MTsort version 4 is a new version of the sort package with improvements in several areas. The input handlers have improved buffering to make running more efficient. The user graphical interface has been changed to improve control.

The functions of reading data, sorting data and optionally writing data have been separated into independent tasks. This allows change of input source or sort program more easily. Thus, the package talks about input handlers, output handlers and event handlers. The input and output handlers allow data to be transferred from tape/disc/online to tape/disc/null(nowhere) independently of compiling the sort program (event handler).

The spectra are based in memory with an associated disc file which is used for saving at the end of the run, or on user demand.

The spectra are allocated in shared memory segments. This allows immediate viewing using the "sort" resource via the usual spectrum browser and spectrum viewer windows.
The shared memory segments may be deleted after the sort run, since the memory-based spectra are saved to disc file.
Note: There must not be a system directory named /sort.

There is also the possibility of sorting directly to disc. This feature is intended only to be used if memory space is insufficient, as the sort will proceed more slowly compared with spectrum updating to memory. The package supports running with a mix of memory-based and disc-based spectrum updating.

N.B. Spectra can be zeroed by starting the spectrum browser from the sort run window.