Manuel Bilderbeek <[EMAIL PROTECTED]> wrote:
> This is the continuing story about a SCSI newbie trying to get his
> harddisk working...
(...long story - skipping to his questions)
> 1 - Why isn't the terminator needed after all? Did I have a bad cable
> before? (When I got the "SCSI Bus is down // Host self test
> failed"-error)
I've used only 1 terminator with my Gouda HD interface (only
interface + 160 MB. IBM drive, ROM v1.51, I think) as well, and this
didn't give any big problem. I've had occasional disk errors (not
ready, disk I/O error), that always went okay after a retry.
Adding a second terminator at the other end of the cable (at the HD
side) didn't change that behaviour at all.
Cable lenght is a big factor in this; with a VERY short cable (few
cm.'s), terminators are don't cares, with longer cables (say >30
cm.), proper termination can make the difference between no problem
at all, or a lot of troubles (I used some 60-70 cm. cable).
And _some_ SCSI devices have active termination, meaning they can
sense somehow where/when termination is needed, and activate
termination if necessary. (I don't think such a 160 MB. IBM drive can
do that)
> 2 - Why doesn't the extended partitiontable work? (Because I have
> Novaxis 1.00 ROM?)
If you have only version 1.00, try upgrading the ROM in any case...
> 3 - If I upgrade to Novaxis 1.51, can I keep all the partitions, and
> all info on the HD? Or do I need to reinstall everything?
I think the never Novaxis ROM's WOULD recognise partitions
used/created with older ROMs, but you know it: no guarantees.
> 4 - What causes the bad sectors, and why does SCANDISK report less bad
> sectors than HDCHECK? (Are they random, maybe?) Why only on the much
> better IBM drive?
a) Bad sectors are in essence normal for HD's
b) Modern drives/systems tend to mask these, so that it APPEARS you
have a drive with perfect disc surface
c) If different tools indicate different bad sectors (different
number, different places) right after another, that would more likely
be an interfacing problem (like bad controller or cables).
Or maybe this software itself isn't writtten right (try these tools
on a different HD/interface combination).
d) If you just have a fixed set of bad sectors: that's okay.
e) Don't try to re-use (for instance by re-formatting) sectors that
were marked bad once; if they really were bad sectors, it's not a
good idea to use these again, if even they work again later.
f) If more bad sectors keep popping up regularly, then either the
interface/HD combination isn't working right, or the HD is about to
give up - take your pick.
> 5 - Did I handle the BAD sectors in a good way? Or are there better
> methods?
I used DiskView (2), if you have a sector number, DiskView can easily
translate this into a cluster number, and lets you mark that cluster
as "bad" in the built-in FAT editor.
If you have another tool for this purpose: use it, less chance you
make a mistake and mark the wrong sectors as bad.
Just make sure these "suspicious" sectors don't get used anymore, at
all.
> 6 - What is the FORMAT command for, since I can't format a partition
> with it? (Or is that the task of NFDISK?)
Normally, partitioning just reserves the space for each partition,
but still doesn't make each partition useable by some operating
system. (That's the way it works with PC's, you still have to format
each partition after you partition a harddisk).
Since there's only 1 file system used on the MSX, a partitioning tool
can do the 'formatting' right away (make bootsector & empty FATs).
After that, the FORMAT command is just used to let you change some
settings, like write protect or enable/disable a partition.
> 7 - Where can I find a manual of NFDISK?
I received a on-disk manual for NFDISK v1.0 with the interface, and
several pages of paper manual about it.
> 8 - What is the difference between all those types of partitiontables?
They were all created to make sure you can't easily exchange files
with other HD users ;-{
> 9 - Why are the Disk I/O errors (e.g. in Multi Mente) gone in a retry?
Because that HD interface software wasn't written smart enough to do
such a retry itself, instead of bothering you with it.
> 10 - I guess an upgrade of the Novaxis ROM is a good thing. Who can do
> it for me, and what would it cost?
Does anyone know if or how a Flash ROM could be placed in the Novaxis
interface, so that software-updates are easy after that?
In relation with that: if you would replace this ROM with a bigger
one, like 1 or 2 MBit (instead of 16 KByte), does the SCSI controller
in this interface maybe have some general-purpose I/O lines you could
use to control block-switching of such a ROM, or would additional
circuitry be needed?
Does anyone have some datasheets of this controller (AMD or WD
33C93)?
> 11 - Are the speeds I got with HDSPEED reasonable? What is the speed
> with a new Novaxis ROM? And what on 7MHz? (Twice as big?) And with both
> 7MHz and new ROM?
If floppydrives get to 12-15 KB's/second, who cares whether your HD
works 8 times, or 15 times faster than that?
Anyway: 7 MHz. and the Gouda (Novaxis) SCSI interface just don't go
well together. Frankly I wouldn't know why not, such controllers &
HD's are made for far higher data rates, so I suppose it's a pure
software-problem.
The software is THE problem with the Novaxis SCSI interface.
For instance:
If you only have one HD connected, with a SCSI-ID that is SOMETHING
else than the interface, the intelligent way would be to scan all
ID's on the SCSI bus at boot time, and make a drive-letter for every
useable partition you find.
Not so with the Novaxis interface: you have to set a 'target-ID' for
the HD, set a 'host-ID' for the interface, and if the target-ID isn't
right, the interface will make you wait loooonnngg after every reset,
and doesn't initialise any drives.
There is LOTS of such shortcomings like this. When all is okay, it
works okay, and fairly fast, but if things aren't entirely right, it
works SHIT.
Apparantly the Bert and Mega-SCSI do better in this respect.
Partition table formats are quite standard for PC's, and if you use a
same format, you can exchange files easily with other HD users.
But even though it doesn't offer ANY obvious advantage, a lot of MSX
HD interfaces (and versions) use different partition tables,
incompatible with one another.
There is one REALLY simple solution for this: 'standard' partition
formats are known, for every incompatible type it would be enough to:
-Write a bare-bones utility to convert existing partitons, or create
new ones to the standard format.
-If neccesary, update the interface software to work with this
standard partition format.
Greetings,
Alwin Henseler ([EMAIL PROTECTED])
http://huizen.dds.nl/~alwinh/msx MSX Tech Doc page
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