HDD Orientation

**Phil B** · 19-09-2005, 09:44 PM

Does it make any difference which way round they are?
I've got mine vertical, plug end up.

Phil

**Terry Porritt** · 19-09-2005, 09:49 PM

No. But it may be good practice to format the drive in the same attitude as it is going to be mounted.
Maybe not as important these days, but it used to be.

**Jen** · 19-09-2005, 09:52 PM

Originally Posted by Terry Porritt

No. But it may be good practice to format the drive in the same attitude as it is going to be mounted.

What was the technical reason for doing this?

**Phil B** · 19-09-2005, 09:53 PM

Thats good. I got a new CPU cooler last weekend & had to do some major case mods to get it in. Got fed up with sitting at what sounded like the end of a runway

Phil

**Terry Porritt** · 19-09-2005, 10:01 PM

Originally Posted by Jen

What was the technical reason for doing this?

The design and head positioning servo motors/systems were not as good in older drives as they are today, ie positioning of the heads was not as good. A term called 'droop' in servo-talk, so if a drive was tilted to a different attitude to that for which it was formatted the heads didnt quite read the right track due to gravitational forces. Data could then be corrupted.
When drives aged and the head springs changed a bit, the problem became worse.

The same thing applied to floppy drives.

**Myth** · 19-09-2005, 10:41 PM

I know some current (either Dell or HP) computers have the harddrive mounted in a vertical position, with the plug end facing up

**Graham L** · 21-09-2005, 02:13 PM

Many MFM drives had the track spacing determined by the step size of a stepping motor (like most floppy drives, still). Gravity made a difference.

Modern drives, with linear servo systems, dedicate one surface to servo tracks. These are written in the factory. The head positioning servo is controlled by the head on that surface. So gravity doesn't rule.

**pctek** · 21-09-2005, 05:23 PM

Originally Posted by Graham L

Many MFM drives had the track spacing determined by the step size of a stepping motor (like most floppy drives, still). Gravity made a difference.

Modern drives, with linear servo systems, dedicate one surface to servo tracks. These are written in the factory. The head positioning servo is controlled by the head on that surface. So gravity doesn't rule.

Considering the number of portable USB hdds around now, it couldn't apply now. I have used my hdd sideways, upside down, end on etc etc with no hassles at all.

**Terry Porritt** · 21-09-2005, 05:43 PM

Originally Posted by pctek

Considering the number of portable USB hdds around now, it couldn't apply now. I have used my hdd sideways, upside down, end on etc etc with no hassles at all.

HHD attitude shouldn't matter at all as you and Graham say, modern ones are so much better made. That's why Seagate offer 5 year warranties. The closed loop servo system with positioning data written to disk during manufacture, and automatic temperature compensation is extremely precise.

It was important with the old XT type MFM drives, but even with IDE drives older ones had a tendency to be influenced by gravity especially when well used.
I used to have several IDE drives around the 40MB size mark, including an old clonky Western Digital, that had to be formatted in the fitted position.
If formatted in the wrong attitude they would not boot.

**Graham L** · 22-09-2005, 03:45 PM

What made the HDD manufacturers go to "voice-coil" head drives was the increased track density.

I'd forgotten just when the change was total. I remember once specifying a "self-parking" 40MB drive for a "portable" (transportable --- about 30 lb) computer used for field data collection about 1980. The stepping motor drives just left the heads where they were when the power went off.

Voice coil servos have a spring to pull the heads to a parking zone.

Mechanical "steps" just weren't precise enough. Look at your 3.5" floppy. 80 tracks at 96tpi was just achieveable to get 2MB (unformatted). The LS120 drive used a laser servo tracking a factory written servo track to get 120MB on a single (expensive) floppy.