|z has quit [Ping timeout: 246 seconds] 2014-09-18 07:30 jow_laptop has joined #qi-hardware 2014-09-18 07:34 panda|z has joined #qi-hardware 2014-09-18 07:34 wolfspraul has quit [Ping timeout: 245 seconds] 2014-09-18 07:39 apelete has quit [*.net *.split] 2014-09-18 07:39 dos1 has quit [*.net *.split] 2014-09-18 07:39 pcercuei has joined #qi-hardware 2014-09-18 07:42 wolfspraul has joined #qi-hardware 2014-09-18 07:50 porchao has joined #qi-hardware 2014-09-18 07:52 valhalla has quit [Ping timeout: 246 seconds] 2014-09-18 07:52 valhalla has joined #qi-hardware 2014-09-18 07:57 wolfspraul has quit [Ping timeout: 240 seconds] 2014-09-18 07:59 wolfspraul has joined #qi-hardware 2014-09-18 08:00 dos1 has joined #qi-hardware 2014-09-18 08:00 apelete has joined #qi-hardware 2014-09-18 08:34 xiangfu has joined #qi-hardware 2014-09-18 09:25 xiangfu has quit [Remote host closed the connection] 2014-09-18 10:03 atommann has quit [Quit: Leaving] 2014-09-18 10:44 wolfspraul has quit [Ping timeout: 245 seconds] 2014-09-18 10:46 wolfspraul has joined #qi-hardware 2014-09-18 11:01 wolfspraul has quit [Ping timeout: 272 seconds] 2014-09-18 11:08 wolfspraul has joined #qi-hardware 2014-09-18 11:16 methril has joined #qi-hardware 2014-09-18 11:17 methril has quit [Remote host closed the connection] 2014-09-18 11:17 methril has joined #qi-hardware 2014-09-18 11:17 methril has quit [Remote host closed the connection] 2014-09-18 12:26 viric has quit [Ping timeout: 260 seconds] 2014-09-18 12:31 viric has joined #qi-hardware 2014-09-18 13:54 dandon has quit [Quit: .] 2014-09-18 16:05 xiangfu has joined #qi-hardware 2014-09-18 16:15 http://cm.bell-labs.com/who/ken/trust.html 2014-09-18 16:15 scary.. 2014-09-18 16:15 not really 2014-09-18 16:16 if you have two compilers that were not designed to be used as a pair, you can detect it in any case very easily 2014-09-18 16:16 i.e. in worst case you just need to write a very bad and slow compiler that can compile your existing compiler yourself. 2014-09-18 16:19 yeah, you have to write your own trustworthy compiler 2014-09-18 16:20 easy, right? :) 2014-09-18 16:20 huh? no 2014-09-18 16:20 not at all 2014-09-18 16:20 I need to write *any* compiler 2014-09-18 16:20 then I compile each of them with one another twice 2014-09-18 16:21 the thing is, in general it is not possible to insert such backdoor (this could be even logically proven, but I'll just say it's obvious) 2014-09-18 16:21 so you have to rely on matching specific code in codebases you know. 2014-09-18 16:21 you have to write a compiler 2014-09-18 16:21 so? 2014-09-18 16:21 writing a compiler is straightforward 2014-09-18 16:22 especially when you don't need to be 1) fast 2) complete 3) display sensible errors for incorrect code 2014-09-18 16:22 without these requirements, it's not only straightforward, it's just trivial 2014-09-18 16:24 ok, you've written a compiler. Now, every time you compile it, you will get a bugged binary 2014-09-18 16:24 and every time you use that bugged binary , you get another bugged binary 2014-09-18 16:25 https://www.schneier.com/blog/archives/2006/01/countering_trus.html 2014-09-18 16:25 most important fragment: 2014-09-18 16:25 >This countermeasure will only fail if both A and T are infected in exactly the same way. The second compiler can be malicious; it just has to be malicious in some different way: i.e., it can't have the same triggers and payloads of the first. 2014-09-18 16:26 in essence, the effort required to detect this hack is not even within an order of magnitude of effort that is required to produce it. it's way, way easier 2014-09-18 16:26 and this process in fact happens in the wild all the time, e.g. when clang and gcc bootstrap each other 2014-09-18 16:27 kyak: the fun is that Ken wrote the C compilers in the go toolchain :) 2014-09-18 16:27 whitequark: ok, i'm reading now 2014-09-18 16:27 would you trust compilers from Ken? 2014-09-18 16:28 no; they created C. 2014-09-18 16:28 economically, likely the worst thing to ever happen to computing. 2014-09-18 16:28 xiangfu has quit [Remote host closed the connection] 2014-09-18 16:29 pcercuei has quit [Ping timeout: 255 seconds] 2014-09-18 16:29 :) 2014-09-18 16:34 whitequark: ok, i get it 2014-09-18 16:36 whitequark: so, when clang and gcc "DDC" each other, is V and W bit-to-bit equivavelnt? :) 2014-09-18 16:36 kyak: compiler bootstrapping does, in fact, check bit-for-bit equivalence 2014-09-18 16:36 as part of natural testing process 2014-09-18 16:37 but it's not really about that 2014-09-18 16:38 my point is that, for example, LLVM's history is public and cryptographically signed, and its internal structures change a LOT 2014-09-18 16:38 ditto for GCC. it's simply not possible to write a payload that would work on future versions of LLVM; you can't predict the future 2014-09-18 16:38 so even if *at some point in past* this happened, it's not working anymore 2014-09-18 16:54 zrafa: yeah.. 2014-09-18 16:54 rx pin keyboard :p 2014-09-18 16:54 you already need more help? :) 2014-09-18 17:18 pcercuei has joined #qi-hardware 2014-09-18 17:25 whitequark: i'm thinking if DDC would work for cross-compilers.. For example, gcc-arm - is there any compiler other than gcc that can compile gcc-arm? 2014-09-18 17:43 pcercuei_ has joined #qi-hardware 2014-09-18 17:46 pcercuei has quit [Ping timeout: 250 seconds] 2014-09-18 17:49 pcercuei_ has quit [Ping timeout: 250 seconds] 2014-09-18 18:02 pcercuei has joined #qi-hardware 2014-09-18 18:55 clang, of course 2014-09-18 18:56 clang can compile gcc ? :) 2014-09-18 18:56 cool! 2014-09-18 18:57 what? of course clang can compile gcc 2014-09-18 18:57 why is this even a question/ 2014-09-18 19:00 maybe gcc requires some strange gcc extetensions ;) 2014-09-18 19:01 I would expect GCC to contain crappy code that only GCC could ever compile :) 2014-09-18 19:01 that would not surprise me at all 2014-09-18 19:05 larsc: well, it sorta does 2014-09-18 19:05 it won't compile on a strict C99 compiler afaik 2014-09-18 19:05 maybe with some hacks 2014-09-18 19:07 I thought that GCC recently switched to C++ 2014-09-18 19:07 they started to welcome c++ code 2014-09-18 19:08 clang is more or less designed to compile what compiled in gcc, no? :) 2014-09-18 19:08 that's the goal yes 2014-09-18 19:08 so no wonder that it can build gcc 2014-09-18 19:09 but there is always some code somewhere that depends on some gcc specific behaviour 2014-09-18 19:09 viric: indeed 2014-09-18 19:09 and that will break on clang 2014-09-18 19:09 although it rejects the more egregious hacks 2014-09-18 19:09 this is becoming less and less true though 2014-09-18 19:10 clang for example does not support variable sized arrays on the stack 2014-09-18 19:10 which is only support by gcc by accident 2014-09-18 19:10 supported 2014-09-18 19:11 because they needed it for ada or something 2014-09-18 19:12 alloca ftw 2014-09-18 19:12 :) 2014-09-18 19:13 clang has alloca, of course 2014-09-18 19:15 variable sized arrays should be doable and easy. 2014-09-18 19:16 if it was the case, they would be supported 2014-09-18 19:16 take a look at clang's ML for details. 2014-09-18 19:16 that was a quick though 2014-09-18 19:16 t 2014-09-18 19:17 I'll read about it another day. Good that there is discusison though 2014-09-18 19:17 I have no idea honestly, but I know that clang devs don't drop a feature solely because of ideological concerns or something 2014-09-18 19:18 if it's not supported, it has a good reason behind it. 2014-09-18 19:27 wolfspraul has quit [Quit: leaving] 2014-09-18 19:46 good reasons don't mean easy agreement :) 2014-09-18 19:46 but can be. I don't use clang at all 2014-09-18 19:46 generally it is maintainability concerns 2014-09-18 19:47 gcc exposes a lot of accidental implementation details 2014-09-18 19:48 I never tried to write a compiler, so I might be not any good to judge :) 2014-09-18 19:49 well they are not part of the standard 2014-09-18 19:50 larsc: clang implements plenty of extensions 2014-09-18 19:50 if you want standard, use -pedantic :D 2014-09-18 19:51 http://clang.llvm.org/docs/UsersManual.html#intentionally-unsupported-gcc-extensions 2014-09-18 19:52 viric: oh, right, VLAs are only disabled *in C++* 2014-09-18 19:52 in C they do work 2014-09-18 19:52 with clang that is 2014-09-18 19:52 VLAs on stack, I mean. 2014-09-18 19:52 clang not having --print-sysroot breaks my Makefiles :( 2014-09-18 19:52 VLAs in structures are a completely different story 2014-09-18 19:53 the former is part of C99, the latter is uh 2014-09-18 19:55 yea, I think that's what sneaked in through the ADA support 2014-09-18 19:55 ah 2014-09-18 19:55 It was never meant to be in the C backend for gcc 2014-09-18 20:23 wej_ has joined #qi-hardware 2014-09-18 20:23 wej has quit [Ping timeout: 250 seconds] 2014-09-18 20:27 wej_ has quit [Ping timeout: 250 seconds] 2014-09-18 20:31 wej has joined #qi-hardware 2014-09-18 21:28 jow_laptop has quit [Ping timeout: 240 seconds] 2014-09-18 21:29 jow_laptop has joined #qi-hardware 2014-09-18 22:20 pcercuei has quit [Quit: dodo] 2014-09-18 22:52 dandon has joined #qi-hardware 2014-09-18 22:57 kristianpaul: he, I am okey so far :)