DECtape ancestry

[Bob Smith]

My recollection was the Linc was inspired by the Whirlwind. Whirlwind
predates it by a few years.
AND of course the Linc inspired the PDP5 and PDP8. Of course some one
correct me if this is wrong, but my sources were DEC when I worked
there 1969-1980, stories with Don White and others, as well as my
sabbatical on site at Lincoln Lab building working on a project, some
interaction with associates of Charles Molnar et al, and their
recollections.
And Linc8 and Link12 were related too.
Here is a link (pardon the pun) to the Digibarn recollection story on LINC.
https://www.digibarn.com/stories/linc/documents/LINC-Personal-Workstation/LINC-Personal-Workstation.pdf

On Thu, Mar 11, 2021 at 8:05 PM Bill Degnan via cctalk
<cctalk at classiccmp.org> wrote:
>
> Paul,
> Very interesting, thanks for sharing.
> Bill
>
> On Thu, Mar 11, 2021 at 7:54 PM Paul Koning via cctalk <
> cctalk at classiccmp.org> wrote:
>
> > I just read part of the Grant Saviers interview from CHM, where near the
> > end he gives a  bit of history of DECtape.  In particular, the fact that it
> > was  derived from LINCtape though the format details are quite different.
> >
> > A question popped into my mind, prompted by having read Guy Fedorkow's
> > paper about Whirlwind just a few days earlier: the Whirlwind tape format
> > has 6 physical tracks but 3 logical tracks (each logical track is recorded
> > redundantly on two physical tracks) and one of those tracks is a clock
> > track.  LINCtape and DECtape have the same redundant recording scheme, and
> > also have a clock track; the difference is that they add a mark track to
> > enable the recording of block numbers and in-place block writing.
> >
> > That made me wonder if LINCtape was, in part, inspired by the Whirlwind
> > tape system, or if those analogies are just a concidence.
> >
> > Incidentally, it's probably not widely known that LINCtape/DECtape is not
> > the only tape system with random block write capability.  Another one that
> > does this is the Electrologica X1 tape system, which uses 1/2 inch 10 track
> > tapes, which include a clock and a mark track.  An interesting wrinkle is
> > that the X1 tape system lets you chose the block size when formatting the
> > tape, and then data block writes allow for the writing of any block size up
> > to the formatted block size.  I'm not sure when that device was introduced;
> > the documentation I have is from 1964.  There's no sign the designers knew
> > of DECtape (or vice versa).
> >
> >         paul
> >
> >