Sujet : Re: Baby X is bor nagain
De : bc (at) *nospam* freeuk.com (bart)
Groupes : comp.lang.cDate : 28. Jun 2024, 15:42:47
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <v5mi57$3cgtg$2@dont-email.me>
References : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
User-Agent : Mozilla Thunderbird
On 28/06/2024 14:48, Scott Lurndal wrote:
bart <bc@freeuk.com> writes:
On 28/06/2024 04:30, Kaz Kylheku wrote:
On 2024-06-27, bart <bc@freeuk.com> wrote:
For most, PIC isn't a necessity.
>
Only because they use a virtual memory operating system which allows
every executable to be mapped to the same fixed address in its own
address space.
>
PIC never seemed to be a requirement during the 1980s and half the 90s.
But then OSes only ran one program a time.
Interactive operating systems in 1967 (e.g. TSS8) were running
multiple programs at a time.
OK, let's say the many millions of PCs used by home and business in that era only ran a program at a time.
Other than that, I'm not familiar with the workings of 1960/70s major OSes. But it's quite possible that two programs could be swapped in and out of the same memory space.
And when virtual addressing came along, and multiple programs could
co-exist at the same address, PIC wasn't really needed either.
Virtual addressing has been part of computer systems since the 1960s.
OK, so was PIC needed for those or not? Did all processes share one virtual address space, or did each have its own?
Re: Baby X is bor nagain