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Member "syslinux-6.03/doc/usbkey.txt" (6 Oct 2014, 2114 Bytes) of package /linux/misc/syslinux-6.03.tar.gz:
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1 The proper mode to boot a USB key drive in is "USB-HDD". That is the
2 ONLY mode in which the C/H/S geometry encoded on the disk itself
3 doesn't have to match what the BIOS thinks it is. Since geometry on
4 USB drives is completely arbitrary, and can vary from BIOS to BIOS,
5 this is the only mode which will work in general.
7 Some BIOSes have been reported (in particular, certain versions of the
8 Award BIOS) that cannot boot USB keys in "USB-HDD" mode. This is a
9 very serious BIOS bug, but it is unfortunately rather typical of the
10 kind of quality we're seeing out of major BIOS vendors these days. On
11 these BIOSes, you're generally stuck booting them in USB-ZIP mode.
13 THIS MEANS THE FILESYSTEM IMAGE ON THE DISK HAS TO HAVE A CORRECT
14 ZIPDRIVE-COMPATIBLE GEOMETRY.
16 A standard zipdrive (both the 100 MB and the 250 MB varieties) have a
17 "geometry" of 64 heads, 32 sectors, and are partitioned devices with a
18 single partition 4 (unlike most other media of this type which uses
19 partition 1.) The 100 MB variety has 96 cylinders, and the 250 MB
20 variety has 239 cylinders; but any number of cylinders will do as
21 appropriate for the size device you have. For example, if your device
22 reports when inserted into a Linux system:
24 usb-storage: device found at 4
25 Vendor: 32MB Model: HardDrive Rev: 1.88
26 Type: Direct-Access ANSI SCSI revision: 02
27 SCSI device sda: 64000 512-byte hdwr sectors (33 MB)
29 ... you would have 64000/(64*32) = 31.25 cylinders; round down to 31.
31 The script "mkdiskimage" which is supplied with the syslinux
32 distribution can be used to initialize USB keys in a Zip-like fashion.
33 To do that, calculate the correct number of cylinders (31 in the
34 example above), and, if your USB key is /dev/sda (CHECK THE KERNEL
35 MESSAGES CAREFULLY - IF YOU ENTER THE WRONG DISK DRIVE IT CANNOT BE
36 RECOVERED), run:
38 mkdiskimage -4 /dev/sda 0 64 32
40 (The 0 means automatically determine the size of the device, and -4
41 means mimic a zipdisk by using partition 4.)
43 Then you should be able to run
45 syslinux /dev/sda4
47 ... and mount /dev/sda4 and put your files on it as needed.