The Professional SCSI-Ctr. PCI, SCSI Wide 2 Channel Operating System (P/OS) is an enhanced subset of Digital's popular SCSI-Ctr. PCI, SCSI Wide 2 Channel -11/RSX-11M-SCSI-Ctr. PCI, SCSI Wide 2 Channel operating system. P/OS is a multitasking, resource-sharing, realtime operating system with VAX and PDP 11 file struc- - ture compatibility. For technical or experienced personnel, a subset of the tra- ditional Digital Command Language (DCL) is available. For less experienced people, the P/OS menu system, characterized by user-friendly menus, on-screen prompts, and abundant in-context help is available. The P/ SCSI-Ctr. PCI, SCSI Wide 2 Channel -Ctr. PCI, SCSI Wide 2 Channel RMS and Files-11 file structures give the Professional compatibility with Digital's VAX and PDP 11 systems. P/OS serves as the primary operating - system for the Professional's outstanding communications and graphics capa- bilities, as well as for the Professional's extensive listing of application develop- ment products. P/ SCSI-Ctr. PCI, SCSI Wide 2 Channel Hard Disk Version 3.1 provides new support for additional terminals and printers, diskless Professional 300 Series systems, the LNO3 printer, and the DECtouch Touch Screen. Order Numbers SCSI-Ctr. PCI, SCSI Wide 2 Channel A3 P/OS for diskette-based system - SCSI-Ctr. PCI, SCSI Wide 2 Channel H3 P/OS diskette update - SCSI-Ctr. PCI, SCSI Wide 2 Channel A3 P/OS for hard-disk-based system - SCSI-Ctr. PCI, SCSI Wide 2 Channel H3 P/OS hard-disk update - SCSI-Ctr. PCI, SCSI Wide 2 Channel UZ P/OS Add Four License -