RS> Sectors are normally numbered form a base
RS> of 1 for various historical reasons.

PE> Do you think that sectors are:

PE> A) 64 sectors, numbered 0 to 63

PE> B) 64 sectors, numbered 1 to 64

PE> C) 63 sectors, numbered 0 to 62

PE> D) 63 sectors, numbered 1 to 63

PE> Last thing I remembered you said A.

RS> Nope, B.

PE> Ok, close enough.  What evidence do you have of this?

RS> The most obvious is sector editors where you specify the
RS> sector in terms of head, cylinder and sector. The only one
RS> that starts from 1 is the sector. LIke Nortons DiskEdit.

PE> No, I meant that it is 64, not 63.  I say it is 63.

It allows you to specify sector 64.

You could prove that more convincingly by say using DiskEdit
to manually write a sector number in the first byte of the
series of sectors, and then go back an reread those and check
that you do have full access to sectors numbered 1-64 etc.

Maybe I am missing your point again, this is VERY basic stuff.

PE> I have been using D in PDOS, and it appears to be working.

RS> Depends on how you decide it 'appears to be working',
RS> if you dont rigorously test for the missing last sector....

PE> I am doing address translation from
PE> absolute number (as used in the fat)

Fats dont even HAVE sectors, they have CLUSTERS. A cluster
is usually more than a single sector except on a floppy.

PE> to physical number (as used by the BIOS),
PE> in order to boot PDOS. It is all working.

Doesnt prove a damned thing if sector 64 isnt
actually used in the boot process, and it isnt.

RS> Its also complicated by what level you are doing the direct access at.
RS> There is lots of translation and faking with a modern IDE drive. You
RS> dont actually have a fixed number of sectors per track anymore, that
RS> varys in bands across the platter and that is faked up into something
RS> completely different at the level of the commands down the cable to the
RS> drive. Even more dramatically if the drive is being used in LBA mode.

PE> Yeah, I'm not talking about that,

You are actually all these processes are going on all the time.

PE> I'm talking about what the "user" sees as the number of
sectors/track.

There aint not such animal, because there are those wide variety
of translations going on all the time at various levels.

There aint even any 'user' numbers, you can do absolute operations
on a drive at a variety of levels depending on what you call with them.

PE> It is shown as 63, and I just want to know if that means 63 or 64.

Christ you're cryptic Paul. Where the fuck 'is it shown as 63'

PE> BTW, the floppy shows as 18. Do you think that means 19?

Nope, a 1.44MB floppy has 18 sectors per track. Numbered 1-18.
@EOT:

---