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Re: Clarifications about /dev devices

Previous thread: internet transfer stalls by Mark Fordham on Thursday, September 13, 2007 - 7:50 am. (1 message)

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[view original message]
From: João Salvatti <salvatti@...>
To: Misc OpenBSD <misc@...>
Subject: Clarifications about /dev devices
Date: Thursday, September 13, 2007 - 8:27 am

Hi all,


I'd like to know why /dev/cd0a and /dev/rcd0a device files (at my

machine) refer to the same physical device, given that one is not a

symlink to the other one, and vice-versa, and also given that cd0a is

a block device and rcd0a is a character device.


Thanks in advance.


--

Joco Salvatti

Undergraduating in Computer Science

Federal University of Para - UFPA

web: http://www.openbsd-pa.org

e-mail: salvatti@openbsd-pa.org
[view original message]
From: Miod Vallat <miod@...>
To: João <salvatti@...>
Cc: Misc OpenBSD <misc@...>
Subject: Re: Clarifications about /dev devices
Date: Thursday, September 13, 2007 - 8:33 am

The kernel handles two kinds of device nodes: ``block'' devices and

``character'' devices. The major numbers of these devices are

platform-dependant, and must match the bdevsw[] and cdevsw[] arrays

in sys/arch/<platform>/<platform>/conf.c.


Storage devices can be accessed either as block devices or character

devices, hence they have one entry in each of these tables. Their major

numbers do not need to match since these are completely independant

numbering spaces.


Miod
[view original message]
From: João Salvatti <salvatti@...>
To: Misc OpenBSD <misc@...>
Subject: Re: Clarifications about /dev devices
Date: Thursday, September 13, 2007 - 9:18 am

Thanks folks.


--

Joco Salvatti

Undergraduating in Computer Science

Federal University of Para - UFPA

web: http://www.openbsd-pa.org

e-mail: salvatti@openbsd-pa.org
Previous thread: internet transfer stalls by Mark Fordham on Thursday, September 13, 2007 - 7:50 am. (1 message)

Next thread: [henning@openbsd.org: help needed with laptop hdd] by Marcus Glocker on Thursday, September 13, 2007 - 9:25 am. (7 messages)