On Mon, 18 Nov 2019, Clem Cole wrote:

> The cat was already out and poking around with the publishing of:  IBM 
> 360 Principles of Operation, DOC A22-6821-0. The APL version of spec 
> just gave it more area to roam.

Yeah, I know about PrincOps; it went into excruciating detail, leading to 
the observation that IBM manuals were designed to impress rather than 
inform...

-- Dave