Radoslaw Skorupka wrote: >Semantics. Yes, there is (was) a controller between host and device. >Control Unit ;-) It was A06, A60, J70, C07, etc. >But it was a controller, not virtualisation engine. No data was stored >on CU disks, MVS wrote (in)directly to real drive, number of devices was >a number of physical drives. Capacity od MVS volume was a capacity of >real tape cart (with compression of course).
Not *exactly*. The libraries do their own thing (often virtualized), the drives have buffered for a long time (and now there's a bigger and much more sophisticated buffer), and starting with the TS1120 the drives do their own onboard cryptographic enciphering/deciphering, all of which the operating systems don't especially know about or have to know about. Over time certain application functions become middleware, certain middleware functions become part of the operating system, certain operating system functions become part of the firmware, and certain firmware functions become part of the physical hardware. Everything gets pushed down, compressed inward, for robustness and richer functionality that's easier to consume, manage, and share across more use cases. It's a long running story that has been underway for decades, and I'm confident it will continue. >TS7700 is VTS. Different animal. A lot of differences. It can work even >without physical tapes. Stipulated, and thank goodness for that! "Y'all" would be very upset with IBM if IBM weren't constantly raising the bar and delivering more value for money. The TS7720 is your much smarter controller. ....But if you want a less talented controller for some reason(s), then please let your friendly IBM representative know. As far as I know there haven't been any use cases taken away or diminished. Quite the opposite. But if I'm wrong, and if there's something you can't do with the TS7720 plus TS1150 at least as well as you did with the old controller, let IBM know the details officially, please. -------------------------------------------------------------------------------------------------------- Timothy Sipples IT Architect Executive, Industry Solutions, IBM z Systems, AP/GCG/MEA E-Mail: [email protected] ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
