[parisc-linux] Boot-up challenges on a 715/75

[M. Grabert]

On Wed, 19 Nov 2003, Steve Bromwich wrote:

> On Tue, 18 Nov 2003, Grant Grundler wrote:
>
> > On Tue, Nov 18, 2003 at 08:38:00PM -0400, Steve Bromwich wrote:
> > > I believe HP machines use a 512 byte sector CD drives (with the standard
> > > being 2048 byte). I'm not sure off-hand if the TEAC supports 512 byte
> > > sectors. Your best bet may be to borrow a CD off a Sun machine, if you
> > > have access to one.
> >
> > I'm only aware of HP using 2k sectors for CD-RO.
>
> Well, this is just from my own personal experience on a 715/75 (which has
> now sadly bitten the dust). A google around would tend to support this
> theory, for example:
>
> http://lists.parisc-linux.org/pipermail/parisc-linux/2000-September/009345.html
> "Last posting to the list was about my SCSI CD-ROM not booting the
> HP-UX INSTALL CD.  Well, it turns out that NECs are in 2048 byte sector
> mode whereas HP requires 512 byte mode.  SUNs and SGIs also require 512
> byte sector mode.  So I just borrowed a SUN external CD-ROM..."
>
> > I've never heard of 512 byte sectors in a CD Drive.
> > Is that a feature unique to CD-RW?
>
> It's the standard for Sun boxes (at least, on all my Sparcstations). This
> of course means I don't have any SCSI 2048 byte CD drives to verify my
> statement! If anyone else would like to verify it I'd be interested, and I
> suppose it might not be a bad idea to add it to the FAQ if true as I'm
> sure it'll bite someone else down the road.

I have several risc boxes (SGI O2, Alpha AS500, Dec 5000, Sun SS20s and HPs),
all of them use 512bytes/sector. I'm actually not aware of any non-intel
platform that uses 2048bytes/sector for SCSI CD-drives.

I once ran into the problem that I couldn't boot from CD using an old Sun
SPARCstationLX, since the SCSI CD-drive was set to 2048bytes/sector.

Most SCSI-CD drives have a switch/jumper to select the default
bytes/sector (ie. 512 or 2048). Most 'newer' drives support to be switched
to either mode via software. 'Newer' meaning less than 8 years old.

However old workstations (like the old SPARCstation I presume) don't
support to switch the SCSI-CD-drive to the 512 mode, so you HAVE to set
the jumper on the back of the drive.

I doubt you'll find any SCSI CD-drives on the market (second hand or new)
that are so old that they support only one of these modes. I bought a
TEAC CD-writer and a Pioneer CD-drive in a ordinary PC shop about 6 years
ago, and they support both modes (and I even couldn't find any that couldn't).
They work with all SCSI machines I have.


greetings,
   Max