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Date:      Sun, 9 Feb 2020 11:13:39 +0100
From:      Polytropon <freebsd@edvax.de>
To:        "Steve O'Hara-Smith" <steve@sohara.org>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: Re  updating BIOS
Message-ID:  <20200209111339.6e42f4b8.freebsd@edvax.de>
In-Reply-To: <20200209084111.8d9764a128bab47ee1c19a86@sohara.org>
References:  <202002090809.01989xgi025440@sdf.org> <20200209084111.8d9764a128bab47ee1c19a86@sohara.org>

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On Sun, 9 Feb 2020 08:41:11 +0000, Steve O'Hara-Smith wrote:
> On Sun, 09 Feb 2020 02:09:59 -0600
> Scott Bennett <bennett@sdf.org> wrote:
> 
> >      The first part of the above, mispunctuated pair of sentences is
> > correct, but the latter part is not.  FreeDOS, like PC-DOS and MSDOS
> > before it, is/was not an operating system, but rather a more primitive
> > creature known as a monitor system.
> 
> 	The DOS part of those names is an abbreviation of 'Disc Operating
> System' - [...]

The common way of spelling here is "disk"; "disc" usually
refers to optical media. Smaller disks were called diskettes.
For example, the first prominent use of DOS was "IBM Disk
Operating System /360", or DOS/360, whose naming convention
was later used for microcomputer operating systems based on
the use of hard disks or diskettes, even though the "conceptual
bowels" of those microcomputer and PC operating systems have
more in common with CP/CMS than with DOS/360.



> [...] clearly at the time they were considered operating systems even
> though they started life as near clones of CP/M (Control Program/Monitor).
> IBM 360 mainframes didn't have virtual memory, processes or any of the
> protections you mentioned, it didn't even have anything that would be
> recognised as a filesystem today (it had record oriented datasets) - but
> OS360 was definitely considered an operating system.

It even carried that intention in its name. ;-)

There are many different criteria (without a common consensus)
of what actually makes an operating system. Some consider the
compiler a required part of the OS, others don't. Some say that
process monitoring and control needs to be part of the OS,
others consider it optional.

Personally, I'd say that understanding DOS (for the PC) as an
operating system is valid, sure, with limited capabilities,
but seen in the context of the time it was developed and used,
it surely fulfilled the critera usually used in the microcomputer
and PC area.



> 	[MS/PC/DR/Free]DOS was a lot more like a mainframe batch operating
> system than a multi-user multi-tasking operating system such as Multics or
> unix, but hijacking the term operating system to mean only the latterm, and
> that only with hardware supported isolation mechanisms is revisionist. I
> recall working on a unix(ish) system in the late 1980s that didn't have
> hardware memory mapping or protection, or even fsck which made recovering
> from (the frequent) crashes rather tedious (icheck, ncheck ...).

A little sidenote regarding terminology in context of history:

If I remember correctly, early versions of CP/M, which is the
primary predecessor of all the DOSes, inherited a lot from CP/CMS,
an operating system typically run using the VM operating system
(we would probably call VM/370 a hypervisor today), even though
it was possible, at least for some time, to run CMS on bare metal.
During further development, it became dependent on VM. The
user-facing part of CMS was the CP, the control program (that's
why CP/CMS means "control program / conversational monitor system).
It had things later known in CP/M, such as the dialog-oriented
command line interface, and "Minidisks" - those became "drive
letters" in CP/M, as well as filenames associated with specific
data sets (mamaged through VM and its virtualization of storage
and access). Later, DOS inherited the drive letters and many
other conceptual ideas from CP/M.

So - yes, the past is still alive.



NB: DOSes = plural of DOS; DOS/ES = an operating system. ;-)



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...



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