National Semiconductor Corp. had sales of $649.4 million for the first quarter ended Aug. 28, compared to $517.6 million for the first quarter of the previous fiscal year.

The company reported a net loss of $30.5 million, or 31 cents per share, vs. net earnings of $13.5 million, or 10 cents per share, in the comparable quarter of the previous year."Although our semiconductor operations experienced strong demand and modest growth in the seasonally slow first quarter, pressures on the Information Systems Group (ISG) continue to affect the company's operating performance," said Charles E. Sporck, president.

"Sales and profits for the Information SystemsGroup were negatively impacted during the quarter. The mainframe sector was affected by both slowing of demand in the large systems business and continued pricing pressure. In addition, the previously announced restructuring at Datachecker and NAS resulted in a one-time pretax charge during the first quarter."

Research and development spending during the first quarter was $79.2 million, or 12 percent of sales, compared to $59.3 million, or 11 percent of sales in the first quarter of fiscal 1988.

"The outlook for the semiconductor group is strong," said Sporck. "We anticipate continued growth in components sales for the second quarter."