Methods and apparatuses for processing input and/or output requests for data storage devices are disclosed. Method embodiments generally comprise receiving a number of requests, wherein at least one of the requests is an isochronous request having an initial deadline value, calculating a new deadline value for the isochronous request, and issuing the isochronous request when the new deadline value is less than a threshold value. Apparatus embodiments generally comprise a request receiver to receive a number input or output requests, a logic module to calculate a deadline value for an isochronous request, where the calculated deadline value relates to the amount of time which has transpired between the creation of the isochronous request and the time the calculation is made, and an issuance module to issue the isochronous request if the calculated deadline value is equal or less than a threshold value.