Re: Multitasking @lleres
I don't recognize your categorization of "Unix die-hards" being proponents of real time computing.
UNIX was made multitasking almost from the beginning in order to allow several people to share what was an expensive and scarce resource. At that time, UNIX was NOT, and never has been a proper 'real-time' operating system like DEC's RT-11 or RSX-11 (note, there have been real-time extension, like AT&T UNIX RTR, but they are not really mainstream).
In fact, completely counter to what you said, the movers and shakers of UNIX (Dennis, Ken, Doug and Joe - although Brian was less involved) were involved in various degrees with Multics, with all of them taking an active role in that project. Multics was multi-user and multi-tasking, and the desire when creating UNIX was to preserve many of the good things in Multics, on much smaller and less costly systems than Multics needed.
So as a result, UNIX was written, pretty much from the ground up, as a multi-user and multi-tasking system.
In my view, if IBM had chosen a cut-down OS based on UNIX rather than what Microsoft provided, the whole computing world would have been better. As it was, proper multi-tasking did not appear on desktop-class machines for many years, and windows was only dragged into the multi-user world very late indeed.
But I take the points made in the article that the poor implementation of many computer OSs and applications does not provide sufficient isolation between each application, but a properly designed OS with the correct resource fences (for CPU, memory and IO) should really do everything that is currently being done by a type 2 hypervisor. Basic UNIX has always provided process and memory separation, and AT&T derived UNIXes had a 'fair share scheduler' back in the 1980's to enforce CPU limits, and AIX has had Work Load Manager (WLM) since AIX 4.3.3, which is used for WPARs (Workload Partitions - much like Solaris Containers) for limiting CPU, memory and I/O resource use.
A proper OS should enforce memory separation (UNIX has since it was re-written on the PDP-11), although the current Meltdown has shown that Linux (note, Linux is not UNIX) has taken some (in hindsight, and IMHO) poorly thought out efficiency shortcuts (like mapping most of the kernel memory space into each process). UNIX never did this, at least not on the PDP-11, s370, VAX, Sun Motorola and SPARC platforms that I know most about.
It would be interesting to look at Intel UNIX ports like Sun/OS i386. AIX PS/2 (damn, I should know this for this platform), Xenix/368, Interactive UNIX, Microport UNIX and UNIXware to see whether those platforms properly separated the kernel address space from user-land.