How to retire (respectfully) legacy systems

They served us for a long period of time, but (for different reasons that I wont cover in this post) now the time to say good bye and to retire them.  Legacy systems exist in each and every enterprise and we all have the experience of retire them. The question is whether your enterprise have a predefine process to retire legacy systems or is just process that happened?   In this post I'll try to share a retirement process for legacy systems.

From what I've seen so far in most enterprises, legacy systems are not going through a process of retirement they are simply abandon (from IT point of view). The users (or should I say most of the users) aren't using the system anymore but, batches keep on running, backup processes still running, they still take some place on the disk, their databases might still take space, etc'. It is worthless to say that if you're going through a process of mapping your IT assets you'll find most of (not all of) the legacy systems and you'll start a process of retirement.

The process, which I'm getting use to do, is composed from five main steps:

1. Mapping: mapping of the legacy system components and their relations to other IT assets. Usually the mapping includes: Permissions, system services (and their consumers), system references from menus, system programs (PL1, Natural, Cobol, VB 6), databases or data files, batches, system data used by other systems, navigation to the system,  usage of software or technology infrastructures, usage of other systems data, etc'
   
2. Discussion: a formal discussion to approve the system retirement with participant from all relevant organization units (following the mapping)
   
3. Writing shutdown procedure : Writing a detailed procedure of all the tasks, task owners and tasks order that needed to be taken when taking the system down. The shut down procedure should be sent to all related IT teams, users and support center.
   
4. Neutralization : taking down system component, with the ability to restore them back to working state very fast. The neutralization includes : taking system references from menus, services and programs. Taking down system databases or renaming system files. Stopping batches. This step check if there are surprised users or unknown navigations or usage.
   
5. Archiving : taking down system security settings, remove linkage from other systems, removing system components and achieving them. After a month of two if no access recorded to system components we can remove them and archive them for further use (how we handle complex IT/software issues in the past). When archiving system, we inform infrastructure providers that the system is down and it wont consume infrastructure services anymore.