instead he went on to build a glittering empire of department stores
and he paid each one of them a monthly salary so that they could write in peace
and yet in the late thirty s salman saw what 's coming
he fled germany together with his family leaving everything else behind his department stores confiscated he spent the rest of his life in a relentlesspursuit of art and culture
such is the power of self study
and these are my parents
they too did not enjoy the privilege of college education they were too busy building a family and a country
and yet just like salman they were lifelong tenacious self learners and our home was stacked with thousands of books records and artwork
i remember quite vividly my father telling me
sophisticated this early awe
with the basics has only intensified
so it 's not surprising that about twelve years ago when noam and i were already computer science professors we were equally frustrated by the same phenomenon as computers became increasingly more complex our students were losing the forest for the trees
and indeed it is impossible to connect with the soul of the machine if you interact with a black box p c or a mac
which is shrouded by numerous layers of closed proprietary software
so noam and i had this insight that if we want our students to understand how computers work and understand it in the marrow of their bones then perhaps the best way to go about it is to have them build a complete
working general purpose useful computerhardware and software from the ground up from first principles
now we had to start somewhere and so noam and i decided to base our cathedral so to speak on the simplest possible building block which is something called nand
it is nothing more than a trivial logic gate with four input output states so we now start this journey by telling our students that god gave us nand laughter and told us to build a computer and when we asked how god said one step at a time
and then following this advice we start with this lowly humble nand gate and we walk our students through an elaboratesequence of projects in which they gradually build
the students celebrate the end of this tour de force by using jack to write all sorts of cool games like pong snake and tetris you can imagine the tremendous joy of playing with a tetris game that you wrote in jack
and then compiled into machine language in a compiler that you wrote also and then seeing the result running on a machine that you built starting with nothing more than a few thousand nand gates
the trick was to decompose the computer 's construction into numerous stand alone modules each of which could be individually specified built and unit tested in isolation from the rest of the project
and from day one noam and i decided to put all these building blocks freelyavailable in open source on the web
project descriptions software tools hardware simulators cpu emulators stacks of hundreds of slides lectures we laid out everything on the web and invited the world to come over take whatever they need and do whatever they want with it and then
and in short order thousands of people were building our machine
and nand two tetris became one of the first massive open online courses although seven years ago we had no idea that what we were doing is called moocs
we just observed how self organized courses were kind of spontaneously spawning out of our materials for example pramode c e an engineer from kerala india has organized groups of self learners who build our computer under his good guidance
and parag shah another engineer from mumbai has unbundled our projects into smaller more manageable bites that he now serves in his pioneering do it yourself computer science program
the people who are attracted to these courses typically have a hacker mentality they want to figure out how things work and they want to do it in groups like this hackers club in washington d c that uses our materials to offer community courses
and because these materials are widely available and open source different people take them to very different and unpredictable directions for example yu fangmin from guangzhou has used fpga technology to build our computer and show others how to do the same using a video clip
and ben craddock developed a very nice computer game that unfolds inside our cpu architecture which is quite a complex three d maze that ben developed using the minecraft three d simulator engine
the minecraft community went bananas over this project and ben became an instant media celebrity
and indeed for quite a few people taking this nand two tetris pilgrimage if you will has turned into a life changing experience
for example take dan rounds who is a music and math major from east lansing michigan a few weeks ago dan posted a victorious post on our website and i 'd like to read it to
so here 's what dan said
i did the coursework because understanding computers is important to me just like literacy and numeracy and i made it through i never worked harder on anything never been challenged to this degree but given what i now feel capable of doing i would certainly do it again
to anyone considering nand two tetris it 's a tough journey but you 'll be profoundly changed so
and it 's quite amazing because these people cannot care less about grades they are doing it because of one motivation only they have a tremendouspassion to learn and with that in mind
i 'd like to say a few words about traditional college grading i 'm sick of it
we are obsessed with grades because we are obsessed with data and yet grading takes away all the fun from failing and a huge part of education is about failing
courage according to churchill is the ability to go from one defeat to another without losing enthusiasm
and yet we don 't tolerate mistakes and we worship grades so we collect your b pluses and your a minuses and we aggregate them into a number like three point four which is stamped on your forehead and sums up who you are
well in my opinion we went too far with this nonsense and grading became degrading so
and we do it on tablets because we believe that math like anything else should be taught hands on
so here 's what we do basically we developed numerous mobile apps every one of them explaining a particular concept in math so for example let 's take area
when you deal with a concept like area well we also provide a set of tools that the child is invited to experiment with in order to learn so if area is what interests us then one thing which is natural to do is to
and at some point you will discover that one thing that you can do among several legitimate transformations is the following one you can cut the figure you can rearrange the parts
you can glue them and then proceed to tile just like we did before
we don 't replace teachers by the way we believe that teachers should be empowered not replaced moving along what about the area of a triangle so after some guided trial and error the child will discover with or without help
now this transformation has doubled the area of the original figure and therefore we have just learned that the area of the triangle equals the area of this rectangle divided by two but we discovered it by self exploration
so in addition to learning some useful geometry the child has been exposed to some pretty sophisticated science strategies like reduction which is the art of
transforming a complex problem into a simple one or generalization which is at the heart of any scientificdiscipline or the fact that some properties are invariant under some transformations
and all this is something that a very young child can pick up using such mobile apps so presently
we are doing the following first of all we are decomposing the k twelve math curriculum into numerous such apps
and because we cannot do it on our own we 've developed a very fancy authoring tool that any author any parent or actually anyone who has an interest in math education can use this authoring tool to develop similar apps on tablets without programming
and finally we are putting together an adaptive ecosystem that will match different learners with different apps according to their evolving learning style
the driving force behind this project is my colleague shmulik london and you see just like salman did about ninety years ago the trick is to surround yourself with brilliant people because
a few years ago i was walking in tel aviv and i saw this graffiti on a wall
the most important thing is to be a mensch
生词表: