JFS.IFS (CONFIG.SYS)

OS/2 Warp Server for e-business includes a new file system, the Journaling File System. This new file system is a file system available with IBM's AIX premier UNIX-type operating system. What it offers, among other things, is the ability to manage volumes that exceed the space on one hard disk. For instance, a volume may consist of pieces from one or more physical hard disks which are seamlessly integrated into one volume. In addition to being able to set up very large volumes, a volume can be expanded at any time so it is larger than it was in real time. IFS=JFS.IFS

Parameters

 * /CACHE: - Specifies the size of the JFS buffer cache in Kilobytes. By default, this size is set to 12.5 percent of real memory.
 * /AUTOCHECK:drive[drive...] - Specifies a list of JFS file systems, identified by driver letter, to be included in automatic recovery by CHKDSK at the time of JFS initialization. If an asterisk (*) is specified instead of a drive letter list, all JFS file systems will be included in automatic recovery during JFS initialization. If any drive letter is preceded by an arithmetic plus sign (+), CHKDSK will perform a full integrity check on the drive even if journal log replay has restored the drive to an apparently consistent state. If the list of drive letters ends with plus-asterisk (+*), CHKDSK will perform a full integrity check on all JFS file systems not specified in the list even if journal log replay has restored them to an apparently consistent state.
 * /AC:drives - The AC parameter specifies which drives should be checked by chkdsk.exe during start up after an improper shut down. Add only the drive letter without the colon. If you want to run chkdsk.exe on a drive at every start up add a plus sign (+) in front of the drive letter (undocumented for JFS.IFS).
 * /F:level - Indicates on which level chkdsk.exe should be run. Level can be in the range from 1 to 3 . Default is 2 (undocumented for JFS.IFS).
 * /Force - With this option set you can get access to a disk that is marked as bad and is not in the Autocheck list (the /AC: parameter). But beware there are may errors in the file system, so run chkdsk as soon as possible (undocumented for JFS.IFS).
 * /L:OFF - Specifies the lazy write parameters in seconds. OFF forces all to be synchronous. (JFS ignores any characters between the L (or l) and the colon, so valid flags are /L: /LAZY: /LW: /lazywrite: etc.)
 * /L: - Synctime is the interval at which the sync thread runs, default is 64. Maxage is the longest time that a modified file is kept in cache, default is synctime*4. Bufferidle is the time indicating a "recent" change. Changes newer than this value are not written unless the last write was older than maxage, default is Min(1, synctime/8).

JFS is a very powerful addition to OS/2; it eliminates any limiting factors and make OS/2 Warp Server the best option for serving files, and applications. A file size can be two (2) terabytes (two thousand gigabytes), the maximum volume size. This, along with OS/2 Warp Server's ability to extend beyond just one processor by using up to 64 processors, makes OS/2 Warp Server the most advanced operating system of its kind for the Intel processor.