My mailer screwed up and didn't CC the news message to mailboxes...
----- Original Message -----
From: "Roderik Muit" <[EMAIL PROTECTED]>
Newsgroups: comp.sys.msx
Sent: Thursday, September 06, 2001 12:25 PM
Subject: Re: Novaxis MAP syntax
> Hi,
>
> Well, some people still know me (and flood my mailbox) It's OK, I've woken
> up now.. ;-p
> Since I'm seeing this message from 4 directions, I'll answer them all too.
>
> (amazing to see a mailinglist + a newsgroup both still working... I had no
> idea...)
>
>
> Gert wrote:
>
> > The sourcecode of NDFISK (written in assembly) should be available via
> > Roderik Muit (the author).
>
> Well, yeah, maybe. I'm not so good at keeping backups from things that
were
> '5 harddisks ago'. I can find out over the weekend whether I still have
> something...
>
> In the meantime I'll jot down some first information (containing big
holes)
> from the top of my head...
>
>
> For starters,
> - MAP.COM was written by Gert de Boom
> - the Novaxis SCSI BIOS was written by Jurgen Kramer - you've got the info
> from that one on ftp.funet.fi already, apparently.
> - NFDISK was written by me, using windowing routines from Jeffrey Timmer
and
> in v1.2 some code from a friend from a friend in Tilburg, whose name I
> forgot...
>
> As far as I can make out, it's the info on the partition types you're
> looking for.
>
> Manuel wrote:
> > Partitiontype : MAK 3.0
> > Partitiontype : Extended
> > Partitiontype : BERT/HPN
> > Partitiontype : Old PC
> > Partitiontype : Old MSX
>
> *churn churn*
> *braindamage*
> ...oh no, this is not going to work...
> I think I wrote some documentation on it. I hope so, since I'm not
planning
> to delve into assembly code in order to get that info. (Although it would
be
> nice to see how unstructured I programmed back then :-)
>
> What I still remember is that the partition table (on sector 0 of the
> harddisk, before any partitions) contains sets of 32 bytes of info for
each
> partition. There should be documents available _somewhere_ which detail
> this, since it's used on every PC...
>
> The 'old PC' format is exactly the same as PC's without extended
partitions.
> There can be 4 partitions maximum, i.e. 4 times 32 bytes.
>
> The 'old MSX' format was exacly the same format but used up to 8
partitions.
> (It just placed the same 4*32 bytes of information behind (or before?) the
> 4*32 bytes for the PC partitions because there is room for that. I have no
> idea why all PCs did not just do it like this.) It must have been used in
> some older interfaces (MAK? others? which ones were there? I don't
> remember.)
>
> The 'MAK 3.0' format also has room for 8 partitions, but did something
> different, so it's not compatible with the other format. (Maybe the offset
> of the area of 8*32 bytes is different from PCs, maybe the order of the
data
> inside the 32 bytes is different from PCs; I don't know...)
>
> The 'Extended' format uses sectors elsewhere on the disk, as does the
> BERT/HPN format.
> The fourth entry in the 'normal pc' partition table in this case does not
> contain data about a partition, but points to another sector somewhere on
> the harddisk which holds data on more partitions (i.e. more sets of these
32
> bytes, at the same position as sector 0). That's the main idea.
> On normal PC's, this is only done once, i.e. you have maximum 2 sectors
with
> partition data - one with info about 3 partitions + a pointer to the
second
> sector, and one with 4 partitions. So you can have max. 7 partitions on a
> PC.
>
> Note that this format is NOT supported by NFDISK (or any other MSX program
I
> know). Back then I did not know anything about how the PC does extended
> partitions, so I just created some partitions with a BERT interface, saw
how
> they did it, copied that, and assumed that that was how the PC did it too.
> What they do is: in sector 0 of the harddisk there are 2 * 32 bytes of
info;
> the first holding data about partition 1, the second being a pointer to
> another sector. In this sector there are 2 * 32 bytes of info; the first
> holding data about partition 2, the second being a pointer to another
> sector. In this sector there are 2 * 32 ...(reiterate until you get to
> partition 32. If I remember correctly that 32 partitions was the maximum -
> anyway, it's an arbitrary limit.)
> (I thought that this format was PC compatible. I now don't really think it
> is, because the PC only does a pointer to another sector once. It may be
> compatible depending on how the particular PC's BIOS is implemented,
> perhaps, maybe, kind of, idunno...)
>
> So what's the difference between 'Extended' and 'BERT/HPN'? Well, I wanted
> the Novaxis 'Extended' format to be compatible with the Bert, but I
screwed
> up somewhere in NFDISK 1.0 (and those routines also got into the Novaxis
> interface) because I did the pointers to other sectors as absolute sector
> numbers, while the BERT had it as a relative offset from the current
sector.
> So in NFDISK 1.1/2 I added the 'BERT/HPN' format. (There must be a very
> small utility around -on some Quasar disk anyway- that converts Extended
> to/from BERT format. If someone knows this by any chance, please tell me -
> because there may be documentation included that proves whether I'm
talking
> nonsense here or not.)
>
> I don't know if I have all details right. I may have mixed up something in
> Extended vs. BERT and in old MSX / MAK 3.0... But this is about it, kind
of.
>
>
> Sooooo.... that's it. Questions:
> - what more do you need to know?
> - how did you guys come to this? Are you planning something? What's UZIX?
>
> This weekend, I'll try to find NFDISK sources and put them on my
homepage...
> I think I remember having lost v1.2 but still having 1.1...
>
> Greetingckxsz, [*]
> Ro.
>
> ([*] which is what I used in my BBS times)
> (Gert: zie je 1 dec!)
>
>
>
--
For info, see http://www.stack.nl/~wynke/MSX/listinfo.html
