What was going on when I was born?

''In these conditions, the National Olympic Committee of the U.S.S.R. is compelled to declare that participation of Soviet sportsmen in the Games of the XXIII Olympiad in Los Angeles is impossible.

Soviet athletes will not compete in the Olympic Games in Los Angeles this summer, Moscow announced. It attributed the decision to a ''gross flouting'' of Olympic ideals by United States officials. In particular, the statement cited plans by anti-Soviet groups to hold demonstrations during the Games and a United States refusal to prohibit such protests. (Page A1, Columns 4-6.) The Soviet decision not to attend the Summer Olympics in Los Angeles was deplored by the Reagan Administration as ''a blatant political action for which there was no real justification.'' Administration specialists on the Soviet Union said they believed that Moscow's action was at least partly in retaliation for the American boycott of the Moscow Summer Games in 1980. (A16:1-4.)

My heart is inditing a good matter; my tongue is the pen of a ready writer.'' The unveiling of those lines from the King James Version of the 45th Psalm, inscribed in stone and raised in song, marked the climax Monday night to the dedication of an American Poets' Corner at the Cathedral of St. John the Divine. Several hundred congregants and guests gathered in the cathedral at Amsterdam Avenue and 112th Street, itself a poem of stone arches and stained glass, to honor the written word, particularly as put down by Emily Dickinson, Walt Whitman and Washington Irving. Outsized candles flickered gamely under floodlights, as sacred music, high language and church ceremony heralded the birth of a tradition.

PASTA is one of the most versatile foods there is, but when you do the things they do. . . .'' Alfredo Viazzi paused for a sigh and a lift of his well-defined eyebrows. ''Cold tortellini salad with pesto,'' he said somewhat sadly, ''it's an outrageous thing.'' Mr. Viazzi is a Greenwich Village restaurateur who has been serving Italian food to New Yorkers for the last 30 years. (He owns Cafe Domel, Trattoria da Alfredo and Tavola Calda da Alfredo.) He is one of several Italian chefs who were interviewed recently about pasta, in particular the variations on pasta that are being offered, and apparently consumed, with enthusiasm these days: colored and flavored pasta, cold pasta salads, pasta in strange and, to Italians, unwieldy combinations. Tortellini, for example, the little doughnut-shaped, meat-filled Bolognese specialty, is now often served cold with pesto, a pungent basil and garlic sauce that is closely identified with Genoa. ''The pesto sauce doesn't match the pasta,'' said Giuliano Bugialli. ''It fights with the pasta.'' Mr. Bugialli, an authority on Recipes are on page C6. the history of Italian food, is a cookbook writer who conducts cooking classes in this country and, in the summer and fall, in his native Florence.

Because of an editing error, a Man in the News article yesterday on Jose Napoleon Duarte, who has claimed victory in the Salvadoran election, misinterpreted a reference to ''leftist idealists'' whom he wants to include in a national dialogue. His reference was to unarmed leftists, mainly those of the Revolutionary Democratic Front.

At least 20 gunmen yesterday reportedly attacked a barracks usually used as a residence by Libya's leader, Col. Muammar el-Qaddafi. After several hours of fighting, their attack was ended by Libyan troops, according to reports reaching the West from diplomats and an Italian journalist in Tripoli, the Libyan capital. Information on the attack was sketchy and in some respects contradictory. But a diplomat said in Rome late in the day, according to The Associated Press, that Colonel Qaddafi had apparently survived another of the several attempts that have been made to overthrow him since he seized power in 1969 as the leader of a coup that ended the Libyan monarchy.

The nation's leading banks raised their prime lending rate half a percentage point yesterday, to 12 1/2 percent, the third such increase in two months. The rise in the key interest rate to its highest level in 18 months brought sharp criticism by the White House of the Federal Reserve Board, which is the nation's central bank. Larry Speakes, chief White House spokesman, said the Federal Reserve had been unduly restricting the supply of money to the national economy, thus driving up the cost of money - interest rates - and threatening to choke off the economic recovery. (Page D6.)

Steel was once at the center of things, the backbone of the economy. It was no accident that President Truman seized the steel mills, or that President Kennedy lashed out at price increases by Roger Blough and United States Steel. And Superman was the man of steel. But nowadays, Big Steel conjures up images of weakness, not power. With each day, it becomes clearer that the industry's plight is neither temporary nor cyclical, but rooted in a simple fact: America gets along with a lot less steel. And the competition is fierce to sell even that, among the giant integrated companies, the importers and the newer mini-mills. While the economy has grown in the last decade, the consumption of steel has declined.

The quarterly roundup of sales and earnings in Business Day on Monday misstated the figures for the Celanese Corporation. For the period ended March 31, the chemical company had revenues of $837 million, up 9 percent from a year earlier, and net income of $44 million, up 633 percent.

The Food Notes column in The Living Section last Wednesday incompletely described the baguettes that are sold for $1.59 a loaf at Zabar's and $2.50 at E.A.T. Those at E.A.T. are four inches longer than those at Zabar's.

The International Monetary Fund warned today that even under optimistic economic assumptions, debt payments would take nearly a quarter of the export earnings of third-world countries in 1987, compared with slightly more than a fifth of the earnings in 1983. The I.M.F. did not provide a breakdown for individual countries, but outside experts said the bite out of exports to finance debt would be much larger for some Latin American countries. Argentina's payments, for example, have consumed all of its foreign exchange earnings, the experts said, and Brazil's ratio has exceeded 50 percent. The projections by the economic staff of the agency, the lender of last resort to debtor countries, underscored the painful choice that many developing countries face: whether to allocate export earnings to internal development or to debt payments needed to sustain the ability to borrow.

The International Business Machines Corporation yesterday introduced the first part of its long- awaited local area network. It will link independent computer systems, usually within a large building, so they can exchange information at high speed. But the company only offered a ''statement of intent'' to market a full network in two to three years. The announcement surprised analysts, who had expected the entire system to be available this year. It prompted speculation that I.B.M. had encountered technical problems and chose to announce the system piecemeal to encourage customers not to install competing products.