On 12/15/2018 09:32 PM, Charles Anthony via cctech wrote: > On Sat, Dec 15, 2018 at 6:15 PM Rod G8DGR via cctalk <cctalk@classiccmp.org> > wrote: > >> All very interesting.. 1201 alarm while I deal will all of the information >> Rod >> >> > 1202 coming up... > > I don't know specifically about the various memory types being bandied > about, but I do know that the destructive read behavior of core memory my > be required for some architectures; "load and clear" type instructions rely > on the suppressing the write-after-read cycle to make the instruction > atomic, allowing the implementation of data locking instructions. For some > architectures, it may be that any replacement memory would have to support > the suppression signal to work correctly. > > -- Charles
That's all fairy land speculation and guessing. The person that started this is working with a PDP-8E so the above does not apply. the 8E and later had both DEC made ram and third parties did when 2102 were cheap enough about 78ish. Later it was battery backed up cmos. For system with disk a rom based booter was enough as who cares if the ram held valid stuff. As to realism, the cost of a core was high enough then if it broke or worse now if it breaks its out of sight. Breakage back then was costly, not its possibly unobtainium. The for the most part with the covers on the only thing noted was binary blisters from the switches and the incessant loud fans. In the mean time the user was interacting with a TTY with its notable noises and if needing service a sometimes bad attitude. The fact that CORE does a R-Rewrite or RMW cycle is both unseen without a scope and had no impact while running a file though PAL-III in all caps. In the end, current generation CMOS ram is the easy out, battery is small, cost is small, and produces much less of the heat that is killer to systems. The only reason to do that is core cost big if you can find it for your machine. I can cost more if you want to run an OS that needs a fair amount of it. AC as well as it can help heat the room and also power as in makes the meter spin. So much lathering and speculation about what and how. When the point is totally missed. Allison
