The Software Requirements Specification (SRS) documents the requirements for the software. This typically includes functional, performance, interface, design, developmental, and other requirements for the software. In effect, this document describes what the Software Device is supposed to do. Examples of some typical requirements that would be included in a SRS are described below. For Software Devices that are identified as Minor Level of Concern, FDA recommends that you provide only the summary functional requirements section from the SRS, including identification of off-the-shelf software. For Software Devices that are identified as Major or Moderate Level of Concern, FDA recommends that you provide the complete SRS document.

Hardware requirements generally include:

• microprocessors
• memory devices
• sensors
• energy sources
• safety features
• communications

Programming language requirements include program size requirements or restrictions and information on management of memory leaks.

Interface requirements generally include both communication between system components and communication with the user such as:

• printers
• monitors
• keyboard
• mouse

Software performance and functional requirements include algorithms or control characteristics for therapy, diagnosis, monitoring, alarms, analysis, and interpretation with full text references or supporting clinical data, if necessary. Software performance and functional requirements may also include:

• device limitations due to software
• internal software tests and checks
• error and interrupt handling
• fault detection, tolerance, and recovery characteristics safety requirements
• timing and memory requirements
• identification of off-the-shelf software, if appropriate

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