Mike,

Put some spaces in your text it hard to read. 

<   I don't have mine handy, so I can't verify the firmware number, but th
<is definitely a TK50Z-Gx, since TK50Z-Fx would _NEVER_ work on something
<like VS3100 M76 whose SCSI is fully generic. (As I have explained in muc
<more detail in my lengthy posting, TK50Z-Gx is a standard SCSI tape drive
<However, you have to be careful with KA410 (MV2000 and VS2000). Unless yo

Ok, here goes.  The only difference between the 3100m76 and the vs2000
scsi is 0/zip/nada/zero!  They both use the NCR5380 chip to drive the 
SCSI bus and whats on the other side is a vax.  Now the NCR5380 is a 
programatically poor SCSI chip as it was designed back in '83ish, I've 
designed a few into z80 CP/M crates back around '85 and hated it.  It a 
good SCSI bus driver but but writing a driver to make it adhere to scsi 
bus protocal is a royale pain.  Don't forget, SCSI is the bus level 
protocal and what's said over the bus can be anything in the way of 
higher protocal just like eithernet.

Now what your talking about is CONSOLE ROM support... and that is whole 
different can of worms.  The VS2000 does have console rom support for 
tk50 via scsi adaptor, but only that.  I've booted via TK50.  No other 
device is known or addressed.  If the vs2k however is running some OS 
that has a 5380 scsi driver suitably configured it can/will/does drive 
any scsi device on the bus.  I call that OS device support.

<reverse-engineer its system ROM (or have a friendly UFO pilot fly right
<into former DEC's archives and steal the sources for you) and significant

At one time I had access to it and passed on it as the project I was 
working on used a MVII chip in a printer (network connected using ELN).
I also have a ADVICE with is a Microvax-II chip on a board as an in
circuit develoment tool but can be used as a standalone computer also 
from the same project.  I guess I'm comfortable with the elemental 
hardware of small vax systems.

<to think. However, if you were to try to BOOT from your TK50Z-Gx from th
<">>>" prompt, or to do anything with it under VMS, you would see a

Mine does and on either.  I suspect it was a late version code.

<   The fact that VMS doesn't support normal SCSI but only supports fake
<TMSCP to TK50Z-Fx doesn't make me cry. One can always throw out VMS and u
<a real VAX OS (currently only NetBSD/vax but I hope to help Berkeley

Damm, I'll have to tell my VMS driver it doesn't work.  You see the same 
driver that pushes the SCSI in the 3100Mxx pizza boxen is also used in 
other vax machines.  the problem here is you confusing scsi with the 
overlying protocal used to talks to a specific device.

A side comment relevent to port-vax since you alluded to it.  Unlike
netBSD all the devices under VMS work and they even work under ultrix.
I'd suggest that commenting on the realness of VMS or any other OS is 
out of line and really not very informative to those trying to get netbsd 
going.  I run enough Qbus and babyvaxen in the room here to know that.
Netbsd has enough bugs and documentation problems and most of this 
discussion is far from relevent to the newgroups aims.

<   1. You can't format SCSI disks using KA410's diagnostics like you can
<with KA42/41's.

That because the rom support wasn't there and considering the year it 
was designed it makes sense.  I can't format MFM drive from my MVII 
(KA630) console either and must use MDM for that.  Same difference
As time went on and eproms became denser more maintainance features 
were incorperated.  At the time the vs2k did more at the console level 
than any other vax that didn't have a console pdp-11.

<   2. You can't boot directly from any standard SCSI devices.

Again the booter is not there that does not say a thing about the scsi
If you load a VMboot that knows the scsi port it will boot whatever 
device it's capable of.  No majik just smaller eproms inthe VS2k and at 
that time they (DEC) didn't have any SCSI drives to boot when the VS2k 
was released.  

<   3. The system ROM's inclination toward TK50Z-Fx may very well interfer
<with an OS'es desire to support standard SCSI devices. First, the

Can't imagine how.  It's not used like a PC rom bios!  If you don't make 
calls to the rom it's not a factor.  Calling roms(eproms) in a vax of 
that generation has speed penalty as fast eproms then were 250ns and 
rams were in the 100ns range.  The MV-II cpu chip has to actually slow 
down(considerably) to access the eproms.

<   I find these problems so severe that I consider KA410's SCSI controlle
<unusable unless an alternative system ROM is written for KA410. KA410 an
<KA42/41 seems to be very similar from the software viewpoint. As far as 

You have never designed hardware and put drivers behind it.  The SCSI is
as I said a chip, if you talk to the chip right it will do a valid
SCSI bus.  It's up to the driver to do that correctly and not wimp out 
call a rom routine that has an access time slower than slow compared to 
ram.  Granted rom boot support is not there. But a floppy or small hard 
disk can store a booter that can.

<   A bad EPROM is not a very plausible explanation. A much more likely

I spent some time today with my prom programmer and yes one of them 
contains all 0FFh... fried since it will not program either.  It has 
little to do with what version but more so with fried parts.  The boards 
however are identical in every other respect and the bad one works with
a functional (copied) Eprom.   One of the small benefit of a career in 
hardware engineering.


Allison