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AS/400 vs. mainframes -- Give me the lowdown!

How does the AS/400 differ from a mainframe system? Which one is powerful in terms of the volume of data it can...

handle?


Comparing a AS/400 and a mainframe is like comparing an apple and an orange. I will tell you what an AS/400 can do, and speak what I can for the mainframe. The AS/400 is one of the best database machines out there. It can now handle terabytes of data and retrieve records extremely fast. The AS/400 manages all "objects" on the system in a journal for fast retrieval and some really smart geeks at IBM developed a formula to find records in three tries or less. What this means is that DB2 will go directly to a "keyed" file and look for the record using a formula, if not found it will try again. Studies have found that no more then three tries by the OS where needed to find a record. I have dealt with files that contain over 100 million records and can SQL, Query, or program read a record in milliseconds. This puppy is fast and when retrieved, all the data fields with in the record are validated. You can reduce the performance of DB2 by creating all types of logical views of the data, but it only hurts the write operation not the retrieval.

My limited experiences with mainframes are with flat record files that are not relational in nature. Although the retrieval is fast, the manipulation of the data can be complex, which reduces the overall speed of the data retrieval. Please remember that I am an AS/400 bigot, so I mean no harm to the "mainframers" and I cannot toot their horn well at all. I hope this helps some.

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A mainframer since 70' (I started very young)
Your experience on the mainframe side is extremely limited. Yes it is like comparing an apple to an orange, but apparently, you have NEVER seen an orange.

I can read flat and build "relationl" databases in memory ... on the mainframe, AS/400, and windows. (look up associative arrays, something that AS/400 is renown for)

If you have ever built an index and alternate index for DB2, MySQL, Informix, MS/Access, ... ... ..., then you know that you can find anything in ONE try. If you use a "spelling corrector" software ... you can find it regardless, if it even exists. I hope you don't hardcode queries. Can you do stored procedures ?

I am available if you need a mentor.
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