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20000517: notifyme and ldm

>From: alan anderson <address@hidden>
>Organization: St. Cloud State
>Keywords: 200005172010.e4HKAp409087 LDM notifyme

Alan,

>A couple more questions re: notifyme
>
>When I run this command the first time on a given day, it performs
>as expected.  I get a long scrolling printout (for DDPLUS anyway),
>and at some point it starts to pause;  at this point it has caught up
>and is showing the data as it is recieved, correct?

Correct.

>So, I have seen enough, and I stop it with Ctrl C.  Ok

OK.

>A few minutes later, I want to look again (short memory) so I type the
>same command again; the message shows it starts OK but there is no 
>output.  Why ?

Without seeing the command typed, I can't tell you.  I would suspect
that the first invocation included the '-o' flag specifying how far
to go back from the present time, and the second invocation did not
include the '-o', but I may be wrong.

>Also, in using the output to judge the delay of data reaching us, it 
>seems to me that of the output list from notifyme that only the last 
>data, where the command has caught up and is telling me of data just
>as it is received, that I can compare the 2 time stamps.

This is how I understand things.

>For the 
>data at the top the output, the first timestamp is stil the current time, 
>and the second is when it was injected,

Correct.

>but if it has been sitting 
>in my file for an hour, wouldn't I expect to see a 1 hour (or longer)
>difference, since I have asked it to go back 1 hr?  

No.  The first time is always the local clock time.  'notifyme' is
using the LDM 'ulog' logging interface which always spits back the
current time as the first time field.

>Can you comment about the comparison of the time stamps for the data
>at the top of notifyme's output, vs the output when it is looking at 
>data just as it comes in?

The comparison tells us nothing about the product latency when looking
back in time via the '-o' flat.  When 'notifyme' has caught up, however,
the current time is a good comparator for the product injection time.

>Just how does the -o (offset) argument 
>determine the way this thing performs?

It simply tells the upstream LDM to look back 'offset' seconds from the
current time in the queue.

>Sorry if I am dense about this, but hey, I am getting old.

Me too :-(

Tom

>From address@hidden Wed May 17 16:46:26 2000
>Subject: 20000517: notifyme and ldm

>Ok, I think I have it.  When using notifyme, look at the time difference
>for the data that is just coming in.