Telelogic AB, a Swedish software development tools company, was acquired by IBM six weeks ago. Instead of disappearing inside Big Blue, Telelogic continues to function in part as an independent subsidiary as opposed to being fully absorbed into IBM's Rational tools unit.

As if to prove it, Telelogic officials announced on Tuesday that the firm has updated its own distinct tool set, carrying out enhancements that were under way before the $845 million acquisition.

"There's some overlap with Rational tools," conceded John Carillo, senior director at IBM/Telelogic, but many aspects of Telelogic's offerings are distinct to the high-end requirements of their users in telecom, automotive, aerospace and defense, he said in an interview.

Telelogic at the time of the acquisition was one of few independent software tool vendors still standing. Microsoft is a platform vendor with its Visual Studio tools; IBM's Rational unit both serves the mainframe and other platforms. But few independent, broad-based tool vendors survive. Borland has become an application life-cycle management vendor and sold its tools unit, CodeGear, to Embarcadero Technologies earlier this month.

There's still Compuware, a $1.23 billion-a-year company with its OptimalJ Java tool and application life-cycle management systems, and Sun Microsystems, with NetBeans serving the Java platform, but not many others.

Telelogic stands out as a tool supplier to vertical industries that, among other things, want to embed software in complex products. Telelogic tools are used in the automotive industry to build brake anti-lock systems. They're used in defense and aerospace for control and management systems and navigation systems.

Earlier this week, Carillo explained the updates to the existing Telelogic tools, Doors, System Architect, and Change.

Doors is a set of requirements management tools that track not only the software changes required in a product but any other changes as well. With a prospective product dependent on its software, hardware devices and external software dependencies, keeping requirements in one tool makes for a smoother development process, Carillo said.