WD and Sandisk 1TB SD Card - Page 1
Forum section: electronics / general

author: strangersound
author_rank: Regular Contributor
timestamp: September 20, 2016, 08:43:13 pm
content: I've seen a few reports today on the anti-social medias about a new SD card with 1TB capacity! It blows my mind that they can get that much storage capacity in that small of a footprint. That has to be at, or getting awful close to the limits of current materials and their physical limitations.Link:http://www.thephoblographer.com/2016/09/20/western-digital-sandisk-announce-new-1tb-capacity-sd-cards/

author: rdl
author_rank: Super Contributor
timestamp: September 20, 2016, 11:08:22 pm
content: I ordered a couple of flash drives from Newegg today to run a FreeNAS setup from. While I was shopping I saw plenty of 64 GB drives in the $15-20 range. Capacities go up and the price comes down. I look forward to the day I can get rid of the last spinning disk I own.

author: MK14
author_rank: Super Contributor
timestamp: September 20, 2016, 11:17:19 pm
content: Quote from: strangersound on September 20, 2016, 08:43:13 pmMy understanding is that they stack the chips (dies/wafers), in 3D. So there is little limit as such (while the wafers are very thin, and the height is not too much). Unlike cpus, which would get very hot if you did that, flash can cope quite well with 3d stacking.https://en.wikipedia.org/wiki/Three-dimensional_integrated_circuit

author: System Error Message
author_rank: Frequent Contributor
timestamp: September 21, 2016, 02:03:08 am
content: Its not only just stacking chips/wafers but the manufacturing process shrinks. Just like with CPUs it allows to pack more into a smaller area/volume.1TB flash shouldnt be a shocker, i've seen servers with 2TB of ram. Imagine being able to just use RAM and not needing any slow storage.There are solutions involving RAM, PCIe cards and backup battery so you can use RAM as storage and it appears as a disk to the OS so if your bios supported PCIe disk booting you would have a really fast system.

author: IanB
author_rank: Super Contributor
timestamp: September 21, 2016, 02:14:49 am
content: I fear that as the capacity grows the storage cells shrink and become less reliable and more likely to lose their contents over time.When I buy USB flash sticks I always try to buy the oldest, lowest capacity ones I can find. Given that flash is an inherently non-permanent storage technology I figure that it will be more reliable if it is not stretched to the limits.

author: MK14
author_rank: Super Contributor
timestamp: September 21, 2016, 02:47:09 am
content: Quote from: IanB on September 21, 2016, 02:14:49 amI agree that later and later processes, seem to be using less and less reliable mechanisms for data flash storage. I especially worry when more than 1 bit per cell techniques are used (i.e. analogue like). But maybe one day, it will improve.My understanding is that the (especially the cheaper ones) flash pen drives (and probably SD cards), use bin sorted, poor quality flash chips, which should not really be used. Hence that is why they are so cheap. I.e. Defects have been found on the chip, and instead of playing safe and binning/rejecting it, they are using it as very cheap storage. I guess that over time the defect(s), can spread and the device can hence break, losing all your data.So it is best to get quality branded flash drives (such as Sandisk, Kingston etc), from reputable sources (to avoid dodgy fakes e.g. don't use ebay) and NOT trust it with important data, keep copies/backups and DON'T use it for long term storage of important data, unless it is another copy/backup of already well backed up/copied data in the first place.

author: raptor1956
author_rank: Frequent Contributor
timestamp: September 21, 2016, 03:09:13 am
content: I'm more blown away by 256GB uSD cards and they've been around for a while. I mean we're talking literally the size of a fingernail.My first full on PC, not counting the Commodore Vic 20, was the very first IBM PC in 1982 and it was maxed out with 48KB of RAM, the Vic 20 had 4KB. We landed on the Moon with computers that had about 100KB as I recall. My first PC with a hard drive, the IBM PS/2 Mod 50, had a 20MB HD. That size HD would be about enough storage to hold about 4 seconds of HD video from my Panasonic GH-2 and less than 1 second of 4K video...Things change...Brian

author: System Error Message
author_rank: Frequent Contributor
timestamp: September 21, 2016, 03:41:19 am
content: Actually as cells shrink their endurance decreases, not their ability to retain data. What happens is that the cell cannot reliably change its state anymore so effectively becomes read only. It is permanent so go buy the latest if you want. There are different types of flash (SLC, MLC,etc) that all have their speed, endurance and other difference.When i buy an SSD i bought intel's midrange as its not too expensive but its reliable and with good read/write endurance.If you are using it as a drive to store documents and stuff permanently than the write endurance doesnt matter.

author: Brumby
author_rank: Unknown
timestamp: September 21, 2016, 03:42:50 am
content: Quote from: System Error Message on September 21, 2016, 03:41:19 amBut is data retention reliable in the long term?

author: System Error Message
author_rank: Frequent Contributor
timestamp: September 21, 2016, 03:45:14 am
content: Quote from: Brumby on September 21, 2016, 03:42:50 amYes, as the term read only implies. Infact SSDs/flash are known to be much better at storing data than hard drives. The final state of an SSD's write endurance is either die or the drive becomes read only. An SSD's life span is determined by how much you write and rewrite to it whereas hard drives have mechanical aging.

author: IanB
author_rank: Super Contributor
timestamp: September 21, 2016, 03:49:45 am
content: I'm not sure that flash memory has reliable data retention. Everything I have read says it doesn't.The technology basically works by storing charge inside an insulated cell (basically charging up a capacitor). It will only retain data for as long as the charge doesn't leak away. As the storage cells get smaller they hold fewer and fewer electrons, and at some point quantum tunneling becomes a statistical probability. Even if the cell is a perfect insulator an electron can tunnel out and escape.Never expect flash memory to retain its data indefinitely. It may hold data for years, but not forever. It is not archival storage.

author: MK14
author_rank: Super Contributor
timestamp: September 21, 2016, 03:50:19 am
content: Quote from: raptor1956 on September 21, 2016, 03:09:13 amI'm also blown away, at how much storage can be put into a tiny micro SD card.I still remember the early days where home computers used cassette tapes for storage. Their capacities were tiny, they were extremely slow (taking minutes, usually to load a 5K approx program), and somewhat regularly the load from the tape, would fail and you'd have to wait another few minutes, after waiting for the tape to rewind.....

author: Halcyon
author_rank: Unknown
timestamp: September 21, 2016, 04:30:05 am
content: Quote from: raptor1956 on September 21, 2016, 03:09:13 amSimilar to this? ;-)

author: Jeroen3
author_rank: Super Contributor
timestamp: September 21, 2016, 06:22:26 am
content: Quote from: IanB on September 21, 2016, 03:49:45 amIt does not. Flash maybe has 20 year-ish before bits start failing. And SD cards don't offer parity as hard disk iirc.If you make them hot, it's even shorter. Sorry desert people.But, SD cards are not designed for long term storage.

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: September 21, 2016, 07:12:57 am
content: People bag magnetic media a lot, but when it comes down disaster recovery, your chances with magnetic media is a hell of a lot better than with flash storage. (Of course, the trick is never getting into that situation in the first place, no matter what you use.)

author: wraper
author_rank: Unknown
timestamp: September 21, 2016, 07:16:07 am
content: Quote from: Brumby on September 21, 2016, 03:42:50 amFor such huge capacity you can expect 1-2 years, then data will start corrupting.

author: XOIIO
author_rank: Super Contributor
timestamp: September 21, 2016, 08:05:01 am
content: Quote from: IanB on September 21, 2016, 02:14:49 amAgreed, I only use 256mb flash drives to back up my laptops 1tb hard drive.

author: dannyf
author_rank: Super Contributor
timestamp: September 21, 2016, 11:07:07 am
content: A recent test I saw had several ssd drives involved in an endurance test where they repeated wrote massive amount of data to those drives until failure. I think 3 of the 5 240g drives started to fail after 1 PETA bytes. The last two were still going at 2 PETA bytes when the test was haulted.That tells you something about the endurance.

author: Chalcogenide
author_rank: Regular Contributor
timestamp: September 21, 2016, 11:35:01 am
content: If I am not mistaken, the endurance specification is such that, after the rated number of P/E cycles, the cells still have the capability to retain the data for 10 years at the maximum specified operating temperature. At least that's what a manufacturer said they do.Thus you can effectively write them a lot more times, you just won't have the specified data retention capability any more.

author: System Error Message
author_rank: Frequent Contributor
timestamp: September 21, 2016, 05:08:43 pm
content: SSDs have some space set aside for this sort of errors. Like with hard drives both have cells/sectors that are preserved incase of an error.I have my OS on raid 0 intel SSDs and the boot times are really fast. I install sdks and programs on it for the same reason. Games i put on raid 0 hard drives for faster loading times and space.SSD's capability to hold data works even for large capacity flash. Both drives have their advantages in how you use them. SSD's get slow with write if cells are all used up as resetting a cell takes time.The backlash that hard drives get is because of monopoly and price. The backlash that SSDs get is fear of a controlled life span despite the fact that flash has longer life span than hard drives. Some SSDs fail prematurely because of the controller so what matters is who makes the chips when you buy flash and the sort of controller/features that SSDs have.By constantly writing to SSDs, it takes 1 year at least to wear out a decent SSD for a lower capacity one. Higher capacity ones take longer. By constantly writing as in writing at the max speed it can, this could be consistently like 500MB/s so 1 year of 500MB/s is a huge amount of data.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: September 21, 2016, 05:24:19 pm
content: Quote from: System Error Message on September 21, 2016, 02:03:08 amSure, but have you seen how much space that RAM takes up? Lay all of the modules out flat and it's hundreds of square inches. An SD card is ~1 square inch. If you could fit 1 TB of ram in the same ~1 square inch SD form factor I would be equally impressed.

author: MK14
author_rank: Super Contributor
timestamp: September 21, 2016, 05:30:47 pm
content: Quote from: suicidaleggroll on September 21, 2016, 05:24:19 pm1 TB in a tiny SD card, is getting crazy.I guess that they can effectively just "PRINT" out flash memory devices these days, and are still not at the Moore's Law limits yet. What with wafer/die stacking, high density memory devices (per die), and the huge ready market for SD cards, SSDs, Flash pen drives, and all the other uses for flash memory, including most MCU's (some built in, some external flash chips).The huge potential market is needed, to raise/pay the billions of dollars for new technological developments in flash and the flash making semiconductor wafer factories.E.g. Google Chrome books, usually come with 32 or 64 GB flash drives built in and other stuff.Wild Speculation:Even blu-ray disks, could one day be replaced by flash devices, if cheap enough. That would be a huge ready market.

author: strangersound
author_rank: Regular Contributor
timestamp: September 21, 2016, 05:49:27 pm
content: Thanks for the replies, folks. Good read.

author: dannyf
author_rank: Super Contributor
timestamp: September 21, 2016, 07:08:10 pm
content: You can esstimate flash life easily.Say that you have a 240gb drive. Flash endurance is 1000 writes. That means lifetime write of 240tb.Assuming 1mb/s writes to the disk (much worse than your typical usage), that translates into 240 million seconds, or 7plus years, with lots of upside.So worrying about ssd life is a little too conservative,

author: David Hess
author_rank: Super Contributor
timestamp: September 21, 2016, 07:33:37 pm
content: Quote from: Jeroen3 on September 21, 2016, 06:22:26 amAll high density NAND flash uses error correction.Old 50nm NOR flash still maintains the 20+ year retention associated with older floating gate memory but high density NAND flash does not and has to rely on idle time data scrubbing which is not something to count on in anything smaller than a SSD.All of the high density USB drives I have tested lost data in just under a year whether powered or not which could explain why specifications for retention time are so rare. I had some older network gear which stored the firmware in NAND flash which lasted about 4 years.

author: Rick Law
author_rank: Super Contributor
timestamp: September 21, 2016, 07:38:01 pm
content: Quote from: dannyf on September 21, 2016, 07:08:10 pmYou are assuming a leveled-write. If you write to the same cell, you are gone in 1000 writes. As it gets cheaper, there may be build-in leveling, or not... Even with leveling, it may not a bit/byte-level leveling but instead a block leveling.Trouble with today's CPA approach (cheapest price available) used by both the manufacturers and the users, it is hard to get quality stuff.Quote from: Chalcogenide on September 21, 2016, 11:35:01 amThen there is the problem of initially specs verses evolving specs as time goes on. Initially, it may follow the manufacturing specs. As time goes on, their production line may move from (say) USA to Japan to China to Thailand to Vietnam then to some other hole in the ground some where. Each move, the spec may go down a bit or the margin got narrower.So, you have your 3 drive in your raid5, replaced one, and the exact model lasted less than the other two original ones. That happened to me with magnetic drives and I imagine the same would happen with flash and other drives.

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 21, 2016, 07:53:33 pm
content: This really is mind blowing. My first computer had a 10GB drive, and I know that you don't have to go THAT far back to see computers with <1TB drives. Floppies were the only removable media at 1.39MB.Now we have flash cards that are basically bigger than the hard drives in computers that were not THAT long ago.Micro SD cards blow my mind too. So tiny.

author: David Hess
author_rank: Super Contributor
timestamp: September 21, 2016, 08:11:17 pm
content: Quote from: Red Squirrel on September 21, 2016, 07:53:33 pmI prefer the SD form factor *because* it is larger and at least you can write an identifier on it. I have already lost Micro SD cards.

author: dannyf
author_rank: Super Contributor
timestamp: September 21, 2016, 08:11:46 pm
content: "My first computer had a 10GB dri"My first computer had punch card readers and a hard drive that sits in an air-conditioned room and sounds like a machine gun on fire.My first PC had a cassette tape record and used a TV monitor.My first IBM PC had a 64k RAM board and used floppy disks.My first ibm PC with a hard drive had a huge 10mb capacity, and a power switch in the back......As to retention, I have a 128mv cf card that I last used about 10 years ago. The pictures on it are still usable.There is a CMU/LSI article that put the retention life of mlc flash memory to 1 yr at room temperature. I doubt that's accurate or representative at all.

author: raptor1956
author_rank: Frequent Contributor
timestamp: September 21, 2016, 08:32:35 pm
content: Quote from: Halcyon on September 21, 2016, 04:30:05 amMinus the Mac...Brian

author: raptor1956
author_rank: Frequent Contributor
timestamp: September 21, 2016, 08:38:58 pm
content: I seem to recall that flash memory that's reached it's end of life due to write cycles can be "refreshed" by thermal cycling. Not sure what time and temp but the idea is that thermally cycling kind of resets things. How long before we have flash memory with integrated heaters to periodically heat them. That would almost certainly wipe anything in memory at the time, but perhaps the device could be programmed to perform the heat cycle when it get near the write cycle limit AND it's being formatted. Might need to pop up to ask user if they want just to format or if they wanted to format with a heat cycle.Brian

author: darko31
author_rank: Regular Contributor
timestamp: September 21, 2016, 08:43:36 pm
content: Important data should be backed up regularly regardless of media used. Mechanical disks are great until they suddenly fail. SSDs at least have read only option when worn down (although my OCZ Vertex 2 failed suddenly, but that is firmware problem, not flash itself).As cost per GB fall, SSDs will surely take over and mechanical disks will be used for legacy systems or some niche market.I usually have more confidence in electronic only systems rather than mechanical/electronic systems. Generally speaking electronic systems proved to be more reliable and cheaper than mechanical.

author: MK14
author_rank: Super Contributor
timestamp: September 21, 2016, 09:03:24 pm
content: Quote from: raptor1956 on September 21, 2016, 08:38:58 pmAll I can easily google about it, is a patentPDF fileEDIT: Replaced with direct link to page:https://www.google.ch/patents/WO2012151454A2?cl=en&hl=deIt basically seems to say that "trapped" electrons, caught in the wrong place, after multiple flash writes, are RELEASED by heating it to about 100 degrees C, and maybe 120 to 150 deg C, for minutes or hours.I would be skeptical, if the only source of this phenomenon is a patent, trying to make money from their possibly wrong theories.I could not quickly find any other confirmation of this flash heating repair/rejuvenation scheme. But it might work, I don't know.

author: dannyf
author_rank: Super Contributor
timestamp: September 21, 2016, 09:06:14 pm
content: "flash memory that's reached it's end of life due to write cycles can be "refreshed" by thermal cycling. N"A Taiwanese company has a paper on that. No commercial products so far.

author: David Hess
author_rank: Super Contributor
timestamp: September 21, 2016, 09:27:14 pm
content: Quote from: dannyf on September 21, 2016, 08:11:46 pmThe first programming language I learned was 8080 machine code ... literally. I did assembly by hand on a special pad of paper and typed the hexidecimal code into a Prolog PROM programmer. This was during the paper tape era.QuoteOlder Flash memory used larger processes so the retention time was better.Quote from: darko31 on September 21, 2016, 08:43:36 pmIn this case though, SSDs and high density NAND Flash memory in general have known issues which lower the reliability that would otherwise apply to an all electronic system.Retention time is low and getting lower although vertical stacking helps with this because of the larger process size used. For floating gate memory built on a larger process like with microcontrollers, this is not a problem because the retention time is high enough to not significantly affect long term reliability when it is limited by other factors.NAND floating gate memory in particular has additional problems including read disturbance and write disturbance where soft errors can be created in adjacent memory cells during normal operations. Even worse, if a write is interrupted, it can result in complete corruption of other areas of memory so special steps have to be taken to ensure all writes are completed. It is not enough like on a mechanical hard disk to ensure writes occur in order. A log file system does not protect against corruption of random locations. This is how I suspect most cases of sudden SSD death occur.So what is to be done about long term Flash storage? Use a Flash device which supports idle time scrubbing and leave it powered. Make sure it either supports write completion or backup its power source.

author: strangersound
author_rank: Regular Contributor
timestamp: September 22, 2016, 07:14:59 am
content: Thanks again for the discussion. I found this and figured it might be appropriate to add:

author: MK14
author_rank: Super Contributor
timestamp: September 22, 2016, 09:00:42 am
content: Quote from: strangersound on September 22, 2016, 07:14:59 amThe thing is, although most/all of EEVblog forum members, would realize that floppy disks use magnetism, and the data can be damaged by external magnets. There are many people who do not realize this, and so can make silly mistakes like that.I like to think that I know about computers, but until I read this thread. I did not even know that you could get 1T SD cards (I would have probably guessed that 256GB or 512GB was the limit, with 1T being a possibility).

author: rdl
author_rank: Super Contributor
timestamp: September 22, 2016, 02:16:04 pm
content: I generally don't trust any spinning disk drive beyond three years or so, depending on how much it's used, but haven't worried about flash memory because I don't use it much. Then I remembered that the CF card in my camera is over 10 years old.I checked on Newegg and for some reason, prices for CF are 4x or more higher than for flash drives or SD cards for any brand I would trust. And of course, anything smaller than 16 GB is scarce. I don't really want that much for a 6 megapixel camera.

author: David Hess
author_rank: Super Contributor
timestamp: September 22, 2016, 03:17:01 pm
content: Quote from: MK14 on September 22, 2016, 09:00:42 amIf it was a ZIP disk, then the embedded servo tracks can be damaged as well as the data rendering the disk unusable.

author: MK14
author_rank: Super Contributor
timestamp: September 22, 2016, 03:55:19 pm
content: Quote from: David Hess on September 22, 2016, 03:17:01 pmIn theory even mechanical hard drives could be (data) damaged by powerful magnets. But in practice, I've not seen that happen.They could have taken over floppies as the standard PC portable/removable re-recordable media, but failed to ever get to that point. I'd mostly forgotten about Zip drives. I guess CD's won the race, once they had writable had rewritable versions available at sensible prices.Not everyone realizes that writeable CD's can be damaged, by long term exposure to sunlight. I.e. not being kept in the proper cases, and left out, uncased on a desk or somewhere. I'm not 100% sure about this, but some sources think that is the case, and the dyes fading in too much light makes sense, especially UV rich sources, such as sunlight.

author: David Hess
author_rank: Super Contributor
timestamp: September 22, 2016, 04:27:59 pm
content: Quote from: MK14 on September 22, 2016, 03:55:19 pmI never saw it happen either. The high coercivity of the media needed to support high density also means that only the directly adjacent write head could generate enough field strength to affect the media.QuoteI never thought this could happen simply because ZIP disks were way to fragile; anything which erased the data also erased the embedded servo information ruining the disk. Floptical designs like the LS-120 did not have this shortcoming and were backwards compatible but ZIP disks ruined it for everybody.Magneto optical on the other hand was impervious to everything short of physical destruction.QuoteIt might not even require UV and some of the dyes degrade rapidly with increased temperature.

author: strangersound
author_rank: Regular Contributor
timestamp: September 22, 2016, 06:02:02 pm
content: The old Zip drives. I forgot about those things. I still have my external Zip drive and a stack of discs, a few of which did the dreaded Zip thing. Everybody knew that of you heard "that noise", then your disc was done for. At the time, though...and with my system at the time, it was decent choice for doing backups...until they got the reputation for failure. But I only had a couple of them fail. I used them for doing downloads and general file storage. It was a good way to have a second drive and keep your primary clean, defragged, and dedicated to OS and software. And the discs were pretty much available everywhere, so if you needed one in the middle of the night, the grocery store would have them next to the floppies.Hard to believe CDr/w's and DVDr/w's have pretty much come and gone. Being a home studio guy, I bought a stand alone CD recorder before computers were really up to the task. A Phillips for $500 and it's sitting here as obsolete as can be. But I used it a lot the first couple of years I had it. For doing mixdowns, it was pretty much untouchable. Plus, it was a dual tray unit, so dubbing CD's was also an option I used a lot.It wasn't too long after that computers got a lot better suited for audio tasks, with better sound cards, speed, etc...and then CDR drives were pretty much standard, and you get could get blank CDRs a dime a dozen. The Phillips required the "Music" designated CDR blanks, which was much more expensive. And the fastest you could dub was 2X, so the computer became the primary tool for burning CDR's. Then DVDr/w's came along and I used those for backups and portable files for a few, but once USB sticks showed up...I was doing some DVDr burning not long back for Linux distros. I was trying every distro I could find and it was easy to just put a distro per disc and then I spent a week giving one of my P4's a workout trying them all. My P4 with 512megs was a good baseline to do a head to head. Ubuntu 10.04 actually runs as quick on that P4/512 as Vista does on the laptop I'm using right now, which is a 2.2GHz with 2gigs of ram. I had first used Ubuntu on a P3 Optiplex and it never seemed to run very long without crashing, so I was pleasantly surprised when it ran so well on the P4. I'm guessing the P3 hardware was somehow not kosher, but I'm no expert.I'm not the oldest computer guy, my first real computer was a Pentium II with 256megs of ram. This was a top of the line HP at the time. I still have it, did quite a few upgrades to it over the years, and it still runs to this day. I graduated to that after using a Brother word processor for a few years. I had friends in Jr High that were into stuff in the TI/Commadore days, but I was into music and stuff. But if you started and floppies were the standard removable media, then a 1TB SD card is pretty mind blowing.

author: MK14
author_rank: Super Contributor
timestamp: September 22, 2016, 06:27:17 pm
content: Quote from: David Hess on September 22, 2016, 04:27:59 pmYou've made me feel better. I thought that I remembered that ZIP drives were optical (and magnetic), so thought I was wrong, when I googled it, and sure enough it is ONLY magnetic.But I was confusing the ZIP drives (which I don't think hit the UK/Europe in any real quantity), with (similar to me) Floptical LS-120 and similar, which DID appear in the UK/Europe, but only in relatively small quantities, as they were not very popular.I guess that new upcoming computer storage media concepts needs a certain combination of low cost, ready availability, popularity with computer manufacture's and supplies etc etc, to succeed.A bit like VHS tapes vs Betamax.E.g. Blu-rays were at one point being competed against HD DVD discs, which rapidly disappeared, once the suppliers/manufacture's of them agreed they had/would lose the war, against blu-rays.Magnetism losses strength extremely rapidly, as distance increases, so I guess it would need a crazy high magnetic field, to damage the data of hard disks. As you said the "The high coercivity of the media ...", and distance forced by the casing of hard disk drives, makes it relatively immune to such effects/damage.Quote from: strangersound on September 22, 2016, 06:02:02 pmI sometimes worry that I've lived long enough (hopefully I'm not that old), to have seen so many things, go from not existing, to being popular, to being obsolete, to being forgotten.Video Tape Recorders etc etc.(I'm not saying if I was around when they first came out) Glass colour crt TV's, are rapidly disappearing.Even tungsten light bulbs (Obviously I'm not more than 100 years old), at least in the UK/Europe where they are banned from sale, in most cases, are rapidly disappearing. Compact florescent bulbs may well disappear, as LED's gain popularity.I'm NOT overly impressed with SD cards. They are a bit unreliable/untrustworthy and tend to lose data and/or break, all too easily. They also are rather slow (relatively speaking, in many cases) and lack some features, such as allowing computers to boot from them and there can be compatibility issues between different devices.As maybe sooner or later, they will be replaced by something which hopefully solves, most/all the problems (and others), I just mentioned.E.g. They should be capable of very fast speeds, these days, and more robust/compatible etc.

author: David Hess
author_rank: Super Contributor
timestamp: September 22, 2016, 08:37:01 pm
content: Quote from: MK14 on September 22, 2016, 06:27:17 pmHard drives became so resistant to this that it became difficult or impossible to securely erase them using standard degaussing equipment leaving just physical destruction.QuoteThis is a major problem where I live. Our power is so dirty that the half life of a CFL or LED bulb is only months making incandescent bulbs more cost effective even with their lower efficiency. The manufacturers and distributors make it as difficult as possible to take advantage of any warranty (or just ignore you) so the theoretical warranties are a joke.QuoteExcept for the corruption caused power loss while writing and low retention time problems, there is nothing which prevents making Flash media reliable. I have old Compact Flash cards which have proven to be reliable enough in light duty continuously powered SSD applications.What is really needed is a signal to the Flash device ordering it to finish writes including those produced by idle time scrubbing and then a reply signal indicating that all writes have stopped or a specified maximum time to idle; then an external power backup could safely remove power from the Flash device. Manufacturers will never implement this though because it would be an admission of the unreliability of Flash despite their marketing lies and it would undermine market segmentation which makes not failing do to loss of power a premium feature.They make SATA to SD card adapters which allow booting from the SD card. I think this is more of a problem with lack of support by the hardware when the SD card interface is integrated.

author: System Error Message
author_rank: Frequent Contributor
timestamp: September 22, 2016, 08:45:31 pm
content: if power supply is dirty your best bet is to get a circuit to clean the output. This is tricky but it also limits the amps. Existing circuits cost a lot so you will need to build one. This is an electronics forum so it should be 2nd nature.Some UPS also have the ability to clean a circuit output. Other ways are to use solar and batteries (similar to UPS too)Some good computer PSUs will provide clean output even on a dirty AC input, you may want one with a universal voltage input and a good quality PSU. With a dirty AC input you cant use the PSU at it's rated watts.You can always buy datacenter grade SSDs, they have better reliabilities, and features you dont get on the cheap mainstream ones.

author: David Hess
author_rank: Super Contributor
timestamp: September 22, 2016, 09:15:19 pm
content: Quote from: System Error Message on September 22, 2016, 08:45:31 pmI have a bunch of online UPSes and some of them can be used for power conditioning without the batteries installed but with the various house lights on separate circuits which may or may not be shared with other things, adding a power conditioner would effectively requires rewiring the whole house.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: September 22, 2016, 09:33:07 pm
content: Booting to SD is a firmware issue with the device you're using. Many computers boot from SD - I boot of onto a customised Windows PE on my Mac quite often.SD cards are fine for burst writes or large continuous files, but their random/4K read/write is mixed, even with UHS Class 10s. More comparable to the dogshit eMMC storage.

author: rdl
author_rank: Super Contributor
timestamp: September 22, 2016, 09:35:13 pm
content: I have one of these.I've never run across a computer that could boot from USB where it wouldn't work. You can still get similar ones, though they look more like a normal flash drive with the card slot in the side.

author: MK14
author_rank: Super Contributor
timestamp: September 23, 2016, 09:18:30 am
content: Thanks for all the help/tips with booting from SD cards.I've got some SD to USB converter things, so I'll try and boot from them, when I'm next messing with that kind of thing.Somewhere I had read that you CAN'T boot from SD cards, and that is why I thought you couldn't.I did know that you can buy devices which let you boot from SD cards (converters). But I read reviews, mentioning that many of them were problematic (if I remember correctly).Compact Flash, are like IDE hard disk drives, and readily boot. I have got a computer, when it worked (it broke), which had a CF slot and could readily boot from it. It was a very low power consumption, and very small PC. Only about the size of a box of 10 5 quarter inch floppies.I did know that some servers can boot from SD cards, with special things, built into the server, such as Dell ones.It means that I can try a few different versions of Linux and stuff, with a handful of cheap SD cards, if I can reliably boot from them. Speed would be really slow, but I can cope with that for test/evaluation purposes.I know you can get HDD slots, with caddies (like on servers), and external HDD Sata boxes, which let you rapidly slot in HDD's (and SSD's), very quickly.It is just so cute, cheap and easy to use SD cards. So if those adapters work, that will be very useful.(My fallback solution is just to use a few USB Flash Pen Drives, but it tends to be a slow way of doing it.).

author: MK14
author_rank: Super Contributor
timestamp: September 23, 2016, 09:47:03 am
content: Quote from: David Hess on September 22, 2016, 08:37:01 pmI feel sorry for you. I've had a similar problem with compact florescent lights, in some of my light fittings. My electricity supply is basically good and fine. Where the bulb(s) were loose in the light socket, they may break too soon. Even sometimes just switching them on, if the switch is slightly noisy (bad contact), it can break the bulb.That was when compact florescent bulbs, could be around £10/$15 each, so it was annoying to lose them like that. They have come down in price a lot, over the years, so it is not so bad.I guess LED bulbs are the thing to go for in the UK, now. When my existing ones wear out, and I use up any spares. I'm going to move over to LED's. My (mostly) compact florescent ones can last for many years, so I've not needed LED's yet.I avoided early LED lights, because I was worried they would be inferior, to other types.If you only go into a room very rarely (toilet, storage cupboard with light etc), tungsten bulbs can do a very good job, with almost instant on, bright and will last many years or more in such a situation.I try and avoid the cheapest bulbs these days and go for good makes and/or positive reviewed bulbs. In the hope they last the longest and will be reliable, with a good/even light source.I'm somewhat annoyed that they had to make a law (in Europe), banning the sale of most/all tungsten bulbs. Because I'd prefer to make my own decision, as to what type(s) of bulbs to use. If they had recommended/advertised/promoted LED and other low consumption bulb types, then fair enough.But banning them seems too extreme for me.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: September 23, 2016, 09:49:21 am
content: Quote from: MK14 on September 23, 2016, 09:18:30 amIf you're serious about it, then I would just pick up a cheap 120-ish GB SSD for about £30-40 and a USB 3 to SATA adapter. Not much more expensive than SD cards and will ultimately save you considerable time with transfers, compatibility and boot/RW speeds.

author: MK14
author_rank: Super Contributor
timestamp: September 23, 2016, 10:05:28 am
content: Quote from: RGB255_0_0 on September 23, 2016, 09:49:21 amI am very serious about it. That is a good idea, because it should be reasonably quick as well.It might be possible to use an ESata connection, to directly plug the SSD's in.SSD's have been falling in price a lot over the years. They are probably cheap enough now, to do exactly what you just said.(The other attraction of SD cards, was that you can get them for say £10 each, with reasonably high capacities).What I've already done, is use the USB flash pen solution. Allowing me to try out different versions of Linux, without committing my self to changing the main HDD's operating system. You don't even necessarily need more than one flash pen, as you can fairly quickly re-purpose the same one, time and time again.BUT the flash pen solution (with a USB2 port, rather than a quicker USB3 port), was too slow. Just about fast enough to use, but too slow, really.Anyway, you have convinced me to use SSD's, in the future. As you say, they are cheap enough now, to use like that now. I can either use USB3 as you suggested, ESata or some kind of rapid Sata plug in system (like you have on many servers, on the front of the rack server. The caddie systems, are available from computer suppliers, for about £50 to £75, for the cheaper ones, with about 4 slots).