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Datacom vs Db2: Migration Cost Reality.

Datacom is a Broadcom (CA) relational database. Db2 for z/OS is IBM relational. Both speak SQL, so the data model gap is narrow, but the migration cost hides at the edges. Here is the head to head and where the cheaper path usually runs, buyer side.

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№ 01

The verdict

Verdict first
Verdict

Because Datacom is relational and already speaks SQL, a move to IBM Db2 for z/OS is a narrower jump than a network database migration like IDMS to Db2, but it is not a swap. The cost concentrates at the edges: native navigational calls, vendor specific SQL behavior, utilities, security, and operational tooling. If the applications run well on Datacom, the faster route to a lower number is almost always to negotiate the Broadcom (CA) renewal hard rather than fund a migration, since Db2 is its own sub-capacity bill, not an exit from the meter. Migrate when the driver is strategic consolidation or skills risk, with licensing as one input among several.

№ 02

Head to head

DatacomDb2

Both are relational mainframe databases, which makes this a closer comparison than most legacy migrations. The differences that drive cost are the navigational access Datacom also supports, the vendor specific behavior on each side, and the licensing relationship behind each product.

DimensionBroadcom (CA) DatacomIBM Db2 for z/OS
Data modelRelational, SQL plus native navigational accessRelational, SQL based
OwnerBroadcom (CA)IBM
LicensingMSU capacity, Broadcom renewal and uplift exposureMLC, sub-capacity MSU via SCRT, Tailored Fit Pricing option
Migration frictionNative calls, utilities, vendor specific SQLSchema and SQL retargeting, operational retooling
SkillsScarcer Datacom expertiseBroad Db2 and SQL skills base
Main licensing leverNegotiate the Broadcom renewal, unbundle itOptimize sub-capacity and evaluate TFP fit

Directional comparison. Confirm your Datacom entitlement on your Broadcom order and your Db2 metric on your IBM agreement; both are capacity based and both are negotiable.

№ 03

Who should pick which

Decision

Stay on Datacom when

The applications are stable, perform, and the real problem is the renewal number rather than the technology. Here the win is on the contract: reconcile consumption against contracted capacity, challenge the MIPS to MSU conversion, cap uplift, and pull Datacom out of any wider Broadcom portfolio bundle so it can be benchmarked on its own. You keep a relational database that works and take the cost down without funding a multi quarter migration program.

Move to Db2 when

The direction is a Db2 consolidation, Datacom skills are a genuine continuity risk, or a broader modernization makes the retargeting worth funding for reasons beyond a single license line. If you go, scope the native call rework, the SQL behavior differences, and the operational retooling with realistic numbers, plan the parallel run, and remember the destination is Db2's own sub-capacity bill, so optimize that licensing from day one rather than inheriting an unmanaged Db2 footprint.

№ 04

Frequently asked

FAQ

Is Datacom a relational database?

Yes. Broadcom (CA) Datacom, also written Datacom/DB, is a relational database management system for the mainframe. It supports SQL access and, distinctively, also serves traditional navigational access against the same tables, so estates often run a mix of SQL and native calls. Broadcom dropped the CA prefix after acquiring CA Technologies, so the product is now branded Datacom, though buyers still search CA Datacom.

Is migrating from Datacom to Db2 easier than IDMS to Db2?

It can be, because Datacom is relational and already speaks SQL, so the data model gap to Db2 is narrower than the gap from a network database like IDMS. But it is not free. The work lives in the differences: native Datacom calls that bypass SQL, vendor specific SQL behavior, utilities, security, and the operational tooling around the database all have to be reworked or replaced. Migration cost concentrates at those edges, not in the table structures themselves.

How are Datacom and Db2 for z/OS licensed?

Both are capacity based on the mainframe. Datacom is a Broadcom (CA) product, commonly licensed on MSU and exposed to Broadcom renewal uplift, the MIPS to MSU conversion question, and consolidation pressure inside a wider Broadcom portfolio agreement. Db2 for z/OS is IBM Monthly License Charge software, billed on sub-capacity MSU through SCRT and increasingly offered under Tailored Fit Pricing. The decision is less about which is cheaper than which renewal you are positioned to negotiate.

Should I migrate Datacom to Db2 to cut licensing cost?

Rarely on licensing cost alone. A migration funded to escape a Datacom line that could be renegotiated is usually a poor trade, and the destination is Db2's own sub-capacity bill, not an exit from the meter. Migration makes sense when driven by strategic direction, skills risk, or a consolidation onto Db2 already underway, with licensing as one input. If the goal is purely a lower Datacom number, negotiating the Broadcom renewal hard is almost always the faster path.

Related comparison: IDMS vs Db2 and keep vs exit. Related concept: the MIPS to MSU conversion question. Publisher hubs: Broadcom (CA) and IBM. Put it to work: Broadcom renewal advisory.

The rewrite is narrower. The renewal table is still faster.

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