6 ms·

> To make problems even worse, that landing zone is only rated for 250,000 to 350,000 cycles or so. I don't understand how a little orange plastic wid

by atap 11y ago

> To make problems even worse, that landing zone is only rated for 250,000 to 350,000 cycles or so. I don't understand how a little orange plastic widget suffers damage or delivers damage to the drive heads during a head parking procedure. It really doesn't seem like parking the drive heads would be an action that requires any kind of contact or friction between moving parts. What's different about parking near the rim, instead of near the spindle?

Sanddancer 11y ago
Eliminating drag. Because the head uses air pressure to keep itself off the platter, that air is also going to be pressing against the drive, causing friction, and requiring the motor to work a bit harder. By parking away from the platter altogether, you're eliminating that source of drag and friction. Regarding the orange widget, the damage happens over hundreds of thousands of park and unpark cycles -- a little wobble and a little rubbing after each one, which will eventually be enough to get things out of alignment and thus, broken. The difference between near the rim and near the spindle is that air pressure. If it's near the spindle, it still has that drag that's making the motor work harder. Near the rim, that pressure is gone.
- atap 11y ago
  It just seems strange that there needs to be an orange widget to act as a "landing zone" at all. Why not park the heads hanging in free space? Ostensibly the plastic widget is probably a guide rail to prevent head crashes, when the head unparks onto a platter spinning at full speed?
  - miahi 11y ago
    The heads (the one above and the one below the platter) would crash into each other if there is nothing to keep them apart, and then you could not put them back on the platter.
  - rzzzt 11y ago
    There's a short whitepaper published by HGST (now part of Western Digital) which discusses the history and benefits of the ramp load-unload mechanism [1]. [1] http://www.hgst.com/tech/techlib.nsf/techdocs/9076679E3EE4003E86256FAB005825FB http://www.hgst.com/tech/techlib.nsf/techdocs/9076679E3EE400...
userbinator 11y ago
It really doesn't seem like parking the drive heads would be an action that requires any kind of contact or friction between moving parts. There is friction - between the head arm and the "load/unload ramp", as it's called. That's what lifts the heads off the platter when they're parked. Here is an extreme close-up of what this looks like: http://cdn1.goughlui.com/wp-content/uploads/2013/03/DSC_0016.jpg http://cdn1.goughlui.com/wp-content/uploads/2013/03/DSC_0016... So a piece of metal rubs against a plastic ramp every time the head parks.

by atap 11y ago

Sanddancer 11y ago

Eliminating drag. Because the head uses air pressure to keep itself off the platter, that air is also going to be pressing against the drive, causing friction, and requiring the motor to work a bit harder. By parking away from the platter altogether, you're eliminating that source of drag and friction. Regarding the orange widget, the damage happens over hundreds of thousands of park and unpark cycles -- a little wobble and a little rubbing after each one, which will eventually be enough to get things out of alignment and thus, broken. The difference between near the rim and near the spindle is that air pressure. If it's near the spindle, it still has that drag that's making the motor work harder. Near the rim, that pressure is gone.

atap 11y ago
It just seems strange that there needs to be an orange widget to act as a "landing zone" at all. Why not park the heads hanging in free space? Ostensibly the plastic widget is probably a guide rail to prevent head crashes, when the head unparks onto a platter spinning at full speed?
- miahi 11y ago
  The heads (the one above and the one below the platter) would crash into each other if there is nothing to keep them apart, and then you could not put them back on the platter.
- rzzzt 11y ago
  There's a short whitepaper published by HGST (now part of Western Digital) which discusses the history and benefits of the ramp load-unload mechanism [1]. [1] http://www.hgst.com/tech/techlib.nsf/techdocs/9076679E3EE4003E86256FAB005825FB http://www.hgst.com/tech/techlib.nsf/techdocs/9076679E3EE400...

userbinator 11y ago

It really doesn't seem like parking the drive heads would be an action that requires any kind of contact or friction between moving parts. There is friction - between the head arm and the "load/unload ramp", as it's called. That's what lifts the heads off the platter when they're parked. Here is an extreme close-up of what this looks like: http://cdn1.goughlui.com/wp-content/uploads/2013/03/DSC_0016.jpg http://cdn1.goughlui.com/wp-content/uploads/2013/03/DSC_0016... So a piece of metal rubs against a plastic ramp every time the head parks.