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Guest

Wed Jan 30, 2019 6:45 pm   



On a sunny day (Wed, 30 Jan 2019 07:21:55 -0800 (PST)) it happened
gnuarm wrote
Quote:
On Wednesday, January 30, 2019 at 9:44:05 AM UTC-5, 69883925...@nospam.org wrote:

You stated that sequentially writing to FLASH was dangerous,
I hope I made it clear to you and everybody else that is bull.
Every OS also does that.

I've never said that.


<quote>
Quote:
but your idea of dedicating a sector per data record
is poor in the extreme. Sectors on Flash are not very reliable. It is a
good idea to have a flash file system to manage the good/bad blocks for you.
I guess you can do that yourself, but are you thinking of that?
end quote



You neither understood when writing that how an OS works, nor how the SDcard's internals work.
I hope you do now, else read that link again:
https://wiki.linaro.org/WorkingGroups/KernelArchived/Projects/FlashCardSurvey?action=show&redirect=WorkingGroups%2FKernel%2FProjects%2FFlashCardSurvey
For SDcards the bad blocks management is in the card.


Guest

Wed Jan 30, 2019 6:45 pm   



gnuarm wrote
Quote:
On Wednesday, January 30, 2019 at 12:12:11 PM UTC-5, 69883925...@nospam.org wrote:
On a sunny day (Wed, 30 Jan 2019 07:21:55 -0800 (PST)) it happened
gnuarm wrote
On Wednesday, January 30, 2019 at 9:44:05 AM UTC-5, 69883925...@nospam.org wrote:

You stated that sequentially writing to FLASH was dangerous,
I hope I made it clear to you and everybody else that is bull.
Every OS also does that.

I've never said that.

quote
but your idea of dedicating a sector per data record
is poor in the extreme. Sectors on Flash are not very reliable. It is a
good idea to have a flash file system to manage the good/bad blocks for you.
I guess you can do that yourself, but are you thinking of that?
end quote


You neither understood when writing that how an OS works, nor how the SDcard's internals work.
I hope you do now, else read that link again:

https://wiki.linaro.org/WorkingGroups/KernelArchived/Projects/FlashCardSurvey?action=show&redirect=WorkingGroups%2FKernel%2FProjects%2FFlashCardSurvey
For SDcards the bad blocks management is in the card.

You are making my case. I didn't say anything about "sequentially writing to FLASH was dangerous".

I didn't say anything about how an "operating system" works. Or do I misunderstand what "OS" means? As usual, you read what
you want to read.

Try opening your mind to understand what I meant, not what you want my words to mean.


Read your own text that I quoted again.

Better even study the link.


Guest

Wed Jan 30, 2019 9:45 pm   



<698839253X6D445TD_at_nospam.org> wrote in news:q2slt3$emn$1
@gioia.aioe.org:

Quote:
For SDcards the bad blocks management is in the card.



Exactly... and that ALWAYS invisible to even the 'file system' placed
within a 'volume' partitioned onto the 'drive'. The internals always
have space set aside for re-assignment of storage space such that from
the perspective of a given file system, there is no such event as a bad
write or 'bad block' to be bypassed or circumnavigated. There is also
no such animal as file fragmentation. Incrementally updated files
always get full rewrites of the entire file or the space for the
incremental update is contiguous with the existing file location.

whit3rd
Guest

Thu Jan 31, 2019 12:45 am   



On Wednesday, January 30, 2019 at 7:22:00 AM UTC-8, gnuarm.del...@gmail.com wrote:
Quote:
On Wednesday, January 30, 2019 at 9:44:05 AM UTC-5, 69883925...@nospam.org wrote:

You stated that sequentially writing to FLASH was dangerous,

I've never said that. My point is that Flash is not reliable. Rely on it at your own risk.


Don't believe such an unqualified statement. Flash has limited erase/rewrite
cycles (and humans have limited lifetime, too). But 'reliable' depends on
usage, and a WORM disk (write-once-read-mainly) is very useful, and
exemplifies good practices for Flash devices. WORM disk is good for 1 write cycle.
Flash devices are good for ten-thousand-to-millions. Moore's law would
suggest Flash is decades more advanced than WORM.

If used like in a camera (write but usually not overwrite when picture taking,
erase only when the user takes action to free space) Flash is totally reliable.
Until the year 2300, my few-days-between handling of the useful
snapshot device won't expose me to any real risk.

Some filesystem actions, though, like defragmenting, journaling, registry
maintenance, will inevitably overwrite in a thoughtless and uncontrolled
manner. Designing a Flash disk to look like a rotating-rust disk was a perilous
decision, and few if any OS controls were really ready for the shift.

So, a busy data center might easily see Flash devices failing, because of
the nature of the traffic through those disks. A savvy use of the resource
can avoid the problem, and let's hope the walled enclaves of OS
gnomes are aware and active enough to fit the Flash resource into our
boxes without overstressing its minor weaknesses.

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