HP's major acquisitions were sometimes followed by major write-downs, but none rivaling Tuesday's shocking revelations about British software maker Autonomy:

- July 2006: HP announces a deal to acquire Mountain View software maker Mercury Interactive for about $4.5 billion in stock. No reported problems.

- May 2008: HP announces plans to buy Texas-based Electronic Data Systems for about $14 billion to bolster HP's technology consulting services. Writes down $8 billion in 2012

- November 2009: HP buys 3Com for $2.7 billion in a deal to expand its networking business. The deal seems to be working.

- April 28, 2010: HP announces it will buy mobile phone maker Palm for $1.2 billion. Writes down $885 million in 2011.

- September 2010: 3PAR acquired for $2.35 billion. Analysts give this deal good marks.

- October 2010: ArcSight acquired for $1.5 billion. Also favorably viewed.

- February 2011: Vertica acquired for a reported $350 million. Favorably viewed.

- September 2011: HP buys Autonomy for approximately $11 billion. Writes down $8.8 billion Tuesday.

- July 2012: As the global PC market slows, HP writes down $1.2 billion from $19 billion merger with Compaq in May 2002.

-- Pete Carey, Staff