SCSI Questions (Was: "Re: Purchased a Microvax 3800")

Ethan Dicks ethan.dicks at
Tue Dec 8 13:34:17 CST 2015

On Tue, Dec 8, 2015 at 11:02 AM, Paul Koning <paulkoning at> wrote:
> One detail on "it doesn't care what the tape is": RSTS kits on 1/2 inch tape come
> in 800 and 1600 bpi versions.  They have different boot blocks, each of them
> designed to work with all tape drives/controllers supported on RSTS that
> support the density in question.  For example, the 1600 bpi kit doesn't boot
> on a TM11 controller, and the 800 bpi kit won't boot on a TMSCP controller.

I remember TM and TS boot issues from the 80s when we were running RSTS
on an assortment of 11/24 and 11/34 hardware and having to migrate tape
controllers and tape drives from place to place for the installs (TMB11 + TS03,
MS11 + TU80...)  I still have a couple of boxes of 800bpi small reels we used
on that TS03.

>  This matters if you try to boot one in an emulator where physical tape density doens't have any meaning.

Hadn't considered the implications, but sure... you would have to completely
emulate the original gear or the stars won't align.


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