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IDMS vs Model 204

IDMS: CODASYL network-model mainframe database, now Broadcom's, still running decades-old COBOL systems. Model 204: Rocket Software's mainframe inverted-list DBMS, in production since 1972 and still getting releases.

key differences

  • IDMS is primarily a network / navigational database; Model 204 is multivalue (Pick).
  • IDMS is built for larger datasets (≤ 1 PB) than Model 204 (≤ 10 TB).
  • Horizontal scaling is addon in IDMS and none in Model 204.
  • Transactions: IDMS offers full ACID; Model 204 offers limited.
  • Only IDMS has joins, compression.
  • Only Model 204 has stored procedures.

choose idms for

  • +Government and utility billing systems on z/OS
  • +Manufacturing and distribution systems built in the 1980s
  • +Exposing legacy IDMS data via SQL and web services during migration

best at · OLTP

choose model-204 for

  • +Maintaining existing government and defense mainframe systems
  • +High-volume record retrieval and update on z/OS
  • +Web-enabling legacy M204 applications through Janus

best at · OLTP

IDMSCODASYL network-model mainframe database, now Broadcom's, still running decades-old COBOL systems.
Model 204Rocket Software's mainframe inverted-list DBMS, in production since 1972 and still getting releases.
overview
Primary model
Network / Navigational
Multivalue (Pick)
Also supports
Relational
–
Type
Database engine
Database engine
Status
Active
Active
Developer
Broadcom (originally Cullinane, Computer Associates)
Rocket Software
First release
1973
1972
Latest version
–
8.0 (2026)
License
ProprietaryProprietary commercial license
ProprietaryCommercial (Rocket Software)
Free tier
—
—
popularity
WhichDB Score
6.2
4.4
Rank
#366
#407
GitHub stars
–
–
Stack Overflow questions
–
–
scale & guarantees
Comfortable data size
Large (≤ 1 PB)
Medium (≤ 10 TB)
Horizontal scaling
Addon
None
Multi-region
Read replicas
None
ACID
Full
Limited
Consistency
Strong
Strong
Schema
Strict
Flexible
Architecture
Client server, Shared storage
Single node, Client server
deployment
Self-hosted
✓
✓
Vendor-managed cloud
—
—
Serverless
—
—
Embedded
—
—
Edge
—
—
Clouds
–
–
capabilities
Transactions
✓
✓
Joins
✓
—
Secondary indexes
✓
✓
Full-text search
—
—
Vector search
—
—
Geospatial
—
—
JSON
—
—
Change data capture
—
—
Triggers
—
—
Stored procedures
—
✓
Materialized views
—
—
TTL / expiry
—
—
Pub/Sub
—
—
Columnar storage
—
—
In-memory
—
—
Durable persistence
✓
✓
Compression
✓
—
Encryption at rest
—
—
Role-based access
✓
✓
Time travel
—
—
Branching
—
—
Online schema changes
—
—
Streaming ingest
—
—
Offline sync
—
—
Runs in WebAssembly
—
—
interfaces
Query languages
DML (navigational), SQL (IDMS SQL option), ADS/Online
SOUL (User Language), SQL (via Model 204 SQL Server)
Client languages
COBOL, PL/I, Assembly, Java
SOUL
Best for
OLTP
OLTP
Add more to this comparisonNot sure either fits? Try smart match

IDMS vs Model 204: FAQ

What is the difference between IDMS and Model 204?

IDMS: CODASYL network-model mainframe database, now Broadcom's, still running decades-old COBOL systems. Model 204: Rocket Software's mainframe inverted-list DBMS, in production since 1972 and still getting releases. IDMS is primarily a network / navigational database; Model 204 is multivalue (Pick). IDMS is built for larger datasets (≤ 1 PB) than Model 204 (≤ 10 TB). Horizontal scaling is addon in IDMS and none in Model 204.

When should I choose IDMS over Model 204?

Choose IDMS for government and utility billing systems on z/OS; manufacturing and distribution systems built in the 1980s; and exposing legacy IDMS data via SQL and web services during migration. Choose Model 204 for maintaining existing government and defense mainframe systems; high-volume record retrieval and update on z/OS; and web-enabling legacy M204 applications through Janus.

Is IDMS or Model 204 more popular?

IDMS ranks #366 on the WhichDB Score (6.2/100) and Model 204 ranks #407 (4.4/100). Popularity is not fit: check the requirements that matter for your project.

Are IDMS and Model 204 open source?

No. IDMS is proprietary, closed-source software. No. Model 204 is proprietary, closed-source software. License: Commercial (Rocket Software).