Comments for nklein software http://nklein.com software development and consulting Fri, 30 Dec 2011 03:29:52 +0000 hourly 1 http://wordpress.org/?v=3.3 Comment on Dusting off my Growl Library by pat http://nklein.com/2011/12/dusting-off-my-growl-library/comment-page-1/#comment-2419 pat Fri, 30 Dec 2011 03:29:52 +0000 http://nklein.com/?p=1782#comment-2419 When I wrote the library, the Mac version didn't support GNTP at all. Then, I tested on my son's Win 7 laptop. This time around, I was testing on my Mac. I was getting an error message, but it was not the correct one. It said: <code>GNTP/1.0 -ERROR NONE Response-Action: REGISTER Error-Description: (null) Error-Code: 2</code> I suppose none of the listed Error-Codes in the GNTP doc really fit, but "(null)" and "2" gave me no clue what went wrong, if it was my fault, how to get more info, etc. When I wrote the library, the Mac version didn’t support GNTP at all. Then, I tested on my son’s Win 7 laptop. This time around, I was testing on my Mac.

I was getting an error message, but it was not the correct one. It said:

GNTP/1.0 -ERROR NONE
Response-Action: REGISTER
Error-Description: (null)
Error-Code: 2

I suppose none of the listed Error-Codes in the GNTP doc really fit, but “(null)” and “2″ gave me no clue what went wrong, if it was my fault, how to get more info, etc.

]]> Comment on Dusting off my Growl Library by brian dunnington http://nklein.com/2011/12/dusting-off-my-growl-library/comment-page-1/#comment-2418 brian dunnington Fri, 30 Dec 2011 02:01:32 +0000 http://nklein.com/?p=1782#comment-2418 Are you having trouble using encryption with the Mac version or with the Windows version? The Mac version does not yet support encryption, so encrypted notifications will fail and should return the appropriate GNTP error response. The Windows version still supports all of the specified encryption options and should work fine if it was working fine before. Are you having trouble using encryption with the Mac version or with the Windows version? The Mac version does not yet support encryption, so encrypted notifications will fail and should return the appropriate GNTP error response. The Windows version still supports all of the specified encryption options and should work fine if it was working fine before.

]]> Comment on If it quacks like a parabola… by pat http://nklein.com/2011/09/if-it-quacks-like-a-parabola/comment-page-1/#comment-2302 pat Thu, 22 Sep 2011 13:56:52 +0000 http://nklein.com/?p=1765#comment-2302 I will check out "Mr. Tompkins". Thanks. And, yes, I knew that for big enough t, it had to be almost a straight line (with slope speed-of-light). I was just thinking that given what $$sqrt{t}$$ looks like compared to $$t$$ would be relevant for $$\sqrt{1+t^2}$$ compared to $$1+t^2$$. And, so I thought that I was ending up with an equation where the instantaneous velocity at the start is unbounded and eventually comes down to the speed-of-light. I should have doubted my intuition long before the 30-th derivation. I will check out “Mr. Tompkins”. Thanks.

And, yes, I knew that for big enough t, it had to be almost a straight line (with slope speed-of-light). I was just thinking that given what sqrt{t} looks like compared to t would be relevant for \sqrt{1+t^2} compared to 1+t^2. And, so I thought that I was ending up with an equation where the instantaneous velocity at the start is unbounded and eventually comes down to the speed-of-light. I should have doubted my intuition long before the 30-th derivation.

]]> Comment on Keeping Server and Client Separate by Trevor Clarke http://nklein.com/keeping-server-and-client-separate/comment-page-1/#comment-2301 Trevor Clarke Thu, 22 Sep 2011 13:51:43 +0000 http://nklein.com/?p=1758#comment-2301 That's the biggest problem with ASN.1...not many good and free implementations (there are some very good and very expensive ones) since it's generally geared for the telcom industry. Unless there are better implementations supporting the full extended XER packing format I think it will always be marginalized. One problem I have with XDR is (AFAIK) there's no rigorous protocol definition language so use is either adhoc or definitions are free form. I like having the rigor or the ASN.1 definitions with tagging and versioning. I haven't looking at Google's Protocol Buffers, I'll have to check out the implementation. That’s the biggest problem with ASN.1…not many good and free implementations (there are some very good and very expensive ones) since it’s generally geared for the telcom industry. Unless there are better implementations supporting the full extended XER packing format I think it will always be marginalized.

One problem I have with XDR is (AFAIK) there’s no rigorous protocol definition language so use is either adhoc or definitions are free form. I like having the rigor or the ASN.1 definitions with tagging and versioning. I haven’t looking at Google’s Protocol Buffers, I’ll have to check out the implementation.

]]> Comment on If it quacks like a parabola… by Zach KS http://nklein.com/2011/09/if-it-quacks-like-a-parabola/comment-page-1/#comment-2300 Zach KS Thu, 22 Sep 2011 13:24:52 +0000 http://nklein.com/?p=1765#comment-2300 I really like the idea of a game where the speed of light is 1 m/s or whatever. It's basically a Gamow's "Mr. Tompkins in Wonderland", the game. It took me an embarrassing long time to find the name of this work considering I work in a building named in his honor. If you haven't read it, it might give a good foundation for all of the concepts involved without reading something more in depth. There is a copy at http://www.arvindguptatoys.com/arvindgupta/tompkins.pdf. I think the tricky bit will be the time dilation effects and the finite information propagation time. If your curious, the approximation $\sqrt{1+a^2t^2} \approx 1+\frac{a^2 t^2}{2} - \frac{(a^2 t^2)^2}{8} + \cdots$ is a Taylor expansion for small $a^2 t^2$. I'm sure about that min/max stuff or where it came from. Remember that at a large enough value of $a^2 t^2$, the 1 under the square root becomes negligible and this should basically equal $at$ (a straight line like your intuition told you), not $a^2 t^2$. I really like the idea of a game where the speed of light is 1 m/s or whatever. It’s basically a Gamow’s “Mr. Tompkins in Wonderland”, the game. It took me an embarrassing long time to find the name of this work considering I work in a building named in his honor. If you haven’t read it, it might give a good foundation for all of the concepts involved without reading something more in depth. There is a copy at http://www.arvindguptatoys.com/arvindgupta/tompkins.pdf. I think the tricky bit will be the time dilation effects and the finite information propagation time.

If your curious, the approximation $\sqrt{1+a^2t^2} \approx 1+\frac{a^2 t^2}{2} – \frac{(a^2 t^2)^2}{8} + \cdots$ is a Taylor expansion for small $a^2 t^2$. I’m sure about that min/max stuff or where it came from. Remember that at a large enough value of $a^2 t^2$, the 1 under the square root becomes negligible and this should basically equal $at$ (a straight line like your intuition told you), not $a^2 t^2$.

]]> Comment on If it quacks like a parabola… by pat http://nklein.com/2011/09/if-it-quacks-like-a-parabola/comment-page-1/#comment-2296 pat Thu, 22 Sep 2011 00:45:19 +0000 http://nklein.com/?p=1765#comment-2296 Interestingly, the $$\frac{1}{a}\left(-1 + \sqrt{1+a^2t^2}\right) \approx \frac{1}{2}at^2$$ looks eerily close to an approximation that I once saw for two-dimensional distance. Doing a little algebra, one comes up with $$\sqrt{1+(at)^2} \approx 1 + \frac{1}{2}(at)^2$$. The 2-D distance approximation formula was that $$\sqrt{x^2 + y^2} \approx \max(x,y) + \frac{1}{2}\min(x,y)$$. The relativity/classical approximation above seems to be $$\sqrt{1 + a^2t^2} \approx \max(1,a^2t^2) + \frac{1}{2}\min(1,a^2t^2)$$ for this early portion where $$at \le 1$$. Interestingly, the \frac{1}{a}\left(-1 + \sqrt{1+a^2t^2}\right) \approx \frac{1}{2}at^2 looks eerily close to an approximation that I once saw for two-dimensional distance. Doing a little algebra, one comes up with \sqrt{1+(at)^2} \approx 1 + \frac{1}{2}(at)^2.

The 2-D distance approximation formula was that \sqrt{x^2 + y^2} \approx \max(x,y) + \frac{1}{2}\min(x,y). The relativity/classical approximation above seems to be \sqrt{1 + a^2t^2} \approx \max(1,a^2t^2) + \frac{1}{2}\min(1,a^2t^2) for this early portion where at \le 1.

]]> Comment on Keeping Server and Client Separate by james anderson http://nklein.com/keeping-server-and-client-separate/comment-page-1/#comment-2267 james anderson Thu, 15 Sep 2011 06:07:30 +0000 http://nklein.com/?p=1758#comment-2267 at least bert and thrift are available in one or more forms in lisp. at least bert and thrift are available in one or more forms in lisp.

]]> Comment on Keeping Server and Client Separate by pat http://nklein.com/keeping-server-and-client-separate/comment-page-1/#comment-2266 pat Wed, 14 Sep 2011 17:18:19 +0000 http://nklein.com/?p=1758#comment-2266 I'm not sure which one's you're thinking of. I don't even mind XDR. But, the IDLs that I can think of (already available in Lisp) are CORBA, ILU, XML-RPC, and SOAP. I don't know if ILU is geared for rapidity. I did see one ONC RPC package for Lisp. I will be checking that out. I’m not sure which one’s you’re thinking of. I don’t even mind XDR. But, the IDLs that I can think of (already available in Lisp) are CORBA, ILU, XML-RPC, and SOAP. I don’t know if ILU is geared for rapidity. I did see one ONC RPC package for Lisp. I will be checking that out.

]]> Comment on Keeping Server and Client Separate by james anderson http://nklein.com/keeping-server-and-client-separate/comment-page-1/#comment-2264 james anderson Wed, 14 Sep 2011 12:25:13 +0000 http://nklein.com/?p=1758#comment-2264 you described the functional requirements for an rpc framework with an idl. i appreciate your aversion to the heavy-weight variations of that type, but do not yet see what prevents you from using one of the available lighter-weight equivalents to xdr? you described the functional requirements for an rpc framework with an idl. i appreciate your aversion to the heavy-weight variations of that type, but do not yet see what prevents you from using one of the available lighter-weight equivalents to xdr?

]]> Comment on Keeping Server and Client Separate by pat http://nklein.com/keeping-server-and-client-separate/comment-page-1/#comment-2251 pat Fri, 09 Sep 2011 15:02:20 +0000 http://nklein.com/?p=1758#comment-2251 DDS stuff falls definitely into the Data-Classes/Data-Object category, doesn't it? Also, my intent here is a client/server for a game. In a game scenario, you rarely want to send the same information to all clients and you want the clients to send requests to the server. One could accomplish this with the server subscribing to each of the clients and having a separate publisher for each client (and maybe some others for publishing to teams or everyone). But, this would be bending the tool to the point of breaking just for the sake of using the tool. DDS stuff falls definitely into the Data-Classes/Data-Object category, doesn’t it?

Also, my intent here is a client/server for a game. In a game scenario, you rarely want to send the same information to all clients and you want the clients to send requests to the server. One could accomplish this with the server subscribing to each of the clients and having a separate publisher for each client (and maybe some others for publishing to teams or everyone). But, this would be bending the tool to the point of breaking just for the sake of using the tool.

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