[TUHS] /dev/drum

Noel Chiappa jnc at mercury.lcs.mit.edu
Tue Apr 24 08:01:11 AEST 2018

    > From: Clem Cole

    > To be honest, I really don't remember - but I know we used letters for
    > the different partitions on the 11/70 before BSD showed up.

In V6 (and probably before that, too), it was numbers:


So on my machine which had 2 x 50MB CalChomps, with a Diva controller, which
we had to split up into two partition each (below), they were dv00, dv01, dv10
and dv11. Letters for the partitions made it easier...

    > The reason for the partition originally was (and it must have been 6th
    > edition when I first saw it), DEC finally made a disk large enough that
    > number of blocks overflowed a 16 bit integer.  So splitting the disk
    > into smaller partitions allowed the original seek(2) to work without
    > overflow.

No, in V6 filesystems, block numbers (in inodes, etc - also the file system
size in the superblock) were only 16 bits, so a 50MB disk (100K blocks) had to
be split up into partitions to use it all. True of the RP03/04 in V6 too (see
the man page above).


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