[Oberon] Doubt from Project Oberon book.
bob at web-options.com
Sun Dec 23 09:40:48 CET 2012
He is describing some ways in which different software components can
communicate with each other.
In a system such as Unix, you execute a command by typing its name and
parameter list at the command line, and pressing <Enter>. The command can
pipe its result to another command, which is executed immediately after the
first command. On completion of a command it is unloaded from memory and the
contents of its variables are lost. If you want to use the command's results
later, ie not immediately after you have executed the command, then you have
to store the results in a file.
Oberon commands do not come with a built-in pipe mechanism. However, Oberon
modules are not automatically unloaded following execution - they remain
resident in memory until you unload them explicitly, so the contents of
their variables are still available and other modules can use them, either
as global variables or by calling one of the module's procedures. This means
that you don't have to use pipes / files to communicate between modules.
Of course if you want to retain the values between system restarts you do
have to store them in files.
> -----Original Message-----
> From: Srinivas Nayak [mailto:sinu.nayak2001 at gmail.com]
> Sent: 23 December 2012 08:03
> To: ETH Oberon and related systems
> Subject: [Oberon] Doubt from Project Oberon book.
> Dear All,
> From the book, Project Oberon, I read,
> 2.2.2. Commands
> The parameter text must refer to objects that exist before command
> execution starts and are quite likely
> the result of a previous command interpretation. In most operating
> systems, these objects are files
> registered in the directory, and they act as interfaces between
> commands. The Oberon System broadens
> this notion; the links between consecutive commands are not
> restricted to files, but can be any global
> variable, because modules do not disappear from storage after
> command termination, as mentioned
> What is the meaning?
> I couldnt understand this.
> Also I found that, this book uses technologies/terminologiesof 1980s
> which make things bit difficult to understand, for us who are used to
> with latest technologies/terminologies. Example, RAM/Memory is referred
> as "store".
> With thanks and best regards,
> Yours sincerely,
> Srinivas Nayak
> Home: http://www.mathmeth.com/sn/
> Blog: http://srinivas-nayak.blogspot.in/
> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related
> systems https://lists.inf.ethz.ch/mailman/listinfo/oberon
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