paulsiu

Compact Flash in True IDE with UMDA support

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With the recent interest in SSD, I was somewhat surprised by the lack of interest in doing a DIY flash drive. After some research, I realized the issues are rather complicated.

In order for a drive to boot from a Compact Flash, the flash drive must emulate a hard drive using True IDE mode. Typically most Compact Flash has a True IDE Mode and a removable drive mode and auto switch between the mode depending on the socket.

A lot of drive these days advertise 45 Mb/s (300x cards), but I notice a lot of people notice a lot slower speed when doing hard disk emulation. This mean UDMA may not be available during True IDE mode. This is when the CF adapter supports UDMA.

I was wondering if anyone have ideas on which cards may support UDMA during True IDE mode (or Fixed Disk mode). From what I read, SanDisk Extreme IV does not support UDMA in True IDE, but Lexar Professional 300x may.

Paul

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I was wondering if anyone have ideas on which cards may support UDMA during True IDE mode (or Fixed Disk mode). From what I read, SanDisk Extreme IV does not support UDMA in True IDE, but Lexar Professional 300x may.

Paul

Paul,

I don't know where you get the info from, but I have an Extreme IV in my lab right now that works as a real HD running windows XP and is in UDMA IV. I am not familiar with Lexar's design, but the one with SanDisk with binary memory (Extreme IV, Industrial, and Ducati) can be used as a HD replacement to a certain extend. The difference between that and their SSD line product is the interface (SATA or CF, which needs adapter to work as PATA), and the wear leveling's robustness for desktop usage profile.

Remember, the performance of Extreme IV's 40MB/S is for FAT file system, NTFS has a lot more writes for integrity reasons and that will not run at 40MB/S. The SSD from SanDisk is of M-System's design and it uses a different flash access engine that is more suitable for windows' main drive.

You got to be very careful on what each brand's promise and reliability. A no name Taiwanese brand may work for 1 week at 300x, but it may not have enough wear leveling to last the warranty period, or it may have only 60x performance in random usage pattern. It is hard to tell without doing some real testing in a controlled lab. If I were you I would buy what Dell is ordering right now, they have very through acceptance test to protect them from bad design and poor quality. From what I understand, Samsung and SanDisk are both approved, but not Lexar yet.

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I was wondering if anyone have ideas on which cards may support UDMA during True IDE mode (or Fixed Disk mode). From what I read, SanDisk Extreme IV does not support UDMA in True IDE, but Lexar Professional 300x may.

Paul

Paul,

I don't know where you get the info from, but I have an Extreme IV in my lab right now that works as a real HD running windows XP and is in UDMA IV. I am not familiar with Lexar's design, but the one with SanDisk with binary memory (Extreme IV, Industrial, and Ducati) can be used as a HD replacement to a certain extend. The difference between that and their SSD line product is the interface (SATA or CF, which needs adapter to work as PATA), and the wear leveling's robustness for desktop usage profile.

Remember, the performance of Extreme IV's 40MB/S is for FAT file system, NTFS has a lot more writes for integrity reasons and that will not run at 40MB/S. The SSD from SanDisk is of M-System's design and it uses a different flash access engine that is more suitable for windows' main drive.

You got to be very careful on what each brand's promise and reliability. A no name Taiwanese brand may work for 1 week at 300x, but it may not have enough wear leveling to last the warranty period, or it may have only 60x performance in random usage pattern. It is hard to tell without doing some real testing in a controlled lab. If I were you I would buy what Dell is ordering right now, they have very through acceptance test to protect them from bad design and poor quality. From what I understand, Samsung and SanDisk are both approved, but not Lexar yet.

Panda Bear I have that same extreme iv 8gb card and I cannot get it to boot in the onboard cf socket of a kontron mitx 986, when installing from xp cd it partitions formats fat 32and copies over files ok but then will not boot from the cf card, it just comes back with disk error.

what adaptor are you useing?

Can you suggest anything?

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With the recent interest in SSD, I was somewhat surprised by the lack of interest in doing a DIY flash drive. After some research, I realized the issues are rather complicated.

In order for a drive to boot from a Compact Flash, the flash drive must emulate a hard drive using True IDE mode. Typically most Compact Flash has a True IDE Mode and a removable drive mode and auto switch between the mode depending on the socket.

A lot of drive these days advertise 45 Mb/s (300x cards), but I notice a lot of people notice a lot slower speed when doing hard disk emulation. This mean UDMA may not be available during True IDE mode. This is when the CF adapter supports UDMA.

I was wondering if anyone have ideas on which cards may support UDMA during True IDE mode (or Fixed Disk mode). From what I read, SanDisk Extreme IV does not support UDMA in True IDE, but Lexar Professional 300x may.

Paul

Hey Paul, I'm one such person who has gotten around to doing such a thing. It's not so complicated as you think, compact flash card are native IDE devices.

I posted a ton of information about it here: http://www.phoronix.com/forums/showthread.php?t=3424 Including my initial reaction, CF information, information about SSD rewrite capability, and etc.

I also have pics up of my rig, if you wish to see the card "in action".(though it just sits there)

My initial CF/IDE adapter gave me some problems, as it didn't support UDMA. Didn't give me proper performance either. My new one gives me this:

[root@localhost ~]# hdparm -Tt /dev/hda

/dev/hda:

Timing cached reads: 558 MB in 2.00 seconds = 278.31 MB/sec

Timing buffered disk reads: 110 MB in 3.01 seconds = 36.50 MB/sec

In case you're wondering, I have a Sandisk Extreme IV card. And I'll never go back to a hard drive again, as a boot drive.

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what adaptor are you useing?

Can you suggest anything?

This is the adapter I picked up:

http://www.newegg.com/Product/Product.aspx...N82E16812186038

Be careful, some compact flash adapters do not support UDMA and will give you some problems.(mostly performance related)

This adapter does not support UDMA like the above one does.

http://www.newegg.com/Product/Product.aspx...N82E16822998002

Newegg is awesome like that, all the specs you need are right there. Check out my phoronix posting in the above post, there's a ton of information about this in there.

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Hi,

I have a Sandisk ExtremeIV with a cf to ide adapter but I'm unable to go in UDMA mode but only in MWDMA2 with only 16MB/sec.

How can I do ?

In the bios settings i can't unable to activate UDMA mode on it. What CF to IDE adaptor you have used ?

Can I modify my adaptor to work in UDMA mode ?

Thanks.

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