Based on MUMPS V1 1.65 from Ray Newman. The master branch gets only bug fixes.

If you are looking for speed, additional MUMPS commands and functions, object-oriented syntactic sugar, multiple volume sets, remote volume sets, online backup use the stable branch.

Changes:

• works on big-endian processors
• works on macOS with clang
• has 31 character label/routine/local/global names
• MCL shell prompt changed to [UCI,VOL], SHUTDOWN command
• %MV1 routine contains the implementation constants
• supports global buffer area over 2GB
• daemon log contains GMT timestamp, process id, restart info
• blkalloc/blkdeall/blkreorg/dqstall statistics

Fixes:

• fixed UCI,VOL parsing in SET command
• display all compilation messages ("Too many tags" got garbaged)
• parser/runtime fix for LOCK (@GLVN1[,...])
• stack overflow during ST_Restore()
• XECUTE could overwrite process stack
• DB lock-up with a small global buffer
• faster Locate()
• db_rekey fixes (level > 3)
• prevent changed Garbit() blocks to leave the global buffer
• fixes from MUMPS V1 1.66 and 1.70
• recursive indirection
• $BP handling
• $FNUMBER() memory leaks
• EINTR handling during semaphore operations
• $JUSTIFY() with negative numbers
• external variable call memory leaks
• standard handle redirection in JOB
• socket communication options (SO_REUSEADDR, SO_NOSIGPIPE)
• robust error handling in MUMPS environment initialization
• no writer deadlock due to full dirty queue
• removed race in global KILL (block removal)
• atomic access in dirty/garbage queue
• reverse $QUERY() for locals
• $FNUMBER() suppress sign for 0
• JOB argument passing
• fixed cached block usage in Get_data() when journaling turned off and writing
• fixed Control-C handling
• close database and journal file on dismount

NOTE: Don't forget you can use RSM. Good luck!