Got two RK05's, looking for a PDP-8 or 11

Tony Duell ard at
Mon Nov 23 13:28:26 CST 2009

> >If the head/voice coil assemblies have been removed you'll have to go =20
> >through the entire alignment procedure which requires a special =20
> >alignment pack.  You'll also want to make sure that all of the dreaded  =

My expeirience is that if you have a drive with a correctly-aligned 
positioner/head assemly, you can remove it as an assembly, and put it 
back in _the same drive_ and it will still be alighed. But if you move 
positioenrs between drives you have to do a realignment.

The alignment procedure is not hard if oyu have the alignment pack. You 
also need a 'scope (but just aout any 'scope will do) and a way of moving 
the heads to a particular cylinder and selecting head 0 or head 1. I had 
no prolems using a PDP11 + the appropriate controller for this, just 
togging values int oteh controller registers from the PDP11's font panel. 
If you use a PDP9/e, I think you have to write a trivial program for this.

> Well right now I'll go for pretty much anything. I guess a 34 or similar =
> is
> a good starter system and on some distant day I'll switch to say an 8/e.

THe disk packs are different between the PDP8 and PDP11 systems. They're 
hard-sectored (by notches in a metal ring on the disk hub), PDP11 packs 
are 12-sectory, PDP8 packs are 16 sector. The former are _much_ easier to 


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