The Shell Mex & B. P. Story
An autobiographical account of my time working on LEO computers
by Chris Reynolds
Why
Shell Mex and BP?
“How much did you say??!!!”
I was working in
my office at the Cooper Technical Bureau in Berkhamsted in 1965, and Chantal,
the young librarian, had just given in her notice and was going to work at the
Shell Mex and BP Computer Centre in Berkhamsted at over £1000 a year. She had
the equivalent of 3 A levels and I had a Ph.D. and she was going to earn more
than I did, which was about £950 a year.
I was furious. I
was employed as an Information Scientist and my job involved ensuring that the
top management of this international organization was aware of any research and
development news from the overseas branches. I had suggested I should learn
about the possibility of using computers to help and had just been told I was
being paid too much to transfer to the computer department. When I got home I
picked up the local paper and saw an advert “Wanted punch girls to systems
analysts.”
At the interview
I explained that I wanted to learn about computers in order to use them to help
management, and as I had no experience they offered me a job starting as a
programmer at £1000 a year, and if I was any good I would transfer to systems
analysis after six months.
My First Week working with computers
At the beginning
of December 1965 I turned up at the computer centre at Hemel Hempstead and the
first hour was pretty routine – getting the paperwork sorted out with the
Personel Department. There was then a pause while they tried to find my new
boss - an apology – there was a problem
and that would have to wait and I was asked to help out on the clerical floor.
The problem was
at the weekend the company had updated its main customer contract files. The
first computer job every day was to take the delivery notes relating to goods
supplied the previous day and process them on the computer to generate
invoices. When the work started on
Monday morning the computer started rejecting many of the sales because the
customer to whom the goods had been sold did not exist.
What had
happened was over the weekend Shell Mex and BP had reorganized its sales teams
and the whole customer contracts file had been printed out on about a million
records cards. To do this time had been purchased on almost every Leo III
computer in the UK and my boss was one of the people who had been working over
the weekend to supervise the printing process. The problem was that some
customer records (I think about 10,000) had somehow got lost and I was just one
of the people roped in to search through the old customer record cards for the
missing customers. A new customer record form was created with the old customer
details on and once this had been added to the customer contracts magnetic tape
the sale could be processed.
In fact the
computer program had worked “correctly.” The change in way the company worked
meant that salesmen were organized by area rather than by product, and each
salesman had submitted forms relating to all the customers that he was
responsible for. The problem was that companies like British Rail had not been
considered. All orders were placed by their offices in Swindon or Derby – but
deliveries could be made to any railway station in the country. Large numbers
of salesmen had not realized (or had not been told) that under the new
arrangement they need to treat all railway stations that accepted deliveries as
potential customers. At the systems level another mistake was that no checks
had been made to check that there was a new salesman reference for all
customers who had been recently been accepting regular deliveries.
There a long term effect of this crisis.
The new cards needed a National Grid Number in anticipation of possible vehicle
routing at later date, but this information was not on the old record
card. To get the new customer ecord
accepted a number had to be supplied. This meant that when, about a year later,
a vehicle routing program was written it was found that a considerable number
of grid reference were wrong by a hundred miles or more!
Learning to Program in CLEO
Once the crisis
had been resolved a small group of new intake, mainly school leavers, were
given an introduction to the computer – starting with a visit to the large
air-condition computer room (normally off-bounds) which contained two Leo III
computers – and impressive rows of large magnetic tape decks, printers and
paper tape readers. My group were the first new intake to be taught CLEO (Clear
Language for Expressing Orders), a high level language designed for commercial
applications which combined features of early COBOL and Algol. Previously
virtually all programming in the company had been written in Intercode, a
symbolic assembly language which was only one step up from machine code.
Our task was to
write a program which recorded the results of cricket matches and calculated
averages. The program was written on coding sheets which were then sent to the
data preparation department to be punched onto paper tape, and there were
delays of several hours before you got back a computer listing. However the
course went well and by the beginning of January 1966 we were all allocated
work to do on the programming floor.
The Retail Market Reporting Suite
I was one of a
number of new programmers who were asked to write a suite of programs designed
to produce monthly reports on sales to garages up and down the country. My job
was to write the program which created and updated the master customer sales
file that held the sales records and targets while the others were allocated to
use the master sales file to produce monthly and annual sales reports.
The master sales
file consisted of 5 reels of magnetic tape (one for each sales region). It was
to be updated once a month and the inputs were the Dealer Site Record
(mentioned by Bill Foster in the Spring 2018 Leo Computers Society Newsletter)
and a tape containing the relevant monthly sales. The output was a new copy of
the master file again on 5 reels of magnetic tape. For each dealer there was a
header record, with information from the Dealer site record, at least one record
for sales of petrol and diesel (separate records where the dealer sold more
than on brand of petrol) and records for lubricating oils, etc. For each product sold there was a sales
target, but the master update program was not directly concerned with the
setting of these targets.
As soon as I got
the systems specification I spotted a problem. The specification clearly stated
what should happen – but my first days with the company were clear evidence
that things didn’t always go as planned. “What happens if we get a sales record
for a customer which does not have a Dealer Site Record?” I asked. It can’t
happen I was told because there is a record of every garage in the country
whether they are customer or not. I wasn’t happy about this so I added a series
of traps to catch problems which I was told couldn’t happen. As it turned out I
was right. When the first test run with
live data was carried out my program generated about 30,000 sets of customer
sales and also spewed out perhaps 500 reports of sales to garages which “did
not exist!” It was a case of the messy
real world doing something the systems analyst had not anticipated. For example
a small car repair shop, which didn’t normally sell our products, had a
customer in for servicing who wanted the engine filled with one of our oils.
What happened. The repair shop phoned our nearest depot and places an order –
and to allow the order to be billed the depot allocates a customer number. The
local salesman, who is responsible for keeping the Dealer Site Record up to
date, was not involved so the relevant magnetic tape was not updated.
Developing a Support Package
After a couple
of months I was finding the process of writing and testing programs boring –
and one of the problems was the delay in completing a coding sheet and getting
the results back from the computer. I needed something to keep my mind busy and
because I was interested in making sure programs worked correctly I started
work on a diagnostic support package which could be used to interrogate the master
dealer sales file and to report on what changed. This not only proved to be a
valuable testing tools but also gave me the opportunity to try out areas of the
CLEO programming language which I had not used before. In addition I was quite
happy to help other programmers track down problems with their programs and I
soon became an unofficial expect in using the CLEO language.
The First Live Run of the Supporting Suite
The first live
run of the Retail Marketing Suite was a major exercise. Targets were set month
by month and were based on the previous month by month sales. The first full
run with live data was in March or April 1966 and meant running the program
month by month for the whole of 1965, then running a year end program (not my
responsibility) to generate the seasonally adjusted targets for 1966. The next
stage was to run the program for January to March 1966 and then run a number of
different programs that printed out salesmen copies of the sales for their
customers, and higher level summary reports for more senior management. Much of this would be dominated by the time
loading, reading and writing magnetic tapes, and finally printing large numbers
of reports. The complete test run was planned to take up to 4 days of Leo 326
time. It was expected that some problems would emerge and once corrected the
first operational run would repeat the process a month later.
The programming
team waited, wondering how many faults the sales staff would find and the
process revealed two faults in my program. If a garage brought one particular
brand of lubricating oil the amount recorded as being purchased was obviously
too high – and the error was due to an incorrect use of “OR” in a single “IF”
statement. In addition Head Office pointed out that the total sales relating to
sales under one heading were 17% above what the actual sales were known to be.
This turn out to be a fault which affected the minority of garages which sold
more than on brand of motor fuel. Neither of these faults could have been
detected using the very limited trial data that had been supplied and were
trivially simple to correct, so the following month the suite went live.
However, because
I was very interested in reducing program errors I was very worried by the
result. The first run had sent out reports to a large number of sales staff in
the organization, who had been asked to check the documents’ accuracy. These
two errors should both have generated a large number of reports – but each was
only reported once. It was clear to me that at least 95% of the sales staff
involved has accepted as correct printouts which contained errors.
Developing a Self-documenting Program
My next major task
addressed a long standing problem connected with reporting sales. The original
sales program was designed in such a way that if goods were sold someone was
expected to pay for them. While most sales were a routine matter of supplying
the goods and sending out an invoice there were some special cases. For
accounting purposes these extra sales could even include a depot selling off
redundant equipment for cash. Each day details of all the sales would be added
to tapes which contained details of all the sales for the current month. Each
department then commissioned the computer department to produce summary sales
reports – and this include the reporting program I had been working on.
So what was the
catch. The example which highlighted the need for change involved central
heating oil. The industrial market had an arrangement which arranged a tax-free
perk for their customer’s senior managers of say 30% (I don’t remember the
actual sum) off the cost of central heating fuel. This was agreed by the
domestic market that supplied central heating fuel and everything seemed to
work well. The monthly reports for the industrial market covered all sales
organized by their salesmen and showed the 30% discount. The domestic market
reports were based on all sales of domestic products and also showed the 30%
discount. OK there was double reporting but no-one was too worried until it was
found that the two discount totals were not the same – and the customers were
actually getting a double discount of 60%.
It turned out that there were other cases where a salesman sold products
normally sold by a different division the sales were either double reported or never
reported at all.
A systems
analyst came to have a discussion with me before drawing up the specification
and I warned of very severe difficulties in testing if the program was written
in the “normal way” (which would be now considered bad programming by today’s
programmers who have access to far more sophisticated tool and program
libraries). The resulting program broke completely new ground within the
company. The result was a table-driven program, written in Intercode, which
started by testing that the tables were lpgically consistent. If no problems
were found there was an option use the tables to generate and print out the
program’s own specification as it had
been implemented. The logic testing and print section of the code was then
“deleted” using machine code (to save computer memory), the current sales
tape(s) were read and each sale was allocated with a company division for
reporting purposes. This approach meant that once the process was started any
system updates could be made by writing amendments of the current computer
produced specification which could then be directly compared with the revised
specification generated by the updated version of the program.
[One point needs
clarification here. Because the Leo326 computers were batch machines using
magnetic tape as storage the tables had to be set up as constants in the
program. On a more modern system with direct access storage the tables would
have been separate data base files maintained using data base software.]
Some other Problems
The above
examples all describe programming problems where I was directly involved – but
I was very interested in any matters that could lead to programs that did not
work as the sales force expected.
Some of the
problems were due to the fact that senior managers often had little
understanding of how computers worked. At one stage a request came down that
for certain reports the infinity symbol should be used where appropriate. When
it was pointed out that the printers did not have an infinity sign the request
came back that we should use an “8” on its side – as clearly the requester had
no idea how the printers worked.
Ignorance at
this level worked in both directions. One day a salesman who had health
problems came to Hemel Hempstead to see if he might be retrained as a programmer.
At lunch he was surrounded with a group of young programmers (probably all
recruited directly after leaving school) asking him questions about his job as
a salesman – and it was very clear that most programmers had very little idea
of what salesmen in a large organization did. (I was lucky as I was brought up
“under the counter” in a retail shop, and remember the salesmen coming into the
shop trying to get my father to stock the products they were selling.)
There were other
incidents where things went wrong because the system specification failed to
allow for some real world complication. For instance a friend of mine was a
jobbing builder and he complained that for several years Shell Mex and B P had
sent a monthly statement saying they owe him £26 – but they refused to give him
the money. The situation arose because in his work he used liquid propane gas,
which was supplied in cylinders. He
started with a regular contract and normally collected new cylinders of gas
from the depot. However when he was working as a subcontractor on a major
contract it might be more convenient to get a full cylinder from the main
contractor’s store and pay cash. After a
year of so he decided to end his contract with Shell Mex & BP and returned
more empty cylinders than he had brought from the depot. The computer programs
had not anticipated any customer returning more cylinders than they had
purchased and the £26 was excess deposit money. As there was no mechanism to
pay the money the computer could have ended up sending out “We owe you …” monthly
statements indefinitely, infuriating the former customer who wanted his money
back.
By this time I
was developing a deep understanding of why computer systems might fail to
produce a satisfactory service, and these thoughts were very relevant to what
happened later.
Time for a Move to Systems?
When I joined
Shell Mex & BP the general plan was that I should move to systems once I
had learnt how to program. Time was slipping by and I was still programming. I
made it clear that I would like to know about the move but nothing happened –
and I am sure the reason was that the standard of my programming was such the
programming department didn’t want to lose me.
I let them know that if I was not moved I would be looking for a new
employer and at the end of 1966 I moved to systems
The Sales Contracts Program
My new task
related to the move to a new generation of computers at Hemel Hempstead. The
biggest and most complex program running on the LEO 326s was the one that used
sales contract information to price the goods that had been delivered. My job
was to look at the current system and identify problem areas so that work could
start on the move once it was known which new generation computer had been
chosen. The most significant change was that the customer master file would be
held on direct access storage, rather than magnetic tape and it might also be
possible for the appropriate sales staff to access it via computer terminals.
It was also extremely likely that the new computer would not be able to run programs
written in Intercode – which suggested that significant reprogramming would be
needed.
My investigation
involved looking in detail in four areas relating to the current system. These
were the program code itself, the associated systems documentation, the
clerical handbook and random samples of actual customer contracts as held on
the existing system.
The existing
program was entirely written in Intercode and was so big that the LEO operating
system had been modified to allow the program to expand. It had already reached
the stage where further amendments were difficult because of the lack of space.
The program was a tangled network of conditional clauses and was poorly
commented, so it was virtually impossible to find out how a particular contract
was processed by following through the code step by step. Despite the pressure
on the program size I found at least two areas of code which could never be
executed. This highlighted a problem. When code had been added to a program to
service a special contract or sales promotion there was no simple way of
removing the code when it was no longer needed. Another problem related to
pricing tables, etc., which were coded into the program but which, if direct
access storage was available would be better held a file in the new computer’s
data base.
The systems
documentation turned out not to be up to date and its limitations were not
investigated in detail. However it was clear that it would be difficult from
the tangled code and the poor documentation to simply rewrite the application
in a different programming language.
The clerical
handbook was full of special codes to identify different contract types, and I
gathered it took months for a new clerk to become proficient. Because of the
problems of tracing pathways through the program’s tangled code it was hard to
verify that the handbook accurately reflected what the program did.
The existing
customer records consisted of a fixed section containing the address and
various codes and a variable length table which contained the contract
information as coded. For instance special allowance code “29” might refer to
the pricing of deliveries of fuel oil to a power station by coastal tanker. The
customer contract records were printed out on about a million cards and when a
request for a contract change came through the clerk would mark the change on
the existing car and prepare an update form for the computer. When the new card
came back from the computer it was checked against the old annotated card – and
if correct the old card was discarded. To get a “random” sample of customer
contract records I simply collected the old cards – as each discarded card
represented a customer who was actively buying and whose contract had changed –
so I could compare the before and after contract. I would then use the clerical
handbook to relate the change to the variables used in the program. Where there
was any ambiguity I would discuss the contract with the clerk responsible.
Back to First principles
Analyzing the
problem was one thing – and coming up with a possible solution was something
different. The computing scene was changing very fast. I now believe that
no-one had successfully moved such a large and complicated commercial program,
written in assembler code from a magnetic tape based batch system to a computer
with significant direct access storage and where programs would normally be
written in a high level language.
The problem of
moving from a magnetic tape system to a direct access system was conceptually
reasonably straight forward, as the data records could be identical – and it
was the mode of accessing them that changed. The problem of interfacing a user,
rather than a computer professional, was an unexplored field.
As far as using
some terminals was concerned there were no available guidelines in 1967. From
the beginning of computing revolution teletypes had been used as operator
terminals, and during the 1960s there had been some work on military and other
real time control systems (often veiled in secrecy) which involved specially
designed keyboards or control panels. There was no published guidelines and
very few of the papers being published in the Computer Journal even
touched the subject of how to interface humans with computers. For instance in
1966 the paper A Simple Program for use in the “Conversational Mode” described a
test package that suggested that interacting via terminals might be useful. The
following year Maurice Wilkes of Cambridge University published a paper called The design of multiple access computer
systems which was really concerned with the software and hardware support
problems. In 1969 there was a paper describing a system which allowed
programmers to amend and compile programs from terminals – but the resulting
compilation listings would be printed offline.
The first paper
in the Computer Journal to describe the use of computer terminals in a
commercial context described an aid to inputting and correcting data was
published in 1969. This was the same year that the first commercial “glass
teletypes” became available – providing a scrolling text screen typically 80
characters wide and about 25 lines high. By 1970 everyone started showing an
interest. Xerox Parc (whose research to the invention of the computer mouse and
windows software) was founded in 1970, as was HUSAT (Human Science and Advanced
Technology Centre) in the UK. The first big international Conference on man-computer
interaction was held at Teddington the same year. The first significant
book on the subject, James Martin’s Design of Man-Computer Dialogues was
not published until 1973 and was clearly concerned with the design of forms to
help people input data to predefined computer programs.
So it is obvious
that in thinking about how to interface sales staff with sales contracts on the
proposed new system I had to go back to first principals as there was no
significant earlier work for me to follow. The fact that I had spent virtually
all my life in the pre-computer age, had learnt about constructing and using
mathematical models doing a Ph.D. in theoretical organic chemistry, and worked
for several years in a complex manual management information system clearly
influenced how I looked at the task. The reason I was first attracted to
computer was contact with the ideas of Vannevar Bush in his 1946 article As we
may think (although I don’t think I read the original paper till a
couple of years later). Vannevar had written how technology was advancing and
introduced the idea of “memex” - which we might now see as a powerful computer
where people pooled knowledge to be held in a vast encyclopedia of knowledge –
in effect predicting something like today’s Wikipedia. My year spent
programming had taught me a lot about why computer systems failed and the
limitation in the way programs were designed and written. The fact that I had
also designed and implemented a self-documenting table based program was also
relevant.
What should the new system do?
At the time my
first brief was to survey the existing system, and identify possible problem
areas – and I didn’t specifically set out with a preferred solution. I didn’t
record my ideas step by step and so the following is, in part, a reconstruction
of how my ideas developed, with the advantage of hindsight based on the factors
Because of my
experience in working in a management information system dealing with matters
which could, in the long term, affect the company’s profitability, I took a
global view in which the sales contracts system was an essential part of the
company’s activities. The market place was part of the complex real world where
things were always changing and so the contracts system had to be able to
change . Nearly all of the problems I had seen with the existing computer
systems were due either to misunderstandings or errors in the initial definition
of requirements, or later modifications due to changes in what was required.
Any solution must reduce such problems – and must also make them far easier to
spot if mistakes are made.
Zooming in – the
job of the sales staff is to negotiate contracts and make sales in a complex
market where things are always happening in ways that are difficult to predict.
Before computers there were clerical staff who had, in precise detail,
accurately priced the goods sold. This worked because the sales staff, working
in a complex real world, used the same contracts language as the clerical
staff, and if there was a problem the clerical staff could always explain to
the sale staff how any particular contract had been worked out. In my eyes the
problem with the existing computer system was that the language used to
describe contracts by the sales staff was a thousand miles away from the
instruction language used by the computer. As a result, errors were easy to
make and hard to detect, changes in the complex real world requirements were
hard to make and time consuming, and the sales staff had very little
understanding of how the computer program worked. If the resulting prices
looked reasonable they were likely to be assumed to be correct. One possible
solution was surely to produce a contracts program which understood the sales
staff’s contract language, and which, if asked, could show them step by step
how the calculations were carried out. (if this seems an impossible dream,
remember that this was 1967 and there was no one to tell me I was “attempting
the impossible” …)
Zooming in
further there was the problem of the terminal. A teletype would print on a
continuous roll of paper and any communications from the computer would appear
line by line and scroll up and the drop down at the back. No more than perhaps
a dozen lines would be visible at any one time so communications would need to
be brief. (Later I also started considering the capacity of the human brain’s
short term memory – but my experience in manual information systems would have
suggested that any such human-computer communication system should have a
comparatively narrow bandwidth.)
Zooming in still
further I had to remember that while the new computer was promised to be faster
and have more memory the existing system had quickly run out of spare capacity.
I had no figures to work with so it would be sensible to start with the idea
that the new program should be no bigger or slower than the existing LEO 326
program, and the individual customer records should be no bigger.
A Possible Solution Emerges
One of my tasks
involved sampling customer contract records – unscrambling all the coding – and
rewriting them in a more easy to understand form. All contract statements
referred to a specific customer and a specific start date and my notes would
have looked something like this:
·
Product Type - Petrol; Standard
contract – Small Garage
·
Product – Antifreeze; Promotion
– Summer purchase; Discount 25%
·
Product – Fuel Oil; Delivery –
Coastal Tanker; Quantity >= 10,000 tons; Discount 3.7 %
I would then
discuss my analysis with the sales clerk responsible for that customer contract
to see if my analysis was correct. The reaction I got was “That’s much easier
to understand than the coded forms we currently have to fill in.” I decided to
look at what this would entail if each line of every contract was replaced by
tagged fields – using data compression techniques to save space. The effect was
surprising – the average length of a customer record would actually get smaller
compared with the existing Leo-based system and it should not be too difficult
to write a program to reformat the existing customer master file.
In addition all
the standard contracts and pricing tables could be held in exactly the same
format. This meant that all contract terms could be represented in the same
way. The pricing program could now be considered as a very large indexed table
containing over a million contract lines. When a sale was made the program
would extract the lines that matched the customer, the product, the date, the
quantity, and any other relevant variables and produce a tailored
“mini-program” individually tailored to that particular sale. This mini-program
would then be processed by an interpreter program to generate the price.
This
table-driven approach had many advantages. The mini-programs could be displayed
using the sales staff’s own language and would almost certainly be less than
the dozen lines. So the relevant contract terms could easily be printed on a
teletype, allowing the system to tell the sales staff the contract rules used
to calculate any price on request. As a
result a draft proposal (which has not survived) was written suggesting the use
of tagged field in this way.
What happened next
I prepared a
short report on how my ideas might be implemented as a new sales contracts
program and was asked to report back on the advantages of the approach. I was
then told that the idea was really research and the new program would be
specified and written in the same general way as the existing one, only using a
high level language instead of a symbolic assembly language like Intercode. I
was to go back to the drawing board and think again. As far as I was concerned
I had come up with an interesting proposal which was not acceptable and that was
that. By this time there were other systems analysts working alongside me, and
one of them, Johnny Johnson I think his name was, was very interested in my
ideas and I understand that some aspects of my suggestions were incorporated in
the new system under the name of “Variants.”
At about the
same time that my proposals were rejected in their original form a contract was
signed and the new computer system was to be provided by Univac. The bid by
English Electric Leo, who provided the Leo 326 computers, was rejected and the
company had know that I had been restless about the delay in being moved from
programming to systems analysis. Within weeks I got an offer to join them – and
my reminiscences will continue in the next episode.
A Retrospective Assessment of the Contracts Program
In retrospect I had three problems in
trying to “sell” my proposals to my employer.
The first
related to the fact that the whole area was breaking on new ground (See Back
to First Principles, above). This meant that there was no agreed vocabulary
for describing the novel ideas. It is clear that if I had come up with similar
proposals fifteen or twenty years later I could have sold my idea as an
Interactive Object Oriented Expert System with a Human-friendly interface
working on a Structured Knowledge Base of something over a million Production
Rules – a description which used most of the key buzz words going around the
industry at the time.
Another problem
was that by the 1960s “everyone knew” that computers were mysterious black
boxes controlled by very clever people and ordinary mortals, such as salesmen,
could never understand how they worked. The argument that the way to overcome
the problem was to design flexible systems which understood their human users
was almost universally rejected as “impossible”.
Perhaps the
biggest problem can best be described in terms of Complexity Theory (a
discipline in its infancy in the 1960s) and formal Computer Science theory
(about which I knew virtually nothing at the time). My approach had to consider a system which
sales staff working in a complex market place interacted with a computer system
which helped them to use contracts to price sales. The existing Leo -based
contracts program worked on the idea that the was a large pile of sales
contracts and the program, and its data files should handle all the contracts
rules in the pile of documents. My boss had clearly been expecting me to come
up with a similar solution.
The difference
between the two approaches is very significant because it highlights the
difference between a complex system where unpredictable change may be expected,
and a complicated but predictable system. In my suggestion contracts, pricing
tables, etc., are reduced to a series of simple rules such as the three
examples given earlier. These are held in a large structured data base of
rules, and for each transactions a small number of relevant rules are selected
to produce what is, in effect a simple individually tailored program for the
particular transaction and simple enough for the sales staff to understand. If
a new requirement comes along due to changes in the market new rules can be
dynamically added by the sales staff without there being any chance of
disrupting the existing arrangements.
The conventional
programming approach effectively tried to combine all the rules into one vast pre-defined
algorithm – which ended up producing a very complicated network of “IF … ELSE
…” statements. The problem of specifying such an algorithm an expensive and
complicated task with many opportunities for errors and misunderstandings. When
real world changes mean that different types of contracts are needed, modifying
the algorithm is neither a trivial or a quick task.
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