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| author | H. Peter Anvin <hpa@zytor.com> | 2007-12-18 15:55:10 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2007-12-18 15:56:50 -0800 |
| commit | 8fd5e917a23b6ba2d1bf9128be3524ca8cf8ab34 (patch) | |
| tree | d5046a4ccb5a2637b65a4b3e1ebaaf68bd31999d /doc/usbkey.doc | |
| parent | 47b318940041cb713958d469a88b1859e14808b0 (diff) | |
| download | syslinux-3.55-pre2.tar.gz | |
Move doc files to doc/, and add man pages from Debiansyslinux-3.55-pre2
Move all the text documentation to the doc/ directory, add man pages
from the Debian syslinux package, and rename sys2ansi.pl to
syslinux2ansi.pl.
Diffstat (limited to 'doc/usbkey.doc')
| -rw-r--r-- | doc/usbkey.doc | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/doc/usbkey.doc b/doc/usbkey.doc new file mode 100644 index 00000000..33613d69 --- /dev/null +++ b/doc/usbkey.doc @@ -0,0 +1,47 @@ +The proper mode to boot a USB key drive in is "USB-HDD". That is the +ONLY mode in which the C/H/S geometry encoded on the disk itself +doesn't have to match what the BIOS thinks it is. Since geometry on +USB drives is completely arbitrary, and can vary from BIOS to BIOS, +this is the only mode which will work in general. + +Some BIOSes have been reported (in particular, certain versions of the +Award BIOS) that cannot boot USB keys in "USB-HDD" mode. This is a +very serious BIOS bug, but it is unfortunately rather typical of the +kind of quality we're seeing out of major BIOS vendors these days. On +these BIOSes, you're generally stuck booting them in USB-ZIP mode. + +THIS MEANS THE FILESYSTEM IMAGE ON THE DISK HAS TO HAVE A CORRECT +ZIPDRIVE-COMPATIBLE GEOMETRY. + +A standard zipdrive (both the 100 MB and the 250 MB varieties) have a +"geometry" of 64 heads, 32 sectors, and are partitioned devices with a +single partition 4 (unlike most other media of this type which uses +partition 1.) The 100 MB variety has 96 cylinders, and the 250 MB +variety has 239 cylinders; but any number of cylinders will do as +appropriate for the size device you have. For example, if your device +reports when inserted into a Linux system: + +usb-storage: device found at 4 + Vendor: 32MB Model: HardDrive Rev: 1.88 + Type: Direct-Access ANSI SCSI revision: 02 +SCSI device sda: 64000 512-byte hdwr sectors (33 MB) + +... you would have 64000/(64*32) = 31.25 cylinders; round down to 31. + +The script "mkdiskimage" which is supplied with the syslinux +distribution can be used to initialize USB keys in a Zip-like fashion. +To do that, calculate the correct number of cylinders (31 in the +example above), and, if your USB key is /dev/sda (CHECK THE KERNEL +MESSAGES CAREFULLY - IF YOU ENTER THE WRONG DISK DRIVE IT CANNOT BE +RECOVERED), run: + + mkdiskimage -4 /dev/sda 0 64 32 + +(The 0 means automatically determine the size of the device, and -4 +means mimic a zipdisk by using partition 4.) + +Then you should be able to run + + syslinux /dev/sda4 + +... and mount /dev/sda4 and put your files on it as needed. |
