Subject: Ftp-WG: Re: minor example error in draft-ietf-ftpext-mlst-10

From: Alun Jones <[email-masked]>
Date: Tue, 13 Jun 2000 06:11:16 -0500

At 05:22 AM 6/13/2000, you wrote:
>If we're (sorry, you're) going over the draft again, is it worthwhile 
>adding a 'transfer-size' or similar fact, which defines the number of 
>octets of the file which would be transmitted using the current mode, 
>type, etc?
>
>With an additional note specifying that the Server-PI may choose not to 
>present this for certain files under certain download parameters, on the 
>basis that this may present a significant cost to the server? (Should the 
>Client really want to know, it can try using SIZE, which may have a higher 
>cost threshold.)

I believe the last time something like this was suggested, it was shot down 
as something that would considerably slow down MLSx responses.  If you're 
in ASCII mode, for instance, you'd have to open _every_ file that was being 
listed, read _every_ byte in every file, and add up the number of 
line-feeds to add to the size of the stored file.

In this case, should the client actually require this information, you're 
right, SIZE is the way to go.  SIZE is documented as producing this data.

The facts for MLSx should be kept to those that can reasonably be provided 
in a directory listing, without unreasonably delaying that listing - if for 
no other reason than that authors are going to be tempted to run FEAT, 
choose _all_ the MLST OPTS they can, and set them on prior to listing - 
after all, more information is _always_ good, right? :-)

Particularly with options for MLSx being switched on and off by a separate 
command, I'd say that adding such a weighty fact to the list would be 
overburdening a server.

Alun.
~~~~

--
Texas Imperial Software | Try WFTPD, the Windows FTP Server. Find us
1602 Harvest Moon Place | at web site http://www.wftpd.com or email
Cedar Park TX 78613     | us at [email-masked].  VISA / MC accepted.
Fax +1 (512) 378 3246   | NT-based ISPs, be sure to read details of
Phone +1 (512) 378 3246 | WFTPD Pro, NT service version - $100.