After finishing his PhD in the
database area in December 1981, Mohan joined
IBM Research in San Jose, working on projects like R*, Starburst, Exotica, and DBCache. He subsequently worked as a visiting scientist at
INRIA Rocquencourt in 1998–1999, then returned to IBM. From June 2006 until January 2009, he worked as the
IBM India Chief Scientist, based in
Bangalore. After his return to
IBM Almaden Research Center at the end of his India assignment, Mohan worked on projects relating to Storage Class Memories,
Big Data,
Hybrid Transactional/Analytical Processing (HTAP) enhancements to
IBM Db2 and
Apache Spark, and
Blockchain and
Distributed ledger technologies. He gave numerous keynotes and other talks on
NoSQL,
NewSQL, modern enhancements to classic
RDBMSs and Big Data. Since 2017, he has lectured on blockchain and distributed ledger technologies, co-organizing seminars and giving a keynote address on the topic. In August 2016, Mohan was named a visiting professor in the School of Software of China's
Tsinghua University. According to
Google Scholar, his
h-index is 68 and his
i10-index is 141. and the industry-standard (e.g.,
X/Open XA)
Presumed Abort commit protocol. His journal papers on ARIES and Presumed Abort are considered classic papers in the areas of transactions, recovery, distributed commit and locking, and are included in a collection of database papers, informally called the "Red Book", edited by ACM
Turing Award winner Prof.
Michael Stonebraker and others under a section titled
Techniques Everyone Should Know. In the introduction to that section, one of the editors of the Red Book, Peter Bailis, while discussing the ARIES paper, has said "In graduate database courses, this paper is a rite of passage. However, this material is fundamental, so it is important to understand." In the ACM SIGMOD Record series called Reminiscences on Influential Papers, with reference to the ARIES paper, Prof. Betty Salzberg of
Northeastern University has said: "The ARIES paper was important for me because it enabled me to envision the mechanisms of recovery in database systems clearly. ... Reading the ARIES paper influenced much of my subsequent research. ... Now it is almost impossible for me to imagine thinking of a database system without ARIES style recovery." Prof. Alan Fekete of
University of Sydney, as part of the abstract of a keynote talk by him in February 1993 said the following: "In the past few years, there have been several exciting advances in transaction management that seem certain to influence future commercial systems. One is the invention and publication of improved techniques for implementation of transaction management. In particular, an exciting series of papers have come from the ARIES project led by C. Mohan at IBM Almaden Research Laboratory. There are new algorithms which provide concurrency control for B-tree indices, recovery compatible with fine-grained locking, and concurrency control allowing long-running audits." Mohan has worked closely with many IBM product groups worldwide and his research results have been implemented in numerous IBM and non-IBM prototypes, and products like
IBM Db2,
MQSeries,
IBM WebSphere,
Informix,
Cloudscape,
IBM Notes,
Microsoft SQL Server and
IBM System z Parallel Sysplex. In a 2003 interview conducted by
Marianne Winslett as part of the ACM SIGMOD "Distinguished Database Profiles" series, Mohan discussed the first 20 years of his IBM career. Video and audio recordings, and the textual transcript of that interview were published. That interview provides a historical perspective on the state of the database research and products landscape then and also on Computer Science work in India. It also discusses Mohan's most important research results and how they came about. A Chinese translation of this interview's transcript is also available. Mohan worked as a technologist during his entire 38.5 years professional career at IBM and avoided becoming a manager! He has often talked about the importance of long-term technical careers with sustained focus in one area to attain excellence and to be effective in innovation. Especially in a developing country like India, during his IBM India Chief Scientist assignment as well as at other times, he has often emphasized the need for good technical people to stay technical and not be too attracted by a management career path. In a front-page story back in August 2007,
Business Standard, one of India's leading newspapers, discussed Mohan's senior most technical position at IBM and elaborated on his patenting activities. == Awards ==