On Wed, 2024-04-10 at 10:17 -0500, Jon Elson via cctalk wrote: > The > 360/25 was a very interesting concept. The microcode was in > the top 16 KB of main storage,
360/30 microcode was in capacitive ROM, implemented using standard-size punch cards with little metal rectangles that could be punched out to make zeroes, sandwiched into metal backplanes. I remember a CE coming out, running a few cards through a 026 to dup them, then installing them. He didn't say whether he was repairing bugs in the 360 instruction set, or the 1401 emulation.
