I personally think that the low level issues are not so important and have been playing with the thought of implementing high-level features of such an OS, i.e. user access control and distributed, sandboxed applications with reasonable process scheduling and resource control. However, I have given up on the idea -- too many other things to do.
Secure, multi-user high-level OS services could be useful even without the capability of running on bare hardware, e.g. on top of a very small GNU/Linux. Best, Erich On Wed, 5 Dec 2012 08:29:04 -0800 (PST) David Blubaugh <davidblubaugh2...@yahoo.com> wrote: > Well > > > Is there a way I can obtain help in acquiring funding in developing > Racket into a real OS?? I would love to see how far we can take this > concept !!! Apple and MacOS watch out here comes something with more > powerful features !!! > David Blubaugh > > --- On Wed, 12/5/12, Matthias Felleisen <matth...@ccs.neu.edu> wrote: > > > From: Matthias Felleisen <matth...@ccs.neu.edu> > Subject: Re: [racket] OPERATING SYSTEM ON A FPGA > To: "David Blubaugh" <davidblubaugh2...@yahoo.com> > Cc: users@racket-lang.org > Date: Wednesday, December 5, 2012, 11:24 AM > > > > In the mid 90s, we had this idea to go for a Scheme OS, SOS. As an > experiment, we asked a student to write a disk driver in Scheme > (Bigloo) and to see what we could do with it. One of the things he > was able to do is hot-swap policies for spinning the disk. This > sounds so quaint in the age of laptops w/o movable parts. > > In the late 90s, Matthew spent an afternoon so that we could boot > Racket (formerly known as PLT Scheme) on raw hardware. Since most of > us had dual-boot machines already (Linux and the other one), we went > to ternary-boot machines: Linux, PLT Scheme, and the other one. None > of us ever had the appetite to add enough device drivers to turn > Racket into a real OS but nothing stands in its way. > > Right now, a Darpa project enables us to experiment with Racket on > the Router (think RoR, though that acronym has been taken). Again, > it's systemish work. This email is going thru the DNS service that we > have built so far. > > In short, doable but we haven't done it. > > > > > > > > > > On Dec 5, 2012, at 11:16 AM, David Blubaugh wrote: > > > To All, > > > > > > I was wondering if anyone has ever created a real time operating > > system with Racket. As well as, create applications within a FPGA > > device by utilizing racket?? Can racket be a solution to ALL > > PROBLEMS that is the question. > > > > > > David Blubaugh > > > > > > > > --- On Wed, 12/5/12, users-requ...@racket-lang.org > > <users-requ...@racket-lang.org> wrote: > > > > From: users-requ...@racket-lang.org <users-requ...@racket-lang.org> > > Subject: users Digest, Vol 88, Issue 18 > > To: users@racket-lang.org > > Date: Wednesday, December 5, 2012, 10:30 AM > > > > Send users mailing list submissions to > > users@racket-lang.org > > > > To subscribe or unsubscribe via the World Wide Web, visit > > http://lists.racket-lang.org/users/listinfo > > or, via email, send a message with subject or body 'help' to > > users-requ...@racket-lang.org > > > > You can reach the person managing the list at > > users-ow...@racket-lang.org > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of users digest..." > > > > > > [Racket Users list: > > http://lists.racket-lang.org/users] > > > > > > Today's Topics: > > > > 1. Re: Whats the difference between a predicate and a flat > > contract? (Harry Spier) > > 2. Re: Whats the difference between a predicate and a flat > > contract? (Robby Findler) > > 3. Re: DRRacket right-click menu fragility in Linux. (Neil > >Toronto) 4. Re: minimum spanning tree (Matthias Felleisen) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Tue, 4 Dec 2012 21:59:42 -0500 > > From: Harry Spier <vasishtha.sp...@gmail.com> > > To: Robby Findler <ro...@eecs.northwestern.edu> > > Cc: Carl Eastlund <c...@ccs.neu.edu>, users <users@racket-lang.org> > > Subject: Re: [racket] Whats the difference between a predicate and a > > flat contract? > > Message-ID: > > <CAJ3b0o9_yd-j4U6tbEOQaB+JKWto_A1XwSrh3_xyRTk=Uviy=q...@mail.gmail.com> > > Content-Type: text/plain; charset=UTF-8 > > > > Are flat-contract and flat-contract-predicate equivalent? > > > > > ((flat-contract 'x) 'x) > > #t > > > ((flat-contract-predicate 'x) 'x) > > #t > > > ((flat-contract 'x) 'y) > > #f > > > ((flat-contract-predicate 'x) 'y) > > #f > > > > > > > Harry > > > > On Tue, Dec 4, 2012 at 9:41 PM, Robby Findler > > <ro...@eecs.northwestern.edu> wrote: > > > It does that for symbols, but not everything. > > > > > > This is the place you should be looking, I think. > > > > > > http://docs.racket-lang.org/reference/contracts.html > > > > > > Robby > > > > > > On Tue, Dec 4, 2012 at 8:38 PM, Harry Spier > > > <vasishtha.sp...@gmail.com> wrote: > > >> OK I see the docs to flat-contract? but not flat-contract > > >> http://docs.racket-lang.org/reference/contract-utilities.html#(def._((lib._racket/contract/private/misc..rkt)._flat-contract~3f)) > > >> mention that flat-contracts are more than predicates. Those docs > > >> don't mention it, but it appears from experimentation that > > >> (flat-contract something) produces a procedure such that > > >> ((flat-contract something) x) is #t if something eq? x . > > >> > > >> Harry Spier > > >> > > >> On Tue, Dec 4, 2012 at 8:57 PM, Robby Findler > > >> <ro...@eecs.northwestern.edu> wrote: > > >>> On Tue, Dec 4, 2012 at 7:28 PM, Carl Eastlund <c...@ccs.neu.edu> > > >>> wrote: > > >>>> On Tue, Dec 4, 2012 at 7:49 PM, Robby Findler > > >>>> <ro...@eecs.northwestern.edu> wrote: > > >>>>> > > >>>>> Flat contracts includes more things than contracts. For > > >>>>> example: > > >>>>> > > >>>>> [robby@yanpu] ~/git/plt/collects/scribblings/reference$ racket > > >>>>> Welcome to Racket v5.3.1.9. > > >>>>> > (flat-contract? 'x) > > >>>>> #t > > >>>>> > (procedure? 'x) > > >>>>> #f > > >>>>> > > >>>>> The flat-contract function is a holdover from the days when > > >>>>> flat contracts weren't able to be used directly as predicate > > >>>>> functions. > > >>>>> > > >>>>> > > >>>>> I'll push a clarification to the docs for flat-contract. > > >>>> > > >>>> > > >>>> Isn't that the wrong way around? The flat-contract function > > >>>> lets you use a predicate as a contract, not a contract as a > > >>>> predicate. Presumably it's from before predicates could be > > >>>> used as contracts, although I hadn't realized there was such a > > >>>> time. > > >>> > > >>> There was a time when you had to call 'flat-contract' to turn a > > >>> predicate into a contract, yep. There was a housecleaning > > >>> (anyone remember the days when there were multiple suffixes > > >>> (not just "/c") on the combinators?) and I probably should have > > >>> gotten rid of it at that time, but I didn't. > > >>> > > >>> (Oh and I mean "contracts" where I wrote "preducate functions" > > >>> above. Oops.) > > >>> > > >>> Robby > > > > > > ------------------------------ > > > > Message: 2 > > Date: Tue, 4 Dec 2012 21:05:45 -0600 > > From: Robby Findler <ro...@eecs.northwestern.edu> > > To: Harry Spier <vasishtha.sp...@gmail.com> > > Cc: Carl Eastlund <c...@ccs.neu.edu>, users <users@racket-lang.org> > > Subject: Re: [racket] Whats the difference between a predicate and a > > flat contract? > > Message-ID: > > <cal3tdomvl4xerbmr9xwqnz3tpjxbsxdfjaijro2n9j6fxrs...@mail.gmail.com> > > Content-Type: text/plain; charset=UTF-8 > > > > Yes ..., I think so (well, eq? probably messes things up, as usual). > > > > But that's a funny question! What's really going on there is that > > flat-contract is coercing the value into a contract, and flat > > contracts also acts as predicate functions (matching what the > > contracts match). flat-contract-predicate takes its argument, turns > > it into the contract and then returns the predicate. This last step > > is useless, as flat-contracts are now predicates without any > > coercion (again, not something that was always the case). > > > > I'll add a similar note to the docs for this function too. > > > > Robby > > > > On Tue, Dec 4, 2012 at 8:59 PM, Harry Spier > > <vasishtha.sp...@gmail.com> wrote: > > > Are flat-contract and flat-contract-predicate equivalent? > > > > > >> ((flat-contract 'x) 'x) > > > #t > > >> ((flat-contract-predicate 'x) 'x) > > > #t > > >> ((flat-contract 'x) 'y) > > > #f > > >> ((flat-contract-predicate 'x) 'y) > > > #f > > >> > > > > > > Harry > > > > > > On Tue, Dec 4, 2012 at 9:41 PM, Robby Findler > > > <ro...@eecs.northwestern.edu> wrote: > > >> It does that for symbols, but not everything. > > >> > > >> This is the place you should be looking, I think. > > >> > > >> http://docs.racket-lang.org/reference/contracts.html > > >> > > >> Robby > > >> > > >> On Tue, Dec 4, 2012 at 8:38 PM, Harry Spier > > >> <vasishtha.sp...@gmail.com> wrote: > > >>> OK I see the docs to flat-contract? but not flat-contract > > >>> http://docs.racket-lang.org/reference/contract-utilities.html#(def._((lib._racket/contract/private/misc..rkt)._flat-contract~3f)) > > >>> mention that flat-contracts are more than predicates. Those > > >>> docs don't mention it, but it appears from experimentation that > > >>> (flat-contract something) produces a procedure such that > > >>> ((flat-contract something) x) is #t if something eq? x . > > >>> > > >>> Harry Spier > > >>> > > >>> On Tue, Dec 4, 2012 at 8:57 PM, Robby Findler > > >>> <ro...@eecs.northwestern.edu> wrote: > > >>>> On Tue, Dec 4, 2012 at 7:28 PM, Carl Eastlund > > >>>> <c...@ccs.neu.edu> wrote: > > >>>>> On Tue, Dec 4, 2012 at 7:49 PM, Robby Findler > > >>>>> <ro...@eecs.northwestern.edu> wrote: > > >>>>>> > > >>>>>> Flat contracts includes more things than contracts. For > > >>>>>> example: > > >>>>>> > > >>>>>> [robby@yanpu] ~/git/plt/collects/scribblings/reference$ > > >>>>>> racket Welcome to Racket v5.3.1.9. > > >>>>>> > (flat-contract? 'x) > > >>>>>> #t > > >>>>>> > (procedure? 'x) > > >>>>>> #f > > >>>>>> > > >>>>>> The flat-contract function is a holdover from the days when > > >>>>>> flat contracts weren't able to be used directly as predicate > > >>>>>> functions. > > >>>>>> > > >>>>>> > > >>>>>> I'll push a clarification to the docs for flat-contract. > > >>>>> > > >>>>> > > >>>>> Isn't that the wrong way around? The flat-contract function > > >>>>> lets you use a predicate as a contract, not a contract as a > > >>>>> predicate. Presumably it's from before predicates could be > > >>>>> used as contracts, although I hadn't realized there was such > > >>>>> a time. > > >>>> > > >>>> There was a time when you had to call 'flat-contract' to turn a > > >>>> predicate into a contract, yep. There was a housecleaning > > >>>> (anyone remember the days when there were multiple suffixes > > >>>> (not just "/c") on the combinators?) and I probably should > > >>>> have gotten rid of it at that time, but I didn't. > > >>>> > > >>>> (Oh and I mean "contracts" where I wrote "preducate functions" > > >>>> above. Oops.) > > >>>> > > >>>> Robby > > > > > > ------------------------------ > > > > Message: 3 > > Date: Tue, 04 Dec 2012 21:30:23 -0700 > > From: Neil Toronto <neil.toro...@gmail.com> > > To: users@racket-lang.org > > Subject: Re: [racket] DRRacket right-click menu fragility in Linux. > > Message-ID: <50becddf.4030...@gmail.com> > > Content-Type: text/plain; charset=UTF-8; format=flowed > > > > Could what you're experiencing have anything to do with tooltips? > > It seems my right-click menu doesn't stay up whenever there's a > > tooltip out. Which is, like, every time I want it. > > > > Neil ? > > > > On 12/04/2012 07:55 PM, Ray Racine wrote: > > > Yea, I didn't want to make a big deal out of it, but the up/down > > > button change did not fix the issue. In fact I'd say no impact > > > positive or negative. > > > > > > It seems to happen when there is additional drawing 'complexity' > > > in co-occurrence with the pop up drawing area. I.e. the pop up > > > menu is drawing where arrows are drawn or error highlighting is > > > occurring etc. Also maybe when the pop up menu area is near the > > > 'edge' of the Dr window and or pane area. But again the problem > > > is not consistently reproducible yet happens more often then > > > not. Its not a once in a blue moon that thing. Sometimes an > > > attempt to right click pop up menu will fail numerous times in a > > > row then succeed for no apparent reason. > > > > > > On Dec 4, 2012 9:07 PM, "Robby Findler" > > > <ro...@eecs.northwestern.edu > > > <mailto:ro...@eecs.northwestern.edu>> wrote: > > > > > > On Tue, Dec 4, 2012 at 6:11 PM, Stephen Chang > > ><stch...@ccs.neu.edu <mailto:stch...@ccs.neu.edu>> wrote: > > > > On Fri, Nov 2, 2012 at 9:33 PM, Robby Findler > > > > <ro...@eecs.northwestern.edu > > > <mailto:ro...@eecs.northwestern.edu>> wrote: > > > >> I've pushed a fix to this. Thanks to Matthew for looking > > >into it and >> sorting it out and sorry for the delay. > > > > > > > > I'm using git head and I'm still seeing this problem > > >(Ubuntu 11.10). I > > > > can't reliably reproduce it but in case it helps, it most > > >recently > happened when I selected tack arrows and now I can't > > >bring up the menu > > > > to untack the arrows anymore. > > > > > > > > > > The particular fix Matthew pointed me to is popping up the > > >menu on a mouse down event, not a mouse up event. > > > > > > > > >http://git.racket-lang.org/plt/blobdiff/27aa99944657c5827eee3772f715df7dd971d1e0..0377bda9474f8848a97509ace898174c83361006:/collects/framework/private/keymap.rkt > > > > > > So I guess there's something else going on, too (because > > >that's the code that pops up the menu with the check syntax items). > > > > > > Robby > > > > > > > > > > > > ____________________ > > > Racket Users list: > > > http://lists.racket-lang.org/users > > > > > > > > > > > ------------------------------ > > > > Message: 4 > > Date: Wed, 5 Dec 2012 10:30:22 -0500 > > From: Matthias Felleisen <matth...@ccs.neu.edu> > > To: Pierpaolo Bernardi <olopie...@gmail.com> > > Cc: Racket mailing list <users@racket-lang.org> > > Subject: Re: [racket] minimum spanning tree > > Message-ID: <ce678990-63d0-4400-af2a-c6b2880e4...@ccs.neu.edu> > > Content-Type: text/plain; charset="iso-8859-1" > > > > > > You are making a very good point here, especially the last one, > > which in a sense exposes the folly of Perlis's maxim (it is better > > to have one data type with a 100 operations than 10 data types > > with 10 operations each). One, the maxim biases programmers > > and before they know it, they have introduced bad dependences > > and performance problems and whoknowswhat. > > > > --------------------------------------------------------------- > > > > Having said that, I think Ian's point is equally good. So here > > is what I am wondering. > > > > Isn't the case of graphs worth a case study where we define > > a WIDE interface for graphs and their operations, which we > > can do so with contracts. Then we implement it in several > > different ways and conduct performance studies (small and > > large). And we advertise, which library is good for which > > kind of scenario. > > > > I am sure that some data structure person has done this > > for C++ or some such language. The Saarbr?cken MPI 1 comes > > to mind. BUT, I am also sure that we don't have it and that > > we would benefit from having one. > > > > NOW: as we conduct this study, we might be able to articulate > > performance "contracts" (that's probably the wrong word) and > > possibly learn how to add those to library implementations as > > a secondary interface. Doing so would once again distinguish > > Racket from other programming languages. > > > > It is probably a dissertation, possibly more. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Dec 4, 2012, at 5:36 AM, Pierpaolo Bernardi wrote: > > > > > On Mon, Dec 3, 2012 at 5:07 PM, J. Ian Johnson <i...@ccs.neu.edu> > > > wrote: > > >> Graph algorithms are often meant to be very fast, and different > > >> algorithms necessitate different representations. Two popular > > >> representations are adjacency lists and shared structures. > > > > > > The representations usually used in general purpose graphs > > > libraries are adiacency lists and incidence matrices. > > > > > > Two good examples that I know of are: Knuth's Stanford GraphBase > > > (available from his home page and in published book form), and the > > > Combinatorica library for Mathematica (code available freely on > > > the net, manual available as a published book "Computational > > > Discrete Mathematics" by Skiena & Pemmaraju). > > > > > >> It also isn't right to call them lists unless you're talking > > >> about multigraphs. Indeed successor nodes should be treated as a > > >> set, but Racket's sets have quite a bit of overhead, especially > > >> for small sets. Should it be fast to compute predecessor nodes? > > >> There are too many considerations for there to be just one > > >> blessed representation, IMHO. > > > > > > Linked lists made of cons pairs are not the best data structure > > > for every possible use of a sequence data structure. However, we > > > find this data structure very useful, don't we? we force them > > > into uses for which they are not optimal, because of the > > > convenience of having available a vast library using them. And > > > when we can't fit them to our purpose we use a more specialized > > > data structure. > > > > > > I think a similar compromise for a graph data structure would be > > > very useful. > > > > > > Cheers > > > P. > > > > > > ____________________ > > > Racket Users list: > > > http://lists.racket-lang.org/users > > > > -------------- next part -------------- > > A non-text attachment was scrubbed... > > Name: smime.p7s > > Type: application/pkcs7-signature > > Size: 4373 bytes > > Desc: not available > > URL: > > <http://lists.racket-lang.org/users/archive/attachments/20121205/52954024/attachment.p7s> > > > > End of users Digest, Vol 88, Issue 18 > > ************************************* > > ____________________ > > Racket Users list: > > http://lists.racket-lang.org/users > ____________________ Racket Users list: http://lists.racket-lang.org/users
