[rescue] CDROM 512-byte boot questions

[Dave McGuire]

   Let me know if I can assist.

          -Dave

On 7/27/23 19:24, John Hudak via rescue wrote:
> 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 <mailto: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>
>      > <mailto: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>
>     <mailto: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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>      >
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> 
>     -- 
>     Dave McGuire, AK4HZ
>     New Kensington, PA
> 
> 
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> 
> 
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-- 
Dave McGuire, AK4HZ
New Kensington, PA