VNC speed?

[Ben Kosse]

Might I also point out that the moral is wrong, too. If you take that text
file and run it through something like PKZip or Gzip, etc. you will notice
that your 25Kbps is pushing through more along the lines of 120-150Kbps of
actual data.

The Linux kernel (2.0.36) is 30,278KB in size uncompressed. Using tar/bz2,
it compresses to 5800KB (both sizes using the 'du' command), for a
compression ratio of 5.22-to-1. The best modems only claim around 4-to-1
compression using ideal data, and deliver closer to 2-to-1 (3-to-1 in
extreme cases) on pure text.

VNC data is typically good for real-time compression, just not with the type
of compression used by modems (I get about 3.5-4KBps on a 28.8 connection
vs. 4-5KBps for text). If a specialized algorithm could be used, we'd fare a
lot better.

> -----Original Message-----
> From: Barry Treahy [mailto:treahy "at" mmaz.com]
> Sent: Tuesday, March 23, 1999 8:13 AM
> To: vnc-list "at" uk.research.att.com
> Subject: Re: VNC speed?
> 
> 
> Were not talking plan ascii text and also, having the 
> compression built it and a
> selectable option would be great for situations where you 
> have a dedicated
> circuit and your routers or the net do not provide hardware 
> compression...
> 
> Mike Kirwan wrote:
> 
> > Not necessarily, in fact  if the data stream is already 
> compresses, modem
> > compression could make things work. On a v90 connection at 
> 49.3kbps a plain
> > ascii file transfers at a rate (for me) of around 79-90 
> kbps. A same size
> > zip file (compressed) transfers at around 25 kbps.  So the 
> moral don't
> > compress compressed files.
> >
> > Mike
> >
> > -----Original Message-----
> > From: owner-vnc-list "at" uk.research.att.com
> > [mailto:owner-vnc-list "at" uk.research.att.com]On Behalf Of Andrey N.
> > Kalinin
> > Sent: Monday, March 22, 1999 11:37 PM
> > To: vnc-list "at" uk.research.att.com
> > Subject: Re: VNC speed?
> >
> > >> It depends on how you want to judge the speed over a 
> 28.8/33.6 link.  It
> > >> isn't fast, but certainly useable in an emergency.
> > >
> > >I tend to disagree about this... If you have any major 
> screen repaints, the
> > >resources on the remote machine often depleat rapidly 
> because of the
> > pending IO
> > >out the modem...  I have experienced this first hand 
> several times, which
> > is the
> > >primary reason for asking to have the compression built 
> into the normal
> > >distribution...
> > >
> > >Barry
> >
> > Will "software compression" in dialup settings (on Win platform)
> > significantly improve speed?
> > That do you think?
> >
> > Thanks.
> > ______________________________________
> > Andrey N. Kalinin  ndz_home "at" mtu-net.ru
> > Cometals Moscow         +7(095)9117960
> > Moscow                          Russia
> >
> > 
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