Mainframe vs. xSeries 3283
Yes. This is another bad side effect of ATT not being in the OS biz. When you pick and choose your customers to the point of eliteness (their awful licensing scheme), your product doesn't get stress tested. There's nothing like 10,000 college-aged kiddies who have nothing to do than make trouble :-). The computer center learns how to plug holes and pbuttes on the lessons to the OS people. Since the product is their bread and butter, these problems get top priority, sometimes all the way to the CEO.
Sometimes, none of this makes sense. All this had an NSA security folklore as its base. Universities were rampant with crackers. The design and code evolution should have been quite different.
Mainframe vs. xSeries 3285
part of the issue in timesharing was that there was a much greater need to separate system command&control...
I think the whole purpose of desktop was to eliminate all work involving these security (and they are all security) aspects of delivering computing services. But it's like picking up dropped mercury; there's more work to get it when it's in 1000 little pieces than in one big glob. You have a mess but your mess is all in one place and can be fenced in. If you have to have a mess, it's much better to have all in one place at the same time.
Mainframe vs. xSeries 3284
misc. historical references of breastan & cambridge univ. it was a 370-165 installed in 1971 (pre 370 virtual memory). following...