Ted and others:

Yes, MPE now deals with 4096 byte pages in and out of memory.  Obviously,
the more you can get in each 4096 disk read, the better.  When you make
files for efficiency, set the blocking factor to 4096 / record size of the
file in bytes rounded down to get the best.  It is also best to set your
CONTROL BLOCKMAX statement at the top of your TurboImage schemas to be 2048
(in words), so that when reading through your databases using TurboImage
calls, the maximum amount of database data gets read in with one read.

> -----Original Message-----
> From: Ted Ashton [SMTP:[log in to unmask]]
> Sent: Friday, March 03, 2000 1:42 PM
> To:   [log in to unmask]
> Subject:      Blocking factor
>
> I've just been looking over the blocking-factor messages in the 3000-L
> archives
> and I'm afraid I'm still somewhat confused.  It has been claimed that the
> best
> blocking factor can be had by just not specifying one and letting MPE
> decide.
> So I did some testing.  Here is a sampling of the results:
>
> BFTEST              1B  FA           0          1 128        0  0  *
> BFTEST              2B  FA           0          1 128        0  0  *
> BFTEST              3B  FA           0          1  64        0  0  *
> BFTEST              5B  FA           0          1  42        0  0  *
> BFTEST              7B  FA           0          1  32        0  0  *
> BFTEST             11B  FA           0          1  21        0  0  *
> BFTEST             17B  FA           0          1  14        0  0  *
> BFTEST             25B  FA           0          1   9        0  0  *
> BFTEST             38B  FA           0          1   6        0  0  *
> BFTEST             57B  FA           0          1   4        0  0  *
> BFTEST             86B  FA           0          1   2        0  0  *
> BFTEST            129B  FA           0          1   1        0  0  *
> BFTEST            194B  FA           0          1   1        0  0  *
> BFTEST            291B  FA           0          1   1        0  0  *
> BFTEST            437B  FA           0          1   1        0  0  *
> BFTEST            656B  FA           0          1   1        0  0  *
> BFTEST            985B  FA           0          1   1        0  0  *
> BFTEST           1477B  FA           0          1   1        0  0  *
> BFTEST           2216B  FA           0          1   1        0  0  *
> BFTEST           3325B  FA           0          1   1        0  0  *
> BFTEST           4987B  FA           0          1   1        0  0  *
> BFTEST           7481B  FA           0          1   1        0  0  *
>
> Looks to me like if you don't specify a blocking factor, MPE divides the
> sector size (256 bytes) by the record size (adjusted upward to be an even
> number if necessary) and drops any fractional portion to get the blocking
> factor and that if the calculated number is less than one, it uses one.
>
> Doesn't MPE deal with 4096-byte pages now?  Does the blocking factor
> matter?
> How does changing it change the efficiency of the storage or of the
> retrieval
> of the data.
>
> TIA for any answers,
> Ted
> --
> Ted Ashton ([log in to unmask]), Info Sys, Southern Adventist University
>           ==========================================================
> The measure of our intellectual capacity is the capacity to feel less and
> less satisfied with our answers to better and better problems.
>                                            -- Churchman, C. W.