Riding the Flow

musings from the shire

Water Cooling? Not Needed!

So I was looking how quiet can I make my recent PC build. CPU was easy with good tower cooler (Noctua NH-U14S). Then I wondered if there any way to make EVGA GeForce 1080 TI SC2 any quieter - it has a decent cooling solution, but still the loudest component on full load.
I was told that "to make such powerful GPU quiet, you have to water cool". Surely, water cooling either by custom loop or by AIO can be done.
But then I wondered - if 2x120mm radiator seems to be enough to run 1080 ti quiet & cool, why such radiator can't be mounted on card directly, akin to CPU cooler? There seem to be enough space. And voila - apparently there is such a thing - aftermarket GPU air cooler. Specifically "Morpheus II" by Raijintek. Cost - about the same as 240mm radiator, but without associated costs (and noise) of extra plumbing & pumping.
Heat sink have arrived and I've mounted 2x120mm SilentWings 3 fans from beQuiet on it. These fans I consider the best performance/noise 120mm fan. At least until Noctua releases their new 120mm "Sterrox" model.
The thing looks really intimidating, with 12 (!) heatpipes. I guess rated 360W of TDP is not a lie!

Washing Machine Modding



So I have this washer-dryer which I really like, used it for years and for this reason even bought exact same model when moved to a new house.
It very good no-frills design, and, most importantly, actually performs all functions well - for example, dryer function actually produces *almost dry* laundry unlike my first Bosch which only produced damp&hot.
But it has one downside - it does not have an audible signal. With the main annoyance that you often miss the end of a cycle, which most commonly happens - you load the machine, it runs for some hours, then you busy with other things, and then its finished, but you've forgotten to check it. Its not the end of the world, but laundry sitting inside drum for long time quickly becomes wrinkled (and in dryer case it gives opportunity for moisture to re-settle).
Also even if you listening for machine to become quiet, this does not actually mean its ready to open the door - because there is time-delay lock on the door which clicks open only some minutes after.
Previously I've already done some repairs to it (when badly clipped cable got in contact with cooling fan which produced screeching sounds when dryer was on and chopped cable insulation). So I was familiar with layout more or less, and even managed to find the service manual with schematics.
So I've decided to mod the end cycle buzzer indication using some dirt cheap Arduino parts. The idea is very simple - Arduino sits here and monitors state of door lock, when it opens, it beeps for my attention.

Unsurprisingly, a lot of sellers from Asia are now looking at Amazon as good trading front for their business. While not being stereotypical and there are always exceptions, there are a awful lot of "cost effective goods" sellers here (read: awful goods when you truly get what you pay for).
I have found (by my own prolonged experience) that great amount of these sellers on Amazon nowadays employ following tactics (almost identical, save by bits of difference here and there):

Powering Your Gadgets in the Wilderness



In discussions with other gadgets users, often the problem of getting extra power comes up. Particularly when you are away from power outlets for prolonged time - e.g. on the nature hike.
Two "miracle solutions" always inevitably come up - using muscle power ("wind-up chargers") or using solar power. On first look, they appear to be perfect. However, they have very significant shortcomings in reality:

My PC configuration involves single big SSD to store data (currently 512GB Crucial M4). This provides best performance and convenience of single hard drive.
However, for obvious reasons it makes regular backups even more paramount - since SSDs are being generally less reliable than usual magnetic drives.
To backup data, I use 2.5" hard drive enclosure, connected with eSATAp(Powered eSATA) interface - this way only single cable is required, while providing maximum speed and transparency.

Previously I was using Windows 7 built in backups (System Image), protected with Bitlocker to Go encryption. But recently I was badly burned by this setup, when my SSD developed single faulty bad sector. It wasn't too bad, until Windows Backup failed to properly backup this and didn't indicate a fault - but aborted backup early indicating a "success". Then it became apparent only after I tried to re-image SSD using this corrupt backup - necessitating a roll-back to previous, 1+ month older backup. At least I've managed to get access to older one, which wasn't very user-friendly either (since Windows Backup stores previous backup versions inside hidden Shadow Copy instead of normal files, also it could purge old ones quite unpredictably).

So, I've started to look for more professional and transparent backup solution, and came over quite big number of alternatives. I've tested them in my configuration (backing a fast SATA3 SSD onto large, but no-so-fast external HDD).

CityHash64 and Finding Collision Samples for it

200px-Hash_table_4_1_1_0_0_1_0_LL.svg[1]CityHash is a modern family of hash functions for strings (variable-length arrays) that provides one of the best performance and quality, requiring only standard 64-bit instructions for optimal performance.
This makes it very useful "general-purpose" hash. In particular, CityHash64 hashes to 64-bit value, which makes it primary function of choice on 64-bit platform.
For some tests (e.g. containers), it's beneficial to know which pairs of strings will produce same hash value (collision). Finding collisions for well-designed hash function could be difficult - since brute force most likely will be most viable approach.
I've recently have calculated some collisions for CityHash64 using multi-threaded birthday attack algorithm. So I provide two such pairs there for your convenience:

  • StrA="oH]pPZccPmOEHjBW" StrB="vm`sd|obCXIKJ}aE" CityHash64=DCBE2B1930540000
  • StrA="?];lLLK:R_@XddTg" StrB="bgW^Wi]IkQgDM3WW" CityHash64=9E75C019D3D94BB7



I've bought the Logitech K360 wireless keyboard in addition to K800 just to try, which one I will like more (K800 was the obvious first choice, because of standard full size layout, palmrest, backlit keys and unifying nano-receiver support).

I wanted to also try K360, because it has compact layout that I like coming from laptops (dispenses with right-side key duplication), and also it looked much like my laptop chiclet keyboard (that I liked).

However, on actually trying the K360 out I've found it to be worse in feel: