search for: block_seq

Hi, i have uploaded a little gz compressed tarball http://scdbackup.webframe.org/block_seq.tgz containing -rwxr-xr-x thomas/thomas 4552 2017-03-21 09:23 block_seq -rw-r--r-- thomas/thomas 315 2017-03-21 09:22 block_seq.c To be unpacked in a suitable directory by tar xvzf block_seq.tgz The binary "block_seq" was compiled on Debian Jessie. If it does not run, do...

On 03/21/2017 01:41 AM, Thomas Schmitt via Syslinux wrote: > Hi, > > i have uploaded a little gz compressed tarball > > http://scdbackup.webframe.org/block_seq.tgz > > containing > > -rwxr-xr-x thomas/thomas 4552 2017-03-21 09:23 block_seq > -rw-r--r-- thomas/thomas 315 2017-03-21 09:22 block_seq.c > > To be unpacked in a suitable directory by > > tar xvzf block_seq.tgz > > The binary "block_seq" was com...

...here. > For isohdpfx.bin it will print: > E if EBIOS > C if not EBIOS (from "CHS"). > Is that interesting for you/us? It will tell us whether C/H/S addressing is a suspect. My main point of interest is which block is really loaded as first one of isolinux.bin. My program block_seq.c to create a stream with recognizable block content is: ------------------------------------------------------------------ #include <unistd.h> int main() { int ret; unsigned int i, j, k; char buf[512]; for(i= 0; ; i++) { for(j= 0; j < 128; j++) for(k= 0; k < 4; k++)...

Thomas Schmitt wrote: > My main point of interest is which block is really loaded as first one > of isolinux.bin. [Program snipped.] > (It could be shorter if i did not insist in big endian words.) Why insisting? Anyway appended is a dumper version. I could put up a binery version if needed. Let me know if so. -- MartinS /*

Thomas Schmitt wrote: > So if we had a MBR which prints the content of the first 512 read bytes > we could tell whether they are block aligned and from which block they > come. Ok. I'll try. Is it the isohdppx or isohdpfx (or both) that is relevant? Meanwhile I have a hacked isohdppx.bin that prints: G if GPT M if MBR <nothing> if no partition info E if EBIOS C if not EBIOS

...cylinder and sectors/head factors. > 00000000000000000000000000000000 > ... > 00000000000000000000000000000000 Well, this is none of the block contents which was written to the stick. Neither the MBR parts nor the data dummy. Do you get the same result if you fill the entire stick with block_seq by omitting dd option count=647 ? /home/dpchrist/sandbox/syslinux/thomas-schmitt/block_seq-20170321-0141/block _seq | dd iflag=fullblock bs=1M of=/dev/sdb which will end intentionally by i/o error. And then again dd if=/home/dpchrist/src/syslinux/syslinux-6.03+dfsg+dpchrist/bios/mbr/martins_...

...gratulations Thomas, you've found the bug! I will for now only take credits for "one bug". Whether it's "the bug" is still questionable, because David reported a read result of all zeros. The found error cannot cause that block content is read from after the end of the block_seq image. The error does not spoil the C component and LBA 8444 is much more than a maximum cylinder size of 8 MiB away from the end of the 647 MiB image. If the H/C and S/H values were the same as with quemu's BIOS, then there would be no reason for the BIOS to refuse reading. (Does isohdpfx.bin...

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 EBIOS */ andw $0x3f,