On Thu, 16 May 2019 15:26:45 +0000, Seymour J Metz <sme...@gmu.edu> wrote: >Well, for some devices the CU and device were in the same box, e.g., 2501.
Yes. A-units (Axx models) often include(d) at least one, possibly two or even four, I/O devices, with B units (Bxx models) providing expansion. Last CU standing in the A/B world was, I think, the IBM 3590, but it all went out the window when the 3592s made their debut. While it was interesting for IBM to wear it's engineering designs on its visible sleeve, it was confusing. Model numbers today are more expressions of marketing than of the underlying technology. Fun times. Alan Altmark IBM ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
