MavEtJu's Distorted View of the World - 2009-10
tzsetup(8) changes
128 bit Operating Systems Riverbed Blog Authorism Distributed telephony done properly Nintendo Wii hardware problems How my brain works DST is here again! Project VP - 50% successrate Back to index tzsetup(8) changesPosted on 2009-10-22 09:00:00 In the last couple of days I have scratched a couple of the itches I had with regarding to the timezone database on the FreeBSD Operating System, all related to the (in)ability to update /etc/localtime automatically or quickly:
This feature is currently only available in FreeBSD -CURRENT, after the release of 8.0 I will merge it back into FreeBSD 8.0 and 7.0. The port misc/zoneinfo and the installation script of src/share/zoneinfo do support these new features. No comments | Share on Facebook | Share on Twitter 128 bit Operating SystemsPosted on 2009-10-18 22:00:00 While Microsoft is preparing Windows 8 to be 128 bit compatible, a lot of people went from "as if we ever need that much space!". 64 bit to address your Random Access Memory, that is indeed enough (for now), but as a Storage Offset number it is nearly there: The terabyte harddisks already need 41 bits offsets! bits addressable space 1 1 byte 2 2 3 4 4 8 5 16 6 32 7 64 8 128 19 256 10 512 11 1024 kilobyte 12 2048 13 4096 14 8192 <- memory of my first computer (Philips P2000T, 1982) 15 16384 16 32768 17 65536 18 131072 19 262144 20 524288 21 1048576 megabyte <- memory of my first "own" computer (AT 286, 1992) 22 2097152 23 4194304 24 8388608 25 16777216 26 33554432 <- my first harddisk in 1992. 27 67108864 28 134217728 29 268435456 30 536870912 31 1073741824 gigabyte <- memory of my computer in 2001 (p6) 32 2147483648 33 4294967296 34 8589934592 35 17179869184 36 34359738368 37 68719476736 38 137438953472 39 274877906944 40 549755813888 41 1099511627776 terabyte <- Fits on one single harddisk in 2008 for AU$ 130 42 2199023255552 43 4398046511104 44 8796093022208 45 17592186044416 46 35184372088832 47 70368744177664 <- for US$ 7,867 (Backblaze, September 2009) 48 140737488355328 49 281474976710656 50 562949953421312 51 1125899906842624 petabyte 52 2251799813685248 53 4503599627370496 <- Internet Archive in March 2009 54 9007199254740992 55 18014398509481984 56 36028797018963968 57 72057594037927936 <- Addressable in a 64 bit offset 59 144115188075855872 58 288230376151711744 59 576460752303423488 60 1152921504606846976 exabyte 61 2305843009213693952 62 4611686018427387904 63 9223372036854775808 No comments | Share on Facebook | Share on Twitter Riverbed Blog AuthorismPosted on 2009-10-12 22:00:00 Guess what! After a "Social Media Introduction Course" last week, today I've been approved as an author for the Riverbed Blog Website. I still don't know what the first article will be about, but I will give it my best try (Did you expect anything else here?) No comments | Share on Facebook | Share on Twitter Distributed telephony done properlyPosted on 2009-10-12 19:00:00 Recently I have been involved in the design and installation of a global VoIP telephone system and learned a few valuable lessons. The call-flow design and requirements were as follows:
So far nothing spectacular, but the issues came when mapping calls on the network. Normally people differentiate between internal and external calls by dialing the 0 (or 9 if you are stuck with an American based PABX, or 91 if you want to make a long distance call in the USA) before dialing the local number. After the 0, you more or less have captured a channel on the PRI and are able to call anything via that, local or national or international as long as you play via the rules of that PSTN. For example in Sydney, Australia: You can dial an eight digit local number, a ten digit local number or a ten digit national number. And if you prefix your call with a 0011, you end up on an international call. On a distributed telephone system connected to various PSTNs, this will be a nightmare for the people to remember (0, 0011, 86 plus a string of numbers for China) which has to be translated by the PABX to +86 plus a string of numbers which has to be send to the PABX in China so it knows how to translate it back to the a China local number etc etc etc. Both a nightmare for the users and for the PABX maintainers, plus a nightmare for the travelling salesman. So, instead of having a single prefix for an external line for a local or national call and an international call, let's split it: Prefix local or national calls with a 0 and make the international access an *. Yes, that's a * because it looks most like the international prefix +. So the PABX maintainers now know when to handle local calls and national calls. The only tricky part is left over with the international calls, but it is less tricky than what it was. Instead of having to write a different parser for for each country to figure out when an international call is placed, they just check for the * prefix: No check of 0,0011 in Australia, an 9,011 in the USA, 0,00 in Europe, just check for the *. Next is to map of the next one, two or three numbers on the remote destination telephone system, which we just send their national call telephone number and wait for it to be connected. So, if you have enough local offices, you will be able to call a lot of international telephone numbers for the cost of a national telephone call! So no more 9,0011 1 415 123 4567 to call, just *1 415 123 4567! It will save money (It will be a cheap local call for the telephone system. Or a free call if the destination is a free number), it will reduce the number of buttons to press (9,0011 -> *) and it will prevent from making silly counting mistakes (missing 1 in the string of numbers to be pressed). The whole system was implemented on the open source PABX Asterisk and a central monitoring / configuration server which kept track of which international prefixes needed to be forwarded to which telephone system. The implementation showed that its fail-safe design worked as expected when the office in Germany lost its internet connectivity for a three days and nobody complained that their calls to Germany didn't work anymore. The overal telephone bill got reduced to 20% of the original cost, having the whole system paying for itself it as little as eleven months! (Although we still have three months to go :-) So: Stop thinking about local calls and national calls and international calls, only think about local / national calls and international calls. Don't think about local international call prefixes, handle that on the PABX. International calls should be routed to remote PABXs which handle it locally. And only if a remote call can't be completed due to no free PRI channels or the remote PABX not being reachable, then handle it locally. No comments | Share on Facebook | Share on Twitter Nintendo Wii hardware problemsPosted on 2009-10-07 12:30:00 Last weekend Hanorah managed to break the Nintendo Wii: Forcing a second DVD into the chassis kind of ruined it for everybody. On its own this isn't a big issue, but considering that this month everybody in the family got addicted to Super Mario Galaxy, the tensions in the house rose faster than a couple of neighbouring countries with old wounds and money to spend on armies. As usual, fixing this thingie seemed impossible. This guide on how to disassemble your Nintendo Wii talked about a tri-wing screwdriver (which I didn't have (but found in a shop in Bankstown)) and a normal small screwdriver. Thanks to the above mentioned guide, I knew which screws to unscrew. Three minutes later I had found the problem (some metal bars of the disk lifting mechanics were bended) and rectified the problem. The disk spinned again! I had removed a total of 20 screws, in six different shapes and sizes. In the good engineering tradition I managed to put the Nintendo Wii back in into its original shape leaving seven screws on my desk which didn't properly fit in any of the holes currently still unoccupied. And this metal cover also didn't make it back into the box... Nintendo, please reduce the amount of different screws because this is just bad design. Anyway, I'm off to collect Star Bits and Stars and Grand Stars, because Bowser still has Princes Peach in his captivity!
How my brain worksPosted on 2009-10-05 09:00:00 With the move to Australia I have learned a particular thing about my brain: I can't remember names without seeing them written down. This presents itself mostly when watching television or movies: The names of persons (an overal problem), but also about medical issues (Skully in the X files, House), city names and star systems (Star Trek :-). Last week I was reminded about this when discussing the latest episode of The United States of Tara: I didn't kow the names of any of the characters except for Tara. I know there is a husband, a son and a daughter (and on the side line a sister, a fast-food shop-manager, a boyfriend of the son and a psychiator), but I don't know any of their names. Neither the name of any of the personages Tara transforms in (except for Buck, which is a name I saw in the subtitles of Kill Bill). I have seen numerous episode of The Bill (UK Police series), but I won't be able to name any of the characters in there. I have seen numerous episodes of House but can't name his colleagues or female boss. This issue has never been a problem when I lived in the Netherlands, because all the foreign television series and movies are subtitled. So I know all the names of the people in Star Trek and Babylon 5, and I know part of them in Battlestar Galactica (Starbuck, Apollo (is he in the new one?), Boomer and Adama because they were in the old series which I saw with subtitles) but the name of the president or the second in command on the Galactica or the name of the scientist are all unknown to me. That didn't mean that having the BBC was useless for me, thanks to the subtitles on the Teletext system "behind" the broadcast I was able to follow everything. So, what does this leave for me in Australia? Not much, there is no Teletext system on the normal channels and there is only one channel, SBS, which has subtitled movies and series (because they are non-english). Before the re-run of every episode of Dr Who and Torchwood I read up on the TARDIS Wikimedia website to make sure I know who is who this time. At least I know the limitations and the workarounds, but it's very tricky sometimes! Show comment | Share on Facebook | Share on Twitter DST is here again!Posted on 2009-10-04 17:45:00 For the next six months, we will have DST in large parts of Australia again. The blogosphere is full with people who don't like it (for the right or wrong, the good and dumb reasons) and are under the impression that their opinion on this issue is important. See also Parkinson's Law of Triviality and the example of the Colour of the Bikeshed.
I for one am happy with the extra hour of daylight.
Give me the DST time of days all of the year! No comments | Share on Facebook | Share on Twitter Project VP - 50% successratePosted on 2009-10-04 17:30:00 After two months a quick status update: The beetroot looks fine, we will hopefully have three rows of beetroot in a couple of months. The carrots is a full failure: Of the seven rows, only ten plants came up. So today I aborted them all and started with a new batch of seeds. We also fertilized it with a full year worm-farm output, which will hopefully kickstart the process again. No comments | Share on Facebook | Share on Twitter |
