Coming from the subject of viruses and cd-roms from below, whilst it is not motoring, a thing worth pointing out.
Electronic media has a life span and will fail beyond it. I don`t rememeber the exact figures but it is something like the following;
Video Tape - 10 yrs
CD-Rom - 15 yrs
Hard Disk - 20 yrs
Don't think that anything will survive on these media if you put it in a cupboard unattended.
Videos need to be recorded digitally asap. CD-ROMs need to be copied about every 10 years, and hard disks used throughly about the same.
If anybody doubts the exact figures, I will confirm them - but they really are more or less accurate. Be careful - too many people have puled the wedding video out of the draw after 15 years and got a shock. Think is, even a video you watch deteriorates - just gradually. Digital media will one day go toes up with little warning.
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All very well, but shouldn't you be helping me annoy Harry Potter the speed prefect?
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He isn't paying attention.
Maybe he has his head up his nose ?
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Kevin, Do you mean not allowing the hard drives going into sleep mode which I allow mine to do.
alvin
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Alvin,
I don't know what sleep mode does on your drive. Different manufacturers have different methods of extending drive life. Sleep mode on some drives moves the heads over a 'park' area and then stops the spindle motor. Other drives (notably the IBM Travelstar etc.), return the heads to a park position and physically lift them from the platters before switching off the motor.
Neither method is as good as leaving the spindle motor running and moving the heads over the disk surface every now and again.
The system I am currently working on has nearly 750 SSA drives. After a complete power-down last Wednesday (never done before), we're running a book on how many drives will croak within 7 days. Two so far, my bet was 6, three days to go.
Kevin...
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Thanks Kevin,
My method of operating sleep mode is simply by the power management energy saving feature in Win 98 in which I have set to turn off hard disks after half an hour.
I have two hard disks, one a Western Digital which is 7 years old and a Samsung which is about 4 years.
Their method of parking is unknown to me so I presume from what you say I would be advised to turn off this feature.
alvin
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Mark, good heads-up for non-IT folk.
Another important point is that hard drives are MUCH more likely to fail after a power cycle. If at all possible leave them powered up and working (heads moving).
With the cost of hard drives now, it really IS affordable to use a second hard drive as first line backup media if you have a spare slot.
Kevin...
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I beg to disagree.
I have Fawlty Towers VHS videos that I bought in 1986, and they are as good as new.
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I think the point here is that media, like most things, has a finite life span.
I worked with optical disks a few years back when the makers were claiming 100 year life. But obviously this was a paper projection as the things hadn't been around that long. That has to be the same as CDs and any other media.
The bottom line is, whether Basil rolls on for another 20 years or not, sooner or later the tape will be useless, and you, the user, will be the one complaining.
If the tape/CD/whatever is important to you, then do a backup while it's still good, and store the backup in a different place just in case of other Acts of God. Better safe than sorry...
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Our hard drive on this PC lasted just over a year from new until we had the dire black screen warning warning "operating system not found". I understand this was because the bios chip was unable to see the hard drive. A contact tested the drive and it was dead.
Why so soon. There was a good reason. We had suffered loads with the Windows 98 shutdown error, it used to hang on shutdown and the mains swich was needed several times a week. I know that isn't advised but it was the only way to make it do anything.
After the drive failed I found out they have a sort of parking area/hard shoulder for the heads and a proper shutdown always brings the heads to this safe area. In shutting down on the mains we were constantly crashing the heads into the disc at random areas. In the end the hard drive became unreadable.
Oddly enough the new hard drive has never really suffered the shutdown fault from the day it was loaded. A better drive or perhaps something that was re-configured in the re-load.
Mark is right too about video tapes. That was a business we were involved in for a while. Some tapes seem to last years and then others can suffer terrible dropout after a moderate period. Make sure you have a backup of that prized wedding video!
David
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Could this mean the same could be expected for EEPROM car ECUs?
If you left the car with a flat battery for 10 years (say in storage) would it work when an attempt was made to start it?
(see what I've done there?)
M.
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Mark
I doubt it. The problem with most magnetic media is that the signals are very low level, and stored by minutely changing the magnetic characteristics of portions of the tape or disc. Therefore this can be more easily corrupted, as adjacent areas affect each other. Apparently too, you can get 'print through' from adjacent layers of tape.
Cds are more robust, but allegedly can suffer from corrosion of the metal layer. Poor storage conditions will make this more likely. I've never found anyone with an audio CD which has failed yet (wait for the shouts), but I don't know how long CDR or CDRW will last.
A car ECU has the programme stored in a chip in a much more robust manner than a tape or computer disc, so shouldn't age in any meaningful manner. It has to be - can you imagine how long a hard drive would last under the car bonnet?
Regards
John
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Interesting question so I went googling.
It appears that memory retention in EEPROM devices is typically between 10 and 50 years depending upon architecture. The most common types only achieve the lower figure.
Manufacturers also state that the actual retention time depends upon the number of write cycles that individual bits are subject to. Apparently the oxide/insulator deteriorates slightly each time the bit is written to.
So, if you want to put your EEPROM-equipped, ECU-controlled car into storage for more than 10 years, back it up to floppy !
Kevin...
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Wedding video?? Mine's still on super-8 movie ;-)
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