in the newer PDP-11 computers not only meant these machines were able to address four times the amount of memory (18-bit addressing, 256K bytes), it also paved the way for the developers to separate user mode processes from the core of the kernel. In 1975 memory management support was again updated for the newer 22-bit addressable PDP-11/70. RSTS systems could now be expanded to use as much as two megabytes of memory running up to 63 jobs. The RTS and CCL concepts were introduced although they had to be compiled in during "SYSGEN". Multi-terminal service was introduced which would allow a single job the ability to control multiple terminals (128 total). Large-message send/receive and interprocess communication became very sophisticated and efficient. By August there are 1,200 licensed systems. In 1977 the installation process for RSTS was no longer dependent on DOS-11. The RSTS kernel could now be compiled under the RT-11 RTS, formatted as a kernel file with RT-11 SILUS, and copied to the system or other disks, while the computer was time-sharing. The BASIC-PLUS RTS (as well as RT-11, RSX-11, TECO and third party RTSs) all ran as user mode processes, independent of the RSTS kernel. A systems manager could now decide during the bootstrap phase which RTS to run as the systems default Keyboard Monitor (KBM). By now, there were some 3,100 licensed systems. In 1978 the final memory management update was included for all machines that could support 22-bit addressing. RSTS could now use the maximum amount of memory available to a PDP-11 (4 megabytes). Support was also included for SUPERVISORY mode which made RSTS the first DEC operating system with this capability. DECnet was also supported as well as remote diagnostics from field service technicians at the RDC in Colorado Springs, Colorado (a DEC subscription service). By the end of the decade, there are over 5,000 licensed systems. 1980s In 1981 support for separate instruction and data space for users with Unibus machines (PDP-11/44, PDP-11/45, PDP-11/55 and PDP-11/70) provided an extension to the memory constraints of an individual program. Compiling programs to use separate instruction and data space would soon give a program up to 64 KiB for instructions, and up to 64 KiB for buffering data. The DCL RTS was included as well as support for the newer revision of DECnet III. By 1983, with an estimated 15,000 DEC machines running RSTS/E, V8.0-06 included support