Now in a new thread with updated subject. ----- Forwarded message from Thomas Schmitt ----- Date: Wed, 22 Jan 2014 08:45:51 +0100>From: Thomas SchmittTo: syslinux at zytor.com Subject: Re: [syslinux] Advice/directions to users of Syslinux Message-Id: <29490645553171871372 at scdbackup.webframe.org> Reply-To: For discussion of Syslinux and tftp-hpa <syslinux at zytor.com> Hi, i now realized that http://www.syslinux.org/wiki/index.php/Hardware_Compatibility#USB-Geometry http://www.syslinux.org/wiki/index.php/Hardware_Compatibility#USB-Miscellaneous are the new wiki sections by Gene Cumm. (Sorry for not reading them when they were announced.) So i ask especially him whether the statement "An examle is a drive of 128,64,32 with a partition ending at 127,63,32 (the last sector of the last whole cylinder)." should be changed and expanded to "An example is a drive of size of 128 MB (or slightly larger) assumed with 64 heads per cylinder and 32 sectors per head, where the partition should end at 127,63,32. Drives larger than 1 GB should be regarded as having 255 heads per cylinder and 63 sectors per head. E.g. an drive of 15794176 blocks (7.5 GB) should have its partition end at 982,254,63. Drives larger than 16434495 blocks should bear as partition end 1023,254,63. Setting the partition end LBA to the full drive size may or may not hamper its bootability." Reasoning: I state "assumed with 64 heads per cylinder and 32 sectors per head" because the values of H/C and S/H are more or less a deliberate decision at partitioning time. I refrain from giving the drive size in CHS, because this is ambigous until the user has chosen H/C and S/H. I do not use digit separators with decimal naumers (15,794,176 versus 15794176) because this could get confused with the CHS commas. I mention the opportunity to set the end LBA higher than the end CHS because else half of a 16 GB drive would be wasted. But maybe one should rather state that if a BIOS is too dumb for uneven partiton endings, then it is probably too dumb for large partitions, too. Any experience around ? Any opinions ? The advise to set large drive ends to 1023,254,63 is taken from http://en.wikipedia.org/wiki/Master_boot_record#Partition_table_entries --------------------------------------------------------- To the wiki admins: I acquired a SYSLINUX wiki account: "scdbackup" Please enable editing. Have a nice day :) Thomas _______________________________________________ Syslinux mailing list Submissions to Syslinux at zytor.com Unsubscribe or set options at: http://www.zytor.com/mailman/listinfo/syslinux Please do not send private replies to mailing list traffic. ----- End forwarded message ----- Groeten Geert Stappers -- Leven en laten leven
On Wed, Jan 22, 2014 at 3:20 AM, Thomas Schmitt <scdbackup at gmx.net> wrote:> > Now in a new thread with updated subject. > > ----- Forwarded message from Thomas Schmitt ----- > > Date: Wed, 22 Jan 2014 08:45:51 +0100 >>From: Thomas Schmitt > To: syslinux at zytor.com > Subject: Re: [syslinux] Advice/directions to users of Syslinux > Message-Id: <29490645553171871372 at scdbackup.webframe.org> > Reply-To: For discussion of Syslinux and tftp-hpa <syslinux at zytor.com> > > Hi, > > i now realized that > http://www.syslinux.org/wiki/index.php/Hardware_Compatibility#USB-Geometry > http://www.syslinux.org/wiki/index.php/Hardware_Compatibility#USB-Miscellaneous > are the new wiki sections by Gene Cumm. (Sorry for not reading > them when they were announced.) > > So i ask especially him whether the statement > > "An examle is a drive of 128,64,32 with a partition ending at > 127,63,32 (the last sector of the last whole cylinder)." > > should be changed and expanded to > > "An example is a drive of size of 128 MB (or slightly larger) > assumed with 64 heads per cylinder and 32 sectors per head, > where the partition should end at 127,63,32. > Drives larger than 1 GB should be regarded as having 255 heads > per cylinder and 63 sectors per head. E.g. an drive of > 15794176 blocks (7.5 GB) should have its partition end > at 982,254,63. > Drives larger than 16434495 blocks should bear as partition > end 1023,254,63. Setting the partition end LBA to the full drive > size may or may not hamper its bootability." > > Reasoning: > > I state "assumed with 64 heads per cylinder and 32 sectors per head" > because the values of H/C and S/H are more or less a deliberate > decision at partitioning time. > > I refrain from giving the drive size in CHS, because this is ambigous > until the user has chosen H/C and S/H. > > I do not use digit separators with decimal naumers (15,794,176 > versus 15794176) because this could get confused with the CHS > commas. > > I mention the opportunity to set the end LBA higher than the end CHS > because else half of a 16 GB drive would be wasted. > But maybe one should rather state that if a BIOS is too dumb for > uneven partiton endings, then it is probably too dumb for large > partitions, too. > Any experience around ? Any opinions ? > > The advise to set large drive ends to 1023,254,63 is taken from > http://en.wikipedia.org/wiki/Master_boot_record#Partition_table_entriesExcellent point. Thank you. I was merely thinking of a relatively easy scenario that could confuse BIOSs/firmwares and cause them to ignore the drive.> --------------------------------------------------------- > To the wiki admins: > > I acquired a SYSLINUX wiki account: "scdbackup" > Please enable editing.Done.> Have a nice day :) > > ThomasThanks. Enjoy. -- -Gene
Hi, me:> > Please enable editing.Gene Cumm:> Done.Thanks. I have now edited http://www.syslinux.org/wiki/index.php/Hardware_Compatibility#USB-Miscellaneous ------------------------------------------------------------ Next i'll try to develop a user oriented hint for SYSLINUX#Creating_a_Bootable_Disk which takes into respect the opinions of Ady, Mattias, me, and of any other who has a viewpoint to add. This needs well thought, because it might be the first thing which an annoyed and partially clueless user reads about mad USB sticks. Have a nice day :) Thomas