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Best of the Newsgroups: xenix

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What is this stuff?

Options you don't have for getting data off of a Xenix box

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From: "Brian K. White" <br...@aljex.com>
Subject: Re: Alternative to SCO
Date: Fri, 5 Oct 2007 23:21:14 -0400
Message-ID: <00cf01c807c7$f39bf5f0$6800000a@venti> 
References: <1191522468.046628.119660@n39g2000hsh.googlegroups.com> <kseag3tjnka90gb656kalu07r7qb70jilc@4ax.com> <1191589825.887474.100700@y42g2000hsy.googlegroups.com> <7ftcg3543jkl3933s8trlopgdbamo3vgj0@4ax.com> 


> Actually, it's easier to deal with the old systems.  The main
> advantage is the very small sizes of the OS and applications.  For
> example, the Xenix system fits in about 500MBytes, most of which is
> data.

Just to point out for those unfamiliar with Xenix, the OS itself is actually 
under 50, heck, under 10!. An entire Xenix filesystem can not even exceed 
512M, though you can have multiple 512M fs's mounted for a total system that 
exceeds 512M.

However, a 320M Xenix system IS huge when you remember all the options you 
don't have for getting data off of a Xenix box.

* Networking - nope. (it existed but I never saw a single box with it, just 
like the C compiler)

* Serial (kermit/rz/sz not PPP, no networking!) - yes, but only at 9600 
unless you have a 3rd party serial card driver and card and the right kind 
of serial cable. Hopefully the box has a 3.5" floppy drive at least to copy 
gzip, rz, sz, and kermit onto the box in the first place, or else you are in 
for some real nostalgia using cu and %put or %take and learning how great we 
all hove it now that most communications protocols have built-in error 
detection, correction and/or retransmit, which cu put/take does not! Oh, and 
beware even if it is a 3.5" drive, it might well actually be a 720K drive 
not a 1.44M drive!

* hd transplant to new hardware to continue to run xenix - if you can find a 
486-100 or slower box that actully runs, reliably. (think 20 year old dried 
out capacitors all out of spec making the circuit unstable at the very 
least, if not a fire hazard! Not kidding! Seen it! Caps out of spec, so 
voltage regulator circuit out of spec, cooked several parts of the board, 
dried up stickers on components and on circuit traces caught fire!).

* hd transplant for linux to read - linux can mount xenix fs's but it can't 
parse xenix divvy tables to know where the fs's start & stop. Theoretically 
you can read the divvy table yourself while still in xenix and write down 
the numbers and calculate the offsets yourself manually and use dd in linux 
to extract the fs to a seperate file. If you can manage that then linux can 
loopback mount the extracted image files effortlessly. I never managed it 
but I think Bela once described the basic steps here.

* hd to hd copy to create partitions or cpio files that linux CAN read - if 
you can find a hard drive small enough that an old 486-66 motherboard bios 
can even see it.

* tar/cpio to floppies - yep, that works. You need to know how to reassemble 
sco's multi-volume tar files unless you happen to be restoring onto a newer 
sco os instead of linux or freebsd. It's not conceptually hard, but is 
incredibly tedious and thus prone to human error, but a simple script can 
and has been written to automate that. So the only problem is that it's 
almost impossible to write to 200 floppies and read from them and have not 
one of them turn out corrupt. An you must be ok with spending a few solid 
hours feeding/swapping floppies into machines every couple minutes.

...hm... I could modify the sco-tar script so that it will retry any given 
volume and not proceed on to subsequent volumes until you say this one was 
OK, giving you a chance to throw away the bad floppy and regenerate the 
volume on the source machine instead of having to start the entire job over 
from the beginning. But is there a way to do the same thing on the source 
machine that is generating the volumes? Have it regenerate a given volume as 
many times as you ask, before proceeding on the the next, giving you a 
chance to read a volume and discover it's bad instead of having to start the 
entire job from the beginning. hm...

* tape drive - if you can find working media for the ancient tape drive in 
the xenix box, and if that drive and it's controller card can then be moved 
and be installed on linux, or if you can install a newer drive on the xenix 
box.

* cd burner - put down the Lagavulin.

So, when faced with an old xenix box, you are actually faced with a pretty 
big problem getting that system off onto other hardware or OS in less time 
than a full weekend unless you are well prepred ahead of time with things 
you would have a hard time finding on short notice.

Someone recently posted on this list that they worked out a recipe for 
taking a full xenix raw hd image and running it in a bochs or qemu emulator. 
I'm dying to try that. If that's possible, then that opens up a fast 
migration option by just taking the hard drive out of the xenix box and 
plugging into any linux box, dd an image of the whole disk in linux in no 
time. You could do it with a laptop and a usb drive enclosure and the drive 
could be cloned and right back into production in the old box in a few 
minutes if necessary. Then you get that working in linux at your leisure, 
then some other time update the clone and switch over to it for live 
production in as little as a few minutes.

Brian K. White    br...@aljex.com    http://www.myspace.com/KEYofR
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