Foreword

I entered college in 1978, and I immediately found a second home at the computer lab on campus. This lab was home to an IBM mainframe and a roomful of noisy keypunch machines. I punched my code onto a stack of cards, and I handed the stack to a system operator. The operator loaded the cards into the reader, and my job was queued for processing. If things went well and the mainframe was not too busy, I would have my cards and my output back within four hours or so. The operator managed the work queue for the mainframe, adjusting the balance of jobs and priorities, looking for hot spots and slowdowns, and keeping the monolithic mainframe as busy and as productive as possible at all times.

As a young, curious student, I always wondered ...

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