Concept Architecture of Unix Systems - Page 3 | Unix Linux Forums | Technology Illustrated

  Go Back    


Technology Illustrated Post a Unix or Linux technology related image and discuss the concepts.

Concept Architecture of Unix Systems

Technology Illustrated


Closed Thread    
 
Thread Tools Search this Thread Display Modes
    #15  
Old 10-04-2012
Neo's Avatar
Neo Neo is offline Forum Staff  
Administrator
 
Join Date: Sep 2000
Last Activity: 18 April 2014, 1:38 PM EDT
Location: Asia pacific region
Posts: 12,898
Thanks: 492
Thanked 846 Times in 381 Posts
Quote:
Originally Posted by Perderabo View Post
But about your onion... the assembler is usually known as "as". You have "as" as an application program. Maybe you should move it the "assemblers and compilers" layer.
It's not anyone's onion in particular. I just pulled it off the Internet to use to kick off this discussion; so there in nothing personal in the image at all
    #16  
Old 10-10-2012
bakunin bakunin is offline Forum Staff  
Bughunter Extraordinaire
 
Join Date: May 2005
Last Activity: 18 April 2014, 9:02 AM EDT
Location: In the leftmost byte of /dev/kmem
Posts: 3,919
Thanks: 39
Thanked 671 Times in 533 Posts
I think "kernel" is a way to broad category. When you examine what a kernel does there are two different groups of services a kernel has to offer:

A) Drivers These are programs which interface with a piece of hardware and create a generic interface with which other programs can work - usually a device file. If there is any one distinguishing concept of Unix and all Unixoid systems that is "everything is a file". Unix uses "files" (loosely defined, anything with an entry in the filesystem) for about everything: inter-process communication (semaphores, pipes, FIFOs), device interaction, even networking! It fits that the "generic interface" a driver presents to the rest of the OS is usually a device file which can be written and/or read.

Drivers are usually processes in their own right but run with kernel privileges. It is a matter of definition if you see them as part of the kernel or as add-ons to it.

B) Service threads These are all sorts of services a kernel offers to keep the system going: (process) accounting, scheduling, resource management, etc.. Nano- (Micro-)kernel advocates (like Andrew Tanenbaum) argue that only these make for the "kernel" at all and that even some of these could be removed from the "core kernel" to make drivers.

As we all know Nanokernels didn't win out because even the last kernel to be developed - Linux - was a monolithic kernel with the drivers included, much to the chagrin of the Microkernel-advocates. This doesn't mean that monolithics are better at all, just that nobody every tried the other approach in a productive environment.


So my personal "onion image" would be:

hardware
drivers
(other) kernel threads
applications

Even more so because "compilers" (or linkers) are ordinary programs at all. They are in no way more special than "sed", "awk" or any similar text filter, because in fact they are filter programs too: the are fed an input file (the source, the object deck, ...) and produce an output file (the object deck, the executable, the archive, ...) from it by following some rules. Any programming language can be interpreted as command within these rules to produce a certain output (the relocatable or executable code) just like a sed script will produce a defined output from an input.

bakunin

Last edited by bakunin; 10-10-2012 at 05:36 AM..
Closed Thread

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

More UNIX and Linux Forum Topics You Might Find Helpful
Thread Thread Starter Forum Replies Last Post
What exactly is the concept of BITS in this unix.com forum? Manjunath B What is on Your Mind? 2 09-28-2012 05:05 AM
Regarding Mail concept in unix krishna_gnv Shell Programming and Scripting 3 08-30-2010 09:48 AM
trying to understand rationale of unix stream i/o concept kaychau UNIX for Dummies Questions & Answers 1 07-16-2009 11:23 AM
UNIX box architecture pratyusha UNIX for Dummies Questions & Answers 5 12-16-2008 10:19 AM
Having difficulty with UNIX concept. Please help! ALon UNIX for Dummies Questions & Answers 4 01-11-2007 10:42 AM



All times are GMT -4. The time now is 02:14 PM.