Solved HDD and BIOS auto/manual configuration of a swap drive.

February 9, 2016 at 20:39:12
Specs: Windows, AMD 1700
I have an IBM IDE hard drive (Model: DTTA-351680) that I am installing in the swap drive bay of an HP513x desktop. BIOS auto configured it as: 16,908MB, 32,760 Cylinders, 16Heads, 0 PreComp, 32,759 Landing Zone, 63 Sector, and UDMA2. It doesn't look like everything matches exactly according to the label which says (16.8GB, 16383CYL, 16HEADS, 63SEC/T). Should I manually configure CMOS with the settings on the label? I am going to be swapping it out from time to time and I assume CMOS is not going to remember any manual settings I enter. Is there any risk in letting it be or will it not run correctly as is?

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February 9, 2016 at 23:58:18
The 16,383, 16, 63 figures are the highest that can be specified for C/H/S configuration. That translates to about 8.4 gig. Drives larger than that use LBA addressing but will typically show 16383/16/63 on their labels and that is what auto detect will find because that's what's written on the drive's firmware.

I don't recall exactly how it works but when a bios 'sees' those figures it knows to use LBA. But I remember a few times when a bios would see a drive larger than 8.4 gig with specs (like yours) that would be accurate if C/H/S were possible.

First check the jumpers on the drive. Some drives about that size used a 'cylinder limiting jumper' for older computer that couldn't recognize the drive at all. That allowed the bios to see it as a 2 gig drive and then you'd have to install drive overlay software in order to use all the drive's capacity. Even if that jumper is set I don't think it would cause what you're seeing but still, it's something to check.

Also I think with some of the older systems you could specify either C/H/S or LBA drive detection. You might check the manual or fiddle with the bios settings to see if that is a factor.

With all that said, if the bios insists on seeing it that way I'd go ahead and leave it and see if it works OK.

Oh, another thing, that's a pretty old drive. Are you sure it's a good one?

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February 11, 2016 at 00:03:35
I played with the BIOS settings. It looks like with auto configuration is using C/H/S. I can select AUTO, CHS, LBA, or Large, but only CHS lets me manually configure its settings. The others can only auto-configure, and they calculate much less capacity when allowed to do so.

Manually configuring it with CHS 16,383Cyl 16Heads and 63sectors it set the capacity to 8.4GB. I'm not sure how it gets this figure as I don't know the bits per sector. But this doesn't match the 16.8GB on the label anyway.

There are many jumper settings on the drive as you said. All use the same eight pin jumper block. The label shows jumper settings for M/S/CS if the drive has 16 heads, 15 heads, or 2GB clip. There are also jumper settings for Auto Spin Disable that look to work together with the 2GB clip settings. I am not sure why it would have settings for 15heads as that is an odd number and the main label shows it as a 16 head drive. I am guessing that it is a stock label they used on multiple drive models.

Looks like I'll have to just let it auto configure and hope for the best.

The drive is a used one I pulled from a surplus PC. It was bootable before I wiped it, but other than that I don't know what condition its in. Is there a hard drive test that can tell me that?

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February 11, 2016 at 01:01:18
✔ Best Answer
There's probably a drive fitness test you can download if you can find support for it anymore. I think those drives are supported by Hitachi but can't remember for sure. A lot of that stuff was on my old computer when the motherboard failed and I never got around to copying the old drives over.

Seems like the 15 head limiter jumper was another adjustment for older bios' that wouldn't see a 16 head drive correctly.

Yeah the specs/label will always show 16383/16/63 for C/H/S on IDE drives 8.4 gig and higher. I remember looking at a list of either Maxtor or WD drives and their C/H/S for 20, 40 and 60 gig drives (whatever that particular series went up to) were all those same figures. Somehow the bios or drive firmware knows to use LBA at that point.

You might check to see if a bios update is available for that computer. If so it may address that problem. If you find one just be careful doing the update.

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February 12, 2016 at 00:25:18
Thanks for the help. I looked for a BIOS update, but didn't see anything in the revision history directed at hard drives. I will look into that more later. For now, I went ahead and just let it do its thing. OS seems to be installing fine so far. Instructions for that Hitachi Fitness test look like it expects to run under windows. I think I might try that once its up, but they make it sound like its designed for just Hitachi drives.

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February 22, 2016 at 00:19:50
OK let us know how it turns out.

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