IEEE-488 addresses like that of the DMM are set by DIP switches on that equipment, and could be changed. I probably just used whatever it came with, since there were no conflicts, ie, no two pieces of equipment had the same one. If they were on HPIL (the serial, daisy-chained implementation of IEEE-488 or HPIB), you can have the calculator look for the device, and you'd probably only do that once and then have it remember the address for the remainder of the program, for greater efficiency. You could have more than one of any given kind, and say for example, "Store this file on the second (or third, or fourth, etc.) HP82161A you find on the loop." (The HP82161A digital microcassette tape drive worked like a disc drive, with a FAT, and was much faster than normal cassettes.) Each device knows its model number, its address, what class of device it is and what it can do, and they can interrupt if necessary.brad wrote:Thanks for the great write up Garth and I apologise for my delayed reply. We have been moving house and have not had much free time!
I guess over time, you would get to know all the numbers that would have been represented by variables I.E. you would know off by heart that 22 is actually DMM etc..
Floppy Days Vintage Computing Podcast #60, which is Part II on the HP-41, just came out a few days ago at http://floppydays.libsyn.com/webpage/2016/06 . Randy started it with my six-minute recording which he requested about how I got into using the HP-41cx as a controller for automating processes on the workbench. The 41 discussion resumes then at about 14 minutes into it. The podcast doesn't go far enough to do justice to this magnificent little machine, but I'll expand on some things like synthetic programming and the processor design if anyone is interested.