N.B. For Squeak/Pharo/Croquet please use the archives whose names begin with Cog or cog. The archives whose names begin with nsvm or Newspeak are for Newspeak and are missing plugins required by Squeak/Pharo/Croquet. VMs with "mt" or "MT" in the name are multi-threaded VMs which support non-blocking FFI calls. The archives containing "Spur" or "spur" are VMs using the new Spur object representation and garbage collector and should be used with Spur-format Squeak/Pharo/Croquet or Newspeak images. There are two variants of the Linux VMs; those ending in "ht" have a heartbeat thread, while those that don't, use an interval timer for the heartbeat (the Windows and Mac VMs have a threaded heartbeat). The threaded heartbeat is better (for example, signals from the interval timer interfere with system calls, etc), but to use it one must have a kernel later than 2.6.12 and configure linux to allow the VM to use multiple thread priorities. To do so, create a file called VM.conf where VM is the name of the vm executable ("squeak" for the Squeak vm, "nsvm" for the Newspeak vm) in /etc/security/limits.d/ with contents: * hard rtprio 2 * soft rtprio 2 e.g. sudo cat >/etc/security/limits.d/squeak.conf <