[Udpcast] Udpcast is great..but need some help

Alain Knaff alain.knaff at lll.lu
Mon Jul 19 19:03:31 CEST 2004

On Monday 19 July 2004 17:59, cmonster at icehouse.net wrote:
> This is a great product! I have already used it a bunch, I imaged 59
> computers on friday in an an hour an half. But I have some questions.
> Question 1
>     Most of my machines have the same hardware, but some have had hard
> drives replaced. so some are bigger... If I go from a big hard drive to a
> smaller one I get and error but it seems to work just fine. But if I go
> from a smaller hard drive to a bigger one it says transfre complete. But
> when I restart the the computer (windows 98) I get invalid system disk. Is
> there any way or trick to be able to copy from a smaller drive to a bigger
> one?

This is very weird. Normally, I'd expect the opposite behaviour:
i.e. copying to a smaller disk should break (because some data isn't
copied, and because the OS is led to believe that the disk is bigger
than it really is), but copying to a bigger one should work fine.

Maybe what's happening in your case is the following:

 1. [Copy from large to small] During casual testing, the data that
 happens to be located at the end of the disk might not yet be needed,
 and hence the problem does not show up. However, continued usage
 _will_ show problems (even if the non-existant sectors were empty to
 begin with, eventually the OS _will_ try to store some data on them,
 and fail)

 2. [Copy from small to large] Maybe an unrelated problem, such as
 different number of sectors and/or heads. Linux does not care about
 such things, but windows unfortunately does.
 This should not be a concern with newer hardware (where the "disk
 geometry" as seen by the OS depends only on the mode (LBA, Large,
 CHS), rather than on the physical geometry). However, when dealing
 with older hardware, there might be surprises...

> Question 2
>    I have been trying to use the command line tool so I can store images on
> a server. I have a computer running Fedora core 2 and I can start the
> recieving process by typing in udp-reciever -f pIII98. It says the
> following: udp-reciever 2004-05-31
>     UDP reciever PII98 at on eth0
> On the sending machine I boot off the cdrom and start the sender, this is
> what it says:
> UDP sender 2004-05-31
> using mcast address
> compressed UDP sender for /dev/hda/ at on eth0
> Broadcasting control to
> Both should be set to use the default port of 9000, but they won't connect.
> They will both just sit there like this. If I boot them both off the cd
> they will connect just fine. I am only not able to connect when using the 
> command line tool.

Possibly mismatched netmasks, or firewall rules.

Try running tcpdump on your server box (where you run the command line
version) and check what packets are send and received.

> If anybody could help me out that would be great.
> Thanks
> Kevin Christensen
> Kuna Joint school district
> Kuna Idaho



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