I’d like to thank Jim Tilbury who is the lead of the IBM i removable media team for writing this blog article.
Last October, IBM i introduced Removable Mass Storage (RMS) technology with the RDX removable disk cartridge. The blog “Removable Mass Storage” reviewed that capability. Today, IBM is adding support to use USB Flash Drives as a second type of RMS technology. Flash drives can hold as much data as multiple DVDs and can typically access the data much faster. This allows a much more convenient way to move data (either IFS or save data) to another machine. IBM does not qualify nor recommended any particular device, but typical USB 2.0 devices from 2 to 32GB have been used in our testing. Performance varies from device to device, but ranges of 1 to 4 MB/S for IFS writes are typical. If a particular flash drive does not work, it may not comply with the USB interface specifications, and a different drive should be used.
The device appears to the system when plugged into a USB port that is configured to be in an i partition. Like RDX, it is an optical class device, and may be used with save/restore or with the QOPT file system in IFS. Because there is no eject button to remove media, users should be careful to not unplug the device when it is in use. The file system expects safe removal of media; for Flash Drives, this is done by varying off the device description, or logically removing the media with the RMVOPTCTG command (option 4 on WRKOPTVOL) prior to unplugging the device.
Once a configuration is active, the operating system will allow the same operations to change media as devices that remain operational when the media is removed. This means the configuration may be varied off and on when the media is removed, and the device will remain operational but report “no media”.
If a flash drive is inserted that has files on it, but displays on the system as unknown format, it is probably formatted with a file system that IBM i does not recognize (Microsoft NTFS, for example). When it is initialized on IBM i, it is initialized with the UDF file system. This file system is supported on Microsoft Windows-7, and files can be moved between i and Windows using this format.
If an IBM i 7.1 TR 6 partition owns the device it will have a device type of 63BC. An IBM i 7.1 partition is capable of hosting this device to another i partition that is at 6.1.1 or 7.1. On a client partition running IBM i 6.1.1 with current PTFs a flash drive will be detected as a device type 632C. On an IBM i client partition running 7.1 a Flash Drive will be detected as device type 63BC. There is no VIOS support for Flash Drives.
Save/restore operations are done just as with a DVD, for example SAVLIB DEV(RMS01).... Because it is an optical class device, you can also use IFS to manage data, e.g. WRKLNK OBJ('/QOPT/RDXVOL'). Commands are the normal optical storage commands (WRKOPTVOL, INZOPT, etc). See this article in the IBM i Information Center.