The basic invention takes some data from inputs encodes it in a certain way and then sends the data out. It sounds like a server and it pretty much in its functionality, but what would i like to patent is how it takes the data and encodes it. So would i have to describe all the types of inputs and all the types of output. There is no formal requirement that a non-provisional have some scope of content as provisional from which it gets priority benefits. However the reason to file s provisional application is to establish that, on the date of filing, you had the invention in hand. Anything you later want to claim as your invention needs to be fully explained in whatever you file whose date you need to reply on. Patent application needs to explain things such that someone in the field can make it and use it without undue experimentation. The more you put into the provisional document the better. 
The provisional application should have enough details to back up the claims that you make later. You cannot later add to the specification or drawing in any new material way. If you do, then that part of the invention gets a priority date of when you actually file the document as an another provisional or regular application. To be safe, you may want to think out your claims although you actually have to provide any provisional application. Also, think of any fallback position you might want to take if the examiner wants to file the prior art or if prior art is found after the patent grant. If you don’t do the thinking early on, then you may not have enough disclosure to get the priority date of provisional. If nothing else give lots of details and example’s of invention that is the part that you figured out. Also think about how someone else could bypass it. Everything else required to complete a regular regular application probably already has a prior art so can be introduced with regular application if needed.
To get the benefit of provisional filing date, the provisional must encompass an enabling disclosure meeting all the requirement for non-provisional. Since we are under first to file, you want your own filing date. In addition, you do not want to get put in position of losing your one year grace period under the AIA for the regular application. You are treading into deep water by filing a “makeshift”, provisional that an examiner reviews and writes a rejection. If you use the rejection to narrow claim in your non-provisional, you have the issue of estoppel if the non-provisional issue and is challenged. If you abandon the provisional and lose the filing date, the non-provisional may be held against you as prior art. 
You may think of the provisional or non-provisional application as two routes of obtaining patents. The non-provisional route providing a one step start to the patent process and the provisional route providing a two step start to the patent process. Either route, when properly carried out can result in patent. The two step provisional process will take about one more year longer to receive a patent than the one step non-provisional route.
Conclusion
Every patent application even a provisional patent application is a complex legal document that must be taken seriously. For this reason its often advisable to work with an attorney or professional with expertise in patent afiling to help ensure you have the best chance of getting the patent issued. There are legal requirements that provisional and non provisional utility application share. A poorly drafted provisional application can actually harm your ability to claim or assert your patent rights.
