On Sat, 23 Apr 2005 21:48:27 +0100, Tony Morgan
wrote:

In message 1txae.1118125$8l.1108640@pd7tw1no, S.Heenan
writes

719,603,712 bytes in 16mins 33 sec

Bits or bytes?

Or 4GB in a little over 94 mins or 61GB/day, all other things being equal.

That's 44Gb, carry on...
On a 512Kbps ADSL connection that's 1432 min (approx 23 hours) for 4GB.
What's this about 61GB/day?
On a 1Mbps ADSL connection, that's 716 min (approx. 11.5 hours) for 4GB.
So in 24 hours that would be about 9GB. What's this about 61GB/day?

Please do not feed the trolls. Have a look at the crossposts (not on
this message, I've trimmed back to just uk.rec.video.digital), it's
going to a load of alt groups. People in other countries often have
much higher data rates than we do, I gather in Sweden for instance
10Mbps is common, that would give over 80GB per day (and some Swedish
ISPs offer 100Mbps at under 100 quid a month!). Some Japanese ISPs are
talking about even faster links.

The UK is backward in broadband speeds, largely caused by BT wanting to
gouge the consumer. Look at the way they've tried to keep speeds down
by saying "you're too far from the exchange", they've recently doubled
the distances and many -- not "one or two" -- ISPs are offering 2Mbps or
more (ADSL modems will generally go up to 8Mbps). They did the same
with ISDN, Germany was pushing ISDN when I was there 8 years ago cheaper
for two analogue lines over ISDN than for one ordinary line, whereas BT
were charging through the nose for ISDN.

(Of course, where you get any decent content for a steady 20GB/day feed,
and how you get any time to look at it, is a different matter. I think
the people who do that sort of thing are mostly wasters, they download
as much as they can and throw away most of it...)

That's 708KB/sec, average value, not instantaneous.

708KBps is 7.79Mbps.

The last time I had 1Mbit ADSL service was late1999.

Finally that penny's dropped - you're now talking Mbps (*bits* not
*bytes*). Because each 8-bit byte also carries one start bit, one stop
bit, and one parity bit, for every one byte there's 11 bits.

You're talking about a serial connection. ATM (which ADSL uses) uses
frames, there is around a 13% overhead with TCP/IP over ATM but it's
nowhere near 11/8, for actual maximum throughput you can generally
reckon 9 bits per byte. That's true for cable as well, I generally get
around 33KBps from a 300kbps cable feed (around 12% overhead).

In fact it's not even true with the higher speed serial modems using
error correction, they strip out the bits from each byte and just
transmit the data in frames, again typically getting well under a bit of
overhead per data byte.

And I haven't factored in the packet loss that usually occurs due to
route-switching and other causes (which means that packets have to be
sent-again), you're likely to lose some on the way.

If you are getting less than 50KBps best case from a 512kbps ADSL line
there's something wrong. Certainly it can be less in specific cases
(slow server, bad routing, dropped packets, contention), but from your
ISP's news server it should be close to the maximum. Of course, with
Usenet you then have the 4/3 or worse overhead of UUencode or Base64
encoding, and article overheads with headers and other NNTP protocol
delays, which is why binaries over Usenet are a really inefficient way
of distributing material...

Chris C

"Chris Croughton" wrote in message
...
On Sat, 23 Apr 2005 21:48:27 +0100, Tony Morgan
wrote:

snip
So in 24 hours that would be about 9GB. What's this about
61GB/day?

Please do not feed the trolls. Have a look at the crossposts (not
on
this message, I've trimmed back to just uk.rec.video.digital), it's
going to a load of alt groups. People in other countries often have
much higher data rates than we do, I gather in Sweden for instance
10Mbps is common, that would give over 80GB per day (and some
Swedish
ISPs offer 100Mbps at under 100 quid a month!). Some Japanese ISPs
are
talking about even faster links.


So who in this instance is the troll, those from the other groups or
our own TM, ISTM that as TM is so under informed about were he was
posting and about speeds in other countries (not even accounting for
companies in the UK that have a high speed DSL 'backbone' connection)
it is TM who is the real troll here...