[thelist] PHP help wanted & fonts tip + OT CSSd down?

Jackson Yee jyee at vt.edu
Mon Oct 28 14:11:01 CST 2002

"Geoff Sheridan" <web2k2 at premonition.co.uk> wrote in message
> That can't be right, surely. You've been on broadband too long :)
> I thought 3 seconds for a 28k modem was a bit quick, so I wondered
> how long a 1Mb file would take by those sums:
> 1000k / 33Kbps = 30.3 seconds.
> I don't think anyone who suffered for years with a dial-up connection
> as I did would think that very likely. It's more like 5-6mins, I
> reckon, and that's a *much* bigger error than can be explained by
> '33kbps isn't always as fast as it says'.

A one Mb file would be 125kB, so since a 28.8 modem can get up to 3.5kB/s
under good conditions, it would take about 30 to 40 seconds to download.
Now, if you're talking about a one MB file, then it indeed would take around
five to six minutes.

Remember that a lower case 'b' means bit, while a capital 'B' means byte.
On most architectures, there are eight bits to a byte, so adjust your times

> I'm also confused as to the right way to work this out - anyone care
> to explain?

I'm going more from my personal experience than anything else.  I've seen a
28.8 modem get up to 3.5kB/s, a 48.8 (56.0 theoretical, but limited by FCC)
modem get up to 4.8kB/s, a 384 kb/s DSL modem get up to 40kB/s, and a
1.5Mb/s cable modem download well in excess of 150kB/s.

As far as calculating download times though, I'd just leave that to the
browser.  There are so many variables that determine download speed - server
load, network congestion, line quality, time of day - that it wouldn't be
much use to tell your visitors how long it would take them to download a
file, even an estimate.  I find it much easier just to give them the size of
the file in MB or kB, and they can judge by their own connection how long it
would take for the download to finish.

Don't get me started on resumable downloads, disconnected downloads, or the
classic "download stops at 99%" issues either.

Jackson Yee
jyee at vt.edu

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