Updated from 12:37 p.m. EDT

Shares of

MRV Communications

(MRVC)

were among technology's losers Thursday, falling 40.6% after the network-equipment maker posted disappointing first-quarter results and issued weak second-quarter sales guidance.

The company reported a loss of $6.4 million, or 6 cents a share, on sales of $62 million. Analysts surveyed by Thomson First Call were expecting a smaller loss of 3 cents a share on sales of $67.1 million. A year ago the company a loss of $4.8 million, or 5 cents a share, on sales of $59.6 million. MRV said that sales were $3 million below the lower end of its guidance because of weakness in its networking business in Europe. Looking ahead, MRV said that it expects an improvement in its net loss and sales of $62 million to $66 million. Analysts had been expecting earnings of a penny on sales of $75.9 million. Shares traded down $1.23 to $1.80.

Komag

(KOMG)

rose 5.4% after the computer storage supplier posted first-quarter results that were better than expected. The company earned $18.5 million, or 59 cents a share, on sales of $140.3 million. Analysts were expecting earnings of 54 cents a share on sales of $130.9 million. A year ago the company earned $18 million, or 61 cents a share, on sales of $123.6 million. Looking ahead, Komag said that sequential sales could be comparable to or up 10% vs. just-completed first-quarter levels. Analysts had been expecting sales of $124.3 million. Shares traded up $1.23 to $23.83.

Shares of

ON Semiconductor

(ONNN)

rose 11.7% after the semiconductor maker posted first-quarter results that were well ahead of expectations. The company earned $14.8 million, or 4 cents a share, on sales of $302.4 million. First-quarter results included charges amounting to $1.1 million. Analysts were expecting earnings of just 2 cents a share on sales of $292.8 million. Looking ahead, ON Semiconductor expects second-quarter sales to be about equal to first-quarter results, give or take 2 percentage points. Analysts are expecting sales of $299.1 million. Shares traded up 35 cents to $3.35.

Kronos

(KRON)

fell 21.1% after the company posted second-quarter earnings and sales that fell short of expectations and warned that third-quarter numbers would come in below expectations as well. The software company earned $11.2 million, or 34 cents a share, on sales of $120.6 million. Analysts were expecting earnings of 37 cents a share on sales of $125.9 million. A year ago the company earned $9.6 million, or 30 cents a share, on sales of $108 million. Looking ahead, Kronos forecast third-quarter earnings of 36 cents to 38 cents a share on sales of $127 million to $132 million, below the 43 cents in earnings and $133.3 million in sales that analysts had been expecting. Shares traded down $10.36 to $38.81.

Shares of

Microchip Technology

(MCHP) - Get Report

rose 9.4% after the chipmaker posted fourth-quarter results that topped forecasts. The company earned $56.4 million, or 27 cents a share, on sales of $208.1 million. Analysts were expecting earnings of 25 cents a share on sales of $204.3 million. A year ago the company earned $46.8 million, or 22 cents a share, on sales of $191.5 million. Looking ahead, Microchip Technology forecast first-quarter earnings of 28 cents a share on sequential sales growth of about 5%, which would yield sales of about $219 million. Analysts had been expecting earnings of 26 cents a share on sales of $212.1 million. Shares traded up $2.39 to $27.92.

Other technology movers included

Microsoft

(MSFT) - Get Report

, down 54 cents to $24.45;

Sirius Satellite Radio

(SIRI) - Get Report

, up 6 cents to $4.73;

Intel

(INTC) - Get Report

, down 32 cents to $23.19;

Cisco Systems

(CSCO) - Get Report

, down 11 cents to $17.14;

Oracle

(ORCL) - Get Report

, down 28 cents to $11.62;

Sun Microsystems

(SUNW) - Get Report

, down 10 cents to $3.44;

Ciena

(CIEN) - Get Report

, up 8 cents to $2.10;

Sanmina-SCI

(SANM) - Get Report

, down 71 cents to $3.79;

Applied Materials

(AMAT) - Get Report

, down 5 cents to $14.88; and

Lucent Technologies

(LU)

, down 7 cents to $2.44.