[CLUE-Cert] Answers to some of the questions from last meeting

Dennis J Perkins dperkins2 at qwest.net
Fri Dec 1 21:36:35 MST 2000

> Named pipes vs pipes
>     From Steven's Advanced Programming in the UNIX Environment (APUE):
>         Pipes are the oldest form of UNIX IPC (interprocess
> communication). They have two limitations:
>             1. They are only half-duplex. Data flows only in one
> direction.
>             2. They can be used only between processes that have a
> common ancestor.

>     Stream pipes get around the first limitation, and FIFOs and named
> stream pipes get around the second limitation. Despite these
> limitations, half-duplex pipes are still the most commonly used form of
> IPC.

I assume that stream pipes is part of the STREAMS package.  Linux doesn't
 and I haven't heard of any efforts to port it.

I have a couple of comments regarding the discussion of the boot process
two weeks ago.  I double-checked and the MBR only takes one sector, not
two.  I also found that the partition table resides in the same sector.
Second, I was wrong about part of the boot sequence.  In rectrospect, it
should have been obvious.  The kernel does load the root partition.
Otherwise, it would not be able to find init and the boot scripts.  But one
of the boot scripts remounts the root partition as read-only in order to
run fsck on it.  If everything is ok, it remounts it again, this time as
read-write.  It then runs fsck on the other partitions listed in /etc/fsck.


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