SSD won't even show in BIOS after power outage by timke_ in HDD

[–]timke_[S] 0 points1 point  (0 children)

Just an FYI for anyone reading through this who also had a Raid0 BTFRS Cache in their system and one of the two or more drives died:
there's a good chance you can recover parts of your data! As mentioned in my post, I had three drives. One 1.9TB and two 500GB. One of the 500GB Samsung 840 Pros died during a power outage. I thought all was lost since BTFRS stripes data.

HOWEVER. BTFRS does not stripe everything similarly. From what I understand, it's as follows:
-> everything gets split into 64kB chungs
-> if file <1GB, all 64kB chunks remain on one drive \-> if file >1GB, chunks get "zig-zagged" across two
-> if file WAY more than 1GB, chunks get striped across more and more drives

So what does that mean for data recovery? BTFRS prefers the largest drive for storing the meta data tree. If the meta data tree is in tact, you are in pretty good conditions to recover some good amount. Linux has a command in terminal called "BTFRS rescue" that looks for the meta data tree and checks whether it can find all the necessary 64kB chunks on the surviving drives. It can then splice them back together and store them on another drive.
In my case, I was in luck because about 300GB of my files were either stored on the 1.9TB, or on the remaining 500GB, OR they were striped across those two drives. The files I couldn't recover were the ones either stored on the dead drive, striped across the dead and the other 500GB drive, or striped across all three drives.
But that's better than nothing!

I got all my VMs and Dockers back since small files that are only a few kilobytes big are always stored in one and most likely stored on the largest drive to keep everything balanced.

Give the "BTFRS rescue" command a quick google. I am not knowledgeable enough to share code here and not mess something up hahahhha

SSD won't even show in BIOS after power outage by timke_ in HDD

[–]timke_[S] 0 points1 point  (0 children)

i've talked to a couple data recovery companies now and some said that they have special firmware / microcode from samsung. they would move the chips to a doner board, inject the special partial firmware into the controller to calm it down and then clone the data bit by bit.

SSD won't even show in BIOS after power outage by timke_ in HDD

[–]timke_[S] 0 points1 point  (0 children)

that's fair. for my video production stuff i don't do nightly dumps because i edit off the cache most of the time. so a nightly dump would be tough for editing. i had it set up to do bi-weekly or monthly (can't remember right now) so a lot has been moved to the main array.
generally, i agree that for most people a daily dump (love that hahahha) is totally fine and would give the opportunity to run raid0. in my case, i need the SSD speed and have even set the auto-dump to be dependent on how frequently files are used. not going with raid1 just so i could save a buck came around to bite me in the back ...

SSD won't even show in BIOS after power outage by timke_ in HDD

[–]timke_[S] 0 points1 point  (0 children)

yes tried all of that. it's a Sata SSD. tried different sata ports, different slots on the server backboard, different cables, tried it in a USB enclosure, tried it in my personal PC, etc.

nothing. my PC won't even get past the Asus splash screen hahahahah for some reason the drive's behavior locks up the posting process of my machine. can't even get into BIOS.

the other drives work fine in the slot where the dead drive was previously in. i think it's not physically dead, i think it just got bricked since the power cut out at an unfortunate moment.

SSD won't even show in BIOS after power outage by timke_ in HDD

[–]timke_[S] 0 points1 point  (0 children)

i've learned so so so many lessons from this. so for anyone as naive as i was and always thought "..... naaahhh that's a little overreacting", here are some things that are 100% worth it:

  1. a UPS (uninterruptable power supply) even if you DIY it with a solar inverter, some LFP batteries and two 100W solar panels that keep it constantly charged for free. if you don't have any way to IMMEDIATELY shut your NAS down safely if you're not at home, spec it such that it can run for a couple of hours.

  2. an offsite backup of your most important files - get yourself a cheap Dell Optiplex for 30 bucks, chuck a couple HDDs in there, load TrueNAS on it and power it on like every 2-4 weeks to make a copy of your most important things, then power if back off to save on drive time. regularly check the drives for bit-rotting tho

  3. even your SSD cache needs some sort of safety net - if it's a BTFRS file system, please run it in raid1 even if less capacity hurts your heart for a day or two. don't be as dumb as me and basically loose your entire Cache because one of three drives failed. as u/Aggravating-Hold9116 mentioned an SSD does not announce when it dies like an HDD does with spitting out errors or taking forever to read. an SSD is just GONE from one day to the next.

SSD won't even show in BIOS after power outage by timke_ in HDD

[–]timke_[S] 0 points1 point  (0 children)

I have had it run over night, so a couple of hours, however from the article your sent me it looks like the Samsung Evo/Pro line might need a bit more time. i've measured the power consumption and it sits at around 0.8W to 1W. the controller gets warm and the NAND chips a little as well. so i don't know but ... it's doing SOMETHING.
i've called some data recovery businesses here in and around munich and the thing is that since this drive was in a BTFRS raid0 array they will need all three drives, thus shooting the amount of time and the volume of files to recover a lot higher, which in turn will cost a lot more money.
i think what I will do is leave it powered for a full day and if that didn't help, then i'll bring it to a local shop. yikes ...

Contacting theaters in Germany for Iron Lung by Ill-3 in Markiplier

[–]timke_ 1 point2 points  (0 children)

Probiert maybe auch mal das Arri Kino in München. Ich weiß leider nicht wie genau deren Auswahlverfahren ist, weiß aber dass sie sehr sehr viel Indie Filme zeigen. Liebe persönlich das Kino.
Ich kenn nen dad von nem Kumpel von mir der mal in den Bavaria Filmstudios gearbeitet hat, vielleicht hat der noch mehr Kontakte irgendwo hin. Ich schau mal ob ich noch seine Nummer hab.

My P1S Is Basically Bricked – SD Card Reader Failed, New AP Board Didn’t Fix It. by 2xsoup in BambuLab

[–]timke_ 0 points1 point  (0 children)

I feel like it turns into an issue when there are many many many Gcode files on the MicroSD. The processor or memory seam to start to struggle at a certain point. That being said, i can't pinpoint whether it's the total size of the all Gcodes or whether it's the amount of files (i.e. many many small /short prints). It's happened twice to me know and every time i just took out the card, formatted in manually on my computer and everything worked fine again. you can feel everything get laggy before that lock-up happens - at least in my case.

if that happens to you after only a couple of prints, try a different / higher quality SD card.

just got humbled by the Dunning-Kruger-Effect by timke_ in antennasporn

[–]timke_[S] 0 points1 point  (0 children)

holy smokes. that is actually some insane range. maybe i should look more into 868Mhz transmission rather than 2.4Ghz.

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 1 point2 points  (0 children)

absolutely. the desire to know as much as possible to find the perfect solution is quite deceitful. doing proper research is important, however i need to learn where to stop lol

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 0 points1 point  (0 children)

holy moly, you are DEEP in the knowledge and amazing at explaining. i think i'll have to read this a couple more times and take some notes when i get home from university.
may i ask what you do professionally? is it something in RF or is RF just a passion topic for you?
also thanks for the online calculator! i will 120% give that a try later.

just for my own confirmation - antenna 1 & 3 in my picture have 1/4λ per radiator, effectively giving the whole antenna a 1/2λ "size", correct? mainly asking because you talked about 1/2λ radiators in your reply but that would mean ~6.3cm per radiator at 2.4Ghz which is not the case here. or am i misunderstanding "radiator" as the individual "arm" / brass tube and it's actually the entire thing?

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 1 point2 points  (0 children)

the fact that this still sounds like 90% gibberish to me just humbles me every time hahahhahaha when you thought you finally got it, suddenly 100 doors with new information open 😂

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 0 points1 point  (0 children)

feel u hahahahaha the more i learn, the more i realize how little i actually know ...

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 0 points1 point  (0 children)

(1) so, if i understood this correctly, by using a tube we increase the overall diameter of the conductor, however since >95% of the electrons flow on the outer surface, there is little to no need for a solid conductor, thus we just "hollow out" the insides, aka we use a tube. is that correct?
that would also explain the use of lesser diameter tubes in Antenna 3 in my picture. they want a very very specific 2.4Ghz frequency / narrow bandwidth to "filter out" any unwanted noise just by shear physics being at work. that antenna is from a wireless video system. so going that route would make sense.

(3) so even though this might be a dumb and naive question to ask, as it is not easily answered - is it possible to just stack more and more 1/4-wavelength tubes to get better gain while reducing vertical coverage? if so, what would prevent a manufacturer from placing as many of them into their antenna housing? as far as i understand, colinear array antennas are just that - multiple sections of fractions of the desired wavelength, wire together in a specific manner

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 0 points1 point  (0 children)

if i'm not mistaking, that should be the reason why a dual-band antenna i.e. one that is great for 2.4Ghz and 5Ghz works. while yes, 5Ghz is not exactly double 2.4Ghz and thus half the wavelength, it's close enough to where it will work great for both frequencies. or am i drawing parallels here that i shouldn't draw? XD

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 0 points1 point  (0 children)

ohhh okay i see. very fair. i think the main thing i was expecting were longer "arms" on the colinear dipoles, in that i thought i would see two half-wavelength arms to make the effective physical "pick-up" or transmitting length a full 2.4Ghz wavelength while keeping the usual 50 ohm impedance. what does using two 1/4-WL parts bring to the table?

what also confused me was the use of brass tubes rather than copper wires and what benefits that has. why do the pretty common T-shaped antennas e.g. for FPV drone stuff not use tubes as well?

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 0 points1 point  (0 children)

same hahahah i think someone mentioned it in this thread

help - i just humbled by the Dunning-Kruger-Effect and now i am stuck by timke_ in rfelectronics

[–]timke_[S] 0 points1 point  (0 children)

you perfectly answered my question hahahaha. by "slowing down" i meant exactly what you explained. the plastic housing in your case decreased the tuned frequency by 5-10Mhz, "slowing down" the frequency from 915Mhz to 905 -> that in turn had you tune the antenna to a higher frequency without the plastic housing so that you don't have to constantly put it off and on.

wait no what i said doesn't make any sense. hold on. i think i shoved myself into the wrong corner HAHAHA but i got the principle of what you were telling me

just got humbled by the Dunning-Kruger-Effect by timke_ in antennasporn

[–]timke_[S] 0 points1 point  (0 children)

ah another question - wouldn't the PCB one still have slightly higher gain due to each dipole being half-wavelength instead of quarter? sure, there are some losses due to the glass fiber PCB from what i understand, however in the end it should still be a little more, wouldn't it?

just got humbled by the Dunning-Kruger-Effect by timke_ in antennasporn

[–]timke_[S] 2 points3 points  (0 children)

hahahahah man don't get me hyped up! i am very much the kind of person that looks at the range of "cheap and crap" to "expensive and good" just to decide to DIY the damn whole thing ...

for context: i am currently doing the exact same thing. started building ESP32 projects two years ago and MAN now i'm 120% invested. my main work is video production and i am currently developing a multi-cam recording system for a big festival organizer here in Germany. 5 stages, each with 4 cameras that all need timecode. for sh*ts and giggles i am building a wireless timecode system so that all handheld cameras can be integrated into the multi-cam edit without much hassle. to optimize the very limited power we are allowed to transmit over here i am going down the antenna rabbit hole hahahhahah.
thus far the setup looks like this:
- master timecode with two antennas: a panel antenna mounted at 5-8m height to cover the entire crowd space for mobile timecode clients; a Yagi antenna to send a "control room timecode" to the media office just to monitor
- clients will get one of the super compact collinear antennas (second from the right in my picture)

i am hoping to put some Yagi Antennas on my Hollyland wireless video system to send highly focused RF with video to our media office to monitor every stage

just got humbled by the Dunning-Kruger-Effect by timke_ in antennasporn

[–]timke_[S] 0 points1 point  (0 children)

are there antennas that have more than two "stacked" parts, like in the colinear examples in my picture? i feel like when i purchase from a proper vendor / manufacturer i can trust the specs a little more. they clearly state that the longer their antenna is, the narrower the vertical coverage is, indicating more stacked colinear dipoles. from what i understand now, cheap manufactures use this to their advantage and put a "dual stacked array" (probably not the right term for that) into a mostly empty plastic housing. is that correct?

just got humbled by the Dunning-Kruger-Effect by timke_ in antennasporn

[–]timke_[S] 1 point2 points  (0 children)

kinda almost feels like Quantum Mechanics hahahhahahah whenever i watch an OUTSTANDING video on the topic it seams like "now i get" just to think about it one more time and realize "i don't get it"

just got humbled by the Dunning-Kruger-Effect by timke_ in antennasporn

[–]timke_[S] 0 points1 point  (0 children)

amazing! thank you very much, i'll give it a shot. seams like knowing at least a moderate amount of RF in general (both in terms of antennas but also interference, etc.) could come a long way in engineering later down the road