Odd "endianness" [was Re: RE: Base 64 posts to the list]

[Lars Brinkhoff]

Rich Alderson wrote:
> From: Chuck Guzis
> Sent: Monday, December 05, 2016 6:15 PM
>> I've seen PDP-10 9-track tapes done two ways--one character per frame
>> and then 4 frames (36 bits) with 5 7-bit characters and the sign bit
>> left over.
>
> Neither of those is entirely accurate.  9-track tapes on the PDP-10
> [...]

I know nothing about physical magtapes.  I have seen this comment about
the MIT ITS machines:

> DM had the only 9-track tape drive; the other machines had 7-track
> tapes, as befit 36-bit machines.

So I suppose many ITS tapes would have stored six frames per word.