09/24/96, Creating File Systems on Removable Tapes or Diskettes SPECIAL NOTICES Information in this document is correct to the best of our knowledge at the time of this writing. Please send feedback by fax to "AIXServ Information" at (512) 823-4009. Please use this information with care. IBM will not be responsible for damages of any kind resulting from its use. The use of this information is the sole responsibility of the customer and depends on the customer's ability to eval- uate and integrate this information into the customer's operational environment. +----------------------------------------------------------+ | | | NOTE: The information in this document has NOT been | | verified for AIX 4.1. | | | +----------------------------------------------------------+ ABOUT THIS DOCUMENT This document describes creating JFS file systems on floppy diskettes. This procedure is not supported and applies only to AIX 3.2. FILE SYSTEMS ON REMOVABLE MEDIA JFS file systems cannot be created on a tape device, for the following reasons: 1. There is no AIX support for this. 2. The JFS logging mechanism for these devices is not there. 3. A tape device is not randomly accessible. 4. Our tape device drivers do not provide a block inter- face. That is why we mount /dev/hd4 (block interface) rather than /dev/rhd4 (character interface). Even if it were possible to create a file system on tape, the performance would be incredibly slow. Creating JFS file systems on floppy diskettes is NOT SUPPORTED; however, the safeguards can be circumvented and a read only JFS file system can be built on a floppy and mounted. The reason that the file system will be read only is that AIX cannot create a journal log on a diskette. Please keep in mind that this is not a sup- ported procedure and that system stability is jeopard- ized. Creating File Systems on Removable Tapes or Diskettes 1 09/24/96, To make the unsupported read only JFS file system on a floppy: 1. Make a subdirectory on an existing file system and place all of the files that the diskette will contain into the subdirectory. 2. Enter the following command to create a prototype file containing information about the new file system, where /directory_structure is the pathname of the subdirectory created in step 1 and proto_filename is the name of the prototype of the file that will be created: proto /directory_structure > proto_filename 3. Place your floppy disk into the drive and format it. 4. Edit the prototype file and replace the first line with the following: [noboot] 0 0 5. Enter the following command to make the file system on your floppy: mkfs -p proto_filename -V jfs /dev/fd0 6. Make the directory upon which you wish to make the floppy-based file system, or you can use the /mnt direc- tory. Then, enter the following command to mount the file system: mount -r -V jfs /dev/fd0 /your_mount_point 7. To unmount the file system, use the command: umount /dev/fd0 DO NOT EJECT THE DISKETTE WITHOUT FIRST UNMOUNTING IT! The fact that the file system is read-only may be a problem but if you are going to use it for utility programs and other data that does not change much, it still may be useful. If you need to change the data, you can copy the directory from the floppy into another directory, make your modifications, and remake the file system using this proce- dure. Creating File Systems on Removable Tapes or Diskettes 2 09/24/96, READER'S COMMENTS Please fax this form to (512) 823-4009, attention "AIXServ Informa- tion". You may also e-mail comments to: elizabet@austin.ibm.com. These comments should include the same customer information requested below. Use this form to tell us what you think about this document. If you have found errors in it, or if you want to express your opinion about it (such as organization, subject matter, appearance) or make sug- gestions for improvement, this is the form to use. If you need technical assistance, contact your local branch office, point of sale, or 1-800-CALL-AIX (for information about support offer- ings). These services may be billable. Faxes on a variety of sub- jects may be ordered free of charge from 1-800-IBM-4FAX. Outside the U.S. call 415-855-4329 using a fax machine phone. When you send comments to IBM, you grant IBM a nonexclusive right to use or distribute your comments in any way it believes appropriate without incurring any obligation to you. NOTE: If you have a problem report or item number, supplying that number may help us determine why a procedure did or did not work in your specific situation. Problem Report or Item #: Branch Office or Customer #: Be sure to print your name and fax number below if you would like a reply: Name: Fax Number: ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ END OF DOCUMENT (fs.floppy.tape.krn) Creating File Systems on Removable Tapes or Diskettes 3