IBM IMS
activeby IBM · since 1968 · also known as IMS, Information Management System, IMS DB, IMS/TM
IBM's 1960s hierarchical database and transaction manager, still running bank and airline cores on z/OS.
Overview
IMS (Information Management System) was built by IBM with Rockwell and Caterpillar for the Apollo programme and became the first commercial hierarchical database. Data is stored as trees of segments navigated through DL/I calls, and IMS Transaction Manager runs extremely high volumes of short transactions on z/OS with Parallel Sysplex data sharing. A large share of the world's banks, insurers and airlines still run core workloads on it, now reachable through SQL, JDBC, REST and Java alongside COBOL and PL/I. IMS 15.6 became generally available in June 2025. It is about as stable as software gets, but it only runs on IBM Z and its skills pool is shrinking.
Strengths & trade-offs
Strengths
- +Extremely high, predictable transaction throughput on IBM Z
- +Decades of production use for core banking, insurance and reservations
- +Parallel Sysplex data sharing for continuous availability
- +Modern access via SQL, JDBC and REST without rewriting COBOL
Trade-offs
- −Runs only on IBM mainframes
- −Hierarchical model is rigid; schema changes need careful planning
- −Scarce and ageing skills base
- −Expensive platform economics
Great for
- +Core banking ledgers and payment processing
- +Insurance policy administration
- +Airline and travel reservation back ends
- +Exposing legacy IMS transactions as APIs
Think twice for
- −Any non-mainframe environment
- −Ad hoc analytics
- −New application development
Capabilities
Native or official first-party support · 7 of 25 tracked
Scale & consistency
- Comfortable data size
- Large · ≤ 1 PB
- Horizontal scaling
- Addon
- Multi-region
- Read replicas
- Transactions
- Full ACID
- Consistency
- Strong
- Schema
- Strict
- Architecture
- Shared storage, Client server
- Query languages
- DL/I, SQL (IMS Open Database)
Parallel Sysplex data sharing spreads one database across many z/OS images; remote site recovery for DR.
Deployment
Ecosystem
Alternatives to IBM IMS
IBM's enterprise RDBMS for Linux, UNIX, Windows and z/OS, with BLU columnar and pureScale clustering.
ibm-ims vs ibm-db2 →CODASYL network-model mainframe database, now Broadcom's, still running decades-old COBOL systems.
ibm-ims vs idms →Inverted-list, multi-value mainframe database paired with Natural, run as a standalone Software AG business.
ibm-ims vs adabas →The enterprise heavyweight: RAC, Data Guard and a converged engine for SQL, JSON, graph and vectors.
ibm-ims vs oracle-database →FIS's high-throughput M (MUMPS) database and compiler, behind major core-banking systems.
ibm-ims vs gt-m →Open-source MUMPS/M hierarchical key-value database forked from GT.M, with SQL via Octo.
ibm-ims vs yottadb →IBM IMS FAQ
What is IBM IMS?
IBM IMS is a hierarchical database by IBM, first released in 1968. IMS (Information Management System) was built by IBM with Rockwell and Caterpillar for the Apollo programme and became the first commercial hierarchical database. Data is stored as trees of segments navigated through DL/I calls, and IMS Transaction Manager runs extremely high volumes of short transactions on z/OS with Parallel Sysplex data sharing. A large share of the world's banks, insurers and airlines still run core workloads on it, now reachable through SQL, JDBC, REST and Java alongside COBOL and PL/I. IMS 15.6 became generally available in June 2025. It is about as stable as software gets, but it only runs on IBM Z and its skills pool is shrinking.
Is IBM IMS open source?
No. IBM IMS is proprietary, closed-source software.
Does IBM IMS support ACID transactions?
Yes. IBM IMS supports full ACID transactions, with strong consistency.
Does IBM IMS scale horizontally?
IBM IMS scales horizontally through an official extension, proxy or edition rather than in the core engine. It is comfortable at large scale (≤ 1 PB). It supports cross-region read replicas.
How can I run IBM IMS?
You can self-host it.
What is IBM IMS best for?
IBM IMS is a strong fit for core banking ledgers and payment processing; insurance policy administration; and airline and travel reservation back ends. Think twice for any non-mainframe environment.
What are the best alternatives to IBM IMS?
Common alternatives to IBM IMS include IBM Db2, IDMS, Software AG Adabas, Oracle Database and GT.M. The right choice depends on your workload, scale and hosting; WhichDB's smart match ranks them against your requirements.
How popular is IBM IMS?
IBM IMS ranks #338 of 844 databases on the WhichDB Score (7.7/100), and #6 among hierarchical databases. The score combines public adoption signals such as package downloads, GitHub activity, job posts and developer discussion.