CHS and LBA

[Egil Solberg]

I have an Asus A7N8X-Deluxe 2.0.
I have used to have "auto" set for all my IDE-devices in BIOS:

Previous setup:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: LBA Maxtor 60GB ATA133
Sec. slave: NEC-DVD-RW 3500A ATA33

As you see, both my drives were autodetected as LBA.

I bought a 200GB Maxtor Diamondmax 10 yesterday. Put it in as sec.
master and took out the 60GB.

Now, with autodetect:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: CHS Maxtor 203GB ATA133
Sec. slave: NEC DVD-RW 3500A.

The 200GB drive worked fine in Windows. I have not yet run powermax to
test it.
I find it strange for my drive to be detected as CHS. I've never had a
drive that got detected as anything else but LBA. I went into BIOS and
changed from CHS to LBA and that worked fine as well. Now the line
reads:

Sec. master: LBA Maxtor 203GB ATA133.

Is this a symptom of anything wrong? Does the setting have any
consequences at all?

 

[Arno Wagner]

I have an Asus A7N8X-Deluxe 2.0.
I have used to have "auto" set for all my IDE-devices in BIOS:

Previous setup:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: LBA Maxtor 60GB ATA133
Sec. slave: NEC-DVD-RW 3500A ATA33

As you see, both my drives were autodetected as LBA.

I bought a 200GB Maxtor Diamondmax 10 yesterday. Put it in as sec.
master and took out the 60GB.

Now, with autodetect:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: CHS Maxtor 203GB ATA133
Sec. slave: NEC DVD-RW 3500A.

The 200GB drive worked fine in Windows. I have not yet run powermax to
test it.
I find it strange for my drive to be detected as CHS. I've never had a
drive that got detected as anything else but LBA. I went into BIOS and
changed from CHS to LBA and that worked fine as well. Now the line
reads:

Sec. master: LBA Maxtor 203GB ATA133.

Is this a symptom of anything wrong?

No. CHA, LBA and occasionaly "large" are not detected values,
they are access options. LBA is the best choice today. Some
BIOSes still go to CHS as default, since old DOS might need it.

Does the setting have any consequences at all?

Today mainfly for boot-managers. Win XP, Linux and FreeBSD all do
direct disk access, bypassing the BIOS setting.

One note: XP out of the box will damage drives over 137GB when
they are starting to approach that fill degree. (Stupid error
by MS where they did not check whether the HDD is larger than
the driver can support). Get at least SP1 if you don not have
it yet.

Arno

 

[Valerio Vanni]

I have an Asus A7N8X-Deluxe 2.0.
I have used to have "auto" set for all my IDE-devices in BIOS:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: LBA Maxtor 60GB ATA133

I bought a 200GB Maxtor Diamondmax 10 yesterday.
Prim. master: LBA Maxtor 122GB ATA133
Sec. master: CHS Maxtor 203GB ATA133

I find it strange for my drive to be detected as CHS.

Is this a symptom of anything wrong?

It's probably caused by partition table's geometry.

Many BIOSes read it, and if it's written with 255 heads they will
consider it "LBA", if it's Written with 16 heads they will consider it
"CHS".

 

[modiftek]

Previous setup:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: LBA Maxtor 60GB ATA133
Sec. slave: NEC-DVD-RW 3500A ATA33

Now, with autodetect:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: CHS Maxtor 203GB ATA133
Sec. slave: NEC-DVD-RW 3500A ATA33


Sec. master: LBA Maxtor 203GB ATA133.

I don't know if I am seeing things or I am misreading you over and
over but, your 200GB is now 203GB.

However, if you are having one of the regular boards with two IDE
controllers [IDE-1 and IDE-2], it means that you have a configuration
problem. You should go back under the hood and look at where the drives
are positioned on the data cables.

If you have two hard drives on IDE-1, one drive jumper must be set to
"master" and the other to "slave". You cannot have two drives set as
master on the same IDE channel.

I am saying this because, I am assuming that you have your NEC-DVD-RW
3500A on IDE-2 and it is set as slave, and you have your 122GB and
203GB both set as master on the same data cable on IDE-1.

If you have those 80-pins cables, put drive jumpers on cable select and
place the original hard drive at the end connector on the cable and see
what results you might get.

A normal BIOS reading, assuming that both channels carry two drives,
would read as follows:

Prim. master: LBA Maxtor 122GB ATA133
Sec. slave: LBA Maxtor 203GB ATA133

Prim. master: NEC-DVD-RW 3500A ATA33
Sec. slave: NEC-CD/RW XX00A ATA33

The drives I mentioned in the above example are just a sample
configuration in no particular order, to show what the BIOS will
display if you have two cables and two drives attached to each. It is
just for demonstration purposes.

I suggest you do the following configuration and then look for the
Clear CMOS jumper on your motherboard and reset your BIOS:

Prim. master: LBA Maxtor 122GB ATA133
Sec. slave: NEC-DVD-RW 3500A ATA33

Prim. master: LBA Maxtor 203GB ATA133
Sec. slave: xxx xxxxxx xxxx xxxx xxx

 

[Folkert Rienstra]

I have an Asus A7N8X-Deluxe 2.0.
I have used to have "auto" set for all my IDE-devices in BIOS:

Previous setup:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: LBA Maxtor 60GB ATA133
Sec. slave: NEC-DVD-RW 3500A ATA33

As you see, both my drives were autodetected as LBA.

I bought a 200GB Maxtor Diamondmax 10 yesterday. Put it in as sec.
master and took out the 60GB.

Now, with autodetect:

Prim. master: LBA Maxtor 122GB ATA133
Sec. master: CHS Maxtor 203GB ATA133
Sec. slave: NEC DVD-RW 3500A.

The 200GB drive worked fine in Windows. I have not yet run powermax to
test it.
I find it strange for my drive to be detected as CHS. I've never had a
drive that got detected as anything else but LBA. I went into BIOS and
changed from CHS to LBA and that worked fine as well. Now the line
reads:

Sec. master: LBA Maxtor 203GB ATA133.

Is this a symptom of anything wrong?

Depends on what the significance is of what your bios considers to be
CHS or LBA in that line. What does your MB manual say about it?

 

[Folkert Rienstra]

It's probably caused by partition table's geometry.

Right, probably.

Many BIOSes read it,

Well, obviously, but it depends what for.

and if it's written with 255 heads they will consider it "LBA",

Probably not that simple.
You have to look at the drive's 'default translation' CHS, then bit-shift it
into a L-CHS (1023 cylinders or less) and compare it with the value in the
MBR. If they don't match then the translation scheme is likely LBA-assist.

if it's Written with 16 heads they will consider it "CHS".

More likely "Normal" as that will amount to less than 540MB.

Which begs the question, what do ASUS mean with "CHS",
Normal or E(xtended)-CHS?

 

[Folkert Rienstra]

No. CHA, LBA and occasionaly "large" are not detected values,

But can be detected/guessed at as such when the values in
the MBR don't fit the rules in a specific translation scheme.
So the bios sets it accordingly.

they are access options.

Only if you want to force those.

LBA is the best choice today.

Not best, but 'best bet' when in doubt.

Some BIOSes still go to CHS as default, since old DOS might need it.

LBA(-assist) is also CHS.

LBA, Large, Bit-shift, (E)CHS, Normal and what have you, have
nothing to do with old or new DOS but with how plain Int13
(or other Ints that deal with CHS) translate (or not) the L-CHS
(the input values to Int13) into a P-CHS (the CHS as used on
the IDE interface) or into a L(ogical) B(lock) A(ddress).

Stupid Arnie has been told this before but still doesn't get it,
and probably never will.

Today mainly for boot-managers.

Depends on whether the bootmanager uses Int13.

Win XP, Linux and FreeBSD all do direct disk access,

So do most OSes since Windows 3, so what.

bypassing the BIOS setting.

Bypassing (ie, not using) the BIOS.
What if Linux programs use CHS.