When a mainframe is upgraded -- given a more powerful 'engine' - there are a couple of ways to do it.
You can swap the existing CPU card (actually, a pretty large piece of hardware, but not enormous) for a more powerful one. Or you can add an additional one (or two, or three, up to the physical limits of the cabinet.)
None of this involves having to mess around with the storage. Your programs are still out on DASD or tape. Once the new CPUs are in place, you do an IPL (Initial Program Load), starting up the system, and you're off and running.
So why does an upgrade of your home PC require a physical swap?
2 comments:
Interesting question. Why do I have the feeling that "planned obsolescence" and "taking dumb consumers for everything we can" both play into it? ;-)
Ever notice that 'planned obsolescence' and 'pissed off' have the same abbreviation?
I think that the obsolescnce is part of it. Another part is that we push the idea of collapsing systems together; the concept of intentionally breaking them apart goes against the trend. Actually designing such a system sounds straightforward to me (as do all things which I don't personally have to do). You already have the physical separation of the storage and the CPU, and you can move the storage out, easily enough, to a server, leaving the main box to be just the CPU and its operating system. The tricky part is in physically swapping or augmenting the CPU. I seem to recall hearing about dual-chip processors, but I don't recall if they were (simply) two CPU cards instead of one, or a single card with more computer power on it.
Other topics of interest: why is it so hard to upgrade the operating system? And why does the operating system let applications stick modules and other code in there with itself, so that an upgrade means affecting the application? (Perhaps it doesn't have a choice: I would think that all apps talk to the OS for data movement, but maybe not.)
Never wanted to be a computer systems engineer, but this does make me wonder whats even possible.
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