Whether we're talking about multiboot, or distro.iso, or NVMe vs. SATA NGFF, or HDD vs. SSD, the over-arching problem is fitting a round peg in a square hole such that the edges of the square are tangents of the circumference of the circle -- in "sector alignment". Illumos uses GPT-approved PMBR partitioning, i.e. "SOLARIS2" for compatibility; format> partition asks for cylinders. Using EFI partitioning still results in PMBR, but it's easy to work around; in which case format> partition asks for sectors or MiB/GiB.
-Eric ---- On Mon, 10 Jun 2024 12:49:59 -0700 Gordon Ross <[email protected]> wrote --- I gather the topic here is partition alignment. (If not, sorry, nevermind:) My previous experience when looking into this for: fdisk, format, etc. is that with "modern disks" (pretty much anything that survives today) partitioning systems should simply use megabyte alignment, and SHOULD NOT bother about cylinders etc. On Mon, Jun 10, 2024 at 2:44 PM Eric J Bowman via illumos-discuss <mailto:[email protected]> wrote: > > CSM isn't compatible with DDR-6. UEFI's won't have CSM, soon. My only > multi-session optical media that works with UEFI-CSM is BD-RE which was never > bootable to begin with. If I had some other multi-session media format, I > don't think it would work without CSM any better than distro.iso's which > forgot -no-emul. Whole lotta Rock Ridge options won't be valid moving > forward, due to incompatibility at the "alignment" level, like offsetting an > overlapping partition containing the real distro.iso -- at best, gets you > 16-bit real mode that only the Intel 8088 MINIX Experience doesn't care about > -- due to NVRAM; it just loses access to system RAM w/o CSM. > > UEFI says Rock Ridge. UEFI* lists some things which translate to, "won't work > without CSM" while hewing to Joliet without saying so, but comes as no > surprise because Joliet's Windows. I don't think Joliet's multi-session > compatible, but I also note, UEFI allows booting a standard .iso in a > partition with an MBR -- not that said MBR is required to point to anything > actually existing, which defaults to pointing to -- Windows. > > -Eric > > > > ---- On Mon, 10 Jun 2024 10:54:02 -0700 Eric J Bowman via illumos-discuss > <mailto:[email protected]> wrote --- > > Indeed. But that's the fs inside the .iso, we're trying to fit the .iso into > a partition UEFI requires to be at least 1 MiB (which should probably be > changed to 2). > > -Eric > > > > ---- On Mon, 10 Jun 2024 10:45:51 -0700 Udo Grabowski (IMK) > <mailto:[email protected]> wrote --- > > > > On 10/06/2024 19:24, Eric J Bowman via illumos-discuss wrote: > > With few exceptions, 'mkisofs -pad' behaves the same way across tools in > > that it's an arbitrary, static value. The others dial the wrong number. > > ... > > Suggest new interop guideline in general -- partition in MiB/GiB using > > values which are a power of 2. Anyone got any drives laying around they > > need partitioned? lol, so easy now... if 'mkisofs -pad' behavior were to > > be "pad to multiple of 65536" would it cause anyone any harm? > > In xa1 mode (muiltisession CD), sectors are 2056 bytes, so that won't > fit into 65536 ... > > illumos / illumos-discuss / see discussions + participants + delivery options > Permalink ------------------------------------------ illumos: illumos-discuss Permalink: https://illumos.topicbox.com/groups/discuss/Te6d81d754118b912-M202bfa9754dd0b49c80d8ab3 Delivery options: https://illumos.topicbox.com/groups/discuss/subscription
