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'[OT]: Hard Drive Crash Recovery'
2002\02\25@111917 by ards, Justin P

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G'day Folks,

I have just had a 2 G hard drive crash. :(   Pulled it apart and found one
of the heads has well and truly crashed into the outer cylinders of one of
the disks.

I really would like the data back but cant afford the $ for the proper
people to have a go.  I am going to buy an identical drive and attempt a
platter change.

I heard some time ago that hard drives keep a table of good and bad sectors
so thought that my plan may fail due to this and perhaps for many other
reasons.

Anyone had a go at doing this sort of thing.

And yes, I do back up and as it turns out this is my backup disk but it
crashed while doing a reformat reload windows thing on my other drive and
did not get the chance to copy the important stuff back.

Would dearly love to get at all my old data.

Any help, experience would be warmly received :)

Justin

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2002\02\25@112348 by Tal Bejerano - AMC

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What drive and model? maybe i can help you

Tal

-----Original Message-----
From: pic microcontroller discussion list [.....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU]On
Behalf Of Richards, Justin P
Sent: Monday, February 25, 2002 6:18 PM
To: PICLISTspamKILLspamMITVMA.MIT.EDU
Subject: [OT]: Hard Drive Crash Recovery


G'day Folks,

I have just had a 2 G hard drive crash. :(   Pulled it apart and found one
of the heads has well and truly crashed into the outer cylinders of one of
the disks.

I really would like the data back but cant afford the $ for the proper
people to have a go.  I am going to buy an identical drive and attempt a
platter change.

I heard some time ago that hard drives keep a table of good and bad sectors
so thought that my plan may fail due to this and perhaps for many other
reasons.

Anyone had a go at doing this sort of thing.

And yes, I do back up and as it turns out this is my backup disk but it
crashed while doing a reformat reload windows thing on my other drive and
did not get the chance to copy the important stuff back.

Would dearly love to get at all my old data.

Any help, experience would be warmly received :)

Justin

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2002\02\25@113423 by Pic Dude

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Recently had this happen to a notebook drive as well.  In my quest
for recovery, I found out a lot.  Can't give you a firm answer, but
perhaps some tips/info might help...

- You shouldn't open it up unless you have a SUPER CLEAN room.
  With all else done right, the smallest spec of dust/hair will foil the
  recovery procedure.
- Data recovery can be has for as little as $200 if  I remember correctly.
- What they generally do is to locate and purchase a drive that is identical
  to the crashed one and reinstall the platters into the new drive, again
  in a clean room.
- Wiha Tools have all the little tools you could possibly need for this.
- I believe file tables are generally backed up, and backup SW
  generally knows where to get the backup tables.
- Check the web for some free/trial backup software.

So it sounds like you're (note I didn't use "your" :-) mostly on the right
  track.

Cheers,
-Neil.



{Original Message removed}

2002\02\25@121122 by DFansler

picon face
I expect you are not going to have much luck.  The inside of a drive is
hermetically sealed in a clean room.  The head of a hard drive is cushioned
above the platter by the air flow created by the platter spinning.  A piece
of dust is several times thicker than the gap, and will cause you to have
another crash.

You are right about the expense - I had several drives recovered in my days
of network administrator.  Finally convinced everyone to save their data on
the server - which was backed up nightly.  Also used the threat (backed by
management) that if they had a disk crash, the company would not pay to have
it recovered since a secure location for saving data was available.

To me one of the best cost/performance tape drive around is the OnStream
units.  Never had a problem with the dozen or so I have used.

Watch word of the day - backups.

David V. Fansler
S/V Annabelle
DFanslerspamspam_OUTMindSpring.com
http://www.dv-fansler.com

{Original Message removed}

2002\02\25@191928 by Dale Botkin

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"David V. Fansler" <@spam@DFanslerKILLspamspamMindSpring.com> said:

> I expect you are not going to have much luck.  The inside of a drive is
> hermetically sealed in a clean room.  The head of a hard drive is cushioned
> above the platter by the air flow created by the platter spinning.  A piece
> of dust is several times thicker than the gap, and will cause you to have
> another crash.

All correct.  And I agree that he probably won't have much luck.  I will say,
however, that I have had many, many drives open for repair and platter
replacements in relatively clean but not "clean-room" conditions.  All
survived fine; in fact, many continued to run for several years without
problems afterward.  Granted these were ST2xx drives with somewhat higher
head altitudes, but I've done some newer 3.5" drives as well.  None have
crashed from dust or other foreign matter...  you just have to be very, very
careful of what you're doing.

> To me one of the best cost/performance tape drive around is the OnStream
> units.  Never had a problem with the dozen or so I have used.

I like mirrored drives a heck of a lot better.  I've had tape media problems
as well as other (ahem, "operator headspace") issues.  I also never need to
remember to swap out a mirror drive...  but I could if I needed off-site
backup storage.

Dale

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2002\02\25@195045 by Jinx

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> All correct.  And I agree that he probably won't have much luck.
> I will say, however, that I have had many, many drives open for
> repair and platter replacements in relatively clean but not "clean-
> room" conditions.  All survived fine; in fact, many continued to
> run for several years without problems afterward"

If I may quote from Scott Mueller's vast tome "Upgrading And
Repairing PCs"

"Many PC users think that hard drives are fragile, and generally
they are one of the most fragile components in the PC. In my
weekly PC Hardware and Troubleshooting or Data Recovery
seminars, however, I have run various hard disks for days with
the lids off, and have even removed and installed the covers
while the drives were operating. Those drives continue to store
data perfectly to this day with the lids either on or off. Of course
I do not recommend that you try this with your own drives ; neither
would I use it on my larger, more expensive, drives"

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2002\02\25@195909 by Dale Botkin

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Jinx <spamBeGonejoecolquittspamBeGonespamCLEAR.NET.NZ> said:

> If I may quote from Scott Mueller's vast tome "Upgrading And
> Repairing PCs"
>
> "Many PC users think that hard drives are fragile, and generally
> they are one of the most fragile components in the PC. In my
> weekly PC Hardware and Troubleshooting or Data Recovery
> seminars, however, I have run various hard disks for days with
> the lids off, and have even removed and installed the covers
> while the drives were operating. Those drives continue to store
> data perfectly to this day with the lids either on or off. Of course
> I do not recommend that you try this with your own drives ; neither
> would I use it on my larger, more expensive, drives"

Quite true.

I used to work on mainframes for a living.  Work on, as in with scope and
wrenches.  The old drives were routinely run for hours exposed to room air
while servicing.  When the drive is spinning, the surface wind is sufficient
to keep dust from landing on the platters anyway.  Granted this was with
2400RPM 10-platter IBM 2314's - yeah, I'm old, but not THAT old, it was an
Army system - but things have not gotten too much worse since.

Dale

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2002\02\25@201908 by Bob Blick

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> I like mirrored drives a heck of a lot better.  I've had tape media problems
> as well as other (ahem, "operator headspace") issues.  I also never need to
> remember to swap out a mirror drive...  but I could if I needed off-site
> backup storage.

Off-site's not a bad idea. This all hits very close to home. The power
supply in my office computer decided to go ballistic and uncontrolled last
week. The fans sounded like jet engines, and almost masked the popping
sounds of chips losing their epoxy. Smoke poured out, the power switch(ATX
soft power, ya know) did nothing.

Everything was toast. The hard drive would not spin. I got an identical
new drive and swapped boards, now it spun up fine, but just went
clack-clack. I guess the internal head electronics was toast. Estimate
from Drivesavers for their "economy" service was $1900 to recover the
data. Luckily I was well backed up.

Except now I have to make friends with a new computer.

Networked backups a good idea, off-site backups even better! I've never
heard of this happening before, but I'm paranoid now.

Cheers,

Bob

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2002\02\25@210046 by Jim

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Heck - the TI 990 systems (mid 80's) used removable disk
platters on the both the T-50 "system disk" and T-200 "user"
disk drives ... in case of increased error count - simply
change-out a drive platter 'stack' and restore from tape.

I saw that done on several occasions right back there in the
computer room.

Jim



{Original Message removed}

2002\02\25@210508 by Jim

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What - no power conditioning/"surge" strips or
UPSes?

Or did these get toasted too?

I have always run the "Isobar" and "IsoTel" series
which are made of extruded aluminum and have *real*
coils and caps (noise/EMI/RFI protection) as well as
surge suppressor (transorb/varistor) devices ...

Jim

{Original Message removed}

2002\02\25@210739 by Patrick J

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Well, with the risk of sounding low-tech.... I have heard that there is
something called CDR for $0.5, that you can store some 700 MB on
and keep off-site ! Very rarely affected by powerspikes etc.

Happy backup-ing :-)


----- Original Message -----
From: "Bob Blick"
Sent: Tuesday, February 26, 2002 2:16 AM
Subject: Re: [OT]: Hard Drive Crash Recovery
> Networked backups a good idea, off-site backups even better! I've never
> heard of this happening before, but I'm paranoid now.
> Bob

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2002\02\25@214011 by Spehro Pefhany

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At 03:06 AM 2/26/02 +0100, you wrote:
>Well, with the risk of sounding low-tech.... I have heard that there is
>something called CDR for $0.5, that you can store some 700 MB on
>and keep off-site ! Very rarely affected by powerspikes etc.

In these days of cheap 100GB drives, a CD-R is looking more and more like
a floppy. 8-(

Best regards,

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2002\02\25@232210 by Dwayne Reid

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At 08:05 PM 2/25/02 -0600, Jim wrote:
>What - no power conditioning/"surge" strips or
>UPSes?
>
>Or did these get toasted too?
>
>I have always run the "Isobar" and "IsoTel" series
>which are made of extruded aluminum and have *real*
>coils and caps (noise/EMI/RFI protection) as well as
>surge suppressor (transorb/varistor) devices ...

Sounds like this was a power supply failure, as opposed to a transient
coming from the outside world.  Standard computer power supplies work by
sampling the 5V output and adjusting the duty cycle of the switch mode
controller so as to maintain the desired output voltage.  If the feedback
quits, the power supply runs wide open - with the results that Bob described.

dwayne


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2002\02\26@042448 by Alan B. Pearce

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>Networked backups a good idea, off-site backups even better! I've never
>heard of this happening before, but I'm paranoid now.

A reasonable scheme is to have several hard drives in those removable
carriers. If it is possible to mirror the drive in the machine, or even do a
file copy of the important directories, and then remove the drive in the
carrier to take home overnight. Next day bring in a different carrier and do
the same again, so you rotate the carrier drives through the machine.

In my days doing computer servicing it was recommended that the tape backup
system had a rotation of minimum three tapes in what was known as
"grandfather-father-son" rotation, and the backup software had flags to
enforce this, although it could be overwritten if you had to. Any sort of
backup system needs to do something like this so you have a fallback
position if the most recent backup does fail.

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2002\02\26@043917 by Ashley Roll

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Hi Everyone,

A good friend of mine has a business with MANY 10s of GB of important data..
When you start to get that much, it really isn't economical to backup onto
tape anymore.. the tapes cost HEAPS (especially if you want a full weekly
rotation) and do eventually wear out..

He uses external hard disks in external cases that provide a USB interface.
Easy and quick. You can even easily take them off site.

The Backup software in XP now _FINALLY_ doesn't suck and can backup to a
file, even a remote network file. He uses the XP backup software so he can
backup all the MS Exchange databases and SQLServer databases that he uses
without having to stop them..

Works well, and pretty fast considering the amount of data.

Cheers,
Ash.

---
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Digital Nemesis Pty Ltd
http://www.digitalnemesis.com
Mobile: +61 (0)417 705 718




> {Original Message removed}

2002\02\26@072553 by michael brown
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> "Many PC users think that hard drives are fragile, and generally
> they are one of the most fragile components in the PC. In my
> weekly PC Hardware and Troubleshooting or Data Recovery
> seminars, however, I have run various hard disks for days with
> the lids off, and have even removed and installed the covers
> while the drives were operating. Those drives continue to store
> data perfectly to this day with the lids either on or off. Of course
> I do not recommend that you try this with your own drives ; neither
> would I use it on my larger, more expensive, drives"

I have done this.  I took an old 20Mb drive and removed the cover.  I had it
sitting in my office running continuous chkdsk's (dos, remember?)  It ran
for weeks with no dust protection.  I even blew cigarette smoke at it, and
that never phased it a bit.  Finally, after several weeks, it started to
develop surface errors and bad space.  Everyone else at work was
flabbergasted that it even ran, since we've all heard how bad (and instantly
destructive) dust or smoke is.  They ARE much more durable than people give
credit.

Disclaimer:  this was an old worthless drive, I have no idea how much of
this abuse a modern drive can take.  I suspect not nearly so much.

michael

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2002\02\26@082747 by Alan B. Pearce

face picon face
>> seminars, however, I have run various hard disks for days with
>> the lids off, and have even removed and installed the covers
>> while the drives were operating. Those drives continue to store
>> data perfectly to this day with the lids either on or off. Of course
>> I do not recommend that you try this with your own drives ; neither
>> would I use it on my larger, more expensive, drives"

>I have done this.  I took an old 20Mb drive and removed the cover.  I had
it
>sitting in my office running continuous chkdsk's (dos, remember?)  It ran
>for weeks with no dust protection.  I even blew cigarette smoke at it, and
>that never phased it a bit.  Finally, after several weeks, it started to

The reason you can do this with minimal problems is the airflow within the
drive. The air is drawn through a particle filter then up the spindle and
out across the platters. This, along with the centrifugal action of the
spinning platters will keep most particles away from where they can do
damage, unless the heads are at the outer limits and you manage to blow hard
enough to get particles onto the inner area of the platter where they will
then proceed outwards towards the heads.
The air is recirculated inside the sealed area with a pressure relief valve
to allow pressure equalisation with the outside air.

This system is also used on all hard disk drives that operate in free air,
but because of the possibility of having dirt particles on the disk surface
after the drive has been stopped for a while, there is always a purge period
where the drive is spinning before the heads are loaded. This period will
depend on the drive. I remember a 300MB exchangeable pack drive which would
be online in about 15 - 20 secs from a standing start, and everytime the
head stack did a seek over an appreciable number of tracks the floor would
shake.

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2002\02\26@123302 by Harold M Hallikainen

picon face
       I always thought that having a backup kept your hard drive from
crashing...  Kinda like having insurance on your car prevents accidents.
The one time I didn't get the CDW on a rental car, a bus ran into me (or,
actually, the rearview mirror got ripped off the car by a bus, but the
car rental company wanted $3,000 anyway...). So, I do nightly backups on
EVERYTHING!
       Now for a question... With Windoze machines, I've been able to take a
backup tape and restore it to a new harddrive and pick up where I left
off. This doesn't seem to work with Linux, since it seems to save a lot
of the machine's state at various locations on the hard drive. I tried
doing a reinstall of RH7.1, then copying back everything (that had been
tarred on tape). It really messed the machine up. I ended up having to
reinstall RH again, copying various config files I could identify,
reinstalling several aps (perl libraries, PHP4, etc.). I was able to just
copy the /home user files back. Copying back the password and shadow
password file seems to have restored user accounts.
       BUT, it seems that there SHOULD be a way to just get the machine back to
where it was, directly from tape. No reinstalls or anything. Can any
linux experts tell me how? It it's easy to do a restore, I'm sure I'll
never get another crash...


Harold



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2002\02\26@124545 by Pic Dude

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"Kinda like having insurance on your car prevents accidents."

Not really -- having insurance means you'll still have accidents cause
the fine-print says that the rates go up exponentially with each
claim.

Cheers.



{Original Message removed}

2002\02\26@165638 by Archmage

picon face
Every one is talking about getting data off a hard drive
I recently had a Fujitsu died with important data ( The back up hard drive
was being used temp for a few days, Ya Murphy's law )
I asked around on ideas on how to get the data off. One trick some one told
me was to stick it in a freezer for a half hour and then try it. I have been
told this will loosen up the barring ( I have a feeling that's not the true
reason it works )
To note the Fujitsu took more convincing as I set it in a heavy duty zip
lock bad and sit it in ice water to get the effect last longer. This worked
a number of times until the zip lock leaked so if any one has a board to a
30G Fujitsu send me a email at EraseMEarchmagespamspamspamBeGoneican.net

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2002\02\26@193824 by Andre Abelian

picon face
Soon USB hard drive will stop.
I use CDR for backup

Andre





Hi Everyone,

A good friend of mine has a business with MANY 10s of GB of important
data..
When you start to get that much, it really isn't economical to backup
onto
tape anymore.. the tapes cost HEAPS (especially if you want a full
weekly
rotation) and do eventually wear out..

He uses external hard disks in external cases that provide a USB
interface.
Easy and quick. You can even easily take them off site.

The Backup software in XP now _FINALLY_ doesn't suck and can backup to a
file, even a remote network file. He uses the XP backup software so he
can
backup all the MS Exchange databases and SQLServer databases that he
uses
without having to stop them..

Works well, and pretty fast considering the amount of data.

Cheers,
Ash.

---
Ashley Roll
Digital Nemesis Pty Ltd
http://www.digitalnemesis.com
Mobile: +61 (0)417 705 718




> {Original Message removed}

2002\02\26@195645 by Ashley Roll

flavicon
face
Um.. How do you back up 10s of GIGA bytes to CD Roms?? :) On a daily basis?

I CDR is 650MB. I think he currently has in the order of 40GB, that's over
60 CDs.. little much to ask to be done in a single day.. :) Not to mention
the environmental nightmare 1000s of useless CDs being dumped cause.. An you
can only zap so many in a microwave oven before it gets boring.. :)

Basically, yes a CD will last a long time (NOT forever though!!) so if you
want to backup a single project as an archive fine, but to backup the state
of his entire business with all the software development, data changes,
email, accounting etc, etc daily they are useless..

If the USB drive breaks, buy a new one (or better, have a spare on hand).
That is why you have multiple backup sets. If one fails you can replace it
and still have at most a day of work lost if everything dies..

Cheers,
Ash

---
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Digital Nemesis Pty Ltd
http://www.digitalnemesis.com
Mobile: +61 (0)417 705 718




> {Original Message removed}

2002\02\27@112231 by Morgan Olsson

picon face
I wathed on TV there is a real pro company somewehere here in Scandinavia that has boult an impressive machine in which they can put disks from any HD, and scan one disk after the other, and have software and brilliant guys putting the data parts together.

Thus they can recover data from computers that has been in fire and also those that are mechanically are very severly damaged.

Quite impressive.
/Morgan

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2002\02\28@031930 by John

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Hello Alan & PIC.ers,

...mmm...
I'd been doing just this for several years, thinking my procedures were
infallible, *then* a couple of months ago I was struck by some-or-other
virus, perhaps a finger trouble or seizure of who-knows what sort
(never did get to the real cause).

My most recently accessed files, over a period of some days, suddenly
evaporated from my drive.
Thinks.. this is what my networked backup *.zip file is for.. go get.
..You guessed, the *.zip also was sans the vanished files.
Upshot,  I'd completely lost all backup of those particular files.

I've since reconstructed things & got back 99% of data. It probably cost me
20 hours of wasted effort. Procedure *now* is regular backup of
data directory onto write-once CD (no recycling possible).
Let the disks pile up & become tomorrow's disposal problem, they're cheap.
Cheaper'n my time anyway, hope this guides someone else out there.


       best regards,   John

>Date:    Tue, 26 Feb 2002 09:23:40 -0000
>From:    "Alan B. Pearce" <RemoveMEA.B.PearceKILLspamspamRL.AC.UK>
>Subject: Re: [OT]: Hard Drive Crash Recovery
>
>>Networked backups a good idea, off-site backups even better! I've never
>>heard of this happening before, but I'm paranoid now.
>
.A reasonable scheme is to have several hard drives in those removable
>carriers. If it is possible to mirror the drive in the machine, or even do
a
>..file copy of the important directories, and then remove the drive in the
>carrier to take home overnight. Next day bring in a different carrier and
do
>the same again, so you rotate the carrier drives through the machine.
>
>In my days doing computer servicing it was recommended that the tape backup
>system had a rotation of minimum three tapes in what was known as
>"grandfather-father-son" rotation, and the backup software had flags to
>enforce this, although it could be overwritten if you had to. Any sort of
.


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'[OT]: Hard Drive Crash Recovery'
2002\03\01@101337 by Chris Loiacono
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I apologize for re-opening this thread....but I am trying to put together a
back-up strategy for a small (6 station) peer to peer windows network and
some of the thoughts that showed up here have me a bit uncertain when I
combine them with what I'm finding when I research the subject elsewhere. I
tend to trust the technical opinions of list members  - especially when
compared to those of technical sale people trying to sell me on their
choice...so please, check out my thinking and reply if you like...

1. HDD's seem most logical to me - lowest cost per Gig, fast read and write
cycles. Swappable drives in arrays such as RAID seem to make even more
sense - pull the drive, put in a fire box and insert the alternate drive.
Yet these seem to be less available and the cost seems the same as it was 5
yrs ago - indicating that this is less than popular.

2. Tape must be less reliable and is definitely slower. Plus there is the
added cost of consumables.  I am finding that many large networks are backed
up on tape - perhaps because the economics of buying many tapes is better
than buying many hard drives. Many small networks are backed up on tape, and
there are still many offerings in this area.


Is there a technical reason that tape is still so widely used, and am I
missing something?
What really is the medium of choice for back-up?

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2002\03\01@112854 by Alan B. Pearce

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>I apologize for re-opening this thread....but I am trying to put together a
>back-up strategy for a small (6 station) peer to peer windows network and
>some of the thoughts that showed up here have me a bit uncertain when I
>combine them with what I'm finding when I research the subject elsewhere.

I would seriously suggest spending money on putting a suitable size hard
drive in one machine - typically the fastest - and using that as a server.
Instill the idea into everyone that they should save everything on that
network drive. This then means that you have only one drive to backup by
whatever means you choose.

If you can justify the money to get the system organised so that you can
have mirrored drives then this will most likely save you time at the end of
the day. When you come to take the backup drive out of the machine in the
evening, put in the replacement, and leave it rebuilding the mirror onto the
replacement drive overnight, it should all be pretty invisible to the staff,
and minimal extra work out side of office hours for the person doing the
changeover.

Remember to factor in enough spare backup units to have monthly and yearly
backups if dealing with accounting files. This is probably one of the
biggest reasons tape gets used - the media is cheap enough that having a
Monday-Thursday set, plus a months worth of Friday sets, plus a years worth
of Monthly sets, Plus however many years of yearly backups you want to
maintain for accounting/tax purposes soon adds up. The problem comes that
someone has to hang around late or come in early to do the backup - I do not
recommend leaving the tape in the drive and going home while it runs. In my
time as a computer engineer I have seen too many problems resulting in a
lost backup.

The worst one, which was a feather in our company's cap, was when an
engineer was called at about 4:30pm on a Friday to say the customers tape
drive had a fault. He went and fixed it, the tapes were put in a fire safe,
and that night the whole factory burned down. The tapes were retrieved from
the safe, and restored onto an engineering machine on our premises, and the
client had an operational machine first thing Monday morning, with the data
as at end of business Friday. It really enabled them to sort out rapidly a
situation that could have been total chaos for them otherwise.

At the end of the day (sic) you have to decide how much data you can lose
before your business is adversely affected. It may be that the most cost
effective way is to get a proper file server system with mirrored drives for
data safety, and a tape drive for backup. a proper server system, such as
Windows NT, 2k, or XP, or Linux, will allow file permissions to be set in a
manner that means people can access only what they need.

A Linux server with Samba software will allow a respectable system to be
built on hardware that does not need to be pushing the bounds of technology,
and should give respectable speed. The samba software makes the Linux file
system look like a windows file system to your network. It also allows any
Linux printers to be used as windows printers.

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2002\03\01@114346 by Chris Loiacono

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Thanks Alan.
We have no financial records at this location, just technical, but your
explanation helped me understand why tape is still so popular, but does not
"feel" like the rightsolution for me.
You have given me much valuable info to chew on.

Chris :)

> {Original Message removed}

2002\03\01@114522 by M. Adam Davis

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Tapes and tape drives are used because they are /more/ reliable.  Modern
hard drives are not meant to be portable.  To much shaking, one drop,
heat and cold extremes.  Tapes endure these things infinitely better
than a hard drive.

Furthermore a good tape backup is actually /much/ more expensive than
backing up with hard drives ($ per gig).  They have more/better data
error correction, and are made only for backup.

That being said, hard drive backups are becoming more and more common.
It is a mistake, though, to move a hard drive more than a few times a
month.  (I do it weeky, but I also have another backup on tape which is
taken offiste, and another onsite HD backup which is not moved.)  They
simply fail at a higher rate than those that are permanently mounted
inside a machine.

You need to be careful weighing the tradeoffs when looking at
reliability, cost, and maintenance.  It's a pain to have an offsite
backup, but it's a little better than a firesafe backup.  It's more
expensive to do tape and HD backup, but you're nearly tripling your
reliability.

Good luck!

-Adam

Chris Loiacono wrote:

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2002\03\01@115928 by Chris Loiacono

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Yikes, more to think about...

I am looking at Firewire hard disk units made specifically for back-up. Does
anyone have experience with these?

I gave up on the swappable drives because unlike fixed drives, the cost was
prohibitive. It makes sense that they would not like being handled often -
another reason why tape is probably still so popular. I guess form the
hardware perspective, tape is more reliable. Didn't the error correction
schemes come about because of the inherent weakness mag tape has, in other
words because the need demanded it?

Chris

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2002\03\01@121738 by Jafta

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Chris

For me Hard Drives have been working for a LONG time now - not hot
swaps, but normal WD's in removable cases.  And we back up info for a
bank.  Our auditors approved it.  The can stand normal handling - 10G+
shock, which is more than a normal fall while in your briefcase - and
it is easier to detect bad sectors than on tape.  Faster back up
times. I still have to get to the tape that can back up 40 Gig as
quickly and efficiently as a xxx.  And they are cheap.

We do some maintenance on the HD's, though - a full surface scan every
week, and a full format each month.  But this happens while other work
gets done - not a train smash.

$ for $, I recommend HD's.  YMMV.

Regards

Chris A

{Original Message removed}

2002\03\01@122352 by Jafta

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Chris

For me Hard Drives have been working for a LONG time now - not hot
swaps, but normal WD's in removable cases.  And we back up info for a
bank.  Our auditors approved it.  The can stand normal handling - 10G+
shock, which is more than a normal fall while in your briefcase - and
it is easier to detect bad sectors than on tape.  Faster back up
times. I still have to get to the tape that can back up 40 Gig as
quickly and efficiently as a xxx.  And they are cheap.

We do some maintenance on the HD's, though - a full surface scan every
week, and a full format each month.  But this happens while other work
gets done - not a train smash.

$ for $, I recommend HD's.  YMMV.

Regards

Chris A

PS - And with - I stand under correction - 100,000 Hour MTBF, - HD's
will last a LONG time

{Original Message removed}

2002\03\01@122600 by M. Adam Davis

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I doubt error correction came only because of magnetic storage, but it's
been used in it forever (it seems).  But any modern form of storage
(nevermind magnetic) has some error correction.  CD-ROMs have it, hard
drives have it, flash memory has it, the ram in your machine has it.

I haven't any experience with firewire drives at all.  But every
external drive I've seen uses a regular IDE or SCSI hard drive inside.
If you must go with a portable hard drive, consider using one which
uses 2.5" laptop hard drives, which are rated for a little more abuse
than 3.5" hard drives.

The trick to getting the right kind of backup is knowing what backup
actually is, and what you need.  There are three kinds of storage,
online, near-line, and offline.  Online would be the file server.
Near-Line would be an automated or slow storage system (not used much
anymore, but could be tape reels, or a huge cassette machine), offline
is any storage that must be plugged in manually.

Furthermore you need to consider off-site and on-site storage.  An
extreme example of this would be the few companies in the WTC not only
had storage of their data off site, but had whole offices off site with
an up to the minute copy of data that could simply be turned on and
instantly used.

There are companies which do encrypted backups over the internet (or
direct lines).

I don't know your situation, but if you plan on physically moving data
from one place to another (either a firesafe or offsite) then go ahead
and get a good tape drive and backup software from a good company.
This would be your offline storage.  You might also do a nightly backup
to another computer onsite.  This would be nearline.  In this case you
have a three points of redundancy.  Your building could burn down and
you'd have the tapes in the safe.  The server could be fried and you'd
have the easily accessed data on the workstation.  The tapes could have
some bad sectors in critical files and you've got the workstation backup.

No matter what you choose, make sure you have a process in place to test
the reliability of your backup.  Do a test restore from your tapes
regularily.  Rotate and keep track of your tapes (good software will do
this for you ) and get new tapes every 100 backups.  Do error scans of
your hard drives, etc.

-Adam

Chris Loiacono wrote:

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2002\03\01@132644 by michael brown

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> Yikes, more to think about...
>
> I am looking at Firewire hard disk units made specifically for back-up.
Does
> anyone have experience with these?

They are very fast.  Basically capable of same speed as an internal drive.
400Mbps is pretty fast.

> I gave up on the swappable drives because unlike fixed drives, the cost
was
> prohibitive. It makes sense that they would not like being handled often -
> another reason why tape is probably still so popular. I guess form the
> hardware perspective, tape is more reliable. Didn't the error correction
> schemes come about because of the inherent weakness mag tape has, in other
> words because the need demanded it?

I have a personal thing against tapes.  I do not ever trust them to work.
The problem with tape is you can't tell if the tape has been damaged by a
magnetic field by looking at it, you also can't tell if you are going to be
able to read it, until you try, UNSUCCESSFULLY  :-(  The big thing is that
doesn't guarantee you will be able to read it again.  In fact, you have just
decreased the odds that you will be able to read it again.  Believe me,
murphy's law was invented due to tapes.  With hard drives, you usually have
more warning before a total failure occurs.  Don't trust tape, it works, but
it WILL screw you, eventually.  Next time you think about tape, remember the
last audio cassette that you dug out of the car stereo.  Tapes, like floppy
disks, rub the media against the read head.  You do the math.

By the time the tape drive (on modern pc's) recognizes the format of a tape,
you could have backed everything up to a fire-wire drive and been on your
way home.

michael brown

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2002\03\01@142606 by Mitch Miller

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On Fri, 1 Mar 2002, michael brown wrote:

> > Yikes, more to think about...
> >
> > I am looking at Firewire hard disk units made specifically for back-up.
> Does
> > anyone have experience with these?
>
> They are very fast.  Basically capable of same speed as an internal drive.
> 400Mbps is pretty fast.

Yeah, but that's Firewire's transfer speed ... not necessarily the
drive's.  If a drive can't keep up, you might burst 400kb/s, but your
overall won't be that fast.

> I have a personal thing against tapes.  I do not ever trust them to work.
> The problem with tape is you can't tell if the tape has been damaged by a
> magnetic field by looking at it, you also can't tell if you are going to be
> able to read it, until you try, UNSUCCESSFULLY  :-(  The big thing is that

Read verification should be done with hard drives, too, if your data is
_actually_ important.  I'll bet I've put data onto a hard drive and not
been able to read it back as many times as tape has failed me.

> doesn't guarantee you will be able to read it again.  In fact, you have just
> decreased the odds that you will be able to read it again.  Believe me,
> murphy's law was invented due to tapes.  With hard drives, you usually have
> more warning before a total failure occurs.  Don't trust tape, it works, but

I'd say that's subjectto the nature of the failure ... how often does a
drive just up and die compared to magnetic data related failures?

Just my $0.02.

-- Mitch

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2002\03\01@153845 by Dwayne Reid

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>2. Tape must be less reliable and is definitely slower. Plus there is the
>added cost of consumables.  I am finding that many large networks are backed
>up on tape - perhaps because the economics of buying many tapes is better
>than buying many hard drives. Many small networks are backed up on tape, and
>there are still many offerings in this area.

Tape is cost effective and reliable.  The best bang for the buck right now
seems to be DDS-2 tape - my cost is less than $10.00 Canadian per tape in
small quantities.  All my tape drives have hardware compression - that
DDS-2 tape holds about 6.4 gigs of typical user data.

While the tape itself has been reliable to date, the tape drives have been
less so.  I just had another HP DDS-2 drive fail - it will cost a hundred
dollars to get it back in working condition.  That is the main reason I
have multiple tape drives: one drive is always off site (with my off-site
backups) and 2 drives are here at work - on separate machines.  I use a DAT
tape control package called DATMAN - it turns the tape drive into a
gigantic but slow floppy drive that is readable just like any other
drive.  You have NO idea how truly useful that is until you try it - most
of my data recovery is to correct finger problems rather than total,
catastrophic failures.  Once the tape is mounted, it appears as a drive
letter and I can browse the tape to my heart's content.

Backup strategies are simple: I back up the server and the "My Documents"
folder on all client machines.  And that's all!  I don't bother with OS,
program files, OS temporary files.    I warn all users: store it on the
server or in your "My Documents" folder or else!

Like always - your mileage may vary.  I've been a huge fan of tape backup
since the days of the inexpensive Colorado drives in the late '80s - it
works for me.

dwayne


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2002\03\01@160745 by Chris Loiacono

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Hi Dwayne:

DATMAN sounds like a good tool. I was about ready to stick to hard drives
after the most recent post, but your confidence in tape has me putting off
the decision.

It seems like this one is a 50/50 split. Some of those that replied have
been rather passionate in favor of one method or the other.

I have had little success with optical drives, CDRW, etc. which made this
the first option for me to eliminate, especially since I know of one PCB
design house that tried doing CD/RW backups - and had disaster after disater
with it.
Is the consensus on this just as negative as my feelings?

Chris


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2002\03\01@163101 by Robert Rolf

picon face
Chris Loiacono wrote:
>
> I apologize for re-opening this thread....but I am trying to put together a
> back-up strategy for a small (6 station) peer to peer windows network and
> some of the thoughts that showed up here have me a bit uncertain when I
> combine them with what I'm finding when I research the subject elsewhere. I
> tend to trust the technical opinions of list members  - especially when
> compared to those of technical sale people trying to sell me on their
> choice...so please, check out my thinking and reply if you like...
>
> 1. HDD's seem most logical to me - lowest cost per Gig, fast read and write
> cycles. Swappable drives in arrays such as RAID seem to make even more
> sense - pull the drive, put in a fire box and insert the alternate drive.
> Yet these seem to be less available and the cost seems the same as it was 5
> yrs ago - indicating that this is less than popular.
>
> 2. Tape must be less reliable and is definitely slower. Plus there is the
> added cost of consumables.  I am finding that many large networks are backed
> up on tape - perhaps because the economics of buying many tapes is better
> than buying many hard drives. Many small networks are backed up on tape, and

Yes, up to a point. Once you have the tape robot, you have economic
inertia, so you keep feeding it tape.

> there are still many offerings in this area.
>
> Is there a technical reason that tape is still so widely used, and am I
> missing something?
> What really is the medium of choice for back-up?

Depends on what kind of $$$ you have to spend.
Tape is rugged. You can drop it 4' and it will generally survive.
If the case breaks, you can rethread it into a new case.
Not so with a HD.

Tape has been around a long time, and the capacities have grown slowly,
but reliably (lots of CRC & ECC written so a few drop-outs/damage
are well tolerated). Tape drives are expensive, and have to be replaced
regularly (3-5 years depending on brand and use).

You can't cheaply (or as quickly) put 60GB of data onto tape, as you
can to a removable HD. It is only of late that HD prices and capacities
have reached a level where they make a good alternative to tape.


Our local Liuux users group had a good discussion about this topic
last month and the concensus was removable HD for home users, mirror
RAID for small business, and tape for those with real $$ to spend.

Gigabit ethernet NICs are not that expensive, and firewire or
fiberchannel drives made for easy/cheaper DIY RAID (particularly with
Linux servers).

My 1.3 Canadian cents worth <G>.

Robert

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2002\03\01@191307 by Lee Jones

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> I apologize for re-opening this thread....but I am trying to
> put together a back-up strategy for a small (6 station) peer
> to peer windows network

> 1. HDD's seem most logical to me - lowest cost per Gig, fast
> read and write cycles. Swappable drives in arrays such as RAID
> seem to make even more sense - pull the drive, put in a fire
> box and insert the alternate drive.  Yet these seem to be less
> available and the cost seems the same as it was 5 yrs ago -
> indicating that this is less than popular.

It's very popular -- for larger servers.  They are much less
cost sensitive than desktop PCs because the reliability needs
are _much_ higher.  And when you are dealing in terabytes of
data the overall system design outweighs costs of single drives.

Personally, I would be concerned about connector system wear if
a spare drives were being removed & inserted on a daily basis.
I don't think that the RAID disk chassis were built for this
many drive exchanges.


> 2. Tape must be less reliable and is definitely slower. Plus
> there is the added cost of consumables.  I am finding that many
> large networks are backed up on tape - perhaps because the
> economics of buying many tapes is better than buying many hard
> drives. Many small networks are backed up on tape, and there are
> still many offerings in this area.

Tape offers compact, robust, stable, removable storage.  Due
to historical incremental development, there is software to
support the concept of off-site backup on to this media.


> Is there a technical reason that tape is still so widely used,
> and am I missing something?

It's reasonably inexpensive and known stable for commercial
time scales (5-10 years) when stored unattended.

This may change because low cost disk drives are now in the
same cost per gigabyte of tape cartridges.  But they will be
more fragile and reliability after multi-year storage is an
unknown (assuming the RAID array still exists).  Products to
automate disk drive swapping don't exist yet -- automated
tape libraries do.

Tape drives have always offered backwards compatability.  In
part to allow reading archival tapes that were written on prior
generation tape drives.

And don't discount social inertia -- since tape has been used
in the past, people will continue to use it.  Managers of large
enterprises aren't real happy with ripping everything out and
changing things all at once; even if the technology is better.

On the product side, you can get automated tape libraries that
have several tape drives and dozens to hundreds of tapes with
a robot to load & unload the tape drives.  They are expensive,
but not nearly as pricey as a human operators on 24x7 service.
With the appropriate software, the cost of the library can be
shared over many servers backing up dozens to hundreds of disks.


> What really is the medium of choice for back-up?

I think a layered approach.  Details depend on a trade-off
between cost and vulnerability.  Like insurance -- the less
risk you assume, the more it's going to cost you.

RAID arrays protect against single device failure for short
periods of time.  But they store only a single snap-shot of
the users' data.  If a user corrupts a file, its content is
lost.  There is no "yesterday's version".  And they are on-site
and suseptible to catastrophic failure (fire, flood, earthquake,
etc).

Tape backups, by using simple rotation and extraction scheme,
are easy to generate a multi-copy off-site library (every day
for a couple weeks, every Friday for a couple months, every
month-end for several years, and year-end forever).  This can
meet the legal requirements for a business to keep financial
and other required records for specified retention periods.

If the amount of data is low enough, CD-R or CD-RW (now) and
DVD-R or DVD-RW (future) may become cost effective, viable
options for backup.

                                               Lee

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2002\03\01@211316 by michael brown

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> On Fri, 1 Mar 2002, michael brown wrote:
>
> > > Yikes, more to think about...
> > >
> > > I am looking at Firewire hard disk units made specifically for
back-up.
> > Does
> > > anyone have experience with these?
> >
> > They are very fast.  Basically capable of same speed as an internal
drive.
> > 400Mbps is pretty fast.
>
> Yeah, but that's Firewire's transfer speed ... not necessarily the
> drive's.  If a drive can't keep up, you might burst 400kb/s, but your
> overall won't be that fast.

That's why I said that the fire-wire drive would be basically as fast as an
internal drive.  ;-)  The comment about 400Mbps was just a side note.

> > I have a personal thing against tapes.  I do not ever trust them to
work.
> > The problem with tape is you can't tell if the tape has been damaged by
a
> > magnetic field by looking at it, you also can't tell if you are going to
be
> > able to read it, until you try, UNSUCCESSFULLY  :-(  The big thing is
that
>
> Read verification should be done with hard drives, too, if your data is
> _actually_ important.  I'll bet I've put data onto a hard drive and not
> been able to read it back as many times as tape has failed me.

The drive does a pretty fair job of self error correcting the data that it
can read.  Usually when a drive just can't read a sector and retries over
and over, it's most likely the media literally detaching from the platter.
When an IDE drive suddenly develops some bad sectors, it's life is over
right then.  It's time to take your data and run, cuz the problem is NOT
going to get any better.  It WILL (absolutely guaranteed) develop more bad
sectors.  This is what most drives do, long before the "click of death" sets
in.  IDE drives that have detectable bad sectors should never be used.
Unfortunately, many people don't know or believe this.

> > doesn't guarantee you will be able to read it again.  In fact, you have
just
> > decreased the odds that you will be able to read it again.  Believe me,
> > murphy's law was invented due to tapes.  With hard drives, you usually
have
> > more warning before a total failure occurs.  Don't trust tape, it works,
but
>
> I'd say that's subjectto the nature of the failure ... how often does a
> drive just up and die compared to magnetic data related failures?

Most (not all) of the failures I have personally seen (and that's been a
bunch) started out subtly.  Most have been related to gradual media failure.
I have seen a few (very few) drives that died after being run continuously
for several years and then turned off overnight.  That seemed to be a
bearing/lubrication related failure.  I have never (never, ever) seen a pc
hard drive self destruct internally suddenly and without any warning
whatsoever.  I have seen allot of people using drives that should have been
replaced long before.  :-(  I hate to see people lose data, but I have seen
so many occasions of people not taking it seriously until it's too late.
Any extra copy of your data (on disk, tape, punched cards or paper-tape if
that's all that's available) that you can have is to your advantage, and
preferably that copy is somewhere else.

Your best backup, IMHO is another copy on another drive.

> Just my $0.02.
> -- Mitch

My (long winded again) two cents several times over.  ;-)

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2002\03\02@041315 by Peter L. Peres

picon face
Afaik the only two advantages of tape are media size (and cost/bit) and
resistance to transportation.

The theoretical unformatted capacity of a 1 hour tape (DAT or such format)
recorded with 10MHz (10MBps uncompressed) is about 3.6 Terabits.

Tape makes a lot of sense for large installations. I use CDROMs for this
(on home PC systems). I used to use an internal hard drive for backup but
it was killed by vibrations from a bad PSU fan ;-(. If you see Murphy send
him this way. I need to *talk* to him.

On a similar line, has anyone observed a correlation between the failure
rates of a certain brand of hard drives vs. another that runs w/o
vibration ? I believe that there is a correlation from what I observed.

Peter

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2002\03\02@071927 by michael brown

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face
> On a similar line, has anyone observed a correlation between the failure
> rates of a certain brand of hard drives vs. another that runs w/o
> vibration ? I believe that there is a correlation from what I observed.
>
> Peter

I can't imagine a ps fan vibrating enough to cause a drive to fail.  The
computer case must have been shaking.  I have noticed that drives seem to
fail more often when not mounted in a flat position.  I know the
manufacturers say it makes no difference, but it sure seems to.

michael brown

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2002\03\04@125205 by Harold M Hallikainen

picon face
On Fri, 1 Mar 2002 11:44:20 -0500 "M. Adam Davis" <adampicspamBeGonespamUBASICS.COM>
writes:
>  (I do it weeky, but I also have another backup on tape which
> is
> taken offiste, and another onsite HD backup which is not moved.)
> They
> simply fail at a higher rate than those that are permanently mounted
> inside a machine.

       What tape drive are you using for backup? What operating system? What
backup software? I'm using a Sony SuperStation (available CHEAP, though
the tapes are almost $40 each). I use Samba to tar my linux machine over
to a separate DOS partition on a windoze machine, then back that up using
the Windoze software that came with the drive. Windoze crashes about 5%
of the time during the backup...  I'd like to find something a bit more
reliable...



Harold


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2002\03\04@125208 by Harold M Hallikainen

picon face
On Fri, 1 Mar 2002 12:19:57 -0600 michael brown <RemoveMEn5qmg@spam@spamspamBeGoneAMSAT.ORG> writes:
{Quote hidden}

       Since I rotate through a couple dozen backup tapes (and each backup
takes 2 tapes), there's always another one to go back to. I have the
backup software do a verify immediately after it does the backup (this is
an all night process). So, it seems that I SHOULD be able to recover
something. In fact, just last night, Windoze crashed and screwed up a
database. I got it back from the tape backup, losing only about 30
minutes work.
       I'm using tape backup both at home and work. I'm not particularly
satisfied with the drive and software (they seem to crash a lot, but
that's probably just Windoze), so I'm watching for the next thing to use.
I see that next year there should be another DVD standard using blue
lasers. It gives something like four times the capacity of existing
DVD's. Maybe that'll be my next backup medium...


Harold




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2002\03\04@131354 by Peter L. Peres

picon face
>I can't imagine a ps fan vibrating enough to cause a drive to fail.  The
>computer case must have been shaking.  I have noticed that drives seem to

Unfortunately *I* can. And the case was shaking (you could feel it with
your hand).

>fail more often when not mounted in a flat position.  I know the
>manufacturers say it makes no difference, but it sure seems to.

Hmm. Maybe the dirt inside falls to the bottom and is recirculated every
time the drive starts. If horizontal it would stay in the filter instead
of falling out. Just a thought.

Peter

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2002\03\04@165734 by michael brown

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face
> >fail more often when not mounted in a flat position.  I know the
> >manufacturers say it makes no difference, but it sure seems to.
>
> Hmm. Maybe the dirt inside falls to the bottom and is recirculated every
> time the drive starts. If horizontal it would stay in the filter instead
> of falling out. Just a thought.

Peter,

My personal opinion is that the sleeve bearing in the motor can't stand all
the weight resting on one side.  Even with the drive spinning at thousands
of RPM's, it still bears the full weight of the platters against one side of
the bearing causing it to get "egg" shaped.  Whereas, when the drive is
mounted flat, the sleeve bearing gets the least amount (and the most
uniform) wear.  The thrust bearing under the platter assembly must be more
durable, or it sits upon a little ball bearing.

michael brown

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2002\03\06@031817 by ards, Justin P

flavicon
face
Tal,

its a
Western Digital Caviar 22100
Drive parameters 4092 cyl.16 heads. 63spt. 2111.8 MB

MDL: WDAC22100-07H
P/N: 99-004219-010
CCC: H3 17 DEC 96
DCM: BNBAKCH

any help would be great.

Justin
-----Original Message-----
From: Tal Bejerano - AMC [.....kooter@spam@spamEraseMEZAHAV.NET.IL]
Sent: Tuesday, 26 February 2002 00:20
To: .....PICLISTRemoveMEspamMITVMA.MIT.EDU
Subject: Re: [OT]: Hard Drive Crash Recovery


What drive and model? maybe i can help you

Tal

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