fond
Model Checking Contest 2021
11th edition, Paris, France, June 23, 2021
Execution of r284-smll-162123894300048
Last Updated
Jun 28, 2021

About the Execution of 2020-gold for TokenRing-PT-010

Execution Summary
Max Memory
Used (MB)
Time wait (ms) CPU Usage (ms) I/O Wait (ms) Computed Result Execution
Status
511.464 3600000.00 88878.00 349.30 TTTFFFFTFTTFFFFT normal

Execution Chart

We display below the execution chart for this examination (boot time has been removed).

Trace from the execution

Formatting '/data/fkordon/mcc2021-input.r284-smll-162123894300048.qcow2', fmt=qcow2 size=4294967296 backing_file=/data/fkordon/mcc2021-input.qcow2 cluster_size=65536 lazy_refcounts=off refcount_bits=16
Waiting for the VM to be ready (probing ssh)
...................................................................................................................................................................................................................................................................................
=====================================================================
Generated by BenchKit 2-4028
Executing tool gold2020
Input is TokenRing-PT-010, examination is ReachabilityFireability
Time confinement is 3600 seconds
Memory confinement is 16384 MBytes
Number of cores is 4
Run identifier is r284-smll-162123894300048
=====================================================================

--------------------
preparation of the directory to be used:
/home/mcc/execution
total 11M
-rw-r--r-- 1 mcc users 95K May 5 16:58 CTLCardinality.txt
-rw-r--r-- 1 mcc users 494K May 10 09:44 CTLCardinality.xml
-rw-r--r-- 1 mcc users 1.1M May 5 16:58 CTLFireability.txt
-rw-r--r-- 1 mcc users 4.2M May 10 09:44 CTLFireability.xml
-rw-r--r-- 1 mcc users 4.2K May 6 14:48 GenericPropertiesDefinition.xml
-rw-r--r-- 1 mcc users 6.6K May 6 14:48 GenericPropertiesVerdict.xml
-rw-r--r-- 1 mcc users 68K Mar 28 16:46 LTLCardinality.txt
-rw-r--r-- 1 mcc users 249K Mar 28 16:46 LTLCardinality.xml
-rw-r--r-- 1 mcc users 459K Mar 28 16:46 LTLFireability.txt
-rw-r--r-- 1 mcc users 1.3M Mar 28 16:46 LTLFireability.xml
-rw-r--r-- 1 mcc users 52K Mar 27 14:11 ReachabilityCardinality.txt
-rw-r--r-- 1 mcc users 173K Mar 27 14:11 ReachabilityCardinality.xml
-rw-r--r-- 1 mcc users 438K Mar 25 20:12 ReachabilityFireability.txt
-rw-r--r-- 1 mcc users 1.3M Mar 25 20:12 ReachabilityFireability.xml
-rw-r--r-- 1 mcc users 15K Mar 22 08:16 UpperBounds.txt
-rw-r--r-- 1 mcc users 35K Mar 22 08:16 UpperBounds.xml
-rw-r--r-- 1 mcc users 5 May 5 16:52 equiv_col
-rw-r--r-- 1 mcc users 4 May 5 16:52 instance
-rw-r--r-- 1 mcc users 6 May 5 16:52 iscolored
-rw-r--r-- 1 mcc users 804K May 5 16:52 model.pnml

--------------------
content from stdout:

=== Data for post analysis generated by BenchKit (invocation template)

The expected result is a vector of booleans
BOOL_VECTOR

here is the order used to build the result vector(from text file)
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-00
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-01
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-02
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-03
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-04
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-05
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-06
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-07
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-08
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-09
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-10
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-11
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-12
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-13
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-14
FORMULA_NAME TokenRing-PT-010-ReachabilityFireability-15

=== Now, execution of the tool begins

BK_START 1621409093798

bash -c /home/mcc/BenchKit/BenchKit_head.sh 2> STDERR ; echo ; echo -n "BK_STOP " ; date -u +%s%3N
[2021-05-19 07:24:57] [INFO ] Running its-tools with arguments : [-pnfolder, /home/mcc/execution, -examination, ReachabilityFireability, -z3path, /home/mcc/BenchKit//z3/bin/z3, -yices2path, /home/mcc/BenchKit//yices/bin/yices, -timeout, 3600, -rebuildPNML]
[2021-05-19 07:24:57] [INFO ] Parsing pnml file : /home/mcc/execution/model.pnml
[2021-05-19 07:24:57] [INFO ] Load time of PNML (sax parser for PT used): 212 ms
[2021-05-19 07:24:57] [INFO ] Transformed 121 places.
[2021-05-19 07:24:57] [INFO ] Transformed 1111 transitions.
[2021-05-19 07:24:57] [INFO ] Found NUPN structural information;
[2021-05-19 07:24:57] [INFO ] Parsed PT model containing 121 places and 1111 transitions in 282 ms.
Parsed 16 properties from file /home/mcc/execution/ReachabilityFireability.xml in 200 ms.
Working with output stream class java.io.PrintStream
FORMULA TokenRing-PT-010-ReachabilityFireability-03 FALSE TECHNIQUES TOPOLOGICAL INITIAL_STATE
FORMULA TokenRing-PT-010-ReachabilityFireability-05 FALSE TECHNIQUES TOPOLOGICAL INITIAL_STATE
Incomplete random walk after 10000 steps, including 0 resets, run finished after 1092 ms. (steps per millisecond=9 ) properties seen :[0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1]
FORMULA TokenRing-PT-010-ReachabilityFireability-15 TRUE TECHNIQUES TOPOLOGICAL RANDOM_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-09 TRUE TECHNIQUES TOPOLOGICAL RANDOM_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-06 FALSE TECHNIQUES TOPOLOGICAL RANDOM_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-04 FALSE TECHNIQUES TOPOLOGICAL RANDOM_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-02 TRUE TECHNIQUES TOPOLOGICAL RANDOM_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-01 TRUE TECHNIQUES TOPOLOGICAL RANDOM_WALK
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 1085 ms. (steps per millisecond=9 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 1049 ms. (steps per millisecond=9 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 1031 ms. (steps per millisecond=9 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 1027 ms. (steps per millisecond=9 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 1025 ms. (steps per millisecond=9 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 1026 ms. (steps per millisecond=9 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 1375 ms. (steps per millisecond=7 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 1057 ms. (steps per millisecond=9 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0]
// Phase 1: matrix 1111 rows 121 cols
[2021-05-19 07:25:07] [INFO ] Computed 11 place invariants in 23 ms
[2021-05-19 07:25:07] [INFO ] [Real]Absence check using 11 positive place invariants in 51 ms returned sat
[2021-05-19 07:25:07] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:08] [INFO ] [Real]Absence check using state equation in 448 ms returned sat
[2021-05-19 07:25:08] [INFO ] Solution in real domain found non-integer solution.
[2021-05-19 07:25:08] [INFO ] [Nat]Absence check using 11 positive place invariants in 64 ms returned unsat
[2021-05-19 07:25:08] [INFO ] [Real]Absence check using 11 positive place invariants in 55 ms returned unsat
[2021-05-19 07:25:08] [INFO ] [Real]Absence check using 11 positive place invariants in 12 ms returned sat
[2021-05-19 07:25:08] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:09] [INFO ] [Real]Absence check using state equation in 448 ms returned sat
[2021-05-19 07:25:09] [INFO ] State equation strengthened by 1010 read => feed constraints.
[2021-05-19 07:25:09] [INFO ] [Real]Added 1010 Read/Feed constraints in 204 ms returned sat
[2021-05-19 07:25:09] [INFO ] Solution in real domain found non-integer solution.
[2021-05-19 07:25:09] [INFO ] [Nat]Absence check using 11 positive place invariants in 20 ms returned sat
[2021-05-19 07:25:09] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:10] [INFO ] [Nat]Absence check using state equation in 546 ms returned sat
[2021-05-19 07:25:10] [INFO ] [Nat]Added 1010 Read/Feed constraints in 192 ms returned sat
[2021-05-19 07:25:10] [INFO ] Computed and/alt/rep : 1101/19210/1101 causal constraints in 284 ms.
[2021-05-19 07:25:14] [INFO ] Added : 140 causal constraints over 28 iterations in 4119 ms. Result :(error "Failed to check-sat")
[2021-05-19 07:25:14] [INFO ] [Real]Absence check using 11 positive place invariants in 19 ms returned sat
[2021-05-19 07:25:14] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:15] [INFO ] [Real]Absence check using state equation in 531 ms returned sat
[2021-05-19 07:25:15] [INFO ] [Real]Added 1010 Read/Feed constraints in 198 ms returned sat
[2021-05-19 07:25:15] [INFO ] Solution in real domain found non-integer solution.
[2021-05-19 07:25:15] [INFO ] [Nat]Absence check using 11 positive place invariants in 20 ms returned sat
[2021-05-19 07:25:15] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:16] [INFO ] [Nat]Absence check using state equation in 502 ms returned sat
[2021-05-19 07:25:16] [INFO ] [Nat]Added 1010 Read/Feed constraints in 178 ms returned sat
[2021-05-19 07:25:16] [INFO ] Computed and/alt/rep : 1101/19210/1101 causal constraints in 171 ms.
[2021-05-19 07:25:20] [INFO ] Added : 165 causal constraints over 33 iterations in 4238 ms. Result :(error "Failed to check-sat")
[2021-05-19 07:25:20] [INFO ] [Real]Absence check using 11 positive place invariants in 16 ms returned sat
[2021-05-19 07:25:20] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:21] [INFO ] [Real]Absence check using state equation in 519 ms returned sat
[2021-05-19 07:25:21] [INFO ] [Real]Added 1010 Read/Feed constraints in 202 ms returned sat
[2021-05-19 07:25:21] [INFO ] Solution in real domain found non-integer solution.
[2021-05-19 07:25:21] [INFO ] [Nat]Absence check using 11 positive place invariants in 17 ms returned sat
[2021-05-19 07:25:21] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:21] [INFO ] [Nat]Absence check using state equation in 484 ms returned sat
[2021-05-19 07:25:22] [INFO ] [Nat]Added 1010 Read/Feed constraints in 172 ms returned sat
[2021-05-19 07:25:22] [INFO ] Deduced a trap composed of 65 places in 311 ms
[2021-05-19 07:25:22] [INFO ] Deduced a trap composed of 65 places in 283 ms
[2021-05-19 07:25:22] [INFO ] Trap strengthening (SAT) tested/added 3/2 trap constraints in 747 ms
[2021-05-19 07:25:22] [INFO ] Computed and/alt/rep : 1101/19210/1101 causal constraints in 135 ms.
[2021-05-19 07:25:26] [INFO ] Added : 135 causal constraints over 27 iterations in 3550 ms. Result :(error "Failed to check-sat")
[2021-05-19 07:25:26] [INFO ] [Real]Absence check using 11 positive place invariants in 16 ms returned unsat
[2021-05-19 07:25:26] [INFO ] [Real]Absence check using 11 positive place invariants in 15 ms returned sat
[2021-05-19 07:25:26] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:26] [INFO ] [Real]Absence check using state equation in 505 ms returned sat
[2021-05-19 07:25:27] [INFO ] [Real]Added 1010 Read/Feed constraints in 192 ms returned sat
[2021-05-19 07:25:27] [INFO ] Solution in real domain found non-integer solution.
[2021-05-19 07:25:27] [INFO ] [Nat]Absence check using 11 positive place invariants in 17 ms returned sat
[2021-05-19 07:25:27] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:27] [INFO ] [Nat]Absence check using state equation in 487 ms returned sat
[2021-05-19 07:25:28] [INFO ] [Nat]Added 1010 Read/Feed constraints in 212 ms returned sat
[2021-05-19 07:25:28] [INFO ] Computed and/alt/rep : 1101/19210/1101 causal constraints in 148 ms.
[2021-05-19 07:25:32] [INFO ] Added : 170 causal constraints over 34 iterations in 4193 ms. Result :(error "Failed to check-sat")
[2021-05-19 07:25:32] [INFO ] [Real]Absence check using 11 positive place invariants in 17 ms returned sat
[2021-05-19 07:25:32] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:32] [INFO ] [Real]Absence check using state equation in 508 ms returned sat
[2021-05-19 07:25:33] [INFO ] [Real]Added 1010 Read/Feed constraints in 202 ms returned sat
[2021-05-19 07:25:33] [INFO ] Solution in real domain found non-integer solution.
[2021-05-19 07:25:33] [INFO ] [Nat]Absence check using 11 positive place invariants in 18 ms returned sat
[2021-05-19 07:25:33] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2021-05-19 07:25:33] [INFO ] [Nat]Absence check using state equation in 470 ms returned sat
[2021-05-19 07:25:33] [INFO ] [Nat]Added 1010 Read/Feed constraints in 184 ms returned sat
[2021-05-19 07:25:33] [INFO ] Computed and/alt/rep : 1101/19210/1101 causal constraints in 120 ms.
[2021-05-19 07:25:38] [WARNING] SMT solver failed with error :java.lang.RuntimeException: SMT solver raised an error when submitting script. Raised (error "Failed to assert expression: java.io.IOException: Stream closed (=> (> t170 0) (and (or (and (> t296 0) (< o296 o170)) (and (> t409 0) (< o409 o170)) (and (> t479 0) (< o479 o170)) (and (> t518 0) (< o518 o170)) (and (> t558 0) (< o558 o170)) (and (> t680 0) (< o680 o170)) (and (> t788 0) (< o788 o170)) (and (> t876 0) (< o876 o170)) (and (> t1030 0) (< o1030 o170)) (and (> t1046 0) (< o1046 o170))) (or (and (> t2 0) (< o2 o170)) (and (> t288 0) (< o288 o170)) (and (> t356 0) (< o356 o170)) (and (> t418 0) (< o418 o170)) (and (> t437 0) (< o437 o170)) (and (> t443 0) (< o443 o170)) (and (> t449 0) (< o449 o170)) (and (> t760 0) (< o760 o170)) (and (> t984 0) (< o984 o170)) (and (> t1103 0) (< o1103 o170)))))") while checking expression at index 7
FORMULA TokenRing-PT-010-ReachabilityFireability-12 FALSE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
FORMULA TokenRing-PT-010-ReachabilityFireability-07 TRUE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
FORMULA TokenRing-PT-010-ReachabilityFireability-00 TRUE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
Support contains 21 out of 121 places. Attempting structural reductions.
Starting structural reductions, iteration 0 : 121/121 places, 1111/1111 transitions.
Applied a total of 0 rules in 143 ms. Remains 121 /121 variables (removed 0) and now considering 1111/1111 (removed 0) transitions.
Finished structural reductions, in 1 iterations. Remains : 121/121 places, 1111/1111 transitions.
Incomplete random walk after 1000000 steps, including 0 resets, run finished after 3388 ms. (steps per millisecond=295 ) properties seen :[0, 0, 0, 0, 0]
Incomplete Best-First random walk after 1000000 steps, including 0 resets, run finished after 2699 ms. (steps per millisecond=370 ) properties seen :[0, 0, 0, 0, 0]
Incomplete Best-First random walk after 1000000 steps, including 0 resets, run finished after 2523 ms. (steps per millisecond=396 ) properties seen :[0, 0, 0, 0, 0]
Incomplete Best-First random walk after 1000000 steps, including 0 resets, run finished after 2746 ms. (steps per millisecond=364 ) properties seen :[0, 0, 0, 0, 0]
Incomplete Best-First random walk after 1000000 steps, including 0 resets, run finished after 2853 ms. (steps per millisecond=350 ) properties seen :[0, 0, 0, 0, 0]
Incomplete Best-First random walk after 1000000 steps, including 0 resets, run finished after 2543 ms. (steps per millisecond=393 ) properties seen :[0, 0, 0, 0, 0]
Probably explored full state space saw : 58904 states, properties seen :[0, 0, 0, 0, 0]
Probabilistic random walk after 352949 steps, saw 58904 distinct states, run finished after 2063 ms. (steps per millisecond=171 ) properties seen :[0, 0, 0, 0, 0]
Explored full state space saw : 58905 states, properties seen :[0, 0, 0, 0, 0]
Exhaustive walk after 352955 steps, saw 58905 distinct states, run finished after 2111 ms. (steps per millisecond=167 ) properties seen :[0, 0, 0, 0, 0]
FORMULA TokenRing-PT-010-ReachabilityFireability-14 FALSE TECHNIQUES TOPOLOGICAL EXHAUSTIVE_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-13 FALSE TECHNIQUES TOPOLOGICAL EXHAUSTIVE_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-11 FALSE TECHNIQUES TOPOLOGICAL EXHAUSTIVE_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-10 TRUE TECHNIQUES TOPOLOGICAL EXHAUSTIVE_WALK
FORMULA TokenRing-PT-010-ReachabilityFireability-08 FALSE TECHNIQUES TOPOLOGICAL EXHAUSTIVE_WALK
All properties solved without resorting to model-checking.

--------------------
content from stderr:

Sequence of Actions to be Executed by the VM

This is useful if one wants to reexecute the tool in the VM from the submitted image disk.

set -x
# this is for BenchKit: configuration of major elements for the test
export BK_INPUT="TokenRing-PT-010"
export BK_EXAMINATION="ReachabilityFireability"
export BK_TOOL="gold2020"
export BK_RESULT_DIR="/tmp/BK_RESULTS/OUTPUTS"
export BK_TIME_CONFINEMENT="3600"
export BK_MEMORY_CONFINEMENT="16384"
export BK_BIN_PATH="/home/mcc/BenchKit/bin/"

# this is specific to your benchmark or test

export BIN_DIR="$HOME/BenchKit/bin"

# remove the execution directoty if it exists (to avoid increse of .vmdk images)
if [ -d execution ] ; then
rm -rf execution
fi

# this is for BenchKit: explicit launching of the test
echo "====================================================================="
echo " Generated by BenchKit 2-4028"
echo " Executing tool gold2020"
echo " Input is TokenRing-PT-010, examination is ReachabilityFireability"
echo " Time confinement is $BK_TIME_CONFINEMENT seconds"
echo " Memory confinement is 16384 MBytes"
echo " Number of cores is 4"
echo " Run identifier is r284-smll-162123894300048"
echo "====================================================================="
echo
echo "--------------------"
echo "preparation of the directory to be used:"

tar xzf /home/mcc/BenchKit/INPUTS/TokenRing-PT-010.tgz
mv TokenRing-PT-010 execution
cd execution
if [ "ReachabilityFireability" = "ReachabilityDeadlock" ] || [ "ReachabilityFireability" = "UpperBounds" ] || [ "ReachabilityFireability" = "QuasiLiveness" ] || [ "ReachabilityFireability" = "StableMarking" ] || [ "ReachabilityFireability" = "Liveness" ] || [ "ReachabilityFireability" = "OneSafe" ] || [ "ReachabilityFireability" = "StateSpace" ]; then
rm -f GenericPropertiesVerdict.xml
fi
pwd
ls -lh

echo
echo "--------------------"
echo "content from stdout:"
echo
echo "=== Data for post analysis generated by BenchKit (invocation template)"
echo
if [ "ReachabilityFireability" = "UpperBounds" ] ; then
echo "The expected result is a vector of positive values"
echo NUM_VECTOR
elif [ "ReachabilityFireability" != "StateSpace" ] ; then
echo "The expected result is a vector of booleans"
echo BOOL_VECTOR
else
echo "no data necessary for post analysis"
fi
echo
if [ -f "ReachabilityFireability.txt" ] ; then
echo "here is the order used to build the result vector(from text file)"
for x in $(grep Property ReachabilityFireability.txt | cut -d ' ' -f 2 | sort -u) ; do
echo "FORMULA_NAME $x"
done
elif [ -f "ReachabilityFireability.xml" ] ; then # for cunf (txt files deleted;-)
echo echo "here is the order used to build the result vector(from xml file)"
for x in $(grep '' ReachabilityFireability.xml | cut -d '>' -f 2 | cut -d '<' -f 1 | sort -u) ; do
echo "FORMULA_NAME $x"
done
elif [ "ReachabilityFireability" = "ReachabilityDeadlock" ] || [ "ReachabilityFireability" = "QuasiLiveness" ] || [ "ReachabilityFireability" = "StableMarking" ] || [ "ReachabilityFireability" = "Liveness" ] || [ "ReachabilityFireability" = "OneSafe" ] ; then
echo "FORMULA_NAME ReachabilityFireability"
fi
echo
echo "=== Now, execution of the tool begins"
echo
echo -n "BK_START "
date -u +%s%3N
echo
timeout -s 9 $BK_TIME_CONFINEMENT bash -c "/home/mcc/BenchKit/BenchKit_head.sh 2> STDERR ; echo ; echo -n \"BK_STOP \" ; date -u +%s%3N"
if [ $? -eq 137 ] ; then
echo
echo "BK_TIME_CONFINEMENT_REACHED"
fi
echo
echo "--------------------"
echo "content from stderr:"
echo
cat STDERR ;