[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