[rescue] CDROM 512-byte boot questions

[John Hudak]

Thanks Dave, you knew where I was headed with this.
Appreciate the feedback
J


On Thu, Jul 27, 2023 at 6:39 PM Dave McGuire via rescue <rescue at sunhelp.org>
wrote:

>
>    This question wasn't directed at me, but I'll endorse it.  I'm
> currently running ZuluSCSI boards in several SPARCstations, two PDP-11s,
> and several VAXen. (PDP-11s and VAXen via SCSI host adapters that speak
> MSCP)
>
>               -Dave
>
> On 7/27/23 18:29, John Hudak via rescue wrote:
> > Interesting information. TY. I am considering getting a ZuluSCSI board
> > since the SCSI2SD v5 is NLA.  Do you endorse it?
> > Thanks
> > J
> >
> >
> > On Thu, Jul 27, 2023 at 4:01 PM vom513 via rescue <rescue at sunhelp.org
> > <mailto:rescue at sunhelp.org>> wrote:
> >
> >
> >      > On Jul 27, 2023, at 12:54 PM, Jonathan Sturges via rescue
> >     <rescue at sunhelp.org <mailto:rescue at sunhelp.org>> wrote:
> >      >
> >      > Hi,
> >      > Nice summary, your understanding is correct.  Some small
> additions:
> >      >
> >      > *  Some OSes -- Solaris2, I'm fairly sure, maybe later SunOS? --
> >     the SCSI drivers can issue the block size change command when the OS
> >     is running (or are able to handle the 2k block size).
> >      > *  OBP 3.x can issue the block change command too, IIRC; it's
> >     really OPB 2.x and prior that have the hard requirement of a
> >     512-byte block requirement for booting.
> >      > *  Besides Plextor, most Panasonic, Toshiba and Pioneer drives
> >     have jumperable block sizes.
> >
> >     Thanks for the reply/confirmation.
> >
> >     I did a bit more experimentation with the ZuluSCI and figured I’d
> >     post my results to the list to benefit any future folks who might be
> >     looking for this type of info.
> >
> >     - CD6.iso : Zulu log shows it coming up in 2048-byte mode, but my
> >     sun4c/m machines boot fine from it.  I don’t see a MODE SELECT in
> >     the log - I guess the ZS is just operating in “soft” block mode and
> >     honoring whatever request comes in ? (This is great by the way - not
> >     looking a gift horse in the mouth)
> >
> >     - CD6_512.iso : Block size specified as 512.  Works as expected.
> >
> >     - CD6_2048.iso : Block size specified as 2048.  Machines will NOT
> boot.
> >
> >     So it seems like _<BLOCKSIZE> is a “hard” setting.  Omitting this
> >     seems to run the device in “soft” mode (hard/soft just my personal
> >     terminology for this behavior).
> >     _______________________________________________
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> >     <http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org>
> >
> >
> > _______________________________________________
> > rescue list - http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org
>
> --
> Dave McGuire, AK4HZ
> New Kensington, PA
>
>
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> rescue list - http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org
>
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