Fast write access to a Compact Flash card (WinCE 5)

[Peter Wucherer]

Hello,

has anyone experience about fast write access to Compact Flash cards?

I want to write many text lines.
Depended on the manufacturer of the Compact Flash I have very wide
range of the writing speed.
One card has 40 seconds for 1 mio lines, the slowest has up to 4.000
seconds with the same test program (50.000 write access). In the
specifications all cards should be nearly the same with writing speed.
One solution is a buffer the data in the RAM. But the program should
be able to write continuous text until the card is full, so I did not
have enough RAM to buffer all data.

Maybe someone has an idea whats the bettest way to write to a Compact
Flash card.

System: Toradex Colibri, Windows CE 5

Thanks
Peter

 

[Chris Tacke, eMVP]

There's no way to "speed it up". The CF card has an internal controller,
which may or may not be doing wear leveling. The actual flash meda also will
have a write speed based on type. There's no guarantee for any one to be
faster than another, and speed will vary across the same part number as well
as with what's on the card.

-Chris

 

[Peter Wucherer]

Thank you Chris,

this is what I was worry about.
Then the only way will be to test some different CF cards and use the
best one.

Peter

There's no way to "speed it up". The CF card has an internal controller,
which may or may not be doing wear leveling. The actual flash meda also will
have a write speed based on type. There's no guarantee for any one to be
faster than another, and speed will vary across the same part number as well
as with what's on the card.

-Chris

 

[Chris Tacke, eMVP]

this is what I was worry about.

Then the only way will be to test some different CF cards and use the
best one.

Yes, but keep in mind that the results will change over time for the same
manufacturer and card. As a card fills up, it gets slower, often
damatically so. In testing I've done, cards 90% full are an order of
magnitude slower than those that are empty.

Also, there's nothing to keep a card OEM from changing internals on their
cards based ont he price of components to them. So two cards fromt he same
manufacturer, with the same size and part number, may have different speed
characteristics.


--

Chris Tacke, Embedded MVP
OpenNETCF Consulting
Giving back to the embedded community
http://community.OpenNETCF.com