David, That's a handy set of calculations and comments on downloads. Another point messes all the technical estimates! Combinations of factors are unpredictable. Over the past month or so I have spotted Opera recording download speeds (not the averages) from 8 bytes/sec to over 8 kb/sec. (56 modem)
Times of day when I reckon the net is experiencing high usage in the UK I regularly get speeds in the hundreds of bytes - sometimes tens. At generally quiet times, and occasionally unexpectedly) the speed can be a continuous 5 kb plus. Also the movement of bits can take minutes to start and can have long inactive intervals. I have followed the debates and discussions on this for a couple of years now and assume these speeds are actually in the laps of the gods! Joseph Joseph Harris Smile Poetry Weekly (fortnightly) www.smilepoetryweekly.com Batty Balls and other Wicket Wit www.ah-mah-son.com ----- Original Message ----- From: David Precious <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, July 25, 2003 4:39 PM Subject: [wdvltalk] RE: Uploading time estimates -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Friday 25 July 2003 12:16 pm, Paul Larue sent the following: > Hi Elan, > You could do a simple estimate based on 'file size' / 'connection > speed'. Thus, for a file of 1024 bytes (1Kb) you'll do something like > 1024/42 if the connection is of 56Kbps. I used 42 since 56k is the > downloading speed and uploading speed is approximately 75% of that. Not to be pedantic, but 56kbps is the max download speed - you'll very rarely see an actual 56kbps, it's normally around 40-50kbps. Upload speed is generally still 33.6kbps. Also, 56kbps is 56 kilo-BITS per second, whereas 1Kb is 1024 BYTES. You can assume 8 bits to a byte, so, ignoring overhead from any parity bits and ignoring the overhead of TCP/IP packet headers etc, you could assume that, if the user's upload speed is 33.6kbps / 8 = 4.2Kb/s data transfer rate. In reality, it's hard to get an estimate that's anywhere near accurate since it'll depend on what else is using their connection (do they have any other downloads/uploads running), the speed of their machine, quality of their phone line, etc etc etc. > However, this would imply that you know the speed of the connection. > Either the user enters it somewhere or you call some obscure Win32API > that would return the connection type selected by the user in "Internet > Options". Check the API Text Viewer or MSDN for more info. No, no! Try to avoid proprietary Windoze API stuff like that - it's only ever going to work on Windows, using IE, and even then probably won't work if the user has their security settings set right. > A better test (and more reliable) would be to upload a small text file > of 1kb to the target server as test and then deduce the upload speed. > You could show that phase to the user as "calculating upload speed" for > example. Even then, you need a pretty big file to get a reliable average transfer rate. Whatever you do needs to be server-side. The browser should supply a Content-Length that you can use to see how big the file is, but I don't *think* that a PHP/ASP script runs until the file is fully uploaded and saved to a temporary directory. I could be wrong on that bit. Anyway, good luck with it! Cheers David P http://www.preshweb.co.uk/ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE/IU8Zrz7S5k65yyYRAqRGAKCh9zJJ8g7uvwbnbFH/AOWZ1g/mggCeLUGz DMZiyAHIpaHxhm/WiB+SMjk= =jGZv -----END PGP SIGNATURE----- ____ . The WDVL Discussion List from WDVL.COM . ____ To Join wdvltalk, Send An Email To: mailto:[EMAIL PROTECTED] Send Your Posts To: [EMAIL PROTECTED] To set a personal password send an email to [EMAIL PROTECTED] with the words: "set WDVLTALK pw=yourpassword" in the body of the email. To change subscription settings to the wdvltalk digest version: http://wdvl.internet.com/WDVL/Forum/#sub ________________ http://www.wdvl.com _______________________ You are currently subscribed to wdvltalk as: [EMAIL PROTECTED] To unsubscribe send a blank email to %%email.unsub%% ____ � The WDVL Discussion List from WDVL.COM � ____ To Join wdvltalk, Send An Email To: mailto:[EMAIL PROTECTED] Send Your Posts To: [EMAIL PROTECTED] To set a personal password send an email to [EMAIL PROTECTED] with the words: "set WDVLTALK pw=yourpassword" in the body of the email. To change subscription settings to the wdvltalk digest version: http://wdvl.internet.com/WDVL/Forum/#sub ________________ http://www.wdvl.com _______________________ You are currently subscribed to wdvltalk as: [EMAIL PROTECTED] To unsubscribe send a blank email to [EMAIL PROTECTED]
