next chair of the computer science division at Berkeley, we decided to go for it,
because that gave us a deadline.
You handed off chapters to one another
via FedExed floppy disks.
DAVID: We prototyped the book as if
it were a computer, with an alpha and a
Microsoft’s David Cutler bought copies
for all members of his design team.
DAVID: I think Microsoft also kept a
copy in the stationery store. Pads of paper, pencils, Hennessy and Patterson…
JOHN: In the first year, we probably
sold as many books to practicing engineers as we did to the academics. That’s
really unusual. Books usually divide one
way or the other—either they’re written
for professionals or for the university
DAVID: The book made those ideas accessible to lots of people.
You also invented a brand new param-
eterized architecture for the book called
DLX that expressed your approach.
DAVID: There are lots of RISC instruction sets, and John is associated with
one and I’m associated with another.
From a textbook writer’s perspective,
we thought that picking one might flavor the book, so we decided to invent a
brand-new instruction set.
MIPS lost out to Intel in the PC market,
but RISC processors now power nearly
but you’ll never get these ideas to work
in real machines that people want to sell
What were the most common objec-
JOHN: We built academic prototypes,
and they didn’t have everything you’d
need for a commercial machine. And
people said, “When you put in virtual
memory support, or support for floating
point, all the advantages you have will
DAVID: The conventional wisdom at
the time was software was buggy because the vocabulary of the computers
it talked to was too low. So there were
all these efforts to try and make the vocabulary closer to that of the languages.
John and I were arguing the opposite,
and that was part of the heresy.
JOHN: I think the other thing that undermined it was that we didn’t have a
good scientific explanation of what was
happening until later. That was part of
our motivation to write the book, so that
we could explain the ideas quantitatively and scientifically.
You’re referring to Computer Architec-
ture: A Quantitative Approach, which
was first published in 1989 and is now
in its sixth edition.
DAVID: I think a lot of faculty are unhappy with the textbooks they use. John
and I talked about it at meetings, and
when I realized I was going to be the
John L. Hennessy
[CONTINUED FROM P. 104]
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