Zip Drive Reliability

[drew1]

My wife is a teacher & going over, consolidating, upgrading lesson plans, etc. She asked me if zip drives were good with deletions ^ saving more on them through the years.

I told her I would post on Pelican for some of the IT folks to share their knowledge.

[SeanPizzle]

Zip drive? didn't those go away about 10 years ago?

[Por_sha911]

I have used Iomega Zip drives ever since they first came out. The first drive I used was 100meg and it plugged in between the computer and printer via a parallel cable! IIRC, the last version were 750's. The 100's and 250's I use are pretty old now but they still work fine. I use an external USB drive. I like that they write and rewrite extremely fast and with the USB I can rely on using them with any machine. I also use an external HD for full backup but the Zips are great for ultra important info that needs to be stored off site. Just save, put in the case and pop it into my pocket. I've never had a problem with data loss.

The only thing to look out for is that the discs themselves do have a lifespan and you will find that after using them for years (maybe thousands of times) they will have "click death" where the disc will keep clicking and take longer to read or write. As soon as that happens, stop everything and move the data to a new disc and throw the old one out because eventually it won't read.

I know Zips are old school but they work well and they are durable long term storage.

[Por_sha911]

Originally Posted by SeanPizzle

Zip drive? didn't those go away about 10 years ago?

So did air-cooled 911's but mine gets 27 mpg highway at 75 mph and I can work on it without needing $100k in Porsche special tools.

[drew1]

I have shown my ignorance. I meant USB Flash Drive.

[Por_sha911]

In that case,

[dad911]

Only time i've lost data on a USB drive was by losing the drive, or leaving it in a pocket and it went through the wash......

I doubt she would ever 'wear it out' by use.

[RWebb]

she should back up her USB drive info onto a Zip drive every year and store it off site

or use a DVD

[stomachmonkey]

I've had a thumbdrive survive the washer and dryer.

[slodave]

Thumb drives seem to die after the third time through the wash.

[djantlive]

solid state flash drive is about as reliable as it gets. you will more likely lose it than having it corrupt on you. data safety and loss is the higher concern here.

[spuggy]

Sold-state (flash) drive long-term reliability is a factor of build/part quality, software quality (of the wear-levelling algorithm used) and the total # of writes (typically 10,000 per individual sector).

Important for an SSD disk you're using for a main system drive (where speedup can be tremendous).

For an impromptu backup drive you use once a week? Sure, go for it with any old $10 USB stick. Also take a backup to DVD now and again and stick the files in the cloud if you have no privacy concerns (or encrypt them if you do).

Certain popular OS's may eat your data at any time; for example, after a power fail you might find yourself stuck with dozens of "recovered" (but unusable/unidentified directories) containing 100's or "recovered" (but corrupted and useless) files.

Backups just aren't optional if you care about the files.

[RWebb]

wear-levelling?

[spuggy]

Originally Posted by RWebb

wear-levelling?

On any computer disk, some files almost never get re-written (program files, shared libraries etc) whereas log files, temporary files, browser cache etc get written all the time.

On a "real" disk, the logical sectors that got written would actually always be the same physical sectors (unless they went bad during use and were re-mapped to a sector from the spare list by the drive itself).

"Wear levelling" is how flash drives transparently shuffle writes around so that constant writing to the same logical sector (as far as the OS/user is concern) actually gets distributed over the entire writeable area, so every part of the drive gets somewhere close to those 10,000 writes before it dies of old age and writes start to fail.

This means that you get a lot more use out of the flash drive - it lasts a lot longer.

USB thumb drives probably don't do wear-levelling. Never bothered to check. If they do, they probably don't do a very good job. Not an issue unless you write to it all the time.

SSD (Solid State Disk) drives intended to replace spinning disk in computer definitely do do (heh, I said "do do" ) wear levelling.

[RWebb]

thx - this means the silicon "wears" out from repeated writes?

at the junctions? or?

[StaceyAnthon]

I also use an external HD for full backup but the Zips are great for ultra important info that needs to be stored off site.

[azasadny]

I've only worn one USB "thumb drive" out and it was a freebie from Symantec, so it probably wasn't up to snuff, quality-wise...

[Halm]

I am a IT consultant and play with all kinds of products and technology as part of my job. I was given a 64 Gb flash drive that I loved. Slowly over a 3-4 month time period, pretty much all my needed / portable files ended up on the drive.

Long story short, it crapped out on me after a few more months and I lost everything that was on it. And it was treated about as gently as one can with theses devices.

I still use them, but smaller capacity and routinely back it up on a fault tolerant system.

YMMV

[Por_sha911]

Bottom line is that the more important the data is, the more redundant your backups should be and there should be a copy off-site in case of fire.

[spuggy]

Originally Posted by RWebb

thx - this means the silicon "wears" out from repeated writes?

at the junctions? or?

Actually, erase cycles. After enough of them, the block cannot be erased, one or more individual memory cells representing a single bit in a larger 8/16/32 bit quantity will get "stuck".

(Curiously, this is pretty much exactly the same way that old UV-erasable EEPROMs used as re-programmable replacements for the factory-supplied, write-once EPROM in the Motronics DME - usually a 2716 or 2732, IIRC - eventually fail in a regular programming rotation; they can no longer be erased/cleared. For these, not putting a sticker over the little quartz window and letting the UV in regular light randomly clear the charge from individual bits/cells over time - corrupting whatever data/program was stored there - is another)

The smallest block, with raw flash technology, that can be erased is quite large, somewhere between 64-128KiB - depending on the chip used and how it is organized internally.

Heh. It's been more than 10 years since I wanted to hack up a driver to manipulate Intel linear flash cards (as used on older Ciscos) directly in *BSD. Couldn't place my Intel spec documents.

So I cribbed the following from the excellent Linux MTD project Memory Technology Device (MTD) Subsystem for Linux.:

Eraseblocks wear-out and become bad and unusable after about 10^3 (for MLC NAND) - 10^5 (NOR, SLC NAND) erase cycles

The following table describes the differences between block devices and raw flashes. Note, SSD, MMC, eMMC, RS-MMC, SD, mini-SD, micro-SD, USB flash drive, CompactFlash, MemoryStick, MemoryStick Micro, and other FTL devices are block devices, not raw flash devices. Of course, hard drives are also block devices.

USB sticks, CompactFlash cards and other removable flash media are not MTD devices. They are block devices. They do contain flash chip inside, but they also contain some translation layer above which emulates block device. This translation layer is implemented in hardware. So for outside world these devices look exactly as hard drives, not like MTD devices.

and

Also note, these devices are "black boxes". The way they implement this flash-to-block device translation layer is not usually published. And in many cases the algorithms used at this layer are far from brilliant. For example, many USB sticks and other cards lose data in case of unclean reboots/power cuts. So, be very careful.