Posted on by Paolo Redaelli

One full week camping at the beach, being just dad, full time.

One full week without turning on a laptop.

Perché la parola inglese “password” non viene quasi mai tradotta?

Eppure la traduzione precisa e corretta è sempre esistita: “parola d’ordine“.

Or mi chiedo,

Perché “password” non è tradotta con “passaparola”?

Certo, può sembrare un orrendo calco dell’inglese. A questo punto mi domando perché gli inglesi sfornano neologismi come una catena di montaggio e trovano nuovi usi per parole vecchie.

Perché noi no?

 

Already?

Posted on by Paolo Redaelli
Inforce IFC 6410
Inforce IFC 6410

I have overestimated the capabilities of my Inforce 6410. To be truly honest I knew that most ARM boards and the OSes running on it are 32bit and this includes Raspberries, but

“everyone knows that 4Gb of address space is enough for everything”

me, now, mocking the famous “640Kb ought to be enough for anybody. ” misattributed to Bill Gates

Ok, ok. Actually I have understimated the requirements of mongodb which – I shall admit – already warned me ominously that 32bit may be a problem.

Oh, my! I would have never guessed that I would have hit the limit. Well, I filled mongodb with 1,8Gb of crypto-trade data. Ok, not a small base of data I shall admit, but far from the addressing limit of 4Gb. This log entry tought scared me a little:

2017-07-03T15:05:22.897+0200 [conn135] ERROR: mmap private failed with out of memory. You are using a 32-bit build and probably need to upgrade to 64
2017-07-03T15:05:22.898+0200 [conn135] Assertion: 13636:file /mnt/cartoni/mongodb/zenbot4.3 open/create failed in createPrivateMap (look in log for more information)

I should have remembered that 32 bit kernels usually leave only 2Gb of addressing space for user-land programs.

I think I will end up using a good old x64. More power hungry, I know, but at least I won’t hit such limits.

All in all I launched only 5 paper-trading zenbots to compare various trading strategies.

Usb flash drive and wear leveling

Posted on by Paolo Redaelli

From: linux – How to correctly partition usb flash drive and which filesystem to choose considering wear leveling? – Super User an useful little change to fstab for usb sticks or SD attached to your ARM boards, like Raspberries or Inforce 6410:

Also, in your fstab, be sure to use the mount option “noatime” to avoid unnecessary writes every time a file is accessed.

As normal settings usually tend to wear out the flash relatively fast.

Posted on by Paolo Redaelli

Ah, the magic of Bash!

for y in {1..30..7}; do
for x in {60..1}; do
DA=$(date -d "-$(($x+$y)) days" +%Y-%m-%d);
A=$(date -d "-$x days" +%Y-%m-%d);
echo -n "Simulazione per $y giorni da $DA a $A: ";
./zenbot.sh sim --strategy trend_ema_reversed --start $DA --end $A | grep "end balance" --after-context=2 |tr "\n" "\t"; echo "...";
done;
done |tee valutazione.txt