Maximum read/write operations on a drive

[jondelac]

Its not clear how many cycles it will have yet.


Its obviously possible to socket the flash area so it can be
changed and you dont need to discard the entire laptop.

However, I doubt there will be much of a market for it myself.

In your opinion, and I'm asking because I feel you respond most
responsibly on this subject , how many years do you think 100,000
read writes will acheive.. that is, assuming that this Samsung chip
does indeed live to 100,000 read writes as advertised, how may
practical years do you think such a chip or hybrid drive can survive?

Jon.

 

[John Turco]

Thanks... what then causes disks to have a life time? If a disk were
not mobile (that is, not in a laptop etc) and stored at ideal
tempratures, what will cause sectors to go bad?

Jon.

Hello, Jon:

Any number of things can cause such problems: Mechanical wear and
tear, head crashes, defective or marginal power supply units, voltage
spikes/brownouts, hardware/software glitches, user errors...and the
list goes on!


Cordially,
John Turco <[email protected]>

 

[mike]

Rod Speed wrote:
ts too small or too slow.

Or you havent been doing it for as long as some of us have.

You're right about that. One of my early recollections is the purchase
order for $2500.00 for a preproduction evaluation sample of a 280MB
5-1/4" full height SCSI drive. Had that newfangled servo drive and no
stepper motors. Had so many platters and sticktion was so bad you had
to give it a quick twist to get it started. Sometimes, little bits of
the head stayed on the platter...and it wasn't long before you had a
doorstop...and they were heavy enough to make a really good $2500
doorstop. Wish I'd saved some of the pictures for those of you who
believe that heads contacting the platters is not a failure mode.
mike

 

[Arno Wagner]

Rod Speed wrote:
ts too small or too slow.

You're right about that. One of my early recollections is the purchase
order for $2500.00 for a preproduction evaluation sample of a 280MB
5-1/4" full height SCSI drive. Had that newfangled servo drive and no
stepper motors. Had so many platters and sticktion was so bad you had
to give it a quick twist to get it started. Sometimes, little bits of
the head stayed on the platter...and it wasn't long before you had a
doorstop...and they were heavy enough to make a really good $2500
doorstop. Wish I'd saved some of the pictures for those of you who
believe that heads contacting the platters is not a failure mode.
mike

Well, they solved this with some additional coating. But
for a time it was a real problem for disks that were started
and stopped often....

Arno

 

[Rod Speed]

In your opinion, and I'm asking because I feel you respond most
responsibly on this subject , how many years do you think 100,000
read writes will acheive.. that is, assuming that this Samsung chip
does indeed live to 100,000 read writes as advertised, how may
practical years do you think such a chip or hybrid drive can survive?

Impossible to say because it depends so much on how the system is used.

If you're primarily web browsing, XP particularly is doing a
lot of local caching of the files in Temporary Internet Files.

If on the other hand you're primarily using Word etc,
and have the automatic saves turned off, the use will
be how often the user chooses to save the work etc.

 

[Rod Speed]

Rod Speed wrote

You're right about that.

I am indeed.

One of my early recollections is the purchase order for $2500.00 for a preproduction evaluation
sample of a 280MB 5-1/4" full height SCSI drive.

Pfft, some of us were using hard drives LONG
before that, before PC had even been invented too.

Had that newfangled servo drive and no stepper motors. Had so many platters and sticktion was so
bad you had to give it a quick twist to get it started. Sometimes, little bits of the head stayed
on the platter...and it wasn't long before you had a doorstop...
and they were heavy enough to make a really good $2500 doorstop.

Some of us still have MUCH bigger drives than that, as big as washing machines.

Wish I'd saved some of the pictures for those of you who believe that heads contacting the
platters is not a failure mode.

No one ever said that last.

 

[Folkert Rienstra]

Infinity. Even if you wirte the same sector over and over again, it
will take longer to go bad than the drive.

Nope, you might actually overheat the whole track.

Flash has the problem that electrons need to be forced through an
isolator on writes. That damages the isolator over time. Changing
the magnetic orientation (HDD), does not damage the material.

But overheating it does.

As there is also no head-surface contact in a HDD,

There can be if the heads and/or surfaces overheat.

 

[Folkert Rienstra]

The OP's use of the phrase "read write cycle" makes me wonder if the OP
thinks that reading from a HD is destructive, like reading from a core
stack of yore.

Reading from a HD is non-destructive, and there is AFAIK
no known wear-out mechanism associated with reading a sector;

Keeping the head(s) over the same track will.

in fact, typical HDs are continuously reading from some track

In fact huh?!

(at least when not writing or seeking).

When "not writing or seeking" -or reading-, they will start moving
the heads to another area at fixed intervals to avoid overheating.

Writing to a HD is not done with a read-write cycle,
but is done by directly over-writing whatever data is already present; and,
AFAIK, there is no known wear-out mechanism associated with writing a sector
(assuming a decent design

and a well-cooled HD).

There you go.

If you want a spec for the lifetime limit on reading a sector, I'll pick
432,000,000,000. Why that number? A 7200 RPM HD, while idle, is reading
each sector of the track on which it is "parked" 7200 times per minute, or
432,000 times per hour; with the kinda-typical HD MTBF of 1,000,000 hours,
you should expect the HD to fail after ~432,000*1,000,000 sector reads of

any given sector.

{Please, I'm not trying to restart the debate over how meaningless MTBF
specs are;

As if you even understand what they mean.

I note only that my "spec" for a lifetime sector read limit is
about as meaningful as the MTBF on which it is based.}

Yes, but for different reasons.

In summary, the magnetic portion of HDs do not wear out, regardless of the
number of reads or writes done to them.

Depends on how they are read/written.

Bearings will wear out, and connectors and electronics will eventually fail,

but those events are also independent of the number of reads or writes.

Not for the headarm bearings it isn't.