(and even architectures) to different client machines in a heterogeneous environment. A directory containing such files had its suid bit set and was made hidden from both ordinary and root processes under normal use. Such a scheme was sometimes exploited by intruders to hide malicious programs or data. CDFs and the CDF filesystem were dropped with release 10.0. Supported hardware platforms HP-UX operating systems supports a variety of PA-RISC systems. The 11.0 added support for Integrity-based servers for the transition from PA-RISC to Itanium. HP-UX 11i v1.5 is the first version that supported Itanium. On the introduction of HP-UX 11i v2 the operating system supported both of these architectures. BL series HP-UX 11i supports HPE Integrity Servers of HP BL server blade family. These servers use the Intel Itanium architecture. CX series HP-UX 11i v2 and 11i v3 support HP's CX series servers. CX stands for carrier grade and is used mainly for telco industry with -48V DC support and is NEBS certified. Both of these systems contain Itanium Mad6M processors and are discontinued. RX series HP-UX supports HP's RX series of servers. Release history Prior to the release of HP-UX version 11.11, HP used a decimal version numbering scheme with the first number giving the major release and the number following the decimal showing the minor release. With 11.11, HP made a marketing decision to name their releases 11i followed by a v(decimal-number) for the version. The i was intended to indicate the OS is Internet-enabled, but the effective result was a dual version-numbering scheme. Version history Versions 1.0 (1982) First release for HP 9000 Series 500. HP-UX for Series 500 was substantially different from HP-UX for any other HP machines, as it was layered atop a Series 500 specific operating system called SUNOS (unrelated to Sun Microsystems' SunOS). 1.0 (1984) AT&T System III based. Support for the HP Integral PC (HP 9807A). The kernel runs from ROM; other commands are disk based. 2.0 (1984) First release for HP's early Motorola 68000-based workstations (HP 9816U, HP 9826U, HP 9836U) 5.0 (1985) AT&T System V based. Distinct versions were available for the Integral PC, the Series 200/300 and the Series 500. Introduced the proprietary Starbase graphics API for the Series 200, 300 and 500. The Series 300 5.x releases included a proprietary windowing system built on top of Starbase named HP Windows/9000, which was also available as an optional extra