[Coco] Can a Basic09 program tell which screen or terminal it is running in ?

[Gene Heskett]

On Thursday 17 October 2019 19:55:43 coco at jechar.ca wrote:

>   I was thinking of how a Basic09 program using
>   temporary files in a multiprocess environment
>   could be sure not to overwrite another process
>   files.
>
>   For example if Program A was puting data in
>   /r0/out.temp and Program B was trying to do
>   the same thing problems.
>
>   One possible solution
>   Suppose Process A is running in /term and process
>   B is running in /w3 then if the process could
>   determine which window it was running in it could
>   add that info to the temporary file name,
>   ie.
>
>   Process A saves to /r0/out-term.temp and
>   Process B saves to /r0/out-w3.temp
>
>   No problem.
>
>   So I was wondering how could Process A figure out
>   that it was running in /term ect. ?
>
>   Charlie

Charlie: nitros9's file locking is by the active sector, and will not 
allow 2 processes to access the same sector. I used to start a long 
assembly, directing the listing to a file, give it 2 or 3 seconds to get 
started, go to another window and start listing that file, and it never 
once overtook the assembler & listed the disk trash ahead of the 
assembler.

This is in a stark contrast to most operating systems which lock the 
whole file. Nitros9 won't complain as long as there is a first sector 
already written.  Your idea could also be implemented using the random 
number generator as part of the filename, with a clash via a repeat of 
the same number being a faint possibility. 

Cheers, Gene Heskett
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