Lead shot in hard drives? Why??

Yep, desiccant.

...Jim Thompson

Those are to absorb any moisure in the air inside the drive.

Silica Gel, to absorb moisture.

The lube on the disc surface tends to turn into mayonnaise, leading to lots of stiction problems in tropical climates. Leaving disc drives in a warehouse in Singapore for a few months is an excellent lube torture test.

Cheers

Phil Hobbs

my

Desiccant to suck up any moisture. The container was likely over the vent hole, which is usually covered with a fiber paper material to act as a filter.

ive opend a drive with them inside, i think there for air filltering.

my

Hmm, last I knew they no longer put "lube" in the platters. AFAIK, the current drives all have head retraction and don't use any gunk on the drives. Stiction is a long solved problem (head design and parking).

-- Keith

Where on the spindles? "Stiction" was cause by the heads dragging/stuck on the platter. Since heads no longer touch the platter stiction shouldn't be a problem.

Top-posting sucks.

-- Keith

No, lube is still used--my next-door lab neighbour is one of the world's experts on disc drives, having invented the self-servowriting technology that broke the 1 GB/in**2 barrier. Heads haven't touched disc surfaces in a long while, at least not *intentionally*. The thing is, if the power goes off, do you want the disc to die? If not, use lube. Only 50 angstroms' worth, of course, since the heads fly at 100-200 angstroms, and it's chemically attached to the surface, not free like an oil film.

Cheers,

Phil Hobbs

AIUI, at least the last few generations of drives have parked their heads off the platter. If the power dies there is enough energy stored to safely park the heads. Of course they don't touch the surface during operation.

The "stiction" problem was with drives that had landing zones and did use a lubricant on the surface of the disk. The lubricant tended to collect in the landing zone (outer part of the surface) and glue the head to the platter.

on the disk spindles, not the heads.

They don't. Maxtor's latest Maxline III and Diamondmax 10 don't. Seagate's latest Barracuda 7200.8 doesn't. Some of the high end Hitachi drives do.

Interesting. I know the last few generations of IBMs (with the glass platters) did. I (wrongly) assumed it was the norm these days. Thanks.

They park off the active data-writing area, IIUC. BTW, Hitachi bought IBM's hard-drive division, so "IBM drives" are sold as Hitachi drives.

No, that's parking the heads in the "landing-zone". The more recent IBM drives retracted the heads so they never touched the platter.

Sure.

Not normally, no. It's designed to do so. The issue here was "stiction", which is impossible with a drive that retracts heads, but may continue to be a problem with drives that park the heads on the platter.

You will likey find those older drives will suffer from stiction. Many even "park" the heads on the active area of the disk.

And if the head lands in a "landing zone", can the head suffer any damage?

I am curious since I still do some things that make some use of a roughly 260 MB drive of late 1993 vintage, although I mostly use drives a lot more recent than that (80 and 120 GB)...

- Don Klipstein ( snipped-for-privacy@misty.com)

Laptop drives often (if not usually) retract the heads, since they need greater shock resistance.

Head retraction isn't necessarily the ideal thing you might think it is. Trying to transition a head from floating over a disk surface to moving up a ramp without running into the disk as it leaves (or returns) is a difficult problem.

The landing zone is usually on the inner tracks. The outer tracks can hold more data than inner tracks can, so the cost to use the outer tracks is higher.

Right, which is well off the active data-writing area.

And IBM added the feature of parking the drive heads whenever a slight motion of the laptop is detected, on the assumption it's falling to the floor, etc. This new feature is so sensitive that one soon learns not to even shift the laptop about on one's lap, or at least to do so very gingerly, to avoid the safety shutoff.