dkchen@uicsrd.csrd.uiuc.edu (03/08/90)
Well, I use the smartdrv of Windows as disk cache on extended memory. I also noticed the bad block problem when using xmodem and ymodem. Sometimes the error rate can go as high as 20%. However, I never had any problem using these transmitted files even though errors were reported. I use Avatex 2400 external modem, if that matters. Dean
cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) (03/10/90)
In article <42900066@uicsrd.csrd.uiuc.edu> dkchen@uicsrd.csrd.uiuc.edu writes:
$ Well, I use the smartdrv of Windows as disk cache on extended memory.
$ I also noticed the bad block problem when using xmodem and ymodem.
$ Sometimes the error rate can go as high as 20%. However, I never had
$ any problem using these transmitted files even though errors were
$ reported. I use Avatex 2400 external modem, if that matters.
The reason you never had any problems is that xmodem and ymodem are
error-resistant protocols. When they detect an error in a packet, they
request that the transmitter re-send the packet. Therefore, all bad
packets are thrown away and re-sent, leading to a final file which has
no errors in it.
What should concern you is that when you get a 20% error rate, 20% of
your packets are being retransmitted so your downloads are taking quite
a bit longer than they would normally. This may not matter for 50k files,
but if you're downloading a 500k file, for example, and you have a 20%
error rate, you end up spending the same time as it should take for a
600k file!
--
Stephen M. Dunn cs4g6ag@maccs.dcss.mcmaster.ca
<std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
****************************************************************************
"Oooh yes I need some love" - Rushkabra437@pallas.athenanet.com (Ken Abrams) (03/10/90)
In article <42900066@uicsrd.csrd.uiuc.edu> dkchen@uicsrd.csrd.uiuc.edu writes: > > Well, I use the smartdrv of Windows as disk cache on extended memory. > I also noticed the bad block problem when using xmodem and ymodem. > Sometimes the error rate can go as high as 20%. However, I never had > any problem using these transmitted files even though errors were > reported. I use Avatex 2400 external modem, if that matters. > >Dean The disk cache problem only occurs under certain conditions with HIGH SPEED modems (9600 and above). I doubt that this is a factor at 2400. More likely, I would think, that you have a defective modem or serial port or (much as I hate to mention it) a line noise problem. You aren't trying to do these transfers under Windows in the BACKGROUND are you? That combo doesn't work very well with most comm. programs especially on an AT or less. Come to think of it, I seem to remember that some comm. programs don't perform well under Windows even in the foreground. -- ======================================================== Ken Abrams uunet!pallas!kabra437 Illinois Bell kabra437@athenanet.com Springfield (voice) 217-753-7965