Hard drive caddy: How does BIOS cope ?

9 replies [Last post]
pegasusvideo
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Joined: Aug 29 1999

I`m considering getting one of those HD Caddy things, the idea being I can slot in a HD appropriate to the job in hand, ie a 17.6GB drive for video, or replace it with a 1.2GB drive for backups/internet work.

But I forsee a dilemma. My operating system currently shows drive D: and E: as being 6.4GB. What happens if I remove one of those drives (as per the caddy) Would the system simply skip the missing drive. Or what if I then place a 17.6GB drive in place when the BIOS says its 6.4GB ?

If I can understand how the computer circumvents this dilemma, I may opt to get a caddy. (I don`t like the 2x 6.4gb whizzing around when I`m not using them; it will shorten their lifespan)

Your comments duly awaited

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miker
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Joined: Apr 27 1999

this is quite tricky to explain -- so, let me tell you how i get around all the potential problems (i'm assuming you're on ide, not scsi):

1. if you are swapping between machines, decide on a standard location on the ide interface for all interchangable drives. i opt to use the caddies on the secondary master.

2. fdisk the drive as a whole -- this may cause problems with bios's that don't detect over 6.4gb -- i don't know exactly 'cos i've made sure all my hardware is newish. if you have older stuff, mayber get a promise fasttrak addin card, which replaces the onboard disk i/o. *or just use scsi*

3. in fdisk, create only a logical drive partition, *not* a dos partition -- this should prevent any exisiting drive letters being rearranged.

4. format, and that's it. Because you've created a logical drive, it should default to the first available drive letter, rather than butting in as, say, your D: drive which may be set up as your CD. BTW, it's good practice to put CD letters way up in the alphabet ...

as for the disks spinning all the time and shortening their life-span, you've obviously never heard of stiction

HTH

Nigel Longman
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Joined: Apr 28 1999

If you leave the BIOS in auto-detect hard drive it should sense the change in drives when you swap them. The size issue is not a problem with recent machines. You should of course power-down your machine before swapping drives.

If spinning hard drives concern you check if your OS has a hard-drive power down option. This tends to be seen as an energy saving rather than a drive saving option.

Incidentally, it could be that a drive left spinning has a longer predicted life than one continually started and stopped. I don't have figures for this, but its an interesting thought.

Nigel

pegasusvideo
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Joined: Aug 29 1999

Thanks for the info guys; I`m half convinced.
Re the drives spinning continuosly, apart from the noise factor of 3 drives, it seems silly to have two video drives and never accessed 8 hrs a day. (I have just swithced on the power save circuit)

Now I`m gonna throw another spanner in the works - which I think the auto detect answer may solve. What if you leave the caddy empty? Will things still work ? (That way, I`ll just have C: and CD rom on the primary channel, and use the secondary channel to install the video drives as and when I do video edits)

David J
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Joined: Nov 23 2000

I've been using caddied IDE drives for three years now with minimal problems. I've got two PCs and swap drives between them as required as well as using caddied drives for temporary arhchiving in mid project.

Most are single partition, but one has two partitions.

One PC has auto detect that works. The older one doesn't.

Without auto detect fully functional, you just have to be careful to reset the BIOS parameters when you change caddied drive. In my case I'm lucky, because manual detect works, even though auto doesn't. But even if manual detect didn't work, it isn't too hard to write down the required settings and put them in each time (assuming you don't change drives every two minutes, that is).

The effect of the extra partition on one disk is minimal. The primary partition comes up early in the drive letter sequence, whilst the secondary comes at the end. I've slugged my CD drives to fixed letters, so the only difference between single and double partitions is an extra drive letter after my fixed hard drives and before the CDs.

Some people (like me) swear by caddies - they give such flexibility.

The only problem I've had with caddies is with the lock. By shorting out the electrical connection through the lock I've removed that source of intermittent faults and everything has worked perfectly every time for about 2 years now.

The other thing to note is that caddy design seems to change quite often and it can be difficult to buy more to the same design later. So buy all you need at one time to save hassle later.

At least one well-known UK NLE dealer complains that caddies are more trouble than they are worth and doesn't want to supply them any more. It would be interesting to hear about people's experiences using caddies to see who is 'right' here.

drsolly
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Joined: Mar 8 1999

<>

Stiction - I used to love that word.

Back when I was running the S&S data recovery
company, Connors were shipping 20 mb (this is ten-twelve years ago) drives that suffered
terribly from this problem. I think it was
the lubricant they coated the platters with, sometimes it acted more like glue than oil.

Anyway, we got a lot of data recoveries with
this as the root cause of the problem. When you turn the drive on, it would hum, but not spin.

At first, we were going inside the drives to
get things going, which is a fairly tedious
process, and you won't want to ever use a drive that's been opened, even in a clean
environment. But then I thought about it a bit, and realised that we could use inertia.

So, we'd put the drive on a very long cable, to give freedom of movement, then you'd rotate the whole drive rapidly, by twisting
the wrist. At the point where you reached the
end of the twist, you stopped twisting, but the platters inside wanted to keep on rotating (inertia). And at that point, you apply power to the drive. And the combined torque of the inertia of the platters, and the start-up of the motor, would overcome the stiction. It took a bit of practice, but once you had the knack, you could do it without really thinking. Then we'd copy all the data off, and give it back to the customer. I called this technique "Windmill".

I remember I once had to do it while a customer stood and watched the entire process. So at the crucial moment, like a conjurer, I distracted her with one hand while I Windmilled with the other, so she never knew exactly what it was I did to get her data off.

Would anyone like to hear about the "Magic finger" technique that works on ST 225 20 mb and ST-255 40 mb drives? It was a closely
guarded secret at the time, it earned me a lot of money, but since the ST-225 (about half of all drives were ST225s at one time)
is a museum piece, I guess I can reveal it.

Ken W
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Joined: Apr 9 1999

Yes Doc
Please tell the magic finger trick, I remember those Seagate days well, (how did Seagate get to be the biggest company at that time with such crummy products?) (Why have I asked that question when Microsoft exists?) Guess the computer industry defies all business logic.
I have a Quantum largish scsi drive that I've been "windmilling" for some time, Quantum don't want to know (nothing changes there) Now it's becoming resistant to even the "windmill" factor. Trouble with me - I can't bring myself to chuck out devices that are sort of, nearly, maybe half working, for fear they may correct themselves miraculously, it has happened.
Regards
Ken

Tony Cox
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Joined: Sep 29 1999

What are the rules to ensure best hard disk access speed when using cadies. Ideally all the HDs you use must be of the same manu facturer/type. But this will not be possible.

Does the Bios recognise the use of faster HDs and the PC "speeds" up or is it alway stuck at the speed of the slowest.

Presumably you cannot use the latest spec on UDMA? access with the standard caddy.

I am interested for the same reason others have mentioned. I want an optimised set up for video editing - but swap to new drive for all the messing around that I/the family do. If we have unistall/clean up problems - my original editing set up will not be affected.

David J
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Joined: Nov 23 2000

Maybe there are other types around, but all my caddies do is to provide an easily breakable connection between te HD inside and the host PC. They do introduce extra chances for noise to get into signal lines, but otherwise the caddies drives are just like fixed drives as far as the PC is concerned.

So, unwanted pickup problems aside, there is no fundamental reason that I'm aware of that stops caddied drives running to their full potential in a given system

Similarly, there is no obvious reason why mixing manufacturers will have any adverse effects. Doesn't cause me any problems on my two Wintel systems, both with caddies and a mix of drive types.

However, I did have to swap a Maxtor 8.4 drive for an IBM to avoid data corruption (when 8.4gb was the tops), so caddied drive bays can be more fussy about particular types of drive than fixed installations. In that instance, the software disk checks all went fine, but I got random noise in video and still images which was put down to line pickup through the extra cabling in the caddy.

pegasusvideo
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Joined: Aug 29 1999

Hi all

Sorry I`ve been aawy from the arguement for a while; its due to that bloody Premiere / Miro thing. It didn`t work correctly, so tried to manually reinstall every item onto PC. That took a week with all the inherent faults ... and the *&^%$£ thing still doesn`t work correctly. So I`ll post another letter in another section.

Anyway guys, many thanks for the input

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