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User talk:Dmitry-kazakov: Difference between revisions
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About the problem you talk about on the ppm output article, I am used to see that it is possible to open a file ''in binary mode'' on your OS. <BR>
Isn't it possible with this programming language ? [[User:Blue Prawn|Blue Prawn]] 11:28, 7 December 2008 (UTC)
: It is OS-specific too. In earlier times, when OS was an OS (:-)), there was RSX-11, for example. It didn't have text files in MS-DOS or UNIX sense. There were record files instead. Each line was stored into a record. The advantage was that a line could contain any characters and LF, CR or NUL had no special meaning.
: I will rewrite Ada solution in order to make it more portable, but I am afraid the problem with it and other solutions as well will persist. Because if we used ''binary'' in the sense ''stream of characters'', then we would have to specify a few more things to make it portable:
:* character is? (octet of bits)
:* line terminator in the file header is? (ASCII LF for example)
:* EOF is? (ASCII LF, NUL, nothing)
:And well, PPM isn't our fault... (:-)) --[[User:Dmitry-kazakov|Dmitry-kazakov]] 12:17, 7 December 2008 (UTC)
:: Binary mode also makes sense a lot of the time on Windows, where for text files the end of line is a multibyte symbol and there is an end-of-file symbol (^Z, which happens to be the official [[ASCII]] EOF character). By comparison, (linear) binary files are just a sequence of bytes. Then there's record-oriented files, but they're seriously out of favor these days; people use proper transactional databases like [[sqlite]] instead. —[[User:Dkf|Donal Fellows]] 12:03, 17 August 2009 (UTC)
::: I agree that handling text files in binary mode is easier under Windows. But let's do not forget, that the reason for that is that Windows text files are broken. Nobody cares if the conventions of text files, because these are not enforced. And they are not enforced because you can open a text file in binary mode and converse. A properly designed file system would never allow this. Guess what would happen if somebody opened database files as texts? --[[User:Dmitry-kazakov|Dmitry-kazakov]] 08:53, 19 August 2009 (UTC)
== exception propagation in Ada. ==
In [[Rendezvous#The_task|Ada's Rendezvous]] what do these lines do:
exception
when Out_Of_Ink =>
null;
end;
They look like they are masking/ignoring the ''Out_Of_Ink'' exception.
:Yes, this is on the server side. When an exception is propagated out of an entry point, that happens both on the server and the client sides. In our case the server just ignores it. The client ends. --[[User:Dmitry-kazakov|Dmitry-kazakov]] 08:32, 19 February 2009 (UTC)
Whereas program appears to propagate ''Out_Of_Ink'' back to ''Mother_Goose''. e.g.
requeue Backup.Print with abort;
Is that because of the ''with abort''?
:''with abort'' means that it is allowed for the client to cancel the rendezvous request while it waits in the queue of ''Backup''. If ''Mother_Goose'' have used a timed entry call:
<blockquote>
<lang ada>
select
Main.Print (...);
or delay 5.0;
Put_Line ("No response from the printer");
end select;
</lang>
</blockquote>
:then if the rendezvous to ''Backup'' would not engaged in 5 seconds (including the waiting time for ''Main'') then it would output "No response from the printer". --[[User:Dmitry-kazakov|Dmitry-kazakov]] 08:32, 19 February 2009 (UTC)
Also: when the task is requeued, does the ''Main'' printer suspend
waiting for ''Backup'' to finish? (Or is the exception propagated directly
back from ''Backup'' to ''Mother_Goose'' without passing through ''Main'')
:No, the server ''Main'' continues when the entry point body is left, the client (say ''Mother_Goose'') stay blocked and waits now for the new server ''Backup'' to service the rendezvous. --[[User:Dmitry-kazakov|Dmitry-kazakov]] 08:32, 19 February 2009 (UTC)
Cheers.... a lot going on in that lil'ol bit of code especially the exception handling.
Many thanX for something to chew on.
[[User:NevilleDNZ|NevilleDNZ]] 11:24, 19 February 2009 (UTC)
== Possible reason for Dmitry's sparse activity lately ==
He is playing hockey in the NHL for the Detroit Red Wings under the name Pavel Datsyuk. Compare:
Dmitry: [http://www.dmitry-kazakov.de/cv/dmitry.gif]<br>
Datsyuk: [http://www.examiner.com/images/blog/wysiwyg/image/Datsyuk_head_shot_2008-09_medium.JPG]
--[[User:Mwn3d|Mwn3d]] 03:40, 17 March 2011 (UTC)
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