Sorry but I'm not clear what you mean by 'information system'.  There are so many kinds of information systems.  Perhaps if we start from a common understanding of the terms it will help. 

If I take Business Analysis to be Business-systems Analysis and Design, then that would target both the manual and the automated parts of a business as a system; and a Business-systems Analyst would aim to understand how that works now and to re-design it such that it is better at what it does. That improvement could be just to the manual parts or to the automated parts or to both or to change the border between where processes are manual and where they are automated.  It could be that just the common-sense of someone experienced in the business will improve it, but normally it needs more than common sense; it needs a methodology for applying analysis and design techniques to reliably arrive at a major improvement.  It could even be to remove the software and computers from the process ( e.g. store your bitcoin key off-line in a safe place on a paper wallet, in a sealed, tamper-evident envelope,...  ) or to remove all manual steps and fully automate.  In my opinion, a BA needs to be able to look at a system at an abstract level, ignoring how it might be physically implemented.  Then after that, be confident in designing both the manual and computer driven parts of the implementation.  Hardware specification, programming and final optimisation would normally not be a concern of the BA unless some aspect of their design was proving to be not feasible, in terms of security or performance.
Some systems such as 4GLs , BPM systems, some CRMs, etc. are able to generate a fully working solution based on a design created by a BA and so the BA would most often be the one to create the prototype and even the final software parts of the solution with little or even no conventional 3GL programmer involved.