RE: random i/o and relative efficiency

[Joel Fritz <JFritz@xxxxxxxxxxxxxxxx>]

First I've heard of the AS/400 random file.  I was thinking of random I/O in
the sense of random access by key.  Didn't mean to be controversial.  

My real question was is a READE cheaper than a CHAIN, and if so, by how
much?  

More generally, does anyone have benchmark data on the various file opcodes.
I've done a lot with unkeyed sequential files--semi acceptable place for
FMTDTA--but I'm curious about the relative costs of using the access path (I
know, RRN too) opcodes. 

> -----Original Message-----
> From: Pat Barber [mailto:MBOCEANSIDE@postoffice.worldnet.att.net]
> Sent: Wednesday, February 17, 1999 3:50 PM
> To: MIDRANGE-L@midrange.com
> Subject: Re: random i/o and relative efficiency
> 
> 
> david.kahn@gbwsh.mail.abb.com wrote:
> > 
> > Pat Barber <MBOCEANSIDE@postoffice.worldnet.att.net>
> > 
> > >Large "random" files can really blaze with a binary search,BUT,
> > >the file has to be in some order...which sort of defeats the random
> > >concept... stick with keyed index files....
> > 
> > Pat,
> > 
> > Are you perhaps confusing "random" with "relative"? AIUI 
> Joel's example
> > _is_ with an indexed file. The choice is between:
> 
> Maybe I misread the note, but as a side note, there was and still is
> a "random" file on the 400 which is accessed by relative record number
> but proably not used by over 2 people in the whole world any more....
> this was a carry over from long,long ago on the older 3/X boxes... but
> as I said earlier, I could have misread the whole thing....
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