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From: mph@rover.UUCP (Mark Huth)
Newsgroups: comp.sys.amiga
Subject: Re: Close Call (Supra hard drive)
Message-ID: <419@rover.UUCP>
Date: Thu, 16-Jul-87 12:43:28 EDT
Article-I.D.: rover.419
Posted: Thu Jul 16 12:43:28 1987
Date-Received: Sat, 18-Jul-87 18:38:54 EDT
References: <1385@crash.CTS.COM>
Reply-To: mph@rover.UUCP (Mark Huth)
Organization: Motorola Microcomputer Division, Tempe, Az.
Lines: 81
Keywords: Amiga hard disk Supra horror story
Summary: Normal Disk Validator Behavior

In article <1385@crash.CTS.COM> mercurio@crash.CTS.COM (Phil Mercurio) writes:
>
>The following is a description of a close call I had with my 20 MB
>Supra hard disk on my Amiga.  
> .........
>Open()'ing "prt:" -- nothing magical going on here.  After a few seconds of
>disk activity, the system froze (no Guru, just an unresponsive system).
> .........
>We administer the Amiga/Vulcan nerve pinch (CTRL-Ah-Ah) and the system
>reboots.  The first command in my Startup-Sequence is Supramount, as
>it should be.  Upon the attempt to be mounted, the Supra starts blinking
>its busy light madly and continuously (it normally mounts in a second
>or so).  This went on for several seconds, maybe a minute, before my
>friend and I realized something was not right.  We rebooted again, and
>
This is normal behavior for a hard disk which has been rebooted with an invalid
bit map!  Those of you with hard disks, do not panic!  The disk validator (I
think) is performing its proper function.  When the drive is mounted the
validator checks out the drive, and discovers that the bit map on the disk is
INVALID.  This usually happens when the system has crashed with files opened
for writing.  Whell, it takes a long time (5 -10 minutes) for the validator to
examine EVERY sector on the drive and determine if it is allocated to a a valid
file or not, and then repair the bit map.  LEAVE IT ALONE while this is
happening a give thanks to those that designed this program WHICH IS SAVING your
hard disk from becoming a useless bit bucket.

I learned this from hard experience.  I am affiliated with a company which is
developing yet another hard disk for the Amiga.  It works through the parallel
port (groan - but there are good points to this as well) and is rather
inexpensive.  I'll give more details of this RSN, as the last bugs are being
ironed out.  Anyway, during the course of development of drivers and backup
utilities, I have left many a hard drive in limbo.  The first time that I
rebooted and the light came on and stayed on I was quite discouraged - so much
so that I couldn't do anything for several minutes.  Fortunate indeed, as I
discovered what was really happening when the light went out and continued the
startup sequence.  Well done!  (Actually, shades of Un*x after a crash.)

Another thing that I have learned is that the DiskDoctor program does work
on properly designed hard drives.  Having gotten the drive to work well enough
that I refused to work without it, I managed to discover some lurking hardware
bugs that occasionally corrupted the data on the disk.  After repairing these
bugs (not yet having developed the backup program) I was faced with many busted
directories.  So, with nothing to lose, I ran DiskDoctor.  It ran, and ran, and
reported its completion.  I did a dir on the drive and found to my horror that
it was empty!  I poked around with a disk dumping routine I've written, and
discoverd that everything was intact, but disconected form the root directory.

Well, thought I, this can be patched (and if Commodore would get off their
duffs and send us the developer kit for which we have paid, I might have used
DiskEd).  I decided to rerun DiskDoctor, and after some thrashing and the
trashing of some unimportant files, it completed.  Now the disk was intact!!
Someone has a sense of humor, though, because what used to be JE_sys_disk was
now called Lazarus.  I ran development on it for several more weeks until just
this weekend I was able to get both backup and restore to perform useful work.

FLAME ON - full heat to Commodore

Jefferson Enterprises played your silly developer games, was granted the 
priviledge of sending in our 50 bucks.  This procedure took several months, but
three months ago, WE SENT IN OUR MONEY.  We called a month later and were told
that the management shakeup had slowed things down a bit - be patient.  Two more
months, have elapsed, and now we get an answering machine and most recently a
recording telling us that the number had been disconnected.  We really don't
want to turn Commordore into the Postmaster General for mail fraud, but 
WHERE IS THE DEVELOPER KIT!!!!!!!!!  You took our money, using the US Mail, now
I want the goodies!  We would relly like to make hardware for the expansion port
but I find that difficult without the bus timing information that is supposed
to be in the developer kit.  We got plans for a really spiffy controller that
will have performance approximating  a RAM:disk but WE NEED INFORMATION!

FLAME OFF - enter keyboard cool down period.


Mark Huth
seismo!nogo!mcdsun!rover!mph

>Phil Mercurio
>DevWare, Inc.
>
>mercurio@pnet01.CTS.COM     Usenet
>mercurio                    PeopleLink or GEnie