"Arny Krueger" wrote in message
...
"WorldJAZZ" wrote in message

"Arny Krueger" wrote in message
...
"Robert Morein" wrote in message


A frequently quoted design lifetime is 1,000 hours of burn time.
This is not an authoritative figure.

Indeed.

Here's a spec sheet for a typical good cheap CD burner

http://www.cdrecordingsoftware.com/liteon5232.html

Relevant spec - MTBF 70,000 (power-on hours). This spec usually
presumes something like a 10-15% duty cycle. So that would
translate to MTBF 7,000 - 10,500 hours of actual use.

FALSE.

The statement is true. True, it does not address EOL directly, but the
concept of EOL had not been introduced at all at the time I made this
post.
Morein, if you want to talk intelligently about EOL, then say that you're
talking about EOL.

http://www.tdk.com/cdburners/velocd48xspecs.html

Relevant spec - MTBF 70,000 (power-on hours). This spec says 100,000
hours
at 25% duty cycle. So that would translate to MTBF 25,000 hours of
actual use.

FALSE.

It's a true stataement. However, its applicability to this situation needs
to be explained. Every document I can find with information about EOL
discusses MTBF. The two are clearly related. Morein, since you have
proposed
yourself as an expert in this field, why not provide us with a coherent
explanation of the two?

This is going to be good.

;-)

The above embodies a misunderstanding of how MTBF is determined for
industrial parts.

The incredible Morein mind reading act rides again. Morien posts a
questionable statement -

"A frequently quoted design lifetime is 1000 hours of burn time"

That he himself says:

"This is not an authoritative figure."

Then Morien personally attacks me on two forums in two different threads.

BTW, note that at the point that I commented Morien had not introduced the
formal concept "End Of Life".

Morien still hasn't substantiated this claim by any means other than
personal attack and introduction of a discussion of hard drives and CPU
fans, not facts about CD burners.

There is a naive misconception as to what MTBF means.

True, but Morein so far you haven't made the issue relevant here.

Specifically, it is quite possible for a part to have an end-of-life
(EOL) of 45,000 hours while rated at an MTBF of 1,000,000 hours.

No problem. Please provide an independent source (i.e., not Bob Morein or
one of his many sockpuppets) that provides information about the EOL of
CD
burners.

For an understanding of this apparent paradox, see
http://www.bluemax.net/docs/Motherbo...Info/mtbf.html

It's very badly written. It describes the problem but does not provide
solutions or even any useful insights about the situation. It's more of a
rant or a sales pitch than a technical paper.

Here's another link for you:
http://www.storagereview.com/php/tik....php?page=MTBF


I appreciate Arny's attempt to be helpful, but in this case, the
explanation he provided is not conformant with the term MTBF as used
in industry.

I didn't provide any explanation. I simply cited some specifications for
MTBF. Is MTBF related to EOL? Yes.
Are they the same thing? No.

No, they are not, and they are independent variables.
Example that shows unequivocally, that they are completely independent
variables:
The following sets of values can exist for a part, without contradiction:
MTFB EOL
100,000 500,0009
100,000 100,000
100,000 10,000
100,000 1000
100,000 10
100,000 1

Example: a lawn mower, which has a tank that holds sufficient gas to run
the lawnmower for exactly one hour.
After one hour, the lawn mower has reached EOL, in the sense that the
consumable part (gas) has reached EOL.
Now let's take 1000 lawn mowers, and run them on a test stand.
After 30 minutes, one has failed.
Service hours = 500 hrs.
The number of failures is 1.
MTBF = 500/1 = 500 hours.

The above illustrates one of several methods of MTBF calculation. MTBF is
not intended to mislead. It is a technical term used by process and
industrial engineers; however, when it finds it's way into consumer
packaging, it does tend to mislead.

Here's a typical laser diode, with lifetime spec:
http://www.wholesaleforeveryone.com/...roduct_Count=0

The lifetime of the device is highly dependent upon how it is driven.
For example, a 5 mw diode with a 1 um active surface has a power density of
167 kW/cm2. Diodes that are driven at levels required to READ a CD have a
much longer lifetime than those required to WRITE a CD.

The following link details an improved laser for DVD writing that has a
lifetime of about 4,000 hours.
http://www.pcworld.com/news/article/0,aid,86784,00.asp
However, this is a statistical term. Users should not expect to get the full
lifetime of the laser.