On Tue, 6 Jun 2017, Dave Wade via vcf-midatlantic wrote:
The CDs can be ripped an written on a normal drive, so that makes sense. Dave
Yeah, I went through this recently-ish with IRIX CDs. (They're EFS filesystem images, not ISO-9660, and the bootloader doesn't handle 2k blocks in that context. Meanwhile, the drives I have that can do this 512-byte thing are old enough that burned CDs are iffy.) Thank you, Neil, for dumping the CD and posting it, even it wasn't in proper .dogfood or whatever "format." :) /jka
On 6 Jun 2017 20:05, "Jonathan Gevaryahu via vcf-midatlantic" < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
AFAIK OSes which require drives with '512 byte blocks' is sort of a scsi hack. The physical data on the cd surface is 2048 byte blocks (plus ECC and subchannel data you don't normally see for 2532 bytes per sector, plus headers and sync marks etc) The whole 512 byte thing is a special mode certain cd drives have which sends each 2048 byte block to the host computer as if it was four separate 512 byte blocks/sectors, but its really just a translation layer. Not all drives do it.
The actual CD contents for these VMS cds are 2048 byte blocks, the 512 byte magic happens in the drive, AFAIK.
I could be wrong about this.
On 6/5/2017 12:48 PM, Brian Schenkenberger via vcf-midatlantic wrote:
Neil Cherry via vcf-midatlantic writes:
On 06/03/2017 11:21 PM, Jim Scheef wrote: > Neil, > Could you pull ISOs
of a couple of the CDs before you take them to IA? > Jim
I'm using my Linux box to see if I can copy the entire CD to an image. I don't know how well this will work but it won't take much space.
-- Jonathan Gevaryahu jgevaryahu@gmail.com jgevaryahu@hotmail.com
-- Jameel Akari