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Mars Rover Controlled By Java

Java, the software developed by Sun Microsystems in the mid-1990s as a
universal operating system for Internet applications, gave NASA a low-cost
and easy-to-use option for running Spirit, the robotic rover that rolled
onto the planet's surface on Thursday in search of signs of water and life.

http://news.com.com/2100-1007_3-5142...l?tag=nefd_top

l8r, Mike N. Christoff

Jul 17 '05
198 18459
In article <bv**********@p egasus.csx.cam. ac.uk>, Nick Maclaren
<nm**@cus.cam.a c.uk> writes
(trimmed)

That is a classic example of what I say is mistaken methodology!
Yes, pretty well everything that you say is true, but you have missed
the fact that interactions WILL change the failure syndromes in ways
that mean untargetted testing will miss even the most glaringly
obvious errors. There are just TOO MANY possible combinations of
conditions to rely on random testing.
(trimmed)
An aspect of a mathematical design that I did not say explicitly (but
only hinted at) is that you can identify areas to check that the code
matches the mode and other areas where the analysis descends from
mathematics to hand-waving. You can then design precise tests for the
former, and targetted soak tests for the latter. It isn't uncommon
for such an approach to increase the effectiveness of testing beyond
all recognition.
Regards,
Nick Maclaren.

I would be very interested to hear more about increasing the
effectiveness of testing beyond all recognition. I am a professional
programmer in an area where we routinely estimate the testing effort as
about equal to the programming effort (in terms of staff time, but not
necessarily staff cost). Do you have references? As a token of sincerity
I will provide references for what we seem to agree is commercial
practice (whether it should be or not):

The main reference establishing commercial practice that I can find
online seems to be "A controlled Experiment in Program Testing and Code
Walkthroughs/Inspections" by Myers, CACM Volume 21, Number 9. The date
shows that some technology transfer might indeed be overdue - Volume 21
translates to 1978! However, I think automated testing, especially
regression testing, has become a lot easier, or at least more popular,
than it was (JUnit, Rational Robot, etc.). The notion of test coverage
tools seems to be of similar vintage and actually became less accessible
for a while as no version of tcov appeared for setups other than K&R C
on Unix. I spent part of last week trying out Hansel, an open source
test coverage tool for Java, available on www.sourceforge.net.

References from within books to hand:
Black box and white box complementary: "Testing Computer Software", by
Kamer, Falk, and Nguyen, Chapter 12 P271.
Code Review invaluable (but few details on how to do one): "Software
Assessments, Benchmarks, and Best Practices", by Capers Jones, e.g.
Chapter on Best Practices for Systems Software, P367
Mars Pathfinder bug ignored during pre-launch tests: "The Practice of
Programming", by Kernighan and Pike, Section 5.2 P121. (The next chapter
is a good short overview of commercial-practice test design circa 1999).
--
A. G. McDowell
Jul 17 '05 #191
"A. G. McDowell" <no****@nospam. co.uk> writes:
I would be very interested to hear more about increasing the
effectiveness of testing beyond all recognition. I am a professional
programmer in an area where we routinely estimate the testing effort as
about equal to the programming effort (in terms of staff time, but not
necessarily staff cost). Do you have references? As a token of sincerity
I will provide references for what we seem to agree is commercial
practice (whether it should be or not):


when we were doing the original payment gateway
http://www.garlic.com/~lynn/aadsm5.htm#asrn2
http://www.garlic.com/~lynn/aadsm5.htm#asrn3

we set up a test matrix ... not for the sotware ... but for the
service. nominal payment infrastructure trouble desk did 5 minute
problem first level problem determination ... however that was for an
infrastructure that was almost exclusively circuit based.

while it was possible to translate the (payment) message formats from
a circuit based infrastructure to a packet based infrastructure ...
translating the circuit-based service operation to a packet-based
infrastructure was less clear cut (merchant/webhost complains that
payments aren't working ... expects internet/packet connection to be
much less expensive than direct circuit ... but at the same time
expects compareable availability).

The claim has been that coding for a service operation is 4-10 times
that of a straight application implementation and ten times the effort
because of needing to understand all possible failure modes
.... regardless of whether they are characteristic of the software or
hardware or some totally unrelated environmental characteristic.

in any case, one of the issues was detailed analysis of existing
trouble desk circuit-based problem determination procedures and being
able to translate that into a packet-based (internet) environment and
still attempt to come close to the goal of being able to perform first
level problem determination in five minutes. When we started there
were cases of trouble ticket being close NTF (no trouble found) after
3hrs of manual investigation.

of course this was also at a time ... when it was difficult to find
any ISP that even knew how to spell "service level agreement".

aka ... it is possible for software to perform flawlessly and still be
useless.

some of this came from doing ha/cmp
http://www.garlic.com/~lynn/subtopic.html#hacmp

misc. related past threads
http://www.garlic.com/~lynn/2000g.html#50 Egghead cracked, MS IIS again
http://www.garlic.com/~lynn/2001e.html#48 Where are IBM z390 SPECint2000 results?
http://www.garlic.com/~lynn/2001f.html#75 Test and Set (TS) vs Compare and Swap (CS)
http://www.garlic.com/~lynn/2001k.html#18 HP-UX will not be ported to Alpha (no surprise)exit
http://www.garlic.com/~lynn/2001n.html#85 The demise of compaq
http://www.garlic.com/~lynn/2001n.html#91 Buffer overflow
http://www.garlic.com/~lynn/2001n.html#93 Buffer overflow
http://www.garlic.com/~lynn/2002.html#28 Buffer overflow
http://www.garlic.com/~lynn/2002.html#29 Buffer overflow
http://www.garlic.com/~lynn/2002e.html#73 Blade architectures
http://www.garlic.com/~lynn/2002f.html#24 Computers in Science Fiction
http://www.garlic.com/~lynn/2002h.html#11 Why did OSI fail compared with TCP-IP?
http://www.garlic.com/~lynn/2002h.html#12 Why did OSI fail compared with TCP-IP?
http://www.garlic.com/~lynn/2002n.html#11 Wanted: the SOUNDS of classic computing
http://www.garlic.com/~lynn/2003b.html#53 Microsoft worm affecting Automatic Teller Machines
http://www.garlic.com/~lynn/2003g.html#62 IBM says AMD dead in 5yrs ... -- Microsoft Monopoly vs. IBM
http://www.garlic.com/~lynn/2003j.html#15 A Dark Day
http://www.garlic.com/~lynn/2003l.html#49 Thoughts on Utility Computing?
http://www.garlic.com/~lynn/2003p.html#37 The BASIC Variations

--
Anne & Lynn Wheeler | http://www.garlic.com/~lynn/
Internet trivia 20th anv http://www.garlic.com/~lynn/rfcietff.htm
Jul 17 '05 #192

"A. G. McDowell" <no****@nospam. co.uk> wrote in message
news:AZ******** ******@mcdowell a.demon.co.uk.. .
In article <bv**********@p egasus.csx.cam. ac.uk>, Nick Maclaren
<nm**@cus.cam.a c.uk> writes
(trimmed)

That is a classic example of what I say is mistaken methodology


I hate to barge in and short-circuit a really very interesting
discussion, but
I think a point has been missed.

The SW on the Rover was designed from the start to be remotely
debugged
and patched. This is a truely wonderful thing. Why spend the effort
it takes
to design bullet-proof SW when you can spend it designing fixable SW?

--arne (I'll take my answer off the air... ;-)
Jul 17 '05 #193
> Example: the priority inversion bug that hit a previous probe

....Mars Pathfinder...
had apparently shown up in testing but been ignored, because it
wasn't what they were looking for at the time.


Of course, that project was run on a shoe-string budget (relatively),
the priority-inversion-caused resets occured sporadically (only a few
times during maybe a year's worth of testing) and unreproducibly, and
most importantly: those guys had a strict deadline, and a lot of other
problems to solve. A rasonable trade-off, all things considered, IMO.

Jan
Jul 17 '05 #194

In article <AZ************ **@mcdowella.de mon.co.uk>,
"A. G. McDowell" <no****@nospam. co.uk> writes:
|> >
|> I would be very interested to hear more about increasing the
|> effectiveness of testing beyond all recognition. I am a professional
|> programmer in an area where we routinely estimate the testing effort as
|> about equal to the programming effort (in terms of staff time, but not
|> necessarily staff cost). Do you have references? As a token of sincerity
|> I will provide references for what we seem to agree is commercial
|> practice (whether it should be or not):

Regrettably not :-( I have seen references, yes, but they were
usually incidental remarks and I can't now remember exactly where I
saw them. The trouble is that they dated from the days when such
things were 'just done' and the techniques were often passed by
word of mouth, or were regarded as so obvious as to be not worth
describing.

One aspect you may be able to find is in the testing of numeric
code. One standard form of targetting is to increase the coverage
of the 'difficult' or boundary areas, because a relatively small
number of tests is adequate for the main sections. I know that
something similar has also been done in compiler test suites.

The only 'theoretical' reference I know of is to a related area:
Monte-Carlo methods. But, if you regard the problem as estimating
the number of bugs, then that is immediately applicable. I use
Hammersley and Handscomb, but that may be out of print.

Thanks for the references. There is certainly stuff dating from
the 1960s and early 1970s, but it could be the devil to track down.
NAG has certainly been doing it since it started (early 1970s),
in the numeric context.
Regards,
Nick Maclaren.
Jul 17 '05 #195
Uncle Al schrieb:
Local atmospheric pressure is 7-10 torr. Earth sea level is 760
torr.


1 torr = 4/3 hPa (hekto Pascal), for those of us who are more familiar with
the metric system.

Carsten
Jul 17 '05 #196
In article <IL************ ******@news.cpq corp.net>,
"arne thormodsen" <ar************ ***@REMOVE.hp.c om> wrote:

"A. G. McDowell" <no****@nospam. co.uk> wrote in message
news:AZ******* *******@mcdowel la.demon.co.uk. ..
In article <bv**********@p egasus.csx.cam. ac.uk>, Nick Maclaren
<nm**@cus.cam.a c.uk> writes
(trimmed)
>
>That is a classic example of what I say is mistaken methodology


I hate to barge in and short-circuit a really very interesting
discussion, but
I think a point has been missed.

The SW on the Rover was designed from the start to be remotely
debugged
and patched. This is a truely wonderful thing. Why spend the effort
it takes
to design bullet-proof SW when you can spend it designing fixable SW?


.... well ... the fixability has to be bullet-proof.
Jul 17 '05 #197
"A. G. McDowell" <no****@nospam. co.uk> writes:
I would be very interested to hear more about increasing the
effectiveness of testing beyond all recognition. I am a professional
programmer in an area where we routinely estimate the testing effort
as about equal to the programming effort (in terms of staff time,
but not necessarily staff cost). Do you have references? As a token
of sincerity I will provide references for what we seem to agree is
commercial practice (whether it should be or not):


this might also be considered a characteristic difference between
platforms derived from batch oriented systems and platforms derived
from interactive oriented systems.

for 40 years or more, batch systems have tended to provide relatively
clear diagnostic information for the application owner ... since the
application owner wasn't around went their program ran; one specificly
clearly diagnosed & reported item for those 40 some year period has
been space full condition.

interactive platforms have tended to be much more laissez-faire about
providing diagnostics for such things. i've seen payroll application
ported from batch platfrom to an interactive oriented platform
.... where the sort would fail because of space full condition ... but
the error didn't get propogated appropriately thru the rest of the
infrastructure. As a result, checks got printed ... but not with
exactly the values expected. some post mortem analysis seemed to
indicate that assumptions were made about individual applications
indicating interactive error message to an human in attendance ... and
the human taking the appropriate action.

now some number of the batch platforms for possibly 20 years now
.... have had facilities that could take advantage of batch paradigm
error infrastructure and for conditions like space full ... take
automated proscriped graceful recovery actions (i.e. there is deadline
for getting checks out and can't rely on the vagaries of being able to
count on some human based mediation).

some fundamental issue about not only trying to turn out perfect code
.... but also providing an instrumented infrastructure that recognizes
errors will probably happen ... and in the absence of direct human
mediation ... other types of facilities need to be provided
(frequently a characteristic differentiation between batch-oriented
platforms and interactive-oriented platforms).

some random posts on batch vis-a-vis interactive paradigms
http://www.garlic.com/~lynn/96.html#8 Why Do Mainframes Exist ???
http://www.garlic.com/~lynn/98.html#4 VSE or MVS
http://www.garlic.com/~lynn/98.html#18 Reviving the OS/360 thread (Questions about OS/360)
http://www.garlic.com/~lynn/98.html#51 Mainframes suck? (was Re: Possibly OT: Disney Computing)
http://www.garlic.com/~lynn/99.html#16 Old Computers
http://www.garlic.com/~lynn/99.html#197 Computing As She Really Is. Was: Re: Life-Advancing Work of Timothy Berners-Lee
http://www.garlic.com/~lynn/2000.html#81 Ux's good points.
http://www.garlic.com/~lynn/2000.html#83 Ux's good points.
http://www.garlic.com/~lynn/2000f.html#58 360 Architecture, Multics, ... was (Re: X86 ultimate CISC? No.)
http://www.garlic.com/~lynn/2001d.html#71 Pentium 4 Prefetch engine?
http://www.garlic.com/~lynn/2001k.html#14 HP-UX will not be ported to Alpha (no surprise)exit
http://www.garlic.com/~lynn/2001l.html#4 mainframe question
http://www.garlic.com/~lynn/2001n.html#90 Buffer overflow
http://www.garlic.com/~lynn/2002.html#1 The demise of compaq
http://www.garlic.com/~lynn/2002.html#24 Buffer overflow
http://www.garlic.com/~lynn/2002f.html#37 Playing Cards was Re: looking for information on the IBM 7090
http://www.garlic.com/~lynn/2002h.html#73 Where did text file line ending characters begin?
http://www.garlic.com/~lynn/2002n.html#41 Home mainframes
http://www.garlic.com/~lynn/2002o.html#0 Home mainframes
http://www.garlic.com/~lynn/2002o.html#14 Home mainframes
http://www.garlic.com/~lynn/2002p.html#54 Newbie: Two quesions about mainframes
http://www.garlic.com/~lynn/2003e.html#11 PDP10 and RISC
http://www.garlic.com/~lynn/2003h.html#56 The figures of merit that make mainframes worth the price
http://www.garlic.com/~lynn/2003j.html#46 Fast TCP
http://www.garlic.com/~lynn/2003n.html#46 What makes a mainframe a mainframe?
http://www.garlic.com/~lynn/2004.html#40 AMD/Linux vs Intel/Microsoft
http://www.garlic.com/~lynn/2004.html#41 AMD/Linux vs Intel/Microsoft
http://www.garlic.com/~lynn/2004.html#43 [Fwd: Re: Mainframe not a good architecture for interactive w
http://www.garlic.com/~lynn/2004.html#47 Mainframe not a good architecture for interactive workloads

--
Anne & Lynn Wheeler | http://www.garlic.com/~lynn/
Internet trivia 20th anv http://www.garlic.com/~lynn/rfcietff.htm
Jul 17 '05 #198
This is all remarkably fascinating!

Just one question:

What does it have to do with Java?

Thanks,
Greg

Edward Green wrote:
Uncle Al <Un******@hate. spam.net> wrote in message news:<40******* ********@hate.s pam.net>...
mitch wrote:
Uncle Al wrote:

Local atmospheric pressure is 7-10 torr. Earth sea level is 760
torr. How many planes do you know that cruise at 100,000 feet absent
any oxygen at all? Martian aircraft are a bad dream.

Hmm. Then the test of a Mars glider plane back in August of 2001 was
just a bad dream? ;-) Work has begun on a propellered version of the
glider cited below. Enjoy.

AMES COMPLETES SUCCESSFUL TEST OF MARS AIRPLANE PROTOTYPE


The empirical fact is that lowland Martian air pressure is 7-10 torr.
The is equivalent to 120,000-100,000 feet terrestrial altitude.

Read the article: the glider was released at 101,000 feet.

If
the silly thing will be diddling at even 1000 ft altitude Martian, the
air will be thinner.

Martian gravity is less, hence the pressure relative pressure
difference between 0 and 1000 feet will be less than that on Earth:
less than 5%.

"Ye canna break the laws of physics."

The Concorde flew at 60,000 feet and gulped air like a madman. The
U-2 did 75,000 feet, breathed air, and it was a bitch to fly. The
SR-71 Blackbird could barely do 100,000 feet while at Mach 3+ with its
cockpit windshield simmering at 620 F. It drank 8000 gallons/hr of
fuel. It breathed 6 million ft^3 of air/minute.

Al ... organizational bashing is fun and rewarding, but must be taken
with up with taste. Sending flawed subtly mirrors into space while
good ones sit in storage, and launching on colder and colder days
until disaster strikes: these are both errors of judgement well within
the capability of the political machine. But making fundamental
science errors in the preliminary design stages, and saying something
(whose gross design parameters are available to anybody willing to
take the time to look) can work when it not only can't but, according
to you, grossly can't?

That is down at the 5 sigma tail of Bayesian probability, and you know
it.

Of your three examples, only the U-2 is remotely relevant, since it
was essentially a powered glider; and it did not gulp air and fuel,
which you seem fixated on. Who the hell said anything about
air-breathing flight, anyway?

The basic principles and parameters are well known: you have your
Martian atmosphere, you have your structural requirements, you have
your power requirements, you have your known solar cell efficiency.
The engineering either comes together or it doesn't. Have you run the
figures? The issue is whether you can build a large enough and light
enough airframe to move enough rarefied gas to generate sufficient
lift to sustain flight at a drag sustainable by some reasonable power
make-up from solar cells. There are people who could do this on the
back of an envelope.

No ... I haven't run the calculations either. But knowing that high
altitude long dwell time solar powered sail planes have been seriously
considered on Earth, that flight costs less power with slower flight
and larger lifting area, knowing the experience with very light weight
miniminally powered structures accumulated by the human-powered flight
school ... all this give credibility to the idea and tends to suggest
that Al is making an ill-considered shot from the hip, as usual.

And this is not to mention aerostats ... you may have noticed also how
the test glider was carried to 101,000 ft? I suppose that was a
physical impossibility too?

Jul 17 '05 #199

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