Saying that it suffered a sudden drop in demand during last year’s third quarter, an upsurge in the normally strong fourth quarter, and another significant decline in early 1993, Amdahl Corp yesterday announced a big new round of cuts, saying that 1,100 jobs, 12.9% of its worldwide workforce, must go in response to current market conditions. It employs 5,000 people in Northern California. Following the earlier reduction of similar size Amdahl says it has been able to restructure or consolidate a number of operations and the new cuts represent a further streamlining.