Origin of "partition" in storage devices

[Warner Losh]

On Tue, Feb 1, 2022 at 1:22 AM Huw Davies via cctalk <cctalk at classiccmp.org>
wrote:

>
>
> > On 1 Feb 2022, at 09:42, cctalk at classiccmp.org wrote:
> >
> > A somewhat broader search found the 1984 RT-11 System Release Notes with
> the following:
> >
> >
> >
> > 1.4.2.4 Logical Disk Subsetting Handler (LD) - The logical disk
> subsetting handler lets you define logical disks, which are subsets of
> physical disks. You define logical disks by assigning a logical disk unit
> number to a file on a physical disk. You can then use the logical disk as
> though it were a physical disk.
> >
> > AA-5286F-TC-T1_RT-11_System_Release_Notes_Jul84.pdf (bitsavers.org) <
> http://www.bitsavers.org/pdf/dec/pdp11/rt11/v5.1_Jul84/AA-5286F-TC-T1_RT-11_System_Release_Notes_Jul84.pdf>
> p15/102
> >
> >
> >
> > Suggests DEC had not yet adopted the term “partition” for a segment of a
> disk
>
> From
> http://bitsavers.org/pdf/dec/pdp11/ultrix-11/2.0/AE-X370C-TC_ULTRIX-11_2.0SPD_Sep84.pdf
> <
> http://bitsavers.org/pdf/dec/pdp11/ultrix-11/2.0/AE-X370C-TC_ULTRIX-11_2.0SPD_Sep84.pdf>
> it seems that at least one part of Digital used partitions as we now know
> it in September 1984. I wonder if AT&T Unix Seventh edition also called
> them partitions?
>

Unix has called these "pseudo-disks" in Unix 4th edition through the 7th
edition, at least in their driver man pages.

The 6th and 7th edition setup guides, however, have this in them:

The big disk drivers (rp.c and hp.c)
have partition tables in them which you
may want to experiment with.

which dates from March, 1975 and seems to be in /usr/start/start in the
distributions.

Warner