Hi, Rod.

RS> BG> You can still use large IDE HDs though, a long as you load
RS> BG> the manufacturer's special disk-manager type software, which
RS> BG> lives in the MBR, and allows full access to the entire drive.

RS> FM> Do you recommend this?

RS> RS> Its not a terrific idea if you can avoid it. It can bite you.

RS> FM> OK, how?

RS> LBA support, best in the motherboard bios.

No, I mean *how* can it bite you? Presumably some people use that disk
manager software, for whatever reason. Quite possibly I will, initially.
How do those people / how might I get bitten? ie, what are the
undesirable things related to the use of that software which "bite" you?

RS> FM> Brenton suggested just partitioning it up into
RS> FM> lots of 250k drives and using no extra software.

RS> RS> I thought you didnt have LBA support in the motherboard etc tho ?

RS> FM> Now I'm mystified. No, I don't have LBA support. Does
RS> FM> that mean I can't FDISK it into lots of 250 *meg* drives?

RS> It means that without LBA support, you need to either get that with
RS> a change of motherboard, or use the drive manufacturers driver which
RS> works around the 1024 cylinder glitch, and then you can do that.

RS> The use of 250MB partitions alone wont fix the glitch
RS> at 1024 cylinders when you dont have LBA support.

OK, that's covered below.

RS> RS> You cant just chop it up to avoid the 1024
RS> RS> cylinder glitch with a drive over 528MB.

RS> FM> Oh? I thought that was a DOS glitch,

RS> Yes, but that applys to the PHYSICAL drive, and so multiple
RS> partitions on a drive with more than 1024 cylinders wont help.

Oh it can't access the PHYSICAL drive with a cylinder number greater
than 1023, presumably only got 10 bits in that parameter.

RS> FM> and if you FDISKed it into little drives you were home clear... ?

RS> Nope.

OK, so that just fixes that other, lower limit - whatever it was. Which
I fixed in DOS 3 by using Compaq DOS 3.3 and which isn't a problem in
current DOSs anyway. Oh and I guess it helps with cluster size too.

RS> FM> Lives in the MBR? Hmmm, yes that's a nice idea. Presumably
RS> FM> you can then boot, using normal DOS, even off a huge drive.

RS> RS> Yes, thats the idea.

RS> FM> Good.

RS> FM> Does it eat any base-640k memory?

RS> RS> Usually. There are a variety supplied with the different large drives.

RS> FM> How much? (Typically)

RS> Cant remember off hand, its not huge. I much prefer the LBA route myself.

Sure you do, but *I* may not go that way initially, and I'm trying to
see *all* the possible consequences of that.

RS> RS> I think LBA support is the way to go, much more convenient for a
RS> RS> variety of reasons. If your current motherboard doesnt have that, and
RS> RS> you can just move your cpu and memory to a new one, its not all that
RS> RS> expensive and you will get some other bonuses like 4*IDE support and
RS> RS> even CDROM support in some of the recent ones. Ditto EIDE and serial
RS> RS> support on the motherboard with convenient cmos fiddling. Not that
RS> RS> expensive if you are considering spending $K class money on a drive.

RS> FM> I agree, but I'm not about to do that at the moment.

RS> Well, I think its the way to go myself, its not expensive and fixes
RS> both the memory hassles with the driver, and the increased risk of
RS> glitches with the driver fanging your data. Particularly with those
RS> very large drives, unless you have a decent backup, and thats really
RS> only a decent tape backup with drives of that size unless you have
RS> VERY specialised drive use, IMO its not worth farting around for the
RS> relatively low cost of an LBA supporting motherboard. Even if you do
RS> bin the motherboard in a year or so, its not a major cost now.

I'm certainly considering doing that, but I'm trying to learn about
*all* the pros and cons of each alternative.

RS> FM> One reason being, is PCI the future? What do you think?

RS> Well, it certainly looks like a viable route. The question of whether VLB
RS> will vanish tho is another matter entirely, currently there is no sign of
RS> that. Currently insisting on PCI does limit your choices quite a bit on
RS> the motherboard particularly. Some of the useful configs like some 30pin
RS> memory slots for example are pretty thin on the ground if you demand PCI.

But are available on VLB? Bloody Hell! Is there a technical advantage to
either one, or is it $, or is it market power that keeps them both
going? Like say VHS / Beta for so long (and then the technically
superior got the flick).

Regards, FIM.

 * * Windows:  an 80486 to XT Conversion Kit.
@EOT:

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