Alexander Leidinger

Just another weblog

Nov
19

ADSL RAM avail­able soon… I hope

I am wait­ing since about two years that my ADSL line gets switched to rate adap­tive mode (ADSL RAM). This would allow my modem to try to use the line until its limit, instead of the fixed rate it has now. I can not get a higher fixed rate (2 MBit down­stream), because the line is too long. My modem tells me that it could do a lot more (less than 8 MBit down­stream). I do not expect that the modem is able to fully pre­dict what it can do when it is allowed to max-out the line, but I expect that it is more than the 2 MBit I have at the moment.

Yes­ter­day a tech­ni­cian of the line-provider I know told me that they are now allowed to switch lines to ADSL RAM (at least in my region). Great news. I directly told he shall have a look if he can switch my line. It will be inter­est­ing to see what I am actu­ally able to push/pull over the line… and if/when the line will be switched (it will be done the offi­cial way by one of his col­leagues).

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Nov
19

Intel­li­gent elec­tric­ity meters? More ben­e­fi­cial things exist (but need improvement).

In Ger­many you need to install an intel­li­gent elec­tric­ity meter if you make larger changes to the elec­tric­ity instal­la­tion in your house (or if you build a new one). At first this sounds inter­est­ing. If you look closer, you need to decide if you want to laugh or to cry.

Such an intel­li­gent elec­tric­ity meter is able to dis­play the cur­rent power con­sump­tion in a dig­i­tal dis­play (if the power con­sump­tion stays the same, you can test with this how much power a spe­cific device needs). It is also able to attribute the power con­sump­tion to dif­fer­ent times of the day. An optional fea­ture (here in Ger­many) is the pos­si­bil­ity to trans­fer cap­tured data to the power com­pany. It is not required that the home-owner is able to see all or even any data from an intel­li­gent elec­tric­ity meter.

The promises are, that with such a device peo­ple could pay less money by using the wash­ing machine or the dish washer or sim­i­lar devices dur­ing times when not much peo­ple want to use energy.

So far so good, but…

  • My wash­ing machine or dish washer are about 1 – 3 years old. We did not buy the cheap­est ones, but they do not offer to start the wash­ing upon input from an exter­nal sig­nal or just by acti­vat­ing the power (if they lose power, the cho­sen wash­ing pro­gram is reset to the default pro­gram). Am I sup­posed to buy a new one?
  • The power con­sump­tion of all the nec­es­sary infra­struc­ture (dig­i­tal stuff in the elec­tric­ity meter, net­work con­nec­tion to the power com­pany) is not zero, and it is the owner who has to pay for this.
  • When every­one is wash­ing when not much peo­ple want to use energy, a lot of peo­ple want to use energy in such moments. It may still help a bit the power com­pa­nies because they do not have to gen­er­ate power (and have expenses because of this) which is not used, but I doubt the con­sumer will get a big reduc­tion then.
  • The dura­tion of such power-surplus times with a reduced price may not last dur­ing the com­plete time a wash­ing machine needs. It may be even the case that a high-price time slot may get acti­vated shortly after (if this is done by (mali­cious) intent or not is not even rel­e­vant, as the con­sumer can not do some­thing about it as he is prob­a­bly sleep­ing when this hap­pens in the night).
  • The power com­pany may be able to get a detailed trace of what hap­pens in a house (the own­ers are get­ting up at 11am, only take a shower every two weeks, have prob­a­bly a big plasma TV which runs all the day, …).
  • I doubt the device is free of secu­rity holes or pro­tected enough against eaves­drop­ping (with all the pro­fil­ing impli­ca­tions, or pos­si­bil­i­ties to manip­u­late the data (pos­i­tively or neg­a­tively) directly in the device before trans­mis­sion to the power company).
  • I do not think the most intel­li­gent and consumer-friendly devices will come with enough sta­tis­tics or access-possibilities to really sat­isfy the consumers.

More inter­est­ing would other things which could help cut costs. For exam­ple small low-power net­worked sen­sors which detect if a window/door is open, the tem­per­a­ture in a room, the out­side tem­per­a­ture, the sun­light inten­sity and so on. Together with some actu­a­tors like for exam­ple to close the win­dow, close the shut­ter, change the heat­ing, turn off lamps and so on, it would pro­vide much more imme­di­ate ben­e­fit. In a new build­ing, the net­work could be wired, but in an old build­ing the sen­sors need to be wire­less and battery-powered.

A pos­si­ble solu­tion could be done via blue­tooth v3 in a mesh net­work (yes, if it is not open source, I would also be scep­ti­cal if the com­pany which pro­duces this has enough knowl­edge to make it secure), polled by a cen­tral sta­tion which could put the sen­sors in silent standby to reduce the amount of radio pol­lu­tion and increase bat­tery life­time. If some of the sen­sors and actu­a­tors are con­nected (e.g. room tem­per­a­ture and heat­ing actu­a­tor plus a clock), you could even let it run in autonomous mode (time based heat­ing to a spe­cific tem­per­a­ture) and only need to con­nect to it if there is a spe­cific need. Such a sit­u­a­tion could be that the win­dow sen­sor detects an open win­dow, so the heat­ing can be turned off. Or maybe the sun­light inten­sity sen­sor detects (or the base sta­tion esti­mates) an intensity-rise of the sun­light, so the heat­ing could be reduced in advance.

Some­thing like this would give imme­di­ate ben­e­fit (in com­fort) to those who install it, and in a long-term view it would/could cut the costs down a bit.

I am aware of some wire­less sensors/actuators, but they are rel­a­tively expen­sive, the radio pol­lu­tion (and type) is unknown to me, and the pro­to­col is not open, so I do not know if it is secure and how to improve things I do not like.

Any­one with enough hard­ware knowl­edge and open source/hardware spirit out there to pro­duce a mod­u­lar base for sensors/actuators (blue­tooth + I/O for sensros/actuators/pc-connection + controler)?

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Nov
02

Are USB mem­ory sticks really that bad?

Last week my ZFS cache device — an USB mem­ory stick — showed xxxM write errors. I got this stick for free as a promo, so I do not expect it to be of high qual­ity (or wear-leveling or sim­i­lar life-saving things). The stick sur­vived about 9 months, dur­ing which it pro­vided a nice speed-up for the access to the cor­re­spond­ing ZFS stor­age pool. I replaced it by another stick which I got for free as a promo. This new stick sur­vived… one long week­end. It has now 8xxM write errors and the USB sub­sys­tem is not able to speak to it any­more. 30 min­utes ago I issued an “usb­con­fig reset” to this device, which is still not fin­ished. This leads me to the ques­tion if such sticks are really that bad, or if some prob­lem crept into the USB subsystem?

If this is a prob­lem with the mem­ory stick itself, I should be able to repro­duce such a prob­lem on a dif­fer­ent machine with a dif­fer­ent OS. I could test this with FreeBSD 8.1, Solaris 10u9, or Win­dows XP. What I need is an auto­mated test. This rules out the Win­dows XP machine for me, I do not want to spend time to search a suit­able test which is avail­able for free and allows to be run in an auto­mated way. For FreeBSD and Solaris it prob­a­bly comes down to use some disk-I/O bench­mark (I think there are enough to chose from in the FreeBSD Ports Col­lec­tion) and run it in a shell-loop.

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