CF Card poll - Interpreting the data so far...

[FlyingPete]

I have been looking at the two CF card poll results and from the information there we can start to see some trends forming, I would like more votes to get the accuracy up though, we are around 60, not enough to draw firm conclusions.

Now statisticians out there I need your help! At the moment we need to make some assumptions without running anther poll there is info we don't have (I tired to work out a way of doing this in the poll, but couldn't figure it out a good way).

The assumption is how many cards people have; we have information on the balance of card types they have.

For now lets assume that the average voter has three cards, so the proportions would look something like this:
Only flash (solid state) cards - 3 flash cards
Mostly flash with one or two Microdrives - 2 flash cards and a Microdrive
An even mix of flash and Microdrives - one of each
Mostly Microdrives with one or two flash cards - 1 flash card and 2 Microdrives
Only Microdrives - 3 Microdrives

Based on the above assumptions and the data so far, I have put everything into a spreadsheet and found the current failure rates for Flash cards and Microdrives as being:

Flash (solid state) card failure rate - 10.5%
Microdrive failure rate - 16.7%

Any thoughts or fine tuning?

Remember still not enough data to call!

[FlyingPete]

The latest scoring:

Flash (solid state) card failure rate - 11.0%
Microdrive failure rate - 14.3%

[Wazza]

Interesting, but also note possibly more people with the problems will report it, than people who have never had a problem, and skipped the thread? They could both be under 10%.

I'm hoping I never get a failure!

[Tom W]

I'm also guessing that the failure rate is much lower. I've used something like 8-10 CF cards over the past few years in various cameras and never had a failure.

[tommykjensen]

I think You need to adjust the number of cards.

For example I voted flash + 1 or 2 microdrives.

In fact I have
- one microdrive
- six cf cards

[FlyingPete]

I think You need to adjust the number of cards.

For example I voted flash + 1 or 2 microdrives.

In fact I have
- one microdrive
- six cf cards

Thanks for that, I do need to fine tune, and was seeking thoughts on my assumptions. I have also found another thread that suggests the number of CF cards people have is higher.

I think two of three would not be far off for the general population, but we are talking enthusiasts here :D

[tommykjensen]

Thanks for that, I do need to fine tune, and was seeking thoughts on my assumptions. I have also found another thread that suggests the number of CF cards people have is higher.

I think two of three would not be far off for the general population, but we are talking enthusiasts here :D

Actually, I just ordered a 2 GB card more :D So when I receive I will have 9 GB in total, I wonder if that will be enough for my 3 week holiday in Florida :lol:

[FlyingPete]

OK we have enthusiasts here :D

I have been though the 'How much storage do you have?' thread, this is what I have found:

The average number of cards held is 5, the most is 16, the least is 1. The majority of people with Microdrives seem to have 2 (this surprised me!).

From this I have changed all the weightings, and entered the latest numbers from the polls to get:
Flash (solid state) card failure rate - 5.9%
Microdrive failure rate - 8.0%

I have calculated my margin of error based on the population stats I just got at around 5%.

Still would like more data, as I don't believe there are enough votes yet, however I thing that most people who are going to vote have, as there was only 2 in the last 24 hours.

Looks like MD's are not as bad as it could be believed.

As someone with an engineering background, I do understand that the MD's are more fragile than the flash equivelnts, however it seems that they are still pretty tough, here are the operating limits:


Operating___________________________Microdrive____ ________Flash
Ambient temperature_________________0° to 70°C____________0° to 60°C
Relative humidity (non-condensing)__8% to 90%_____________85% to 96%
Shock (half sine wave)______________200 G/2ms_____________50 G/11ms
Vibration (swept sine peak)_________1.0 G_________________15.0 G

Non Operating_______________________Microdrive________ ____Flash
Ambient temperature_________________-40° to 70°C__________-20° to 85°C
Relative humidity (non-condensing)__5% to 95%_____________85% to 96%
Shock (half sine wave)______________2000 G/1ms____________50 G/11ms
Vibration (swept sine peak)_________5.0 G_________________15.0 G


It is a shame I could not get the vibration measurements for the same time periods. What appears to be the main difference is vibration, but go and fnd somewhere you and the card are putting up with 5+ G's of vibration - Ouch!

[FlyingPete]

Latest numbers, MD's up to another failure report:

Flash (solid state) card failure rate - 5.5%
Microdrive failure rate - 10.0%