Origin of "partition" in storage devices

Tom Gardner tom94022 at comcast.net
Mon Jan 31 16:42:38 CST 2022

A somewhat broader search found the 1984 RT-11 System Release Notes with the following: 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




-----Original Message-----
From: Tom Gardner [mailto:tom94022 at comcast.net] 

FWIW a Google search:  "partition site:http://www.bitsavers.org/pdf/dec/pdp11/rt11" returns no relevant hits prior to 1983


I suspect that ESDI and MFM controllers emulating RL/RK disks are also later than 1983




-----Original Message-----

From: Zane Healy [ <mailto:healyzh at avanthar.com> mailto:healyzh at avanthar.com] 

Sent: Monday, January 31, 2022 12:40 PM

To: Paul Koning; General Discussion: On-Topic and Off-Topic Posts

Cc:  <mailto:t.gardner at computer.org> t.gardner at computer.org; Tom Gardner

Subject: Re: Origin of "partition" in storage devices


On Jan 31, 2022, at 11:28 AM, Paul Koning via cctalk < <mailto:cctalk at classiccmp.org> cctalk at classiccmp.org> wrote:


> Both of these are memory partitions.   The only OS I can think of predating the ones you mentioned is RT-11, the later versions (V2 did not have them).  When did Unix first get partitions?


>             paul


Partitions are pretty important in RT-11 v5.x, after all, there is the partition size limit, so you have to have multiple partitions for almost any HD, except very small ones.


Let�s not forget hardware enforced partitioning, the WEQSD/04 ESDI controller comes to mind.  It see�s a single large ESDI HD as a single disk, but you can partition it on the controller, and the OS sees each partition as a separate physical disk.  I seem to remember some MFM controllers that made the MFM drive appear to be RL01/RL02 or RK05 packs.





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