Rate of Fire
Rate of Fire, commonly abbreviated RoF, is the rate at which your weapon fires (i.e. the number of shots fired per second). Rate of Fire can be affected by skills (such as Sniper Class or Speed Demon Class), Augmenters, and Overloaders.
Recoil Time
Rate of Fire is often measured by its inverse, recoil time, which is the time delay (in seconds) between shots of a weapon. Recoil is a statistic listed on each weapon, ranging from .1 seconds for a Faranji Gatling Laser to 3 seconds for the Delayed Blast Hunleyite.
Maximum Firing Rate
It is important to realize that there is a maximum firing rate due to limitations in how the Star Sonata server is implemented. The server updates information around 10 times per second, but damage is not always calculated on every update (or 'tick') so the effective maximum firing rate is approximately 6 times per second (which equates to a .166 sec recoil time). In some cases, the image for the weapon cannot be displayed by the client due to limitations in your computer's CPU or graphics speed. Interactions between the client frame rate and the server update speed may also play a role in the effective maximum firing rate.
Once you start doing damage with a weapon above the RoF cap, some shots are dropped. It is important to take this into account in DPS calculations, because there are setups that would have unreal damage if this did not apply. For example, the Faranji Gatling Laser (Fgat) does 13 damage per shot with .1 sec recoil time. With 3 Ares augs and no Augmenter Tweaking the recoil time calculation is as follows:
.1 / 1.35 / 1.35 / 1.35 = .0406 or almost 25 times per second (1/.0406 = 24.6)
The "theoretical" damage per second for this setup is 24.6 * 13 = 319.8, which for a tech 1-2 weapon is pretty outrageous. If you had Speed Demon Class 20 you would do nearly twice that much. Thankfully, the server can't dish out a refresh rate that fast, so the actual DPS is much lower. In fact, the Ares augs don't help this weapon's DPS at all!
Energy Usage
Boosting the Rate of Fire also increases energy used per second, since most weapons use energy for each shot fired. If you can handle the energy usage, it is possible to get a bigger DPS boost with augs that boost Rate of Fire than augs that boost Damage, because the aug bonuses to RoF are larger than for Damage for a given tech level.