I am no genius in mainframes. So what I will try to do is, collect information from internet, books, people and will dump it down here.
Obviously, it will be gradual with a flow in it because I am myself doing it for the first time. So we will start with some introduction, and will go into details more complex day after day.
I WANT TO THANK YOU EVERYONE FOR THE INFORMATION PROVIDED IN THIS AND FORTH COMING POSTS. MOST OF THE TIME I WILL BE COLLECTING INFORMATION FROM VARIOUS PLACES AND WILL BE DOING MIXING PIXING SO AT TIMES IT WILL BE DIFFICULT FOR ME TO GIVE CREDIT TO THE ORIGINAL AUTHOR. BUT ALL KUDOS TO GEEKS OUT THERE. I RESPECT YOU FROM BOTTOM OF MY HEART. PLEASE WRITE TO ME IF YOU WANT ANY THING OUT OF THE BLOG WHICH YOU OWN, AND I WILL BE MORE THEN HAPPY TO RESPECT YOUR OWNERSHIP.
That said, let's start:
- By Lance H. Vaughan
The "new paradigm" (so called) proclaims that a clustering of small, limited architecture machines, interconnected by elaborate topologies, is the or going to be the wave of the future. Lost to a nontechnical senior management (as most of the firms have) is the fact that in implementing this new computational model they are at the same time eliminating the most powerful, comprehensive, and sophisticated class of computing platforms ever brought to the marketplace - MAINFRAMES.
The essential characteristics of a mainframe are: rapid and continuing evolution, general purpose orientation, hardware implemented solutions, and the criticality of user input to all of these processes.
"A mainframe is a continually evolving general purpose computing platform incorporating in it architectural definition the essential functionality required by its target applications."
"Mainframes used to be defined by their size, and they can still fill a room, cost millions, and support thousands of users. But now a mainframe can also run on a laptop and support two users. So today's mainframes are best defined by their operating systems: Unix and Linux, and IBM's z/OS, OS/390, MVS, VM, and VSE. Mainframes combine four important features: 1) Reliable single-thread performance, which is essential for reasonable operations against a database. 2) Maximum I/O connectivity, which means mainframes excel at providing for huge disk farms. 3) Maximum I/O bandwidth, so connections between drives and processors have few choke-points. 4) Reliability--mainframes often allow for "graceful degradation" and service while the system is running."
1) Maximum reliable single-thread performance: Some processes, such as the merge phase of a sort/merge (sorting can be subdivided...) MUST be run single thread. Other operations (balancing b-trees, etc) are single thread and tend to lock out other accesses. Therefore, single thread performance is critical to reasonable operations against a DataBase (especially when adding new rows).
2) Maximum I/O Connectivity: Mainframes excel at providing a convenient paradigm for HUGE disk farms; While SAN devices kind of weaken this to some degree, SAN devices mimic the model of the Mainframe in connectivity "tricks" (at least internally).
3) Maximum I/O Bandwidth: Despite the huge quantities of drives that may be attached to a mainframe, the drives are connected in such a way that there are very few choke-points in moving data to/from the actual processor complex.
4) Reliability - is reliability. :P
Next post: We will start with Evolution of OS/390 moving on to MVS and so forth. (Don't worry about the jargons. Even I don't have any idea). Mainframe is a big machine which can do huge calculations and store large amount of data. (ye ye !!)