What you have to consider when working with such a small cache.

For normal OS's, when files are changed, there has to be a method to find the new file along with the old file. This is normally done with a fixed size table the OS recognizes, be it a FAT, or variant type.  In order to make the physical changes of data, these lookup files have to be loaded to RAM in order for them to be updated. This fixed size lookup combined with data manipulation, employs the use of large RAM resource.

Link list type lookup management with RAM, yet another  method utilized to manage the data on a flash. It's a self contained file as the above is,  pointing to all object on the media....managed with a RAM resource.  However, it's not of a fixed size, lookup can start off small....however, as the data grows on the media, the RAM resource must grow in order to accommodate the growing file lookup. This non fixed size lookup combined with data manipulation....employs the use  RAM resource that must be sized to the eventual usage....which will lead to  the use of large  resource.

Link list type lookup management without  RAM(from the above in an on going state metamorphose). Others manipulate the link list lookup file directly in the media utilizing a minimal of RAM....4K byte being the smallest I read. It's still a separate self contained file that will grow in size, as the physical data on the media grows. You have a condition of growth in the media that happens at both stages...requiring an overhead resource to manage both events. IMO..These types of systems will be given the greatest attention and considerations of IP infringement regarding caching schemes....and making sure they say as separate growing file issues.

e.Digital does not employ either of the above. They have the ability to make everything happen, closer to a physical condition without the RAM resource or the separate lookup file issue. They utilize the cache for data manipulation only. They do not worry about their lookup growing...it does not require RAM resource to manage it. With that, there is an overhead resource requirement for one event only.

doni