Re: Replacement hardware?
My personal experience was that aerospace companies tended to keep what they had running for as long as possible because their product developments times were so long, they liked to have the same IT equipment throughout the development term (At least in the 70's, 80's and 90's). I recall PDP-84 having SCSI disks so this was definitely an option, but it would probably be like VAX's replacing RA82, RA90's with SCSI/DSSI disks it was definitely an option but if you had spent a small fortune on RA90's for instance people tended to want to get their money worth not to mention that the computer company would want to keep the nice high margin maintenance contract going