HDAT2 forum

Could the next version of HDAT2 include a feature to enable/disable Error Recovery Control? AIUI, this would improve RAID stability.

Section 5.3 of the following document describes the standard.

Information Technology - SMART Command Transport (SCT):
http://www.t13.org/Documents/UploadedDo ... r5-SCT.pdf

The following Wikipedia article also has some information.

Time-Limited Error Recovery:
http://en.wikipedia.org/wiki/TLER

It is inside for a long time, but not tested yet and therefore is this menu item in SMART SCT disabled.

Now I am completing version 4.7 for PCI AHCI.
OK, I can enable this feature, but it is a little bit risky without testing.

In these days I don't have disk drive supported this SCT feature.

O.K. I have done it,
it will set time limits for READ and WRITE commands.

New version will be as soon as possible.

I'm new to this board. I looked at downloading a version that allows changing of the WDTLER/CCTL and all the versions on the download page seem to say tests are disabled. Which version is this item allowed?

"test are disabled" - it means device tests for bad sectors etc.

You should download the last version 4.7.1.

Changing TLER/CCTL is in SMART menu - SMART Command Transport (SCT) Menu,
there is "Error Recovery Control Menu".

I downloaded 4.71. I tried the program. I'm having difficultly finding the menu item. I go to the SMART menu first - it offers Read Log Menu, Routine Menu, Command Menu. What is the right set of choices from here?

Every menu appears in the menu list only if the device supports the given feature.

If you don't see the menu item "SMART Command Transport (SCT) Menu",
it means your device doesn't support the SCT feature.

You can go to Device information menu to check which commands and features
supports you device.

I tried a WD1001FALS and got to the menu - thanks. I had been using a Seagate ST3000641AS-9BD148-304 and was surprised there wasn't an ERC choice.

I'm thinking of buying a new set of drives for a RAID. I've heard the latest crop of WD1001FALS do not allow for WDTLER changes anymore (reported two days ago on Newegg's reviews). Do folks know if Samsung's HD154UI or HD103SI allow for CCTL?

Samsung HD154UI - yes
Samsung HD103SI - I don't know
SpinPoint F1R HE103UJ - yes

I believe the recommended read/write timer values are 7 seconds for most hardware raid controllers. I am using the md software raid driver on linux. Should I also use 7 seconds? (Samsung HD154UI)

It depends on the recommendation from the manufacturer
and on the user also.

My understanding is that the drive's TLER/CCTL/ERC timers should be set so that the drive times out before the RAID controller.

Dear cbl,

Samsung HD154UI - yes
Samsung HD103SI - I don't know
SpinPoint F1R HE103UJ - yes

Are the modifcation of the timers persistent across power cycle ?
Is this a feature from the SCT standard or manufacturer/drive dependant.

Thanks

This feature is from SCT and/or ATA-8/ACS2 standard.

According to SCT/ATA document:

"Read and Write command timer values are set to default values at power-on but may be altered by a SCT
command at any time. These settings are unaffected by software (soft) or hardware (pin 1 or COMRESET) reset.

The SCT Error Recovery Control command sets time limits for read and write error recovery. For commands that
are not TCQ commands or NCQ commands, these timers apply to command completion at the host interface.

For TCQ commands or NCQ commands where in-order data delivery is enabled, these timers begin counting
when the device begins to process the command, not when the command is sent to the device. These timers do
not apply to streaming commands or to queued commands when out-of-order data delivery is enabled.

The typical usage for this command is when a device has its write cache function enabled. With write cache
enabled, the device may not be able to report an error on a write command. This is because the write command
with which a device is experiencing difficulty is one for which the device has reported status (i.e., considered by
the host to be complete). This leaves no recourse for the device other than to reallocate any sectors with which
it is experiencing difficulty."

Thanks cbl for your prompt feedback.

If I well understand, hdat2 cannot be used to permanently enable CCTL on Samsung desktop class drives so they behave like entreprise ones when plugged in RAID arrays from Linux based NASes (ReadyNas, Synology, QNAP, ...)

Am I (unfortunately) right ?