Anyone who shorted Apple ( AAPL) over the last few months would have been in sorry shape because of a "short squeeze." A short squeeze is when traders who have shorted a particular stock scramble to cover their positions, driving up the price of the stock.Not all the computer companies have risen as much as Apple, but some are heavily shorted, and on any good news, they could shoot upward. Stockpickr reviewed the list of computer companies and came up with the top 10 most heavily shorted computer stocks based on the short ratio. The short ratio is also referred to as the "Days to Cover Ratio," which is the number of days short-sellers would need to cover their positions based on the average daily trading volume of shares. Stocks with the higher short ratios can have greater upward price movements when unexpected good news is announced, such as revenue coming in greater-than-expected or possible takeover rumors. At the top of the list is Silicon Graphics ( SGIC), with a short ratio of 27, which means that it would take the short sellers more than 27 days to cover their positions based on the current volume. The company just filed its 10K with the SEC in mid-September and reported an 11% drop in revenue over the prior year. However, the comparison is difficult because the prior year involved a predecessor company and bankruptcy court. The stock has a price-to-earnings ratio of 28.