A day earlier, the market had slumped on news that Seagate Technology, among others, was forecasting slower growth.
The cause is likely to be an abrupt decline in the fortunes of Seagate Technology, the industry giant.
And Seagate Technology, which was recommended by a number of analysts, soared 3 1/2, to 45.
Hitachi is now the second-largest disk drive maker, behind Seagate Technologies.
And Seagate Technology, which three weeks ago reported a rise in quarterly profits, fell 3 7/8, to 12 1/4.
The two founded Seagate Technology, the first maker of 5.25-inch hard disks, in 1979.
It was a majority owned subsidiary of Seagate Technology, the largest independent disc drive and related components company in the world.
Control Data said the quarterly results were helped by the sale of a disk drive subsidiary to Seagate Technology.
The company began as the removable storage systems division of Seagate Technology.
For example, he is buying shares in Seagate Technology, which already accounts for 2.5 percent of the fund.