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Re: maximum hard drive limitations?

> This question isn't strictly Linux, but I hope you'll be kind :)
> I have a Toshiba 490CDT model, which comes with a 3.8GB harddrive, and the
> Toshiba docs seem to be saying that the maximum drive that can put in the
> computer is 6GB.
> Now I would like to upgrade my drive, and jumping to a 10GB or 20GB drive
> would seem much more sensible to me at the moment than 6GB.
> I am thus extremely frustrated about this alleged 6GB limit.  It doesn't
> make sense, seems unnecessary. 

The actual limit is not a disk size, directly.  There are two things to 
consider, one of them is critical, and the other may be less important to 

1) There is a physical height limit to the size of your hard disk bay deep
   inside the computer.  Some manufacturers, but Toshiba has been well known
   for this, don't have a very tall bay.

   Typical sizes are 8.5mm, 9.5mm (normal laptops), and 12mm ("high capacity"
   laptops - most of your large desktop replacement types).

   8.5 mm drives are uncommon, so it may be hard to find them in larger sizes.

2) The BIOS may have trouble addressing larger disks, if it was made in an
   era when all drives were smaller.  Under Linux this usually isn't a 
   problem, as long as the kernel is within recognizable "low" disk space
   for LILO.  After we hit the kernel we leave the real BIOS behind forever.

> I know there was some 2GB limit under DOS on
> older BIOSes, and I seem to recall an 8GB in Win95 or Win98, OS driven
> rather than BIOS driven.  But a 6GB limit?  What's that supposed to mean?

It means that was the largest 8.5mm drive they knew of at the time they 
shipped that model, probably.

> Is it really a BIOS limitation?  Is there really any good reason why Toshiba
> can't update the BIOS to handle larger drives ? (I've recently updated to
> the latest 8.0 BIOS, but Toshiba, in their wonderfully helpful
> proprietryness, neglected to provide a README explaining exactly what it was
> the new BIOS fixed).  I would have thought, if the drive fits inside
> physically, and if the cables fit in properly, then why wouldn't it handle
> 10 or 20GB? 

It should.  If you are unafraid of opening your machine, see if the drive is
a precise, tight fit, or has 1mm to spare.  The drive itself will have a model
number on it.  You should be able to hit the search engines with that and 
determine if it is an 8.5mm or 9.5mm drive.

> In a cynical moment I'm inclined to think they refuse to update the drive
> handling as a marketing ploy to make you buy the latest model (which of
> course would only force me to look at another brand altogether).

Nice conspiracy theory, but most companies aren't aware enough of what 
all their hands are doing to pull these sorts of stunts.

> Anyway, I'm writing to ask if any of you can confirm the reality of this
> kind of drive-size limitation?  If it is real, can you explain why?  Do I
> just have to put up with it, or do I have a "right" to be cranky with
> Toshiba about it?
> And can anyone say what the 8.0 BIOS improved over the older 7.2 or 7.5
> BIOSes?  

This, I don't know, but the toshiba list you're on probably has someone 
who knows.

* Heather Stern * star@ many places...

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