Ideas page up­dated

I up­dated my ideas page. I ad­ded an entry about us­ing com­pressed air to auto­mat­ic­ally re­move snow (or sim­il­ar) from sol­ar cells, and an entry about maybe us­ing heat from thermal sol­ar cells to gen­er­ate elec­tri­city at home. I also up­dated the entry for non-​optimal weath­er op­tim­ized sol­ar cells with a link to a com­pany which seems to do some­thing sim­il­ar (us­ing a lens) to re­duce the cost of sol­ar pan­els. To cool down the photo­vol­ta­ic cells, the com­pany is us­ing a heat ex­changer to make a com­bined photovoltaic/​thermal pan­el. Un­for­tu­nately they are mak­ing an un­fair com­par­is­on of the com­bined out­put of this pan­el (the thermal power out­put is much high­er than the elec­tric power out­put) with a nor­mal photo­vol­ta­ic cell. A nor­mal house­hold needs more elec­tri­city than heat so you do not want to use a lot of such pan­els, but de­pend­ing on the feas­ib­il­ity of my idea about us­ing heat to pro­duce elec­tri­city, such a pan­el could be in­ter­est­ing.

Google’s new RE en­gine

I stumbled over Google’s new RE en­gine. Un­for­tu­nately it is not hand­ling back­refer­ences, so it is not a drop-​in re­place­ment for the reg­u­lar ex­pres­sions code in FreeBSD. It has a POSIX mode, but this only seems to be enough for the egrep syn­tax. For people which need back­refer­ences, they refer to the Google Chrome’s RE en­gine ir­reg­exp which in turn ref­er­ences a pa­per from 2007 which is titled Reg­u­lar Ex­pres­sion Match­ing Can Be Simple And Fast.

The tech­niques in the pa­per can not be ap­plied to the ir­reg­exp en­gine, but maybe could help to speed up awk, egrep and sim­il­ar pro­grams.

I think it would be in­ter­est­ing to com­pare those re­cent de­vel­op­ments to what we have in FreeBSD, and if they are faster, to see if it is pos­sible to im­prove the FreeBSD im­ple­ment­a­tion based upon them (either by writ­ing new code, or by im­port­ing ex­ist­ing code, de­pend­ing on the cor­res­pond­ing li­cense and the lan­guage the code is writ­ten in).

Maybe a can­did­ate for the GSoC?