[Coco] Re: Using that 16/32/64 MB RamDrive.

[Rodney V Hamilton]

In article <EFEDDBF1-5A03-11D8-A69A-000A95AFE1F0 at concentric.net>, 
alxevans at concentric.net says...
>
>On Feb 7, 2004, at 1:01 PM, William Astle wrote:
>
>> On Sat, 7 Feb 2004, Gene Heskett wrote:
>>
>>> As a matter of fact, I got rather dissappointed in other OS's because
>>> I couldn't do that, not with amigaos, nor with linux, although I
>>> haven't really tried that hard or recently in linux.  But, time goes
>>> only forward.
>>
>> You have, of course, investigated the "tail" command? Should work on 
>> just
>> about any unix variant.
>
>Different variants of Unix provide varying levels of file sharing.  On 
>some variants including early versions of Linux do not permit you to 
>read a file which is open for writing by another process.  I believe 
>that this is permitted in current versions of Linux.  Even in those 
>versions which do permit this will give you different results from 
>OS-9.  In OS-9 if you attempt to read past the end of a file which is 
>currently being written by another process the reading process will 
>block until the file has been written to that point, or the writing 
>process closes the file.  In Unix (assuming that you can open the file 
>for reading in the first place) it will react as if the end of the file 
>is at the point where it has been lat written to.  Some of us (myself, 
>Gene, and perhaps others) miss the OS-9 manner of handling this.  The 
>"tail" command is of no help in this.

That's why tail had a '-f' (follow) option.  That would make tail
go into an endless loop at the end of the input file, wherein it
would sleep for a second and try to read any additional data that
may have been appended, until tail was killed.  This was commonly
used to monitor the growth of a file being written by another task.
The Linux version of tail also has a '-s' option to set the number
of seconds to wait with the '-f' option.  [man tail]

Rodney Hamilton