How did Basia, the company that took on "LAST BOSS COBOL," rewrite 20,000 programs in Java?

https://xtech.nikkei.com/atcl/nxt/column/18/02239/102500001/

Masayoshi Ando Nikkei Crosstech

2022.10.27

　The BaySea Group, which owns Cain's, Workman, and BaySea, completed the elimination of its mainframe and the migration of its COBOL assets in May 2022. We will take a look at the entire project, which took about three years, in two installments.

The core system should not be a drag on the business.

　The BaySea Group has been gradually migrating from a mainframe-based system to cloud services and other systems for about 20 years. However, the common system for the BaySea Group, which includes some functions such as product master, ordering, and inventory management, and the core system for BaySea remained on the mainframe. In this article, these two systems will be referred to as the core systems for convenience.

　This mission-critical system was developed on a Fujitsu mainframe using the COBOL programming language. Originally, the BaySea Group started with the BaySea supermarket, and then launched new companies such as Workman and Cain's one after another. Whenever a new company was formed, additional functions were developed in COBOL for that company, and the COBOL program was extended or branched out to use the parts that could be used in common.

　The COBOL application had become bloated after about 30 years of expansion, but we knew it would be difficult to secure COBOL engineers in the future. Minoru Hirata, General Manager of the Open System Promotion Department, Solution Management Division of Basia Group Solutions, who was involved in the project to open the core system, recalls the challenges they faced before the renewal.

Minoru Hirata (left), General Manager of the Open System Promotion Department, Solution Management Division of Basia Group Solutions, and Kenji Shigeta, General Manager of Solution Management Division, who serves as an executive officer. In the background is the mainframe that was previously used.

(Photo: Nikkei Crosstech)

[Click on image to enlarge].

　Kenji Shigeta, General Manager of the Solution Management Division and Executive Officer of Beisia Group Solutions, believes that "the core IT system must not be a hindrance to the Beisia Group, where each subsidiary is launching numerous IT initiatives in rapid succession. With this in mind, the company decided to migrate its legacy mission-critical systems, eliminating mainframes and starting the migration of its COBOL assets, which were considered the "last bosses.

A huge system with 20,000 COBOL programs in operation

　The legacy migration of the core system began in February 2019. In general, legacy migration of systems built with COBOL includes rebuilds that completely renew the system and rewrites that change the programming language. Mr. Hirata confides, "At the beginning of the project, we were considering a complete renewal of the system through scratch development.

　However, the core system of the Basia Group is not as large as those of megabanks, but it is still quite large. Specifically, there were more than 20,000 COBOL programs, or about 6 million lines in terms of number of steps, about 800 screens, and about 10,000 JCL (job control language) programs used for operations.

　In addition, some of the programs did not have specifications, and it was anticipated that analyzing the entire program would be difficult. On the other hand, the mission-critical system handles processes essential to daily operations, such as order placement and inventory control, and must not be halted due to problems. Mr. Hirata and his team were looking for a way to safely migrate the legacy system in a short period of time.

　One case study that caught their attention was that of TIS. The COBOL system, which was the same size as that of the Basia Group, was rewritten in Java using TIS's "Xenlon - Shinryu Modernization Service. Moreover, the system has been operating stably since the renewal.

　Xenlon may be able to meet our needs. With this in mind, Mr. Hirata worked on a proof-of-concept (PoC) project in cooperation with TIS. The results were positive.

　The rate of automatic conversion from COBOL programs to Java programs using TIS's tools exceeded 90%, and almost 100% of the programs that handled business logic could be converted. Although there were some COBOL programs that had to be reworked, "the high conversion rate was a relief," said Mr. Hirata. The project was thus carried out jointly with TIS.

　For the hardware after the migration, it was decided to use an on-premise Fujitsu Linux server. The company considered using a cloud service, but decided against it because of the 88 systems connected to the core system and the approximately 1,200 data files. They decided that it would be risky to suddenly migrate a huge system to the cloud, even when considering maintenance and operation," he said.

Although some additional development was required, the conversion to Java proceeded smoothly.

　After the PoC was completed, requirements definition proceeded from February to April 2019. They conducted a detailed analysis of the system, selected COBOL programs to be converted to Java, and worked out performance requirements.

　The mission-critical system had been expanded over and over, and there were many programs mixed in that were rarely used, such as programs used only when launching a new company, and programs that were not currently in use. When these programs were identified, it was found that about half of them did not need to be migrated.

　Full-scale program migration began in May 2019. A total of 90 engineers from both Basia Group and TIS converted the COBOL programs to Java programs. Some performance issues were encountered with some of the programs, but they were overcome by tuning the programs and making modifications such as caching loops with a large number of times.

　In late 2019, when the conversion work was nearing its end, the team encountered an unexpected situation. After conducting tests, it was discovered that additional development was necessary.

　The COBOL program had been narrowed down to about half of the programs that had been used in the past, but there were programs that were needed to execute the process even though they had not been used in the past. Director Hirata recalls, "There were programs that were hidden in the shadows of operations, beyond the scope of our past knowledge.

　Despite the bumps caused by additional development, the company was able to convert most of the COBOL programs needed to run the system to Java programs by the end of 2019. However, the project was to hit a further plateau. The year 2020, when the testing phase began, was a difficult time and the peak of development," said Director Hirata.