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IBM Presents OS/2 Software Hits 1995
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OS-2_SW_HITS_2ND_EDITION_1995.ISO
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i17
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ur423841.dsk
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CSDX.DFI
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RUPOLL.DOC
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1993-09-18
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RUPOLL is a tool that uses LAN Network Manager 1.1's command line
interface (LAN.EXE) to poll the ring utilization of many segments at a
user-defined interval. The results of these queries are
stored in a table created in the LAN Network Manager database,
allowing you to create a history of ring performance similar to
the Bridge Performance tables that come with LAN Network Manager 1.1.
RUPOLL will not produce any data unless LAN Network Manager is running
on the same machine and is successfully reporting ring utilization for
the rings you wish to query.
Requirements
------------
LAN Network Manager 1.1 is required and must be capable of
reporting ring utilization itself.
Using RUPOLL
------------
When you start RUPOLL, you see a listbox of segments RUPOLL is
currently polling and the polling interval. To start querying
a segment, select the 'Add' pushbutton.
ADD - Specifies the segment you want to query and the query
interval in minutes. The minimum interval is 1 minute
(see Performance Considerations) and the maximum is 9999,
nearly one week.
At the specified interval, RUPOLL causes LAN.EXE to be executed
and requests the ring utilization of the specified segment.
If polling is successful, RUPOLL writes data into the
RING_PERFORMANCE database table.
To change the frequency at which RUPOLL queries a segment,
select the 'Change' pushbutton.
CHANGE - Changes the interval at which RUPOLL polls segments.
To change the segment number, add a new query.
The change dialog appears once for each segment selected in the
listbox.
The delete button removes a query from RUPOLL's list and stops
logging data for the selected segments. Delete works on every
segment selected in the listbox. You are prompted once for
confirmation.
RUPOLL does not use any LAN Network Manager DLLs and
can be started and stopped independently of LAN Network Manager.
New Sessions in a Task List
---------------------------
RUPOLL creates an OS/2 command session to execute LAN.EXE.
RUPOLL appears in your task list as 'RUPOLL Poller Work Session'.
Performance Considerations
--------------------------
If LAN Network Manager has a significant level of activity,
use RUPOLL with caution. RUPOLL uses almost no CPU time when
idle. No performance concerns occur when RUPOLL queries a few
segments at substantial intervals of time. If you query 60 segments
at one minute intervals, however, RUPOLL may have performance problems.
Once each minute, RUPOLL will step through its list of segments
to query. If a segment interval has expired, RUPOLL starts
LAN.EXE through the OS/2 command session the RUPOLL spawned
when it started. LAN.EXE then communicates with LAN Network
Manager, which communicates with LAN Station Manager, which
communicates with an adapter on the ring in question.
LAN Station Manager responds. LAN Network Manager sends the response
back to LAN.EXE, which writes the information. RUPOLL reads
the information and writes it to the database. The information
passes through 5 processes (RUPOLL->CMD.EXE->LAN.EXE->LANM->LSM) on the
way in and the same 5 on the way back, not including time spent
sending a frame out to the reporting station on the ring, passing
through bridges on the way. If RUPOLL runs 60 queries each minute,
a query must complete in less than a second to give RUPOLL time to
write the information to the database and start the next query.
RUPOLL is entirely dependent on LAN.EXE, which in turn is dependent
on LAN Network Manager. Actual polling intervals will not correspond
exactly to the intervals you requested. In practice, each interval
requires additional time. When a query runs slowly, it has a domino
effect on the queries following it. RUPOLL has to wait for each
invocation of LAN.EXE to finish. LAN.EXE is synchronous and cannot
execute 2 copies at the same time. If one query takes a long time
to complete, RUPOLL will be late starting the next query.
Technical Information
---------------------
RUPOLL executes a session of CMD.EXE through DosStartSession and
redirects the stdin, stdout and stderr of that session to anonymous
pipes which RUPOLL created before starting the session. RUPOLL has
a write pipe which mimics stdin of the OS/2 session and a read pipe
which traps anything going to stdout.
Each segment/interval combination is stored as a node in a linked list.
At initialization, RUPOLL starts a timer with WinStartTimer which pops
once per minute. On each timer tick, a second thread walks the list and
checks to see which query has waited long enough. For each query
whose interval has expired, RUPOLL writes the command
'lan segment util seg=xxx' to the pipe which mimics stdin and
then monitors the read pipe for LAN.EXE's output. Once RUPOLL
receives the output, it parses the output, writes that data
to the RING_PERFORMANCE table, and continues traversing the linked list.
Data in the database table includes:
Segment number the given record relates to.
Time the record was generated.
Date the record was generated.
Interval (in seconds) between the time this record and the last
was logged.
Date and time represented as the number of seconds
since 1/1/1970 (this number will wrap in the year 2038).
Ring utilization expressed as xxx.x%.