FICON represents a major improvement over the older ESCON architecture for connecting storage to IBM-style mainframes. FICON offers higher throughput, more flexibility, more distance between devices and better scalability. All this is fine, but while FICON can be as much as six times more cost-effective, converting a storage system from ESCON to FICON is still expensive.
Fortunately there are alternatives to doing a 'forklift upgrade' on your existing ESCON system. If you're experiencing very high rates in traffic growth over your storage network or if you need to connect multiple remote storage centers, you may well want to do a total replacement. If your needs are more moderate, there are a couple of money-saving strategies for integrating FICON into your enterprise.
One alternative is to use a FICON bridge on an existing ESCON installation. The bridge connects the existing ESCON director to a FICON adapter on the mainframe and gives the advantages of FICON between the mainframe and the director. Depending on the user profile, this can provide a significant improvement in performance without having to upgrade peripherals.
Another option is running both ESCON and FICON simultaneously by adding a FICON director to the system and migrating the fastest-growing and most performance-hungry parts of the storage system to FICON. This preserves the investment in ESCON and still gives the benefits of full FICON for the most critical parts of the system.
Rick Cook has been writing about mass storage since the days when the term meant an 80K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last twenty years he has been a freelance writer specializing in storage and other computer issues.
This was first published in September 2002