decoration decoration
Stories

GROKLAW
When you want to know more...
decoration
For layout only
Home
Archives
Site Map
Search
About Groklaw
Awards
Legal Research
Timelines
ApplevSamsung
ApplevSamsung p.2
ArchiveExplorer
Autozone
Bilski
Cases
Cast: Lawyers
Comes v. MS
Contracts/Documents
Courts
DRM
Gordon v MS
GPL
Grokdoc
HTML How To
IPI v RH
IV v. Google
Legal Docs
Lodsys
MS Litigations
MSvB&N
News Picks
Novell v. MS
Novell-MS Deal
ODF/OOXML
OOXML Appeals
OraclevGoogle
Patents
ProjectMonterey
Psystar
Quote Database
Red Hat v SCO
Salus Book
SCEA v Hotz
SCO Appeals
SCO Bankruptcy
SCO Financials
SCO Overview
SCO v IBM
SCO v Novell
SCO:Soup2Nuts
SCOsource
Sean Daly
Software Patents
Switch to Linux
Transcripts
Unix Books

Gear

Groklaw Gear

Click here to send an email to the editor of this weblog.


You won't find me on Facebook


Donate

Donate Paypal


No Legal Advice

The information on Groklaw is not intended to constitute legal advice. While Mark is a lawyer and he has asked other lawyers and law students to contribute articles, all of these articles are offered to help educate, not to provide specific legal advice. They are not your lawyers.

Here's Groklaw's comments policy.


What's New

STORIES
No new stories

COMMENTS last 48 hrs
No new comments


Sponsors

Hosting:
hosted by ibiblio

On servers donated to ibiblio by AMD.

Webmaster
Operating System definition | 113 comments | Create New Account
Comments belong to whoever posts them. Please notify us of inappropriate comments.
Operating System definition
Authored by: mbouckaert on Monday, November 26 2012 @ 07:23 PM EST
We may need to add that most operating systems introduce a
distinction between the part of themselves (per your
definition) that is active for a given task and runs on
behalf of that task; and the part of themselves that does
the actual sharing of the underlying hardware.

On most current architectures, the separation is enforced
with the help of the hardware. The parts that run "on
behalf" of a given task are run using one "mode" of the
underlying hardware; the sharing part runs in another
"mode". Typical names for these are "user vs. supervisor
mode" or "application vs. Kernel mode". This is because, by
design of the hardware, code executing in "user" mode cannot
touch, access or even "know about" the activities taking
place in "supervisor" mode; the hardware does not provide
"user-mode" programs with a way to even name such
information.

Some processors of the Intel family (on which Microsoft
products were built) did start providing the hardware
facilities in question around 1985. However, these
facilities were expensive. The target population for
Windows was mostly machines equipped with "lesser"
processors of the same family.

Therefore, the hardware did not enforce any distinction
between the parts of the Windows code that ran "on behalf
of" user tasks and the parts that were more central in
sharing.

Because of that, whether a given part of the Windows code
was one or the other was defined (mostly) in the
documentation and in the plans for future releases of the
code, rather than in the code itself.

It could be argued that, if Windows 95 sq. had used the
hardware assist described above, the harm made to middleware
designers like Novell would have been much less. As it was,
however, the documentation of the API was even more
important for third party developers if their product had to
survive routine changes to the OS.

---
bck

[ Reply to This | Parent | # ]

Operating System definition
Authored by: eric76 on Saturday, December 01 2012 @ 05:36 AM EST
Keep in mind that an operating system does not have to support multiple users or
tasks. That today's operating systems support multiple users or tasks is beside
the point.

[ Reply to This | Parent | # ]

Groklaw © Copyright 2003-2013 Pamela Jones.
All trademarks and copyrights on this page are owned by their respective owners.
Comments are owned by the individual posters.

PJ's articles are licensed under a Creative Commons License. ( Details )