How to Create a File System on a USB Mass Storage Device

A USB diskette must be formatted before you can add a file system to it. All other USB mass storage devices just need a PCFS or UFS file system before they can be used. Keep the following key points in mind when formatting a USB device:

• Do not use the rmformat -F except on a USB diskette.

• If the default slices are not acceptable, use the rmformat -s command to create slices. Use the fdisk utility to partition a USB device, if needed. For step-by-step instructions, see:

  • How to Modify Partitions and Create a PCFS File System on a USB Mass Storage Device Without vold Running

  • How to Create a Solaris Partition and Modify the Slices on a USB Mass Storage Device Without vold Running

  • If the USB device is automatically mounted, you will have to unmount it before you can create a file system on the USB device.

Perform steps 4-5 only if you need to format a USB diskette.

1. Become superuser.

2. Add the USB device to your system. For information on hot-plugging USB devices, see:

   • Hot-Plugging USB Mass Storage Devices

   • Hot-Plugging USB Devices With the cfgadm Command (Task Map)

3. (Optional) Identify the USB device.

   For example:

   # cd /dev/rdsk # ls -l c*0 | grep usb lrwxrwxrwx 1 root root 55 Mar 5 10:35 c2t0d0s0 -> ../../devices/pci@1f,0/usb@c,3/storage@3/disk@0,0:a,raw

   In this example, the diskette device is c2t0d0s0.

4. Insert a diskette into the diskette drive, if necessary.

5. Format the diskette, if necessary.

   % rmformat -F long raw-device

   For example, on a SPARC system:

   % rmformat -F long /dev/rdsk/c2t0d0s2

   For example, on an x86 system:

   % rmformat -F long /dev/rdsk/c3t0d0p0

6. Determine the file system type and make sure the device is unmounted. Then, select one of the following:

   For more information about unmounting a USB device, see How to Mount or Unmount a USB Mass Storage Device Without vold Running.

   • Create a PCFS file system.

     # mkfs -F pcfs -o nofdisk,size=size raw-device

     Specify the -size option in 512-byte blocks.

     The following example shows how to create a PCFS file system on a 1.4-MB diskette on a SPARC system:

     # mkfs -F pcfs /dev/rdsk/c2t0d0p0 Construct a new FAT file system on /dev/rdsk/c2t0d0p0: (y/n)? y

     The following example shows how to create a PCFS file system on a 1.4-MB diskette on an x86 system:

     # mkfs -F pcfs /dev/rdsk/c2t0d0s2 Construct a new FAT file system on /dev/rdsk/c2t0d0s2: (y/n)? y

     The following example shows how to create a PCFS file system on a 100-MB USB memory stick on a SPARC system:

     # mkfs -F pcfs /dev/rdsk/c5t0d0s2:c

     The following example shows how to create a PCFS file system on a 100-MB USB memory stick on an x86 system:

     # mkfs -F pcfs /dev/rdsk/c5t0d0p0:c

     This command can take several minutes to complete.

   • Create a UFS file system.

     # newfs raw-device

     For example:

     # newfs /dev/rdsk/c4t0d0s7

     Consider using the newfs -f 4096 option or newfs -T option for large USB hard disks.

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     Note –

     UFS file system overhead consumes a significant portion of space on a diskette, due to a diskette's limited storage capacity.

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   See the next two procedures for a detailed example of creating a PCFS file system and modifying slices on a USB mass storage device.