8" drive variations

Chuck Guzis cclist at sydex.com
Tue Mar 13 12:06:43 CDT 2007

On 13 Mar 2007 at 11:32, Jules Richardson wrote:

> As hinted at in another post a few days ago, I'd like to add an 8" drive (or 
> possibly more than one if necessary) to my Imagedisk machine in order to be 
> able to archive 8" media.

On many 8" drives, HS and SS operation is set by jumpers on the drive 
electronics board.  Some drives have an onboard FM data separator.  
Seek rates and mechanisms can be all over the map.  Pinout need not 
be the same (IIRC, Calcomp drives feed their power through the 44-pin 
connector).  There is less of a standard form factor ((i.e. floppy 
slots and latch positions are not usually the same from manufacturer 
to manufacturer).  Power connectors can be significantly different.  
Some drives have binary select; others have radial select; many have 
both.  Options (e.g. door lock, eject) can vary.  Some require +24, 
+12, +5 and -5 power supplies; others will get by fine on +24 and +5 
only.  Some have a DC motor; most full-height models use an AC mains-
powered motor.   Some are single-sided only--others are double-sided.

Generally, the later the drive was produced, the more likely it is 
that it conforms to a Shugart SA-850 interface.  Early 8" drives 
mostly demonstrate how different implementations can be.  For me, 
some early Japanese drives are still a mystery.

Forget about using a hard-sector drive with a 765-type controller.  
It doesn't work that way.  Get a Catweasel if you want to do those.

That's what I can think of at the moment.  I'm certain there's more.

Personally, I have a liking for the full-height Siemens and Qume 
drives.  I never cared much for the half-height 8" drives.


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