Editing RT-11 (section)

===Distributions and minimal system configuration===
The RT-11 operating system could be booted from, and perform useful work on, a machine consisting of two 8-inch 250KB [[floppy disk]]s and 56KB of memory, and could support 8 terminals. Other boot options include the [[RK05]] 2.5MB removable hard disk platter, or [[magnetic tape]]. Distributions were available pre-installed or on [[punched tape]], magnetic tape, [[TU58|cartridge tape]], or floppy disk. A minimal but complete system supporting a single real-time user could run on a single floppy disk and in 8K 16-bit words (16KB) of RAM, including user programs. This was facilitated by support for swapping and overlaying. To realize operation on such small memory system, the keyboard command user interface would be swapped out during the execution of a user's program and then swapped into memory upon program termination. The system supported a [[real-time clock]], printing terminal, VT11 vector graphic unit, 16 channel 100&nbsp;kHz A/D converter with 2 channel D/A, 9600 baud serial port, 16 bit bidirectional boards, etc.