Obsolete computer...trivia

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I recently scrapped out a 386 that had been setup as a voice mail system.

I decided to open it up and have a look before it went to the recycler  
and was surprised to find a 1GB IDE hard drive in that thing.

So...the machine must have been a lot newer than I thought.

When looking at the file dates it appears the machine was used around  
1997 or so.

When I Googled I was surprised to see that 386 cpus were still  
manufactured up until 2007 (for embedded systems)

Re: Obsolete computer...trivia

philo wrote:
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Did you bench that IDE drive in HDTune ?

I bet it has a smokin transfer rate.
Probably good for 4-5MB/sec.

As for the manufacturer of obsolete hardware,
it gets hard to do that after a while, since they
tear down the fab and the ability to make it

I had a project at work, stopped before the end of
the sales cycle, when the fab making the custom ICs
was torn down. We would have needed to buy and
stockpile a huge pile of ICs, which is "risky"
from a business point of view. They usually give
you a year of advanced warning, that the fab is
becoming a hole in the ground.

One place the old processors are preferred, is for
space applications. Where the large geometry chips
are more resistant to radiation upset. But I doubt anyone
was doing that with 386. They've used some weird stuff
for space. For example, the stuff on this page
for sale today, is running at 25MHz. "Open the
Pod Bay doors HAL..."



Re: Obsolete computer...trivia

On 11/03/2015 07:26 PM, Paul wrote:
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I did not bench mark the drive but it ran msdos 6.22 just fine.

I save small hard drives for older machines that I put Linux on.

Now another question:

The drive had a bad sector that was mapped out by scandisk.

If I would re-use the drive for dos or Windows, I assume the OS would  
not try to use that sector...but does scan disk map it out just for  
ms-based operating systems...or is it mapped out at a lower level?

My question is if I used the drive for Linux would that bad sector cause  
a problem?

My guess is that scan disk only maps it out for MS operating systems.

What I did was use both test disk and d-revitalize to attempt to make  
that bad sector invisible to any OS.

I again ran scandisk and it shows no bad sectors.

Can I assume it's been mapped-out at a lower lever than the OS?

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Re: Obsolete computer...trivia

philo wrote:
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At the sector level, the disk has automatic sparing, as a
feature of the IDE controller. If a bad sector is detected,
a spare is used in its place.

If the drive runs out of (local) spare sectors, the sector
is then un-repairable. The drive returns "CRC error" when the
sector is read.

Now, it's up to the file system to mark it. The file system
uses a sparse file, which keeps track of sectors or clusters
with CRC errors. That's how it would take a bad area out
of circulation. The "real space on disk" taken by the sparse
file, grows with the more bad areas it needs to map. Even though
the virtual size of the file is as large as the disk, space is only
actually used to store that file, when there is a need to mark an
area of the disk as bad.

You would need to research the various file system types,
to see what mechanisms they use.


    Bad blocks     Cluster tagging


    Bad blocks     $BadClus (MFT Record)


    Bad blocks     Table

So it looks lkke they all have some sort of mechanism.

Another way to handle the issue (for the simplest cases),
is to move the partition so it does not sit on top of the
bad area.

I had one disk, where all the "trouble" was in a single
well defined area. For that disk, it would be feasible to
move the partitions away from there. And then I would
only lose around 14% of the drive capacity.


Re: Obsolete computer...trivia

On 11/04/2015 12:17 AM, Paul wrote:
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<snipped but read>
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Yep , I've done that already back in the old days.

Re: Obsolete computer...trivia

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For ext4 (and the older ext2 and ext3) in Linux specifically, one can
give the -c option to mkfs.ext4 when creating the file system so that
it'll scan the drive for bad blocks and map them out if any are
found. Alternatively this can also be done with fsck -cc to an existing
file system.

With a quick look it seems other file systems one might want to use on
Linux (xfs, btrfs, f2fs, zfs) don't have a similar thing.

Re: Obsolete computer...trivia

Anssi Saari wrote:
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I can sorta understand their reasoning. Running
a drive when it shows CRC errors, is just asking
for trouble. On a modern drive, you may not have a
lot of time between "CRC error" and "completely
unresponsive". Years ago, when I had failing
Maxtor drives, I'd get symptoms on Monday, and
the drive would be dead on Tuesday :-) I don't
take chances any more. Too many unhappy Tuesdays.


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