Notes"The manual for Mental Blocks claims that, for both C64 and IBM, you put the diskette in label-side up. I thought that had to be a typo, since every single mixed C64/IBM or Apple/IBM diskette I have ever seen is a “flippy” disk where one side is IBM and the other side is C64 or Apple — until I looked at the FAT12 for the disk and saw that tons of sectors in an interleaved pattern were marked as BAD — very strange usage."Unfurl
Notes"In essence MapReduce works by repeatedly sorting and merging data that is streamed to and from disk at the transfer rate of the disk. Contrast this to accessing data from a relational database that operates at the seek rate of the disk"Unfurl