BladeLogic Inc., a Lexington, Mass.-based provider of data center automation software, has filed for a $75 million IPO. It plans to trade on the Nasdaq under ticker symbol BLOG, with Morgan Stanley and Merrill Lynch serving as co-lead underwriters. The company has raised around $35 million in total VC funding since its 2001 inception, from firms like Battery Ventures (21.3% pre-IPO stake), Bessemer Venture Partners (21.7%), Globespan Capital Partners (17.2%) and MK Capital (7.2%). www.bladelogic.com