Wild swings once again marked the action for small-cap stocks Friday as the tech-heavy Nasdaq rallied while the Dow and S&P 500 spent much of the day in the doghouse. Iona ( IONA) shares climbed 20% to $3.31 after the Dublin, Ireland-based software company confirmed that a third party had expressed interest in buying it. Also shining was TerreStar ( TSTR), shares of which shot up 24% to $5.61 after announcing that the Reston, Va.-based wireless communication provider had secured a $200 million investment from EchoStar ( SATS) and Harbinger to fund a satellite and, subject to approvals, acquired rights to 1.4 GHz spectrum from the two companies. In return, EchoStar and Harbinger get two seats in TerreStar's boardroom. Photon Dynamics ( PHTN) jumped 11% to $9.19 on strong first-quarter earnings announced Thursday after the close. The San Jose, Calif., provider of yield management solutions for flat-panel screens posted a non-GAAP loss of $5.7 million, or 31 cents a share, on revenue of $16.2 million. Analysts surveyed by Thomson Financial were looking for a loss of 32 cents a share on revenue of $16.7 million. The company also said the flat-panel market would improve in 2008 and guided for a fiscal 2008 loss between 11 cents and 5 cents a share, which is narrower than the 20 cents a share the average analyst expects. Among the losers was PDF Solutions ( PDFS). After the bell Thursday, the San Jose, Calif.-based developer of semiconductor infrastructure technology announced pro forma fourth-quarter income of $5.8 million, or 21 cents a share, vs. $2.3 million, or 8 cents a share, in 2006. The performance beat the Street's expectation by a penny. The company also announced guidance for the first quarter of 2008, predicting non-GAAP earnings per share between 8 and 10 cents. Analysts are looking for EPS of 14 cents. RBC Capital Markets downgraded PDF Solutions to sector from outperform. Shares plummeted 29% to $5.90. Reston, Va.-based comScore ( SCOR), a tracker of online consumer behavior, lost 17% to $22.83. The company forecast first-quarter EPS between 10 cents and 11 cents, excluding charges. Analysts see earnings of 16 cents a share. Shares were still down after the AP reported confusion about comScore's inclusion of a 39% tax rate that would hold back earnings. Analysts had not taken that charge into account, according to the report. More broadly, the Russell 2000 was recently down 0.5% to 698.97, and the S&P SmallCap 600 descended 0.4% to 369.00.