Path: utzoo!attcan!uunet!aplcen!samsung!munnari.oz.au!basser!metro!natmlab.dap.csiro.au!ditsyda!evans
From: evans@ditsyda.oz (Bruce Evans)
Newsgroups: comp.os.minix
Subject: Re: How to use a hard disk with Minix
Message-ID: <2341@ditsyda.oz>
Date: 3 Dec 89 12:52:26 GMT
References: <312@trux.UUCP> <89332.220027TAR@MAINE.BITNET>
Reply-To: evans@ditsyda.oz.au (Bruce Evans)
Organization: CSIRO DIT Sydney, Australia
Lines: 55

In article <89332.220027TAR@MAINE.BITNET> TAR@MAINE.BITNET (Thom Rounds) writes:
>In article <312@trux.UUCP>, car@trux.UUCP (Chris Rende) says:
>>
>>(I used hd0 because I don't have the partitioning part of xt_wini working
>>yet...).
>
>    I hope there was nothing on that disk, because if there was, you trashed
>it.

Sounds like the disk wasn't even working before.

>    To answer your question, yes. Fdisk partitions you hard disk for you. Re-
>partitioning your hard disk has the same effect as reformmatting it. The data
>is all there, but you can't get at it. You have to reformat it first. /dev/hd0

With luck, restoring the partition table (just 1 sector on the disk) will
recover the data. The best way to learn this stuff is to start with an *empty*
hard disk and move partitions around on it like little files. The partition
table is .001% as complicated as a file system.

>/dev/hd4 is the entire second hard disk, etc. Try to remember, re-partitioning
>your hard disk means you lose what is on it. I learned this the hard way.

No, /dev/hd4 is partition 4 on the first disk and /dev/hd5 is the entire
second disk. In theory you can delete and move around some partitions
without affecting the others.

>>2) If you only have a 5Mb hard disk to use, what's the best way to use it?

Make a 5M partition and mount it on /usr (or "mount" it on / in v1.5).
Partitions always fill up so you want them big. Too big makes them too hard
to back up.

>>3) I'd like to the RAM disk for as little as possible (if at all). Is it
>>   wise to use the hard disk as the ROOT FS?

It is far more convenient, but a little slower.

>>4) When I get my second drive (10Mb) to work, what would be a good disk layout
>>   for using the two drives together?

5M for binaries mounted on / (hope that drive is fastest) and 10M for source
on /usr.

>>I can see the head positioning mechanism moving on the HD while the disk is
>>operating. Minix seems to do alot of seeks back to the start of the file
>>system, cyl 0, super block, or whatever. While doing a "cat somefile" the

I would not expect "cat" to a terminal to cause so many seeks. Operations
involving more than 1 file often thrash the disk cache (it's too small). The
file may be scattered all over the disk. These things often cut disk
throughput by a factor of 10 (beyond another factor of 2 to 9 for rotational
latency).
-- 
Bruce Evans		evans@ditsyda.oz.au