Cleaning packs

Tony Duell ard at p850ug1.demon.co.uk
Wed Nov 25 15:18:13 CST 2009


> 
> 
> On Nov 24, 2009, at 1:08 PM, geoffrey oltmans wrote:
> 
> > Dumb question (perhaps), but do the relative positions of the disk  
> > platters in the pack matter on these systems? I suppose it might for  
> > interleaving purposes for data already recorded.
> 
> I would suspect yes but never having cleaned multi-platter packs, I'd  
> only do that on packs that I don't care about the data (ie I'm going  
> to format the pack as soon as it's "clean").  If I care about the data  
> that *might* be on them I probably wouldn't disassemble (ie de-stack)  
> the pack.

I qwould be very careful about dismantling the pack for another reason. 
Often there is no automatic centring of the platters. If you seprate 
them, you will have to centre them up. On the (crashed) 5-platter pack I 
dismantled about 25 years ago (for interest), there were holes throuch 
the top and bottom hparts of the hub through which you put long rods to 
keep the platters and spacers _approximately_ cententerd. But then, I 
think, you have to put the hu on the drive spindle (or a similar spindle 
in a test rig) nd  use a dial gauge to position the platters so there's 
no run-out when you rotate the stack by hand. Given that moving one 
platter is likely to slightly move all the others, this is a long and 
tedious job.

-tony



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