Thinkpad ECDT (or EDCT) ACPI, Linux & Win2k

[rnfolsom]

Previous subject: Thinkpad ACPI & EDCT

My earlier version of this message was seriously flawed in that it did not spell "ECDT" correctly. That is now repaired, and I have drastically overhauled this message accordingly --- including new content defining ECDT, and about EDCT, which occurs in some relevant discussions, and which probably is a typographical error although it may be a related acronym.

From the links cited below, I gather that in the context of Thinkpad computing, ECDT is some sort of table that has to do with ACPI (Advanced Configuration and Power Interface), that causes trouble for Linux, and at least to some extent for Windows also (see my first Google result below).

But what is the actual meaning of "ECDT"? Or the meaning of "EDCT"?

A search of these Thinkpads forums for either term gives "No topics or posts met your search criteria," although I am new to this site and I may not be searching correctly.

My usual sources --- Thinkwiki, Whatis.com, TechEncyclopedia --- don't list either term (meaning that I can't find it there).


However, on GuruNet's Answers.com, a search for Thinkpad ECDT gives
http://www.answers.com/Thinkpad%20ECDT
which includes a message by Takayoshi Kochi, "Subject: Re: Problems reading ACPI battery status on IBM ThinkPad T30" at
http://mail-index.netbsd.org/current-us ... /0000.html

This message states that "The ECDT is a static table that ACPI BIOS provides to describe the resource used for embedded controller (ec)." More precisely, "ECDT . . . [stands for] embedded controller description table, IIRC [where IIRC stands for "If I recall correctly'?]."


To get more information, a Google search for Thinkpad ECDT gives numerous results involving Thinkpads and Linux and ACPI, starting with
"Howto override your buggy ECDT table for the IBM Thinkpad under Linux" at
http://www.poupinou.org/acpi/ibm_ecdt.html
(listed also at http://www.answers.com/Thinkpad%20ECDT).

A Google search for Thinkpad EDCT (vice ECDT) also gives some results involving Linux and ACPI, starting with
"AW: Re: IBM Thinkpad A31 | ACPI problems" at
http://blog.gmane.org/gmane.linux.acpi. ... h=20020201


BACKGROUND

My Thinkpad A31 is running Windows 2000.

My question about the meaning of ECDT arises from making a backup image of an A31 hard drive, using Apricorn's EzGigII imaging software, after booting from the EzGigII CD. (EzGigII is not yet installed on my A31).

EzGigII is Linux based, although designed to make backup images of Windows (9x, 2000, and XP) hard drives and partitions. (EzGIGII appears to be a simpler version of Acronis.)

When the EzGigII CD boots and starts to load EzGigII, the following message appears:

"ACPI: Could not use ECDT"

After displaying this message, the EzGigII software loads, and I can make a backup image with no problem. But I'd still like to know what that message means.

After reading the links above, I am guessing that the message means that Apricorn's EzGigII Linux cannot deal with ACPI due to my A31's ECDT table being buggy. (My A31 is very newly acquired, so I have not yet looked for BIOS updates.) Since I don't think I need need ACPI when temporarily loading Apricorn's Linux from a CD in order to make a backup image, I am hoping that this "Could not use ECDT" message isn't impairing the backup image.

But I'd feel better about that guess-hope if I knew more about what the message means.

Thanks for any help.

Roger Folsom

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P.S.: Answers.com/ECDT includes a link to a paper on "Extended Convex Differences Tree (ECDT) Representation for n-Dimensional Polyhedra"
http://www.cs.huji.ac.il/~arir/ecdt-abs.html
that states that "ECDT can be viewed as an extension to the Convex Differences Tree scheme" used with Boolean operations. Later answers.com/ECDT pages include additional "convex differences tree" links. But whether Thinkpads use that sort of ECDT, I know not.

Answers.com/ECDT gives not only the links above, but also also a lot of noncomputing meanings.
Answers.com/EDCT turns up only "Estimated Departure Clearance Time" used for aircraft scheduling.)