The heart-stopping gyrations of the Dow Jones Industrial Average index this week tell the tale: On Monday, the Dow plunged 634.76 points; on Tuesday, it jumped 429.92; on Wednesday it dropped 519.83 points; on Thursday it rose 423.37 points. The tech-heavy Nasdaq and the S&P 500 indexes rose and fell in parallel with the Dow.

In Friday afternoon trading, volatility calmed somewhat and shares across a broad range of sectors, including IT, were up for the day, aided by a government report that July retail sales rose higher than they have in four months. The Dow was up by 141.15, the Nasdaq rose by 19.49 and S&P 500 was up 8.64.

Nasdaq computer stocks, which have moved along with other sectors this week, were up 5.74 points in aggregate in midafternoon trading.

Though the consumer market for PCs has been soft this year, enterprise spending on IT has fueled profits for tech vendors. The big concern for tech is whether the market chaos and concerns about the economy -- or, at worst, a slump back into recession -- will cause businesses to curb IT spending and consumers to further cut back on purchases of computers.

Even though the markets seemed to take a breather Friday, economic news was mixed. A survey by Reuters and the University of Michigan showed that consumer sentiment over the last few weeks fell to a 30-year low.