On 11/3/24 12:56, paul.kimpel--- via cctalk wrote: > CAREY SCHUG wrote: >> 2. remember that record mark? if you ever executed an instruction with a >> record mark in >> the address, you got a MAR check red light, a hard reset was required to >> escape. probably >> if in the op code also. And some hard stop for any invalid op code, but >> these may have >> been in the category below. > > Shouldn't these be considered good error-trapping features and not in the > same league as HCF? An RM had the 8 and 2 bits set, so it wasn't a valid > decimal digit, and couldn't be used in an address. An RM in the Q field of an > immediate instruction was okay, though.
On card-oriented CADETs, there were a few alternatives to the nuisance of having to multipunch a record or group mark on an 026. I seem to recall that a period read numerically translated to 8-2-1 and worked just as well. Among other shortcomings of the 1620, there was no way to test for numeric blank (8-4). You just had to know that it was there. There were several such bugaboos, with which Dijkstra had issues. Still, the 1620 was capable of doing real work--and its 1710 relative was capable of industrial process control application. --Chuck
