I had been hired by this Australian national office of a multi-national mini-computer manufacturer, to setup the internal data processing systems.
Spare-Parts Inventory Tracking
A major issue was their spare-parts management which was getting "slammed" by the auditors for enormous write-offs/adjustments after every annual stock-take.
The spare-parts system was a national, warehouse-centric system using the US head-office software. All transactions came in on "movement tickets" for keying. These covered engineer "consumption" in repair of client machines, inter-office transfers (of both good and faulty parts) and repairs (faulty in, good repaired out). The potential for transcription and keying errors was high. There was the issue of "handedness" where left-hand and right-hand variants had similar part numbers. But from a financial point-of-view, variants of circuit boards was more critical - a more expensive board with more memory or a faster processor might vary in part number only by a suffix.
Customer "Loans" Issue
But it was "home-brew" software by one branch office for tracking their own spare parts use, that finally brought home the real culprit. On service calls, engineers took out some good parts in anticipation of what might be wrong, then on site replaced the faulty customer part with a good part. If they were identical part numbers then all good. But if an identical good part was not available, the engineer would put in a good part of a higher rating (eg. more memory), so the faulty part brought in (for repair) had a different part number. In theory, when the customer's part was repaired, it was supposed to be taken back, installed and the original good part brought back. This "home-brew" local system kept track of these "loans" and reminded the engineers. A similar issue arose with sales reps. "lending" customers a higher rated board to trial before buying. Again, the national system did not cater for this concept of "loaning" parts to customers.
On-line Data Entry Client with Transaction Logging
My solution had a couple of phases. Firstly, the new system would be multi-user on-line data entry at each point where the original movement tickets would have been written. On-line data entry then provided immediate data validation of part numbers. A new transaction type of "Loan" was then introduced - this was expanded from the loan to customer", to recording of ALL good parts that a service engineer took on his service call and recording everything he brought back, good, faulty or alternate part number. Initially, inter-office movements still needed the manually prepared movement-ticket from the non-automated office.
The second phase was implementation of this system in all the branch offices. This is especially important in a country as geographically dispersed as Australia. In the states of Queensland and Western Australia, engineers go out on week-long circuits of preventive maintenance of remote sites and so have to take a large stock of spare parts with them.
Transaction Server
Both phases had issues that led to a single solution. Real-time data entry into a system that did not have a robust database with transaction level data integrity, had potential of data loss with no fall-back paper work for data re-entry. At this time, the INTERNET was not yet available, and leased-line networking to all the branch offices was not economical.
My solution was a custom developed transaction processing system, which we would now call "client-server". Multiple data-entry front-ends accessed the database read-only for data validation, and compiled a transaction record that was sent (by inter-process communication) to a single threaded database updater process. The first step of the updater was to write the transaction records to a serial transaction log. These transaction logs were backed-up daily. In the branch offices, these transaction log files were written to mag tape and sent to head-office along with the regular parts-for-repair transfer. At head office, the transaction log files for all branches were then read (off tape) and fed into the same head-office database updater process, so that a National database was now available. For the first time, the national spare-parts planner had a reasonably up-to-date picture of the distribution of parts across all offices. At head-office, parts receipting now simply checked off the electronic parts transfer "ticket" received from the sending office. New weekly reports to each branch manager listed all parts currently out on "loan" that had to be retrieved or swapped-back.
The test of this system of processing transaction logs files, came when the National system first went live. The Melbourne (National) office had been using what would become the Branch system. When the National database was initialized with the backup after the last stock-take, we simply processed six-months worth of transaction logs to bring the National system up-to-date, without a hiccup.
International Adoption
Subsequently, this system was adopted by the European subsidiaries who were having the same issues with the US warehouse-centric system.
Integration in Service Call Management
Subsequently, this system was integrated into a Maintenance Call Centre system for dispatching engineers to service calls, recording of travel, time and parts used, which all fed into the service costs analysis system.
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