For years I badgered my mother with questions about whether Santa
Claus is a real person or not. Her answer was always Well, you asked
for the presents and they came, didnt they? I finally understood the
full meaning of her reply when I heard the definition of a virtual
device: A software or hardware entity which responds to commands in a
manner indistinguishable from the real device. Mother was telling me
that Santa Claus is a virtual person (simulated by loving parents) who
responds to requests from children in a manner indistinguishable from the
real saint.
Mother also taught the IF … THEN … ELSE structure: If its
snowing, then put your boots on before you go to school; otherwise just
wear your shoes.
Mother explained the difference between batch and transaction processing:
Well wash the white clothes when we get enough of them to make a load, but
well wash these socks out right now by hand because youll need them this
afternoon.
Mother taught me about linked lists. Once, for a birthday party, she
laid out a treasure hunt of ten hidden clues, with each clue telling
where to find the next one, and the last one leading to the treasure.
She then gave us the first clue.
Mother understood about parity errors. When she counted socks after
doing the laundry, she expected to find an even number and groaned when
only one sock of a pair emerged from the washing machine. Later she
applied the principles of redundancy engineering to this problem by
buying our socks three identical p airs at a time. This greatly
increased the odds of being able to come up with at least one matching pair.
Mother had all of us children write our Christmas thank you notes to
Grandmother, one after another, on a single large sheet of paper which was the
n mailed in a single envelope with a single stamp. This was obviously an
instance of blocking records in order to save money by reducing the number of
physical I/O operations.
Mother used flags to help her manage the housework. Whenever she
turned on the stove, she put a potholder on top of her purse to reminder
herself to turn it off again before leaving the house.
Mother knew about devices which raise an interrupt signal to be
serviced when they have completed any operation. She had a whistling tea
kettle.
Mother understood about LIFO ordering. In my lunch bag she put the
dessert on the bottom, the sandwich in the middle, and the napkin on top
so that things would come out in the right order at lunchtime.
There is an old story that God knew He couldnt be physically present
everywhere at once, to show His love for His people, and so He created
mothers. That is the difference between centralized and distributed
processing. As any kid whos ever misbehaved at a neighbors house finds out,
all the mothers in the neighborhood talk to each other. Thats a local area
network of distributed processors that cant be beat.
Mom, you were the best computer teacher I ever had.