Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!udel!mmdf
From: korni@sietec1.sietec.de (Jochen Kornitzky)
Newsgroups: comp.os.minix
Subject: Re: disk controllers
Message-ID: <34974@nigel.ee.udel.edu>
Date: 30 Oct 90 20:44:54 GMT
Sender: mmdf@ee.udel.edu
Lines: 50

+---- "Kenneth J. Hendrickson" about "disk controllers" :
|
| I have learned that on the NeXT (and possibly other *nix systems), there
| is a /etc/disktab animal that lists characteristics of disks, much like
| /etc/termcap lists the capabilities of a terminal.  This sounds like a
| good idea to me.  The kernel could read this file and configure itself
| for the correct number of tracks, sectors, cylinders, heads, etc. 

As I known the *ix-world, /etc/disktab is not read by the kernel
itself (there is no reference to ANY filename inside the kernel)
( ... mumble mumble ... oh: /etc/init ;-)
but by various tools (as markbad, mkfs, low-level-format, disklabel ...).
When formatting and partitioning a disk, such a tool writes the
selected (from /etc/disktab) characteristics *on the disk* where the
kernel can read it.

| Thus
| this information would not need to be hardcoded into the kernel as it is
| now.  I don't know much about disk controllers, but could this help the
| compatibility problem, and development of SCSI and ESDI device drivers?

There could be various device drivers in the kernel and decide at startup
which to run.

| It is kind of "begging the question" to use this if you are booting from
| a hard disk, but it makes perfect sense if you are booting from a
| floppy.

That's why it's written onto the disk.

| 
| What say the device driver gods?
| 
Oh Lord.
|
+----

	Jochen


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