Re: (Fwd) Re: cbm 9060/9090 scsi command set

From: Ethan Dicks <>
Date: Fri, 15 Nov 2013 02:32:25 -0500
Message-ID: <>
On Thu, Nov 14, 2013 at 4:45 PM, didier derny <> wrote:
> The other problem is the identification string, (if the 9060 is checking it)
> It could be programmed with a console (serial port)  and stored in the
> eeprom...

I am reasonably certain the D90x0 firmware isn't issuing any IDENT
packets (are those SASI or only SCSI?)  The DOS board doesn't expect
any other SASI board than the one that's in there, and you tell it if
you have a TM602S or TM603S by moving a jumper which it reads on an
I/O pin.  It doesn't ask the drive, the person assembling the unit
tells the board with a jumper.  The firmware just picks 4 heads vs 6
from a geometry table.  Bridge cards (SCSI/SASI-MFM) of that era had
different ways of knowing what the drive geometry looked like that
usually started with a human somewhere causing that geometry to be
stored in firmware or a special track of the disc because you can't
"query" MFM drives for anything.  It's why PCs have CMOS RAM.  The
human tells the BIOS what the drive looks like.  Asking the drive came
later, with embedded SCSI and IDE.


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Received on 2013-11-15 08:00:05

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