ISO: Manual or information on 3M DCD3-30 tape unit

[Tony Duell]

> 
> Anyone have any information for this early QIC drive?  Model DCD3-
> 30/90.  The controller board is pretty simple--just some 7400 series 
> TTL, made by Solid State Systems.  The most complex IC is an AM27S21 
> 1Kbit bipolar PROM.  There's a 220/330 terminator pack near the 50 
> position header, if that's any help.
> 
> Is this a QIC-36 interface drive (50 pin header on the controller 
> board)?

If byu 'controller board' you mean the thign that plugs into the host 
computer (such as into an ISA slot), then I would think it's more likely 
to be QIC-02. That's also a 50 pin interface, but is a 'formatted' 
interface and needs very little logic on the host side. All the 
trasnlation between 8-=bit bytes and the data stream to the head is 
carried out in the drive. The drive is probably wuite complicated with at 
least one microcontorller and some buffer RAM to handle this data conversion.

Originally (I am thinking back to the Archive Sidewinder here, a QIC-11 
format drive in an 8" floppy form factor), the basic drive had a QIC-36 
interface, there was then a controller (2 stacked boards that connected 
ot this and had a QIC02 interface back to the host. I've seen a later 
drive (5.25" form factoer) that did much the same thing

-tony