inventory balance, our inventory reserve has ranged between 15.0% and 30.6% during fiscal years 2013 and 2012. As of January 27, 2013, our inventory reserve represented 22.0% of our gross inventory balance.

 

Warranty Liabilities



Cost of revenue includes the estimated cost of product warranties that are calculated at the point of revenue recognition. Under limited circumstances, we may offer an extended limited warranty to customers for certain products.  Our products are complex and may contain defects or experience failures due to any number of issues in design, fabrication, packaging, materials and/or use within a system. If any of our products or technologies contains a defect, compatibility issue or other error, we may have to invest additional research and development efforts to find and correct the issue.  Such efforts could divert our management’s and engineers’ attention from the development of new products and technologies and could increase our operating costs and reduce our gross margin. In addition, an error or defect in new products or releases or related software drivers after commencement of commercial shipments could result in failure to achieve market acceptance or loss of design wins. Also, we may be required to reimburse customers, including our customers’ costs to repair or replace products in the field. A product recall or a significant number of product returns could be expensive, damage our reputation and could result in the shifting of business to our competitors. Costs associated with correcting defects, errors, bugs or other issues could be significant and could materially harm our financial results.

   

During the three fiscal years ended January 30, 2011, we recorded a cumulative net charge of $475.9 million, most of which was charged against cost of revenue, to cover customer warranty, repair, return, replacement and other costs arising from a weak die/packaging material set in certain versions of our previous generation MCP and GPU products used in notebook configurations. Determining the amount of the warranty charges related to this issue required management to make estimates and judgments based on historical experience, test data and various other assumptions including estimated field failure rates that we believe to be reasonable under the circumstances. The results of these judgments formed the basis for our estimate of the total charge to cover anticipated customer warranty, repair, return and replacement and other associated costs. If the actual repair, return, replacement and other associated costs and/or actual field failure rates exceed our estimates, we may be required to record additional reserves, which would increase our cost of revenue and materially harm our financial results.



Income Taxes



 We recognize federal, state and foreign current tax liabilities or assets based on our estimate of taxes payable or refundable in the current fiscal year by tax jurisdiction. We recognize federal, state and foreign deferred tax assets or liabilities, as appropriate, for our estimate of future tax effects attributable to temporary differences and carryforwards; and we record a valuation allowance