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December 13, 2012 18:29
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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -81,4 +81,11 @@ be blunt, you owe both your undergraduates and your good name much better. - Bryan ---------------------------------------------------------------------------- Bryan Cantrill, Solaris Kernel Development. [email protected] (650) 786-3652 (*) On some (horribly ill-advised) operating systems, 0x0 is mapped to a zero-filled page (IBM's AIX is the most famous example; there are other more obscure examples). When students give the response that "y gets zero", we immediately ask them to qualify it with an operating system. Suffice it to say, none of the Cornell candidates qualified their answer with an operating system which maps 0x0. -
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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -0,0 +1,84 @@ From bmc Mon Oct 2 15:12:34 2000 Subject: Undergrad systems curriculum To: [email protected] Date: Mon, 2 Oct 2000 15:12:34 -0700 (PDT) X-Mailer: ELM [version 2.4ME+ PL31H (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 4065 Status: RO Cornell CS faculty, I work in Solaris Kernel Development at Sun Microsystems. Recently, I (along with another engineer from Solaris Kernel Development) interviewed students at Cornell for both full-time and internship positions within our group. While the students we interviewed were clearly bright and motivated, they were woefully unprepared for the design or implementation of computing systems. To elaborate: our most coarse-grained filter for assessing preparedness is to ask the candidate what (in the absence of compiler optimizations) the following C program does: int main() { int *x = NULL; int y = *x; ... This is not a trick; I expect one hundred percent of graduating seniors in Computer Science to be able to answer this question. Indeed, we only ask this question as a segue to more subtle issues: I expect candidates to be able to write the program in the assembly of their choosing, and -- assuming they have had an OS class -- be able to discuss in some detail the hardware and software which lie between loading from an invalid address and the ensuing death of the incurring process. At Cornell, all of the students we interviewed had taken 414 (and many had taken 415), but most students gave us the response "y gets zero" (with a sizable minority telling us that the program would "throw a NULL pointer exception"). Obviously, neither is correct(*) (though at least the second is in the ballpark). Further probing, however, revealed that even the students who gave the second (Java-centric) answer had virtually no understanding of OS implementation, or (more generally) of the interaction between hardware and low-level system software. And most disconcertingly, the students with no understanding of OS implementation included a TA for 414. Surprised by the anemic preparation of otherwise high-caliber students, we asked about the specifics of the Cornell CS curriculum in general and about 414/415 in particular: we were astonished to learn that 414 has no implementation requirement, and that the implementation in 415 consists largely of a disk simulator written in Java (it has been our experience that even a featherweight OS course requires some implementation in Nachos or equivalent). Even more surprising, students graduating with a CS degree from Cornell _never_ learn C or C++ or Pascal or _any_ language that deals with memory explicitly. Just as the revolution in structured programming languages did not push machine architecture out of the undergraduate curriculum, so should the proliferation of Java not displace the teaching of lower level systems and languages. By purging this technology tier from your curriculum, you are generating students who are thoroughly confused and completely unprepared to develop any core technology (after all, JavaVM's aren't written in Java). And should you think me unfair: we ask the same questions at every school at which we interview. At schools with superlative OS courses (Princeton and Brown come to mind), _every_ candidate blows this first question out of the water (after all, it _is_ the "gimme" question). So why am I wasting my time writing you? We won't recruit at Cornell again, so there's nothing in it for us. But we just met too many generally bright, grossly underqualified students who were allegedly interested in systems implementation to not make you aware of your acute problem. To be blunt, you owe both your undergraduates and your good name much better. - Bryan ---------------------------------------------------------------------------- Bryan Cantrill, Solaris Kernel Development. [email protected] (650) 786-3652