search for: secpercyl

Hi, given the fact that the conversion has the factor HC*SH = "secpercyl", which is invariant under swapping, there remains as suspect in read_sector_cbios only this division: divb (sectors) There is a suspicious discrepancy in the code: heads = (stack-16) sectors = (stack-18) ... /* here we computer CHS values or just do some dummy computation for E...

..._os /* Not a valid boot sector */ movw %bp, %sp /* driveno == bootsec-6 */ popw %dx /* dl -> drive number */ @@ -258,12 +274,12 @@ read_sector: /* This chunk is skipped if we have ebios */ /* Do not clobber %es:%bx or %edx:%eax before this chunk! */ read_sector_cbios: - divl -6(%bp) /* secpercyl */ + divl -36(%bp) /* secpercyl */ shlb $6, %ah movb %ah, %cl movb %al, %ch xchgw %dx, %ax - divb -2(%bp) /* sectors */ + divb -32(%bp) /* sectors */ movb %al, %dh orb %ah, %cl incw %cx /* Sectors are 1-based */ @@ -275,7 +291,7 @@ read_common: leaw 16(%si), %sp /* Drop DAPA */ po...

...17e1efe..a693ccb 100644 --- a/mbr/isohdpfx.S +++ b/mbr/isohdpfx.S @@ -48,8 +48,8 @@ isolinux_start_hybrid = 0x7c00+64+4 stack = 0x7c00 partoffset = (stack-8) driveno = (stack-14) -heads = (stack-16) -sectors = (stack-18) +sectors = (stack-16) +heads = (stack-18) ebios_flag = (stack-20) secpercyl = (stack-24) _______________________________________________ Syslinux-commits mailing list Syslinux-commits at zytor.com http://www.zytor.com/mailman/listinfo/syslinux-commits ----- End forwarded message ----- And please see also the patch in http://www.syslinux.org/archives/2017-March/025706....

This patches add support for dynamic sectors to GPT MBR code. First 3 patches are trick and optimizations to gain some space for the forth patch. I have a modified version of SeaBIOS, some code and some script o test it I'll send on a different mail.

...6d8ab36..5a8b267 100644 --- a/mbr/isohdpfx.S +++ b/mbr/isohdpfx.S @@ -48,8 +48,8 @@ isolinux_start_hybrid = 0x7c00+64+4 stack = 0x7c00 partoffset = (stack-8) driveno = (stack-14) -heads = (stack-16) -sectors = (stack-18) +sectors = (stack-16) +heads = (stack-18) ebios_flag = (stack-20) secpercyl = (stack-24) -- MartinS

...b/mbr/isohdpfx.S > @@ -48,8 +48,8 @@ isolinux_start_hybrid = 0x7c00+64+4 > stack = 0x7c00 > partoffset = (stack-8) > driveno = (stack-14) > -heads = (stack-16) > -sectors = (stack-18) > +sectors = (stack-16) > +heads = (stack-18) > ebios_flag = (stack-20) > secpercyl = (stack-24) Yes. It is. However by now we know that that correction is wrong. You need to revert that and use the one in <http://www.syslinux.org/archives/2017-March/025706.html>. Here pasted (so might not apply cleanly): diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S index 17e1efe..14eca14...

...] + 1; + disk->s = oreg.ecx.b[0] & 63; } } @@ -370,24 +374,24 @@ struct disk *bios_disk_init(void *private) } - disk.disk_number = devno; - disk.sector_size = sector_size; - disk.sector_shift = ilog2(sector_size); - disk.part_start = part_start; - disk.secpercyl = disk.h * disk.s; - disk.rdwr_sectors = ebios ? edd_rdwr_sectors : chs_rdwr_sectors; + disk->disk_number = devno; + disk->sector_size = sector_size; + disk->sector_shift = ilog2(sector_size); + disk->part_start = part_start; + disk->secpercyl = dis...

...078c0fb isolinux_hybrid_signature = 0x7c00+64 isolinux_start_hybrid = 0x7c00+64+4 .globl bootsec /* Important: the top 6 words on the stack are passed to isolinux.bin */ stack = 0x7c00 partoffset = (stack-8) driveno = (stack-14) heads = (stack-16) sectors = (stack-18) ebios_flag = (stack-20) secpercyl = (stack-24) BIOS_kbdflags = 0x417 BIOS_page = 0x462 /* gas/ld has issues with doing this as absolute addresses... */ .section ".bootsec", "a", @nobits .globl bootsec bootsec: .space 512 .text .globl _start _start: .byte 0x33, 0xed /* xorw %bp, %bp */ cli movw %bp,...

Hi, funny or enlightening observation: With my qemu-system-i386 it would work if the detected Heads/Cylinder and Sectors/Head factors would change positions ! The effective read operation seems to use H/C = 32 , S/H = 63. The correct LBA would be addressed by H/C = 63 , S/H = 32. -------------------------------------------------------------------------- Reasoning: I have transplanted the

This set of patches add some support for sector size >512. Currently it fixes extlinux, MBR for GPT and ext partitions. Other code is unaffected. This set of patches has been tested on a read Dell machine running a beta firmware.

Hello, when testing FreeBSD-7.1-BETA i discovered that the floppy disk controller doesn't work correctly. Trying to format a floppy (perhaps with bad blocks) i get: Processing fdformat: ioctl(FD_FORM): Device not configured instead of the normal E letter. I then checked the same problem is present on FreeBSD-6.3 and it has been reported by Beech Rintoul (*) in 2006! Of course the floppy disk

So last week I was wondering if XFS was still working -- even with its last on-disk structure changes -- and it _suprisingly_ worked as expected. Right, now I can finally get rid of GRUB and use Syslinux to boot my Linux on EFI from a rootfs with xfs. Shit, I have two partitions (the first one being the required ESP) so there is no way to access the other partitions since because Syslinux does not

Hello, the following patches should get multidisk access working. The syntax accepted is the following: (hdx,y)/path/to/file where x is the disk number and start at 0 and the y is the partition number starting at 1. So (hd0,1) is the first partition of the first disk. the other accepted syntax is using MBR's 32 bits disk signature so for example: (mbr:0x12345678,2)/foo/bar would address